Dissertations / Theses on the topic 'MICROSTRIP LINE COUPLER'

Thesis advisor: Krzysztof Kempa
The resonant modes of a sequence of periodically spaced microstrip resonators is studied. The system is analyzed as transmission line with periodic capacitive gaps, as a waveguide with apertures via normal mode expansion, and through a derivation of the static fields in the gap between two microstrip resonators via conformal mapping. FDTD simulations are also performed to numerically calculate the resonant modes of the sequence and also its absorption spectrum when it contains a lossy dielectric. It is found, as expected, that when the gap size is large, the microstrip resonators are uncoupled and there resonant modes are unperturbed. As the gap size narrows, the resonators become strongly coupled, and changing boundary conditions perturb the resonant modes upwards in frequency. Moreover, an additional resonant mode is observed that does not correspond to any uncoupled mode
Thesis (BS) — Boston College, 2011
Submitted to: Boston College. College of Arts and Sciences
Discipline: College Honors Program
Discipline: Physics Honors Program
Discipline: Physics

Full wave analysis of microstrip lines at microwave frequencies is performed by using method of moments in conjunction with closed-form spatial domain Green&rsquo
s functions. The Green&rsquo
s functions are in general Sommerfeld-type integrals which are computationally expensive. To improve the efficiency of the technique, Green&rsquo
s functions are approximated by their closed-forms. Microstrip lines are excited by arbitrarily located current sources and are terminated by complex loads at both ends. Current distributions over microstrip lines are represented by rooftop basis functions. At first step, the current distribution over a single microstrip line is calculated. Next, the calculation of the current distributions over coupled microstrip lines is performed. The technique is then, applied to directional couplers. Using the current distributions obtained by the analysis, the scattering parameters of the structures are evaluated by using Prony&rsquo
s method. The results are compared with the ones gathered by using simulation software tools, CNL/2&trade
and Agilent Advanced Design System&trade
(ADS).

A model is presented which incorporates the advantages of a mixed mode simulation to characterize transmission line behavior in multiple coupled Transmission line systems. The model is intended for use by digital circuit designers who wish to be able to obtain accurate transmission line behavior for complex digital systems for which continuous time simulation tools such as SPICE would time prohibitive. The model uses a transverse electromagnetic wave approximation to obtain solutions to the basic transmission line equations. A modal analysis technique is used to solve for the attenuation and propagation constants for the transmission lines. Modal analysis done in the frequency domain after a Fast Fourier Transform of the time-domain input signals. Boundary conditions are obtained from the Thevinized transmission line input equivalent circuit and the transmission line output load impedance. The model uses a unique solution queue system that allows n-line coupled transmission lines to be solved without resorting to large order matrix methods or the need to diagonals larger matrices using linear transformations. This solution queue system is based on the method of solution superposition. As a result, the CPU time required for the model is primarily a function of the number of transitions and not the number of lines modeled. Incorporation of the model into event driven circuit simulators such as Network C is discussed. It will be shown that the solution queue methods used in this model make it ideally suited for incorporation into a event-driven simulation network. The model presented in this thesis can be scaled to incorporate direct electromagnetic coupling between first, second, or third lines adjacent to the line transitioning. It is shown that modeling strictly adjacent line coupling is adequate for typical digital technologies. It is shown that the model accurately reproduces the transmission line behavior of systems modeled by previous authors. Example transitions on a 8-line system are reviewed. Finally, future model improvements are discussed.

On developpe en 1ere partie un formalisme matriciel pour n lignes microbandes couplees dans le cas du mode quasi tem afin de pouvoir caracteriser leurs proprietes. En seconde partie on developpe des techniques de simulation et de filtrage en frequence pour selectionner les multiples modes generes. Autre que le quasi tem, on retient la technique de simulation tlm (transmission line matrix) apres avoir reduit le temps de calcul et l'occupation memoire. Pour le filtrage de mode, c'est au niveau du traitement du signal que l'apport est fait. Toutes ces techniques permettent d'etudier des structures multilignes et d'avoir acces aux caracteristiques de rayonnement des antennes imprimees

Una línia de transmissió three-line-microstrip consisteix en tres pistes paral·leles practicades sobre la cara d'un dielèctric amb un pla de massa inferior. La propagació en aquesta línia es pot descriure en termes de tres modes fonamentals anomenats ee, oo i oe. Tot i que aquests modes són ortogonals interaccionen entre sí a qualsevol transició, discontinuïtat o asimetria. En el pla d'una transició o asimetria es genera un intercanvi d'energia o conversió modal en el que prenen part tots els modes.
En aquest treball s'analitza la conversió modal que s'origina en un conjunt de transicions i asimetries construïdes sobre línies three-line-microstrip. L'estudi es realitza aplicant la tècnica de l'anàlisi multimodal. L'ús d'aquesta tècnica permet la deducció d'una sèrie de models multimodals (un per a cada transició) que proporcionen una anàlisi simple, rigorosa i quantitativa d'aquest fenomen.
La validesa d'aquest estudi es verifica de manera experimental. Els bons resultats obtinguts demostren que els models multimodals proposats prediuen de manera precisa el comportament de les transicions. Aquest fet permet el seu ús per analitzar circuits o estructures constituïts per trams de tres pistes acoblades. En el cas d'aquesta tesi, han estat aplicats als camps de l'EMC i de les microones. Pel que fa a l'EMC, s'ha realitzat un estudi de l'acoblament i la integritat del senyal en configuracions de PCB amb trams de tres pistes acoblades. Aquest estudi ha permès identificar les transicions i asimetries en aquests circuits com a possibles fonts d'interferència i de degradació dels senyals ja que la conversió modal es pot interpretar com a un procés d'interferència que involucra tots els senyals presents. Pel que fa a les microones, s'ha realitzat una anàlisi multimodal de filtres spurline. Aquesta anàlisi ha permès desenvolupar dues noves estructures, la principal característica de les quals és la seva compacitat que, a diferència d'altres estructures similars, s'aconsegueix permetent la presència d'un nou mode en el procés de ressonància. L'ús dels models multimodals per a l'anàlisi d'aquestes estructures ha permès una interpretació clara i senzilla del seu funcionament així com el desenvolupament d'una sèrie de regles de disseny que permeten un ajust fàcil i ràpid de certs paràmetres dels filtres com ara la freqüència central i l'ample de banda.
Una línea de transmisión three-line-microstrip consiste en tres pistas paralelas practicadas sobre la cara de un dieléctrico con un plano de masa inferior. La propagación en esta línea se puede describir en términos de tres modos fundamentales llamados ee, oo i oe. Aunque estos modos son ortogonales interaccionan entre se en cualquier transición, discontinuidad o asimetría. En el plano de una transición o asimetría se genera un intercambio de energía o conversión modal en el que toman parte todos los modos.
En este trabajo se analiza la conversión modal que se origina en un conjunto de transiciones i asimetrías construidas sobre líneas three-line-microstrip. El estudio se realiza aplicando la técnica del análisis multimodal. El uso de esta técnica permite la deducción de una serie de modelos multimodales (un per a cada transición) que proporcionan un análisis simple, riguroso i cuantitativo de este fenómeno.
La validez de este estudio se verifica de manera experimental. Los buenos resultados obtenidos demuestran que los modelos multimodales propuestos predicen de manera precisa el comportamiento de las transiciones. Este hecho permite su uso para analizar circuitos o estructuras constituidos por tramos de tres pistas acopladas. En esta tesis doctoral, han sido aplicados a los campos de la EMC i de las microondas. En el primero de ellos, se ha realizado un estudio del acoplamiento y la integridad de la señal en configuraciones de PCB con tramos de tres pistas acopladas. Este estudio ha permitido identificar las transiciones y asimetrías en estos circuitos como posibles fuentes de interferencia y de degradación de las señales ya que la conversión modal se puede interpretar como a un proceso de interferencia que involucra todas las señales presentes. En el campo de las microondas, se ha realizado un análisis multimodal de filtros spurline. Este análisis ha permitido desarrollar dos nuevas estructuras, cuya principal característica es su compacidad que, a diferencia de otras estructuras similares, se consigue permitiendo la presencia de un nuevo modo en el proceso de resonancia. El uso de los modelos multimodales para el análisis de estas estructuras ha permitido una interpretación clara i sencilla del su funcionamiento así como el desarrollo de una serie de reglas de diseño que permiten un ajuste fácil i rápido de ciertos parámetros de los filtros como por ejemplo la frecuencia central y el ancho de banda.
A three-line-microstrip transmission line consists of three parallel coupled strips printed on a grounded dielectric substrate. The propagation in this line can be described in terms of three fundamental modes, namely the ee, oo and oe modes. These modes are orthogonal and propagate independently unless a transition or asymmetry is present in the line. Any transition or asymmetry will generate an energy exchange or modal interaction among all the propagating modes.
In this work, the modal interaction of a set of transitions and asymmetries in three-line-microstrip transmission lines is analyzed. The study is carried out by using the multimodal analysis. By means of this technique a set of multimodal circuit models (one for each transition) is derived. These models provide a simple and a quantitative interpretation of the modal interaction.
The proposed multimodal analysis is experimentally validated. The obtained results show that the derived multimodal models accurately predict the behavior of the transitions. Due to this fact, they can be used for the analysis of circuits and structures composed of three-coupled-strip sections. In this work, the models have been applied to both the EMC and microwave fields. In the former, they have been employed to study the cross-talk and signal-integrity problems in PCB configurations involving tree-coupled-trace sections. The performed analysis has shown that transitions and asymmetries in these circuits must be considered as a source of interference and signal degradation since the modal interaction can be interpreted as an interference process that involves all the present signals. In the latter, a multimodal analysis of spurline filters has been performed. This study has allowed the derivation of two new filter structures whose main feature is their compactness, which, in contrast to other analogous filters, is achieved by allowing the presence of an additional mode in the resonance process. The use of the multimodal models for the analysis of these structures has permitted both a simple interpretation of the filter operation and the derivation of a set of design rules which allows a rapid fine tuning of some filter parameters such as the center frequency and the bandwidth.

