Статті в журналах: "Electronically steered antenna"

1

Kumar, Raj, Pramendra Kumar Verma, and M. V. Kartikeyan. "A Wide Beam Printed Quadrifilar Helix based Circularly Polarised Radiating Element for Electronically Steered Antenna." Defence Science Journal 71, no. 1 (February 1, 2021): 66–70. http://dx.doi.org/10.14429/dsj.71.16100.

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Wide beam and low axial ratio performance of printed quadrifilar antennas result in very attractive circularly polarised radiating element for wide scanned Electronically Steered Antenna. A compact printed quadrifilar Helix antenna (PQHA) has been designed and realised at S-Band frequency. Simulation and optimisation of designed antenna has been performed using ANSYS’s high frequency structure simulation (HFSS) software for its impedance, axial ratio (AR) performance and radiation characteristics. The developed circularly polarised antenna has 3-dB beam width of 130° and peak gain of 3.4dBic at 2.6 GHz. The developed antenna shows excellent AR performance over the frequency band as well as over the radiated beam. Half power axial ratio bandwidth of developed antenna is 27.4% (2.2 GHz - 2.9 GHz) while the impedance bandwidth is 32% (2.1 GHz - 2.9 GHz). Design has been validated through measured results. Designed wide band PQHA can be used as radiating element for electronically steered antenna for large beam steering application.

2

Mathew, Jestin John, Nitish HS, Dr Jayavrinda V. V, and Dr Raghunandan S. "Implementation of Beam Steering using Phased Array Antennas." International Journal of Innovative Science and Research Technology 5, no. 6 (July 9, 2020): 1006–8. http://dx.doi.org/10.38124/ijisrt20jun716.

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Beam steering is a phenomenon of varying the direction of the main lobe in the radiation pattern, so in radar systems it can be achieved by changing the relative phases of the antenna being implemented.But,some of the setbacks of implementing beam steering in mechanical antennas like microstrip antenna is that the directivity and, gain is low,and interference is very high.Whereas,in our project we have implemented beam steering using phased array antennas which has produced better results.So,an phased array antenna is electronically scanned antenna ,which produces a beam of radio waves that can be steered to different points based on our requirements by keeping the antenna stationary.Also,these type of antennas require less maintenance as compared to mechanical antennas

3

Oppermann, Martin, and Ralf Rieger. "RF Modules (Tx–Rx) with Multifunctional MMICs." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2017, NOR (July 1, 2017): 1–5. http://dx.doi.org/10.4071/2017-nor-oppermann.

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Abstract Next generation RF sensor modules for multifunction active electronically steered antenna (AESA) systems will need a combination of different operating modes, such as radar, electronic warfare (EW) functionalities and communications/datalinks within the same antenna frontend. They typically operate in C-Band, X-Band and Ku-Band and imply a bandwidth requirement of more than 10 GHz. For the realisation of modern active electronically steered antennas, the transmit/receive (T/R) modules have to match strict geometry demands. A major challenge for these future multifunction RF sensor modules is dictated by the half-wavelength antenna grid spacing, that limits the physical channel width to < 12 mm or even less, depending on the highest frequency of operation with accordant beam pointing requirements. A promising solution to overcome these geometry demands is the reduction of the total monolithic microwave integrated circuit (MMIC) chip area, achieved by integrating individual RF functionalities, which are commonly achieved through individual integrated circuits (ICs), into new multifunctional (MFC) MMICs. Various concepts, some of them already implemented, towards next generation RF sensor modules will be discussed and explained in this work.

4

Aboualalaa, Mohamed, Hesham A. Mohamed, Thamer A. H. Alghamdi, and Moath Alathbah. "A Pattern Reconfigurable Antenna Using Eight-Dipole Configuration for Energy Harvesting Applications." Sensors 23, no. 20 (October 13, 2023): 8451. http://dx.doi.org/10.3390/s23208451.

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A pattern reconfigurable antenna, composed of eight elements, is proposed for energy harvesting applications. Pattern reconfigurable antennas are a promising technique for harvesting from different wireless sources. The radiation pattern of the proposed antenna can be steered electronically using an RF switch matrix, covering an angle range from 0 to 360 degrees with a step size of 45 degrees. The proposed antenna primarily consists of an eight-dipole configuration that shares the same excitation. Each dipole is excited using a balun comprising a quarter-wavelength grounded stub and a quarter-wavelength open-circuit stub. The proposed antenna operates in the frequency range of 4.17 to 4.5 GHz, with an impedance bandwidth of 7.6%. By switching between the different switches, the antenna can be steered with a narrower rotational angle. In addition, the antenna can work in an omnidirectional mode when all switches are in the ON state simultaneously. The results demonstrate a good agreement between the numerical and experimental findings for the reflection coefficient and radiation characteristics of the proposed reconfigurable antenna.

5

Bialkowski, M. E., S. T. Jellett, and R. S. Varnes. "Electronically steered antenna system for the australian mobilesat." IEE Proceedings - Microwaves, Antennas and Propagation 143, no. 4 (1996): 347. http://dx.doi.org/10.1049/ip-map:19960396.