Avui dia cada vegada s'ha de tenir més en compte com es realitza el traçat de pistes en les plaques de circuit imprès (PCB). Això és degut a que cada vegada més hi viatgen senyals amb components freqüencials més elevades. Per tant, paràmetres com la desadaptació per impedància característica, acoblaments, ressonàncies i comportaments complexes de les transicions que es troben els senyals en la seva propagació per les pistes, han de ser considerats per evitar problemes d'integritat del senyal i garantir la compatibilitat electromagnètica (EMC) amb el seu entorn.
El present treball de tesi s'ha centrat en l'estudi del comportament d'una situació particular, però molt habitual, de pistes: dues pistes sobre un pla de massa, formant el que es coneix com una línia de transmissió microstrip acoblada. Els senyals que viatgen a través d'una línia microstrip acoblada es poden descompondre en dos modes bàsics de propagació: mode comú (on la tensió està definida entre el pla de massa i cada pista) i el mode diferencial (on la tensió està definida entre les pistes). Aquesta descomposició és molt habitual en el món de la compatibilitat electromagnètica ja que les tècniques de filtratge de les interferències varien depenent si aquestes viatgen en mode comú o en mode diferencial.
El treball desenvolupat s'ha focalitzat en l'estudi, des d'aquest punt de vista multimodal (que té en compte simultàniament tant el mode comú com el diferencial), de les diferents transicions que es pot trobar el senyal en la seva propagació degut al traçat de pistes. Com a resultat d'aquest estudi s'han obtingut uns models circuitals que permeten l'anàlisi i simulació dels diferents modes que intervenen i que han estat validats de forma experimental. Aquest fet ha permès l'ús d'aquests models en l'anàlisi de problemes d'integritat del senyal que són comuns en el entorn de la compatibilitat electromagnètica (EMC). Els resultats obtinguts han estat presentats en congressos nacionals i internacionals.
Hoy en día cada vez se debe tener más en cuenta como se realiza el trazado de pistas en las placas de circuito impreso (PCB). Esto es así debido a que cada vez más viajan por ellas señales con componentes frecuenciales más elevadas. Por lo tanto, parámetros como la desadaptación por impedancia característica, acoplamientos, resonancias y comportamientos complejos de las transiciones que se encuentran las señales mientras se propagan por las pistas, deben ser tenidos en consideración para evitar problemas de integridad de la señal y garantizar la compatibilidad electromagnética (EMC) con su entorno.
En el presente trabajo de tesis se ha centrado en el estudio del comportamiento de una situación particular, pero habitual, de pistas: dos pistas sobre un plano de masa, formando lo que se conoce como línea de transmisión microstrip acoplada. Las señales que viajan a través de una línea microstrip acoplada se pueden descomponer en dos modos básicos de propagación: modo común (donde la tensión está definida entre el plano de masa y cada pista) y modo diferencial (donde la tensión está definida entre pistas). Esta descomposición es muy habitual en el mundo de la compatibilidad electromagnética ya que las técnicas de filtrado de las interferencias varían dependiendo si estas viajan en modo común o en modo diferencial.
El trabajo desarrollado se ha focalizado en el estudio, desde este punto de vista multimodal (que tiene en cuenta simultáneamente tanto el modo común como el diferencial), de las diferentes transiciones que puede encontrarse la señal durante su propagación debido al trazado de pistas. Como resultado se han obtenido unos modelos circuitales que permiten el análisis y simulación de los diferentes modos que intervienen y que han sido validados de forma experimental. Este hecho ha permitido el uso de dichos modelos en el análisis de problemas de integridad de la señal que son comunes en el entorno de la compatibilidad electromagnética (EMC). Los resultados obtenidos han sido mostrados en congresos nacionales e internacionales.
Nowadays, the placement of the strips in a printed circuit board (PCB) has to be performed with increasing care, because of the rise of the spectral content of the signals propagating through the strips. Due to this fact, mismatches of the characteristic impedances, crosstalks, resonances and complex behavior of the transitions that the signals may encounter in their propagation have to be considered in order to avoid signal integrity problems and to guarantee the electromagnetic compatibility with their environment.
This work is focused on the study of the behavior of a particular, but also a very common way of routing strips: two close strips above a ground plane, forming a extit{coupled microstrip transmission line}. The signals present at this transmission line can be decomposed into two basic signals known as common mode (where its voltage is defined between the ground plane and each strip) and differential mode (where its voltage is defined between the two strips). This decomposition is often found in electromagnetic compatibility because the different techniques of filtering interferences depend on their main mode of propagation.
The study carried out in this thesis is focused on the analysis from a multimodal point of view of different transitions that signals encounter during their propagation in a coupled microstrip transmission line.
As a result of this analysis, a number of circuit models for different transitions have been obtained and experimentally validated. These models have been used to successfully study signal integrity problems found in EMC and they have been presented in national and international symposiums.

In this thesis, an analysis technique for the slot coupled patch antennas using MoM in conjunction with the closed form Green&rsquo
s functions is presented. Slot coupled patch antennas are fed by a microstrip open stub which is coupled to the patch through an electrically small slot. Current distributions over the microstrip line, slot line and the patch are represented by rooftop basis functions. First, a relatively simple structure, microstrip coupled slot line is investigated using the proposed technique. Then the method is extended to the slot coupled patch antenna geometry. By using the method, current distributions on the feedline and the patch are calculated for a generic slot coupled patch antenna. Then by using the distributions, return scattering parameters of the antenna is approximated with complex exponentials using Prony&rsquo
s method. A parametric study is carried out to observe the effect of each antenna component on the antenna performance. Current distributions and return loss calculations are repeated for modified antennas to observe and demonstrate the performance differences. All simulations are verified using HFSS®
software and the results available in the literature.

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CAPES
O presente trabalho aborda o desenvolvimento e a implementação de acopladores híbridos em quadratura mais compactos e com largura de banda e desempenho similares as do acoplador branch-line convencional. Para isso, fez-se uso de uma classe de estruturas denominadas linhas de transmissão artificiais (LTA). Uma nova estrutura desse tipo, composta por três linhas de transmissão conectadas em cascata, é analisada e utilizada neste trabalho. Foram derivadas equações matemáticas para o projeto deste tipo de estrutura que podem ser utilizadas para obter LTAs com uma matriz de espalhamento idêntica, para uma dada frequência de operação, a de uma linha de transmissão com uma impedância característica e comprimento elétrico quaisquer. Essa técnica foi aplicada no projeto de acopladores híbridos em quadratura em microfita para as bandas GSM em 920 MHz e ISM em 2.45 GHz usando-se o substrato FR-4 com espessura de 1.6 mm. Obteve-se dispositivos com áreas aproximadamente 70% menor do que a área do acoplador branch-line convencional operando em 920 MHz e aproximadamente 50% menor do que o acoplador de 2.45 GHz. Os acopladores obtidos foram simulados, fabricados e medidos, mostrando que os seus desempenhos são comparáveis aos dos acopladores convencionais. A técnica desenvolvida neste trabalho é geral o suficiente para ser aplicada ao projeto de outros dispositivos que usem trechos de linhas de transmissão.
This thesis is concerned with the design and implementation of compact hybrid couplers with similar bandwidth and performance to the conventional branch-line coupler. To achieve this, a class of structures, called artificial transmission line (ATL), was used. A new structure of this type, made of three transmission lines connected in cascade, is analyzed and used. Mathematical equations have been derived for the design of this type of structure that can be used to obtain ATLs with an identical scattering matrix, for a given frequency of operation, to that of a transmission line with a given characteristic impedance and electrical length. This technique was applied in the design of microstrip quadrature hybrid couplers for the 920 MHz GSM band and for the 2.45 GHz ISM band using a 1.6 mm-thick FR-4 substrate. These couplers have surface areas approximately 70% smaller than the area of the conventional branch-line coupler operating at 920 MHz and approximately 50% for the 2.45 GHz coupler. The couplers obtained were simulated, manufactured and tested, showing that their performances are comparable to the conventional coupler. The technique developed here is general enough to be applied to the design of other devices using transmission line sections.

Dielectric High-frequency transmission lines are natural alternative to the lines made of metal in term of low loss. These lines are mainly used in microwave techniques of measuring. The main object is to describe basic parameters of metal and dielectric transmission lines and their comparison. Next point is a basic overview of the excitation the lines from metal and it's application on dielectric transmission lines. Then make the simulation of microstrip directional couplers and coupler made by dielectric waveguides. The last point of work is construction these directional couplers and measuring their most important parameters.

Le but de ce travail était de développer des filtres passe-bande RF dans la technologie de PCB, avec trois objectifs principaux. Le premier objectif était de développer des formules de synthèse tosimplify la procédure de conception du filtre. Le deuxième était de parvenir à un rejet wideout bande sans modifier les caractéristiques de la bande de filtrage. Le troisième objectif est de contrôler la fréquence centrale du filtre en utilisant diode varicap
The purpose of this work was to develop RF bandpass filters in PCB technology,with three main objectives. The first objective was to develop synthesis formulas tosimplify the design procedure of the filter. The second was to achieve wideout-of-band rejection without modifying the in-band filtering characteristics. Thethird objective was to control the center frequency of the filter by using varactordiode.The bandpass filter topology treated in this thesis is based on Stub-LoadedResonators (SLR). The main features of this filter topology were treated. Equivalentcircuits based on J-inverters and susceptance parameters were derived. Based onthese equivalent circuits, synthesis formulas were developed. Simulations werepresented to validate the synthesis theory. For a proof-of-concept, third orderstripline bandpass filters were designed and fabricated based on this synthesis.Analysis technique using odd- and even- mode was achieved on the SLR. Thusresonance odd- and even-mode conditions were derived. These conditions aim toeasily control the first spurious frequency. Moreover, to go further in improving theout-of-band rejection a new technique, called “U corner structure”, was developedand design rules were derived. Based on these design rules an extended out-of-bandrejection was achieved without any modification in the passband and by maintainingthe compactness of the filter. A first spurious frequency was localized at up to ninetimes the working frequency in the case of the Parallel-coupled Stub-Loadedresonator (PC-SLR) filter. Also, by applying this technique into the classicalparallel-coupled filter the first and second spurious frequencies were rejected. Toaddress the issue of tunable filters, the SLRs were correctly loaded by variablecapacitors (varactor diode). The center frequency of the PC-SLR filter was easilycontrolled by maintaining a large out-of-band rejection

La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés
MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied

This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented.
Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular.
Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular.
Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004
TESIS

In this project, a symmetrical microstrip line directional coupler has been designed using the synthesis technique. The introduced design procedure does not require the prior knowledge of the physical geometry of the coupler and requires only the information of the port impedances, coupling level, and operational frequency. The width of coupled microstrip lines, spacing between them and length of the coupler is then determined. The directivity of the conventional coupler designed is improved by bringing the changes in the physical geometry of the coupler by phase velocity compensation, which utilizes the coupled microstrip with square wiggles on its inner edges. In this project, a directional coupler has to be designed at the operational frequency of 1.5GHz with the coupling of -15dB. The width, length and spacing of coupled microstrip line are calculated with the help of Agilent ADS linecalc and then S-parameters of this coupler are calculated. The layout is plotted down in the layout window and is simulated. Then, the changes in the geometry of the coupler are made in order to improve the isolation and thus the directivity. The change in geometry raises the odd mode inductance more strongly than that of even mode and this results in phase velocity compensation between even- and odd-modes. The coupler is designed on Rogers-R03210 substrate with dielectric constant of 10.2 and thickness of 0.5mm. The simulations are carried out with the help of software Agilent Advanced Design System 2008.