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6

Gonzalez, Manuel J., Ana Ruiz, Alberto Pellon, Jose Luis Flores, Palma Garcia, Keith Howland, Nigel Silverthorn, and Jaime Perez-de-Diego. "Enabling In-Flight Connectivity with the new Generation of Electronically Steered Antennas." IOP Conference Series: Materials Science and Engineering 1226, no. 1 (February 1, 2022): 012109. http://dx.doi.org/10.1088/1757-899x/1226/1/012109.

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Abstract In-flight communication (IFC) services offered to passengers and crew are of great importance to the air transport sector. The improvement of the satellite capacity with High Throughput Satellites (HTS) in GEO and the advent of MEO and LEO constellations will support the forecast growth of the IFC market. Antenna equipment for satellite communications will need to address multiple scenarios from G2G (Gate-to-Gate) to multi-operation under GEO-MEO-LEO systems. Under these conditions, antennas with the ability to track multiple satellites and having superior performance and reliability will play a key role. Electronically steered antennas (ESA) have emerged as a viable solution in response to these demands. The EU-funded LESAF project proposes an ESA solution of reduced size and greater efficiency for the next generation of in-flight connectivity services. This will be managed through the requirements definition, system analysis, technology assessment, prototyping and validation of ESAs. The project has successfully passed the first milestone corresponding to requirements consolidation, baseline architecture definition and candidate technology trade-offs. Multi-beam Electronically Steered Antennas, separated apertures for both transmission and reception, a flexible modular approach coupled with planar multilayer integration and an advanced beamformer design are the basis for the proposed concept. The following project phase will be focused on the design and validation of an antenna demonstrator aimed at proving the superior added value of ESAs technological solution for the aviation industry needs.

7

Kumar, Raj, Pramendra Kumar Verma, and Machavaram Venkateshwar Kartikeyan. "Wide scanned electronically steered conformal active phased array antenna for Ku-band SATCOM." International Journal of Microwave and Wireless Technologies 11, no. 4 (December 18, 2018): 376–81. http://dx.doi.org/10.1017/s1759078718001599.

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AbstractThe paper describes the design and development of a low profile wide scanned conformal active 1 × 32 phased array antenna for Ku-band SATCOM applications. The realized antenna is diagonally polarized and covers full transmit frequency band (i.e. 13.75–14.5 GHz) of Ku band SATCOM. All the developed sub-systems of the antenna, i.e. conformal radiating array, conformal transmit module, manifold network, and beam steering unit are described. The VSWR of the antenna is better than 1.65 over the complete transmit frequency band. The antenna has the beam steering capability of ±60° in the array plane. Designed antenna is best suited for airborne applications, where antenna profile contributes considerable aero drag and RCS to the host platform.

8

Yatongchai, Auychai, Peerasan Khamsalee, and Rangsan Wongsan. "EFFICIENCY IMPROVEMENT FOR ELECTRONICALLY STEERED DUAL-BEAM ANTENNA BY USING METAMATERIAL BASED RADOME." Suranaree Journal of Science and Technology 30, no. 4 (October 9, 2023): 010249(1–16). http://dx.doi.org/10.55766/sujst-2023-04-e0862.

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Efficiency improvement for electronically steered dual-beam antenna by using metamaterial based radome are a PCB based circular-patch antenna design for dual beam steering is presented. This design employs the symmetrical slots inserted into the surface at eight angles of circular-patch antenna, thus, the original circular-patch antenna is reconfigured as consisting of eight small square-patches placed on eight angles and separated by such the slots. The beam steering property of this antenna can be implemented by controlling the on/off state of PIN diodes, which connected between each small square-patches and main patch at each angle of the structure. When the diode is on, the small square-patch becomes a part of radiating patch, whereas is off, the small square-patch becomes the parasitic element. The antenna is designed for the future high altitude platform such as, drone, Aircraft, missile, etc. That can be tracked or commanded from its control station within the given range and without disconnection. This antenna is investigated at 5.8 GHz of frequency and provided the bandwidth at 113 MHz, which is high enough for the unmanned aerial vehicles UAVs application, The antenna provides the gain of 7.13 dB without meta radome and switchable the dual-beam in eight different space quadrants for the azimuth plane by exciting forward bias with binary sequence to the PIN diodes. While it provides the constant tilted beam of 35° and angular width (3dB) 52.4° in the elevation plane and efficiency improvement for the antenna provides a gain of 10.18 dB with meta radome, approximately.

9

Kumar, Raj, Pramendra Kumar Verma, Rajesh Roy, and Machavaram Venkata Kartikeyan. "POLARIZATION MATCHED RADIATING ARRAY FOR ELECTRONICALLY STEERED PHASED ARRAY ANTENNA." Progress In Electromagnetics Research Letters 79 (2018): 115–20. http://dx.doi.org/10.2528/pierl18092606.