Abstract In this project, a symmetrical microstrip line directional coupler has been designed using the synthesis technique. The introduced design procedure does not require the prior knowledge of the physical geometry of the coupler and requires only the information of the port impedances, coupling level, and operational frequency. The width of coupled microstrip lines, spacing between them and length of the coupler is then determined. The directivity of the conventional coupler designed is improved by bringing the changes in the physical geometry of the coupler by phase velocity compensation, which utilizes the coupled microstrip with square wiggles on its inner edges. In this project, a directional coupler has to be designed at the operational frequency of 1.5GHz with the coupling of -15dB. The width, length and spacing of coupled microstrip line are calculated with the help of Agilent ADS linecalc and then S-parameters of this coupler are calculated. The layout is plotted down in the layout window and is simulated. Then, the changes in the geometry of the coupler are made in order to improve the isolation and thus the directivity. The change in geometry raises the odd mode inductance more strongly than that of even mode and this results in phase velocity compensation between even- and odd-modes. The coupler is designed on Rogers-R03210 substrate with dielectric constant of 10.2 and thickness of 0.5mm. The simulations are carried out with the help of software Agilent Advanced Design System 2008.

碩士
國立高雄第一科技大學
電子工程研究所
102
This paper presents a compact microstrip branch-line coupler using short-circuit spur lines. It can not only keep the function of the traditional branch line coupler but also reduce the area of the circuit 39.99% and 54.75%. In this paper we presented short-circuit spur lines equivalent to equal to the quarter-wave transmission line of the miniaturization circuit. This miniaturization circuit is composed of two short-circuit spur lines and the grounding element called y=jb by using parallel connection. In this use of open-circuit stub to achieve the equivalent admittance b, where the open stub is divided into single segment with two-stage. And the parallel admittance y = jb equivalent circuit architecture placed short-circuit spur lines, it can effectively reduce the area of branch line coupler size. The short circuited spur lines branch line coupler is distinguished from the open-circuit stub. The result of the measurement with the single-stage open stubs miniaturized branch line coupler is S_11=-20.96 dB, the power difference|S_21 |-|S_31 |(0±1 dB) bandwidth of 19 MHz, the phase difference∠S_21-∠S_31(〖90〗^o±〖10〗^o) bandwidth of 16 MHz, |S_41 |≤10 dB frequency band of 930~975 MHz, The result of the measurement with the two-stage open stubs miniaturized branch line coupler is S_11=-20.96 dB, the power difference|S_21 |-|S_31 |(0±1dB) bandwidth of 33MHz,the phase difference∠S_21-∠S_31(〖90〗^o±〖10〗^o) bandwidth of 30 MHz, |S_41 |≤10 dB frequency band of 840~945 MHz and total measure of area is 1089 mm^2,reduce the area of the circuit 54.75%. In addition, the paper propose short-circuit spur lines coupler not only area-reduction but also it can further study to pursuit low cost and easy fabrication in the future.

The electromagnetic coupling of a microstrip transmission line (MS-TL) to a metamaterial backward wave Negative-Refractive-Index transmission line (NRI-TL) is the primary investigation of this dissertation. The coupling of forward waves in the MS-TL to the backward waves in the NRI-TL results in the formation of complex modes, characterized by simultaneous phase progression and attenuation along the lossless lines. Through network-theoretic considerations, we investigate the properties of these modes in the complex-frequency plane of the Laplace domain to help unravel the confusion that has existed in the literature regarding the independent excitation of a pair of conjugate complex modes. We show that it is possible to arbitrarily suppress one of the modes over a finite bandwidth and completely eliminate it at a discrete set of frequencies using proper source and load impedances. Hence we use conjugate modes with independent amplitudes in our eigenmode expansion when we analyse various coupling configurations between the two types of lines (MS/NRI-TL coupler). We derive approximate closed-form expression for the scattering parameters of the MS/NRI-TL coupler and these are complemented by design charts that allow the synthesis of a wide range of specifications. Moreover, these expressions reveal that such couplers allow for arbitrary backward coupling levels along with very high-isolation when they are made half a guided wavelength long. The MS/NRI-TL coupler offers some interesting applications which we highlight through the design and testing of a 3-dB power splitter, a high-directivity signal monitor and a compact corporate power divider. We have included design, simulation and experimental data for the fabricated prototypes exhibiting good agreement and thereby justifying the theory that has been developed in this work to explain the coupling between a right-handed MS-TL and a left-handed NRI-TL.

碩士
國立臺灣大學
電信工程學研究所
94
In this thesis, the parallel coupled lines are used to design the microstrip bandpass filters. The main objectives of this study are to improve the selectivity and to suppress the spurious responses of bandpass filters. By suitably introducting the cross-coupling path in the filter circuit, multiple transmission zeros may be generated to improve the filter selectivity. The filters based on quarter-wavelength coupled line have spurious passbands at odd-multiples of passband center frequency. In this study, the coupled-line sections are made shorter than quarter wavelength so that the spurious response may be suppressed. The next spurious passband then appears around five times the center frequency.

碩士
國立中正大學
電機工程研究所
101
This paper presents two designs. First, a novel design equations and examples of the modified arbitrary power ratio microstrip tandem coupler are presented. In order to obtain a wide passband, couplers with triple poles at the return loss are proposed. Compared to the conventional couplers such as Lange couplers and parallel coupled line couplers, high impedance transmission lines and narrow coupling gaps are not required for the proposed microstrip coupler. In terms of measured results, there is a wide bandwidth of more than 70%. Moreover, good agreement between theoretical predication and measurement validates our proposed structure. In the second design, a novel wide passband microstrip bandpass filter with broader stopbands is provided. The proposed bandpass filters is composed of the stepped coupled line and two short-circuited stubs. Each stage of electrical length of the stepped coupled line has been optimized and cascaded together for harmonic suppression. Moreover, the stepped coupled line with weak–strong–weak coupling results in a wide stopband. Furthermore, with short-circuited stubs connected at the input/output port, there is a steeper passband skirt and broader passband. In addition, the agreement between theoretical prediction and measurement validates our proposed structure.

博士
國立臺灣大學
電信工程學研究所
100
This dissertation focuses on the planar forward-wave directional coupler (FWDC) design by using the concept of periodic structure. Compact sizes and broadband performances are two goals achieved in this thesis. In the beginning, a three-layered FWDC with periodic mushroom-shaped ground plane is developed for the purpose of size reduction. The electrical length of odd-mode is kept linearly dependent on frequency, but the even-mode electrical length is dramatically enlarged due to the capacitive enhancement. The phase difference between odd- and even-mode is significantly increased because the even-mode phase delay is getting higher. Besides the large phase difference, the characteristic impedances of these two modes can be designed to be 50 Ω simultaneously for the impedance matching without using additional matching networks. The proposed coupler is designed with the length of 1.26 λg as an example. Compared to the conventional microstrip forward coupler, the size reduction of the proposed structure is more than 80% due to the slow-wave effect of the even-mode. Next, a two-layered FWDC with periodic defected ground structure (DGS) is proposed to reduce both the cost and coupler size. The odd-mode electrical length of the proposed structure is linearly dependent on frequency, but the even-mode electrical length is enhanced due to the inductive loading. The phase difference is also enlarged because the even-mode phase delay is getting higher. Input impedances of these two modes can be perfectly matched by adjusting the electrical lengths. For example, 0-dB and 3-dB coupler with periodic DGS are designed with the length of 0.55 λg and 0.275 λg, respectively. Compared to the microstrip forward coupler, the size of the proposed structure reduces by more than 92%. The aforementioned works concentrate on the design of size reduction. Finally, a novel forward coupler is developed with periodic H-shaped structure for broadband applications. The broadband impedance matching for even- and odd-modes can be achieved and the phase difference between these two modes can be maintained as constant within a wide frequency range. For example, 0-dB and 3-dB couplers are designed with the fractional bandwidth (FBW) 64% and 44%, respectively. The lengths of them are 1.93 λg and 0.96 λg , respectively. Compared to the conventional works, the proposed H-shaped forward couplers have wider operational bandwidth with the compromise on the size.

博士
逢甲大學
電機與通訊工程博士學位學程
107
The conventional branch-line coupler is consisted of four quarter wavelength transmission lines. Coupler devices are used to divide power and generate phase difference in radio transceivers. Conventional 90° hybrid couplers are implemented in balanced amplifier or mixer circuit design. With advancement in technology, communication systems have rapidly evolved in recent years. Currently, all cost-reduction efforts, including size reduction and low-cost fabrication, are focused on the components of modern wireless communication systems. In the study, the novel compact coupler was designed with equal different structure and folding structure without any implementation of lumped elements, via-holes, and bonding wires. However, the use of unoccupied area of coupler interiors reveals overlap problems. The design equations of the equal difference structure and folding structure were derived, and a compact branch-line coupler was designed and assembled on FR4 substrate with a 900 MHz operating frequency. Additionally, the circuit area of the equal difference structure and folding structure couplers achieves a size reduction of 84.2% and 85.1% compared with that of a conventional coupler at the same operating frequency. The proposed coupler was successfully designed for easy integration with modern wireless communication systems.

碩士
長庚大學
電子工程學系
99
The purpose of this dissertation is to explore the theory and application of periodically loaded microstrip coupled lines. By adding periodic loads on a parallel coupled line, Bloch wave modes can be generated. The characteristic impedances and propagation constants can be derived by applying even-odd analysis to the structure. We found that codirectional, contradirectional and trans-directional couplers, the three common types, can be realized. Compared to conventional microstrip parallel couplers, this new structure can provide higher coupling factors and reduce the length of the coupler. These three kinds of couplers are designed and fabricated to operate at 2.4 GHz with coupling factor 3-dB. The measured fractional bandwidths are 15%, 2.1% and 26.25%, respectively. The measured insertion losses are 4 dB、4.15 dB and 3.38 dB. A planar crossover is also realized by a 0-dB codirecitional coupler with measured bandwidth and insertion loss 24.2% and 1.32 dB, respectively. All these measured results are in good agreement with simulated results, proving our concept and theory.

碩士
國立中央大學
電機工程研究所
95
In this study, several kinds of microstrip coupled-line structures are used to implement compact bandpass filters, which are based on quarter-wavelength resonators. Compared to the conventional parallel-coupled bandpass filters that are based on half-wavelength resonators, the circuit size of proposed filters are reduced by more than half. The passband of proposed coupled-line filter can be made switchable by a proper circuit layout along with the incorporation of diodes to change the resonance characteristics of quarter-wavelength resonators. An on-off isolation of more than 20dB up to 3 has been achieved. In addition, by utilizing the inherent transmission zeros of coupled-lines, the 30dB stopband bandwidth of proposed filter can be extended up to 4 . Moreover, by manipulating the phase of input reflection coefficient, we can implement diplexers based on proposed filter structures with smaller circuit size than conventional designs. Additional cross-coupling between non-adjacent coupled-line sections can also be introduced to improve the selectivity. 　　In this work, the characteristics of different kinds of coupled-line sections are thoroughly investigated to make the best use of them in bandpass filter and diplexer designs. Simple and clear design flows have also been proposed for all designs, which allow the easy extension of proposed filter structures for further improvement in the future.

碩士
國立臺灣科技大學
電子工程系
101
In this thesis, to eliminate the common mode noise induced by the right-angled differential transmission line, an inductance-compensated and capacitance-compensated right-angled differential transmission line is proposed. The frequency-domain differential-to-common mode conversion is greatly reduced, having a maximum reduction of 30 dB, and the time-domain common mode noise is reduced from 0.056 V to 0.019 V. Besides, as compared with the inductance-compensated right-angled differential transmission line or the capacitance-compensated right-angled differential transmission line, the circuit size is greatly reduced, which in turn saves the production cost and reduces the low frequency reflection coefficient. Besides, to reduce the far-end crosstalk noise induced by the coupled microtrip line, a coupled microstrip line using the front-end capacitor is proposed. As compared with the literatures, the coupled microstrip line using the front-end capacitor can eliminate the routing complexity and reduce the far-end crosstalk noise from 55 mV to 26.8 mV. Also, since the far-end crosstalk noise has an antisymmetric waveform, the far-end crosstalk noise can be totally eliminated when the receiver uses an integrator. In order to reduce the near-end impulse crosstalk noise and further reduce the far-end crosstalk noise induced by the coupled microstrip line using the front-end capacitor, a coupled microstrip line using the distributed capacitors is proposed. As compared with the coupled microstrip line using the front-end capacitor, the near-end crosstalk noise can be reduced from 71 mV to 28 mV while the far-end crosstalk noise is nearly zero.

碩士
國立交通大學
電信工程系所
94
The inherent zero of a microstrip coupled stage near twice the design frequency (2fo) is found tunable by varying its coupling length. This zero is used to suppress the unwanted response of paralle-coupled line filters at this frequency. The above idea is extended to design over-coupled middle stages of the filter for the spurious |S21| peaks at 3fo and 4fo, so that the upper stopband can be greatly enhanced to 5fo. The passband preserves a response as good as the traditional design. Measured results have a good agreement with simulation data and show that the idea works very well. Corrugated coupled lines are also devised to design microstrip bandpass filters with multispuriois suppression. Quarter-wave corrugated stages are tuned to allocate inherent transmission zeros at 2fo and 4fo. Stages with proper coupling lengths are arranged to cancel the unwanted peaks at 3fo, 6fo and 7fo, and the tapped input/output scheme is employed to tackle that at 5fo. The measured data of designed bandpass filters show rejection levels better than 30dB in the upper stopband. Three circuits are fabricated and measured to demonstrate the idea. Periodic stepped-impedance resonators (PSIRS) are proposed to design bandpass filters for multispurious suppression. Denoted as PSIRN, a PSIR of ��/2 long at design frequency fo consists of N periods of hi-Z and low-Z sections. A PSIRN coupled section shows transmission zeros at various frequencies. The zero can be tuned by changing the impedance ratio of the hi-Z and low-Z sections, and be adopted to suppress the spurious peaks. Responses of the PSIR filters show good rejection in the upper stopband.

碩士
國立交通大學
電機學院碩士在職專班電信組
98
In this thesis, two-stage microstrip bandpass filters are designed to have a relatively wide stopband. The input/ output stages are designed to create a transmission zero to suppress the second harmonic. The coupled section of resonators is designed to generate a transmission zero to suppress the third harmonic. In addition, open stubs are added to suppress the fourth harmonic. For reducing the circuit size, a substrate with Er = 10.2 and thickness h = 1.27mm is used. This structure has two zeros beside passband which caused by symmetric tapped in or skew-symmetric tapped in. Based on this structure, two-order filters can suppress second, third and fourth harmonic response. Measured and simulated results have a good agreement.

碩士
國立臺灣科技大學
電子工程系
106
Cosstalk causes variation and distortion to the signal transmitted in the microstrip line. It raises the concern of signla integrity. Cross talk can be classified as near end crosstalk and far end crosstalk, the accumulation property of far end crosstalk causes the large impa ct to signal integrity. The thesis propose alternated stub to improve the far end crosstalk, combine the consecutive orthogonal array and taguchi method with the object function – Sum of power from S-Parameter to achieve the optimized configuration.

碩士
國立彰化師範大學
工業教育研究所
81
This thesis presents a full-wave, spectral domain technique for the analysis of leakage problem of coupled microstrip transmission lines. The problem is formulated with an electric field integral equation (EFIE) method which is based on a field equivalence principle and the identification of equivalent current induced on the microstrip device surface. The EFIE expresses the electric field in terms of the device current integrated into an electric Green''s function;boundary condition are incorporated in their full generality in the Green''s function. For validation of this approach, the general coupled integral equations are specialized to the case of two identical axially-uniform microstrips. An entire-domain basis method of moments (MoM) is implemented for numerical solution in both lossless and leaky regimes. current distributions for the first three higher-order coupled modes will be presented. Results from this research will serve as valuable reference for the design of novel coupled microstrip devices and for future study in this area.

The main subject of this work is the modular design of multilayer printed arrays. The need for a multilayer feeding network is evident in large arrays with a large number of power dividers or phase shifters. Due to space considerations the spurious coupling between the network and the radiating elements, or between different parts of the network itself, can be significant enough to degrade performance. In addition, corporate feed network radiation can affect the sidelobe and cross-polarization characteristics of the array. The use of a multilayer feed network located in a different plane than the radiating elements can alleviate these problems. The transfer of power between two adjacent layers in a multilayer structure can be done using either a pin which makes an electrical contact, or via coupling apertures in the ground plane separating the layers. Beyond the advantages of fabrication, aperture coupling leads to inherently symmetric feed network layouts which further simplify the design. The Green's functions for multilayer dielectric substrates can be used to compute the characteristic impedance of any printed planar transmission line and the full-wave analysis of an entire multilayer network can be obtained. In the past, full-wave solutions were derived for different configurations involving the coupling from one layer to another by means of a rectangular slot. The number of possible configurations is quite limited, since in a typical planar multi layer structure there may be only two microstrip layers (the outermost layers), while the inner layers are typically stripline. This leaves two types of aperture coupling transitions: microstrip to stripline and stripline to stripline. Assuming that the coupling between separate apertures and the coupling between patches is negligible, having a model for each of these two transitions is enough to analyze and design the whole multilayer structure. The radiating elements can also be fed by aperture coupling, and a separate analysis has to be performed for each configuration. Furthermore, the radiating element layer can be placed in a plane perpendicular to the feeding network. The theory used in the modeling of different transitions will be presented first. The reciprocity technique first developed in (9) and further extended in (10) proves to be computationally efficient and gives good results for these cases. The models for individual transitions are validated by measurements and subsequently used in the design of a number of prototype multilayer planar arrays.

碩士
國立交通大學
電信研究所
85
In the thesis, we present a method for the design and synthesis of double and triple coupled nonuniform microstrip lines. The method is originated from an electrical lengthmatched procedure for single nonuniform microstrip line. The system performances we considered are bandwidth and ripple peak of scattering parameter S11, so the Tchebtcheffresponse is adopted as the initial response for our design. Using the electrical lengthmatched procedure double or triple coupled nonuniform microstrip lines with smaller reflection can be synthesized. The reduction of ripple peak and the increase of bandwidthare impossible to obtain at the mean time and there must be a tradeoff between them.According to the system demands, the designer may adjust the parameters such as tolerable reflection coefficient and cutoff angular frequency for each mode so that desired performance can be achieved.

碩士
國立海洋大學
電機工程學系
85
The purpose of the thesis is to study the dispersion characteristics of shield ed coupled microstrip lines. Firstly, The shielded coupled microstrip line structures and the exicted dispersion models are introduced in detail. Secondly, The quasis-static characteristics of shielded coupled microstrip lines are analyzed. Moreover, the frequency- dependentcharacteristics of the shielded coupled microstrip lines are studied, including the even- and odd-mode effective dielectric constantsand characteristic impedences. From the results of analysis, it is noted that the even- and odd-mode effective dielectric constantsand characteristics impedences are increased with the frequency. Finally, the signal dispersion on shielded on shielded coupled microstrip linesis executed. From the results of analysis, it is noted that the dispersion effect will be more pronounced when the shielded coupled microstrip lines are designed with largersubstrate dielectric constant or strip conductor width, thicker strip conductor or substrate and higher shielding height or strip conductors.

博士
國立交通大學
電信工程系所
94
This dissertation presents the research and applications of microstrip coupler with high directivity. In the first part, we proposed a meandered parallel-coupled line. It can speed up the even-mode phase velocity and make the modal phase velocities to be equal in microstrip structure. Therefore, we can get a good directivity in microstrip parallel-coupled coupler. With proper design, we can get an ultra high directivity in a narrow band or get a high directivity performance over broad bandwidth. We also apply the proposed structure to a half wavelength band pass filter and successfully cancel the first spurious passband. All the synthesis procedures of the proposed structure are described in detail. The second part presents a solution for miniaturizing microstrip loose coupler with high directivity.

碩士
國立高雄大學
電機工程學系碩博士班
105
Conventional branch line coupler is composed of four quarter-wavelength transmission lines. T-shaped or Π-shaped transmission line circuit can use to replace the quarter-wavelength transmission line. In each series line of T-shaped or Π-shaped transmission line circuit, the length is short when the characteristic impedance is high. In general, microstrip line of high characteristic impedance is usually suffered from difficult realization problem. This study proposes three branch line couplers using defective ground structure T-shaped or Π-shaped transmission line circuits to improve high impedance microstrip line process limitations.

碩士
國立臺灣海洋大學
通訊與導航工程學系
103
In this thesis, we start with the original branch-line coupler, which has spurious band problems at odd multiples of the center frequency.We propose the use of aperiodic T-shaped structure to develop modified couplers. The modified couplers are aimed at mitigating spurious band problems. We also minimize the circuits of the modified couplers. Finally, compact designs capable of suppressing spurious bands are realized. Keyword：branch- line coupler, spurious band, T-shaped structure

A novel microstrip patch antenna topology is presented for achieving a dual-band response with arbitrarily closely spaced resonances. This topology is based on a coupled transmission line structure in order to take advantage of the separation in propagation constants for parallel (even-mode) and anti-parallel (odd-mode) current modes. Applying a metamaterials inspired design approach, periodic reactive load­ings are used to design the underlying transmission line to have specific propagation constants necessary to realize a desired separation between two resonant frequencies. Using a single probe feed for a finite coupled line segment, both even-and odd-mode resonances can be excited to radiate efficiently at their respective design frequencies. The efficiency of the odd-mode radiation is enhanced by separating the two lines, while strong coupling is maintained by inserting a series of narrowly-separated thin loops between them. Several example resonant antenna designs, in the 2.45 GHz band, are presented. The directivities of these microstrip patch antennas are enhanced by optimizing the physical length of the resonant structure. For a resonant antenna obtained by cas­cading several unit cells of reactively loaded microstrip segments, dispersion analysis is employed for the unit-cell design. Maximum directivity is achieved by choosing the overall physical length to be slightly less than a half wavelength in free space at the design frequency. This gain optimization is applied to three coupled-line antennas, as well as a single resonance patch. Excellent agreement is observed between simulated and measured responses across all designs. The potential of loading the coupled line structure with active components is also explored. Varactor diodes are placed on coupled-line structures in two configurations. In one configuration, both resonant frequencies are affected. In the other configura­tion, only the odd-mode characteristics are reconfigured. In this way, the resonant frequency of either one or both modes can be adjusted by applying a DC bias voltage to the varactor diode loading elements. Two antennas, one employing each of these topologies, were designed and fabricated. Control of the resonant frequency over the predicted range through applying a bias voltage is observed with the fabricated prototypes.

碩士
國立中正大學
電機工程研究所
89
This thesis analyzed and designed directional couplers including broadband backward couplers, bandpass backward couplers, and bandpass forward couplers for special wireless communication needs. Based on the theory of phase-velocity matching between the even-mode and odd-mode waves, we developed a synthesis procedure and formula to achieve broad bandwidth and high directivity with various types of coupled microstrip such as nonuniformly spaced and wiggled at inner edges and/or at outer edges. Then 3D fullwave EM simulation was performed to have optimal response. Excellent agreement is found between the simulation and measurement results.

碩士
國立臺北科技大學
電子工程系
107
This thesis presents two Length Shorten Bandpass Filters implemented by periodically Loaded microstrip coupled-lines. The operating frequency is at 2 GHz and the bandwith is 10 % GHz.Using periodically loaded microstrip coupled-lines can shorten the length of coupler, higher coupling factor than conventional parallel couplers and achieve a variety of coupling types. The periodically loaded structures are implemented by integrated components instead of commercial discrete lumped components to avoid soldering and losses in the component itself. The substrate layer supporting microstrip lines are replaced with air to further reduce the loss caused by substrate, improving circuit insertion loss. Then we fabricate two sets of filters with the electrical lengths of the coupled lines are 30 degrees and 45 degrees respectively, to explore the effect of different e length of line. The measurement results show that the 30 degree coupled-lines filter has a 450 MHz frequency offset and a narrow passband. The 45 degree filter has good performance with the ideal model.

碩士
南台科技大學
光電工程系
97
This thesis presents parallel coupled lines UWB bandpass filters for ultra-wideband communication system. Those are short-circuited parallel coupled bandpass filter, open-circuited parallel coupled bandpass filter, a diplexer and a stop band improvement UWB Bandpass filter, respectively. The response characteristic of short-circuited and open-circuited parallel coupled lines are exhibited all stop frequency response and the stop band appeared at 3f0 and 2f0, respectively. The central frequencies of open-circuited and short-circuited parallel coupled lines are designed at 4 GHz and 8 GHz which the electrical lengths are quarter-wavelength and half-wavelength, respectively. The short-circuited and open-circuited of parallel coupled lines are coupled to the electrical length 1800 of slot-line resonator (SLR) which can produce low band (3~5 GHz) and high band (6~10 GHz) bandpass filters for UWB application, respectively. A diplexer is designed to combine the proposed two BPFs by using microstrip impedance match which the operating frequencies are 3.2 ~ 4.8 GHz for low passband and 6.5 ~ 9.8 GHz for high passband, respectively. In additional, a novel wide stopband filter is proposed using a pair of shunt and embedded open stubs which connected the input and output ports with the UWB BPF to improve the harmonic response. A wide stopband of the proposed BPF from 10 to 20 GHz can be achieved. Final, this thesis proposes a dual-band BPF using ring open-loop resonator for wireless communication network which the operating frequencies are at 2.4 GHz and 5.7 GHz, respectively. The proposed dual-band BPF has compact, low insertion loss, good stopband response and easy fabrication. Experiment and measurement results are in good agreements with simulation results.

Yes
A novel dual-polarized patch antenna for ultra-wideband (UWB) applications is presented. The antenna consists of a square patch and four capacitively coupled feeds to enhance the impedance bandwidth. Each feed is formed by a vertical isosceles trapezoidal patch and a horizontal isosceles triangular patch. The four feeds are connected to the microstrip lines that are printed on the bottom layer of the grounded FR4 substrate. Two tapered baluns are utilized to excite the antenna to achieve high isolation between the ports and reduce the cross-polarization levels. In order to increase the antenna gain and reduce the backward radiation, a compact surface mounted cavity is integrated with the antenna. The antenna prototype has achieved an impedance bandwidth of 112% at (|S11| ≤ -10 dB) whereas the coupling between the two ports is below -28 dB across the operating frequency range. The measured antenna gain varies from 3.91 to 10.2 dBi for port 1 and from 3.38 to 9.21 dBi for port 2, with a 3-dB gain bandwidth of 107%.
IEEE Antennas and Propagation Society

碩士
國立交通大學
電信工程系
87
A full-wave mixed spectral-domain approach (MSDA) is employed to investigate the propagation and attenuation characteristics of single and coupled buried microstrip lines (BMSL's) with finite strip metallization thickness. The influences of structural parameters on line parameters are presented. It is shown that BMSL's have high-isolation characteristics and are suitable for high-speed signal transmission in high-density integrated circuits.

In recent years, the wireless industry has witnessed tremendous development for the defense and commercial segments. The explosive growth in the modern radio frequency and microwave systems leads to an increased interest in the research of miniaturized microwave circuits with superior performance. Broadband components, in particular band pass filters (BPFs) and couplers are some of the widely used components in the modern communication systems, software defined radios, cognitive radios, imaging systems and positioning radars. In order to meet these requirements, the use of innovative geometries, a thorough understanding of their behavior by appropriate analytical techniques and the use of appropriate fabrication approaches are essential. This thesis is an effort in this direction. In this thesis work, an aperture in the ground plane is used to achieve the tight coupling in the edge and broadside-coupled coupled lines which may be otherwise difficult due to the fabrication limitations. Since microstrip lines with an aperture in the ground plane are found to be very useful in various MIC and MMIC components, closed form analytical expressions developed here will be useful for their initial synthesis. The performances of components using these are enhanced using open/short circuited resonators, spurlines and stubs. A quasi-static approach has been investigated to obtain simple closed form expressions for a microstrip line with a rectangular aperture in the ground plane. The effect of a rectangular aperture in the ground plane has been incorporated in the commonly used expressions of a regular microstrip line by introducing the concept of an equivalent effective height. The expressions for the effective height microstrip geometries with defected ground are obtained and this has been further extended to various possibilities of two-conductor and three-conductor coupled lines. Analysis of the filters and the couplers are mainly based on the even and odd mode propagation characteristics of coupled lines. This approach is extended in this thesis for three conductor coupled lines. Novel broadband BPFs and couplers and dual band pass filters employing various coupled line configurations and defected ground have been developed in this research work. Most of these components have been implemented on a regular microwave laminate or LTCC medium (planar or multi-layer) and tested for the required RF performances. The experimental results were compared against the analytically computed results based on the circuit models and the full wave simulations using electromagnetic (EM) simulations for the validation. The results are in good agreement. With practical requirements of the organization in mind, additional design elements such as open circuit stubs have been incorporated in some of these designs to achieve the desired performance. It is expected that the wideband filter (3.0GHz to 3.8GHz) and the broadband coupler (4GHz to 6GHz) developed in this thesis work would be deployed in systems developed at the Central Research Laboratory, Bharat Electronics Limited, Bangalore, India. In summary, the present doctoral work strives to (i) establish a simplified analysis method for the microstrip lines and coupled microstrip lines with a rectangular aperture in the ground plane, (ii) extend the even and odd mode analysis of the coupled lines for several new coupled line configurations, (iii) design novel broadband microwave filters, dual band filter and couplers using both these, (iv) fabricate these devices using the planar technologies including LTCC, and (v) validate the analysis and design with important practical applications.

In recent years, the wireless industry has witnessed tremendous development for the defense and commercial segments. The explosive growth in the modern radio frequency and microwave systems leads to an increased interest in the research of miniaturized microwave circuits with superior performance. Broadband components, in particular band pass filters (BPFs) and couplers are some of the widely used components in the modern communication systems, software defined radios, cognitive radios, imaging systems and positioning radars. In order to meet these requirements, the use of innovative geometries, a thorough understanding of their behavior by appropriate analytical techniques and the use of appropriate fabrication approaches are essential. This thesis is an effort in this direction. In this thesis work, an aperture in the ground plane is used to achieve the tight coupling in the edge and broadside-coupled coupled lines which may be otherwise difficult due to the fabrication limitations. Since microstrip lines with an aperture in the ground plane are found to be very useful in various MIC and MMIC components, closed form analytical expressions developed here will be useful for their initial synthesis. The performances of components using these are enhanced using open/short circuited resonators, spurlines and stubs. A quasi-static approach has been investigated to obtain simple closed form expressions for a microstrip line with a rectangular aperture in the ground plane. The effect of a rectangular aperture in the ground plane has been incorporated in the commonly used expressions of a regular microstrip line by introducing the concept of an equivalent effective height. The expressions for the effective height microstrip geometries with defected ground are obtained and this has been further extended to various possibilities of two-conductor and three-conductor coupled lines. Analysis of the filters and the couplers are mainly based on the even and odd mode propagation characteristics of coupled lines. This approach is extended in this thesis for three conductor coupled lines. Novel broadband BPFs and couplers and dual band pass filters employing various coupled line configurations and defected ground have been developed in this research work. Most of these components have been implemented on a regular microwave laminate or LTCC medium (planar or multi-layer) and tested for the required RF performances. The experimental results were compared against the analytically computed results based on the circuit models and the full wave simulations using electromagnetic (EM) simulations for the validation. The results are in good agreement. With practical requirements of the organization in mind, additional design elements such as open circuit stubs have been incorporated in some of these designs to achieve the desired performance. It is expected that the wideband filter (3.0GHz to 3.8GHz) and the broadband coupler (4GHz to 6GHz) developed in this thesis work would be deployed in systems developed at the Central Research Laboratory, Bharat Electronics Limited, Bangalore, India. In summary, the present doctoral work strives to (i) establish a simplified analysis method for the microstrip lines and coupled microstrip lines with a rectangular aperture in the ground plane, (ii) extend the even and odd mode analysis of the coupled lines for several new coupled line configurations, (iii) design novel broadband microwave filters, dual band filter and couplers using both these, (iv) fabricate these devices using the planar technologies including LTCC, and (v) validate the analysis and design with important practical applications.

碩士
國立臺北科技大學
電腦與通訊研究所
99
In the modern generation of digital data transmission, crosstalk is one major source of noise to interfere with signal integrity (SI). Generally, crosstalk can be reduced by adding a guard trace with shorting-vias between the victim and aggressor areas of the circuit. However, the shorting-vias in the guard trace induced the resonance in the frequency domain and the ringing noise in the time domain. We propsed the step guard trace to compensate capacitive coupling between the guard trace and signal trace. Our method offers minumum number of shorting-vias to increase the flexibility on the circuit routing and decrease the ringing noise. The experimental results indicated that the step gaurd trace could reduce near-end crosstalk (NEXT) and far-end crosstalk (FEXT) by 34% and 26% compared to without guard trace in the time domain, respectively. Therefore, in a parallel-terminated interface, the FEXT is more problematic than NEXT since it seriously affects the SI at the receiver side. Since a large number of shorting-vias and resistances reduce the flexibility of the circuit routing and increase cost, we propose a method to reduce the FEXT and timing jitter by using rectangular resonators (RRs) structure. In which, the shorting-via and resistance are not necessary to be used for improving the FEXT and timing jitter. The experimental results indicated that the RRs structure could reduce FEXT and timing jitter by 57% and 18% compared to without guard trace in the time domain, respectively. These experimental results confirmed that our proposed RRs structure not only shows better performance than the alternatives, but also no requires extra components such as terminating resistors or shorting-vias to reduce noise significantly. Accordingly, the new concept and method might be approached to the practical engineering.

碩士
華梵大學
電子工程學系碩士班
101
In this thesis, using the three groups of the same side short coupled lines and seven capacitances to design high out-of-band rejection filter RF band-pass filter, the first to use the admittance inverter is designed for band-pass filter component values and the coupling of the electrical length parameters, using the same side of the parallel port. The short coupled lines cross ports can control high rejection rate of transmission zero position, it obtained by two different design formulas, and Mathcad identify the intersection of transmission zero position can be the first to know. In order to verify the accuracy of the transmission zeros after the completion of each components defined band-pass filter specifications, components by Mathcad computing, each component values into ADS and microstrip transmission line for electromagnetic simulation. Observed electromagnetic simulation of the transmission zero position is drawn with Mathcad transmission zero position coincidence. When component values computing and simulation analysis, you can layout and simulation. The circuit used two FR4 0.4mm plates, the layout of the results from the engraving machine to carve, by the network analyzer frequency response obtained with the response graph layout simulations differ, using a 10x optical microscope and found that the size of each component's size and layout of the difference approximately ± 0.1mm, then explore the difference is how to produce, and then consider the situation and implement further changes made to the layout mimic diagram and observe the actual circuit simulation and layout differences.

碩士
中原大學
電子工程研究所
103
This work proposes and investigates new noise reduction schemes for reducing CMN and reflection noise in a weakly coupled differential microstrip lines (WCDMLs) that crosses a weakly coupled differential embedded microstrip lines (WCDEMLs) at 45 degrees (also called a “conventional traces crossing structure”). Time- and frequency-domain analyses of the proposed schemes are performed to investigate and reduce the CMN and reflection noise by studying the differential-to-common mode conversion and the time-domain reflection (TDR) waveform using the 3-D full-wave simulator CST and HFSS. The proposed solutions reduce the peak-to-peak amplitude of the CMN in the conventional traces-crossing structure of weakly coupled differential lines, by approximately 76%~97% , while the differential impedances of the two crossing differential lines remain matched. The range of frequencies over which the magnitude of the differential-to-common mode conversions (Sc2d1, Sc4d3, Sc3d1, Sc1d3) are significantly reduced is very wide – about 0.3–16 GHz. Furthermore, the voltage drop (reflection noise) in the TDR waveform is greatly reduced using the proposed designs. Finally, a favorable comparison between the simulated results and measurements verifies the excellent CMN and reflection noise reduction performance of the proposed schemes.