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10

Catalani, Alfredo, Franco Di Paolo, Marzia Migliorelli, Lino Russo, Giovanni Toso, and Piero Angeletti. "Ku Band Hemispherical Fully Electronic Antenna for Aircraft in Flight Entertainment." International Journal of Antennas and Propagation 2009 (2009): 1–7. http://dx.doi.org/10.1155/2009/230650.

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The results obtained in the frame of the ESA activity “Advanced Antenna Concepts For Aircraft In Flight Entertainment” are presented. The aim of the activity consists in designing an active antenna able to guarantee the Ku band link between an aircraft and a geostationary satellite in order to provide in flight entertainment services. The transmit-receive antenna generates a single narrow beam to be steered electronically in a half sphere remaining compliant with respect to stringent requirements in terms of pattern shape, polarization alignment, EIRP, G/T, and using customized electronic devices. At the same time, the proposed solution should be competitive in terms of cost and complexity.

11

Alonso, J. I., J. M. Blas, L. E. Garcia, J. Ramos, J. de Pablos, J. Grajal, G. G. Gentili, J. Gismero, and F. Perez. "Low cost electronically steered antenna and receiver system for mobile satellite communications." IEEE Transactions on Microwave Theory and Techniques 44, no. 12 (1996): 2438–49. http://dx.doi.org/10.1109/22.554576.

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12

Lesueur, G., H. Gilles, S. Girard, T. Merlet, and M. Queguiner. "Optical Sensor for Real-Time Reconstruction of Distortions on Electronically Steered Antenna." IEEE Photonics Technology Letters 20, no. 21 (November 2008): 1763–65. http://dx.doi.org/10.1109/lpt.2008.2004681.

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13

Lakshmaiah, Akumalla, N. N. S. S. R. K. Prasad, and K. P. Ray. "Investigations on Monolithic Radome Interactions with Active Electronically Scanned Array on Fighter Platform." Defence Science Journal 71, no. 5 (September 2, 2021): 662–69. http://dx.doi.org/10.14429/dsj.71.16398.

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The conventional fighter aircrafts are often equipped with fire control radar (FCR) using mechanically scanned antenna (MSA) with passive slots enclosed with monolithic conical radome. When the fighter platforms get upgraded with the modern active electronically steered array (AESA) FCR for better mission capabilities, even though radome change is desirable for optimum performance of AESA, it may not be feasible due to development time. This necessitate the evaluation of AESA radar with the existing monolithic radome. Hence active antenna aperture radiation pattern is required to be assessed with monolithic radome. To address this issue, simulation is preferred over physical testing, due to the reduced cost, time and complexity in measurements and ability to verify compatibility. In the present paper, the influence of monolithic radome on the active antenna radiation patterns are simulated and analysed. The characterisation studies helped for better optimisation of active aperture, optimum size for new radome development and additional space on fighter platforms that can be used for integration of new subsystems. Simulations are performed at two different locations of antenna inside radome. Experimental validations have been carried out to prove the efficacy of simulated results, which are in agreement.

14

Abdul Malek, Norun, Rob D. Seager, James A. Flint, and Zuhairiah Zainal Abidin. "Analysis, Optimization, and Hardware Implementation of Dipole Antenna Array for Wireless Applications." International Journal of Antennas and Propagation 2022 (August 30, 2022): 1–14. http://dx.doi.org/10.1155/2022/1741454.

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The antenna pattern synthesis is one of the significant problems in the phased array antenna. Pattern synthesis refers to the optimized weight excitation of each antenna element in order to steer the beam electronically without mechanically rotating the antenna. It can be achieved by using a combination of phase shifters and attenuator circuits. In this paper, a 2 by 2 dipole antennas with an RF beamforming circuit has been designed to steer the main beam along the azimuth plane. The main beam coverage from 100° to 140° with a step size of 10° has been successfully optimized using a hybrid of the induced EMF method and a genetic algorithm. The optimization results were compared to the full-wave simulation technique implemented in Empire XCCel. The design is realistically implemented at 2.45 GHz, with both simulation and measurement results shown. The measured reflection coefficient of the phased array antenna is −48 dB at 2.56 GHz. The feasibility of the beam synthesis has been validated successfully with the main beam being steered at 110°. The possibility of a fabrication discrepancy resulting in minor radiation degradation is also discussed in this research. The dipole antenna system with RF beamformer circuit can be applied to indoor positioning systems such as Wi-Fi, wireless local area network (WLAN), and fifth-generation.

15

Ivić, Igor R. "An Approach to Simulate the Effects of Antenna Patterns on Polarimetric Variable Estimates." Journal of Atmospheric and Oceanic Technology 34, no. 9 (September 2017): 1907–34. http://dx.doi.org/10.1175/jtech-d-17-0015.1.

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AbstractOne of the main challenges of using phased array radar for weather observations is the implementation of dual polarization with acceptable errors of polarimetric variable estimates. This is because the differences between the copolar antenna patterns at the horizontal and vertical polarizations, as well as cross-polar fields, can introduce unacceptable measurement biases, as the main beam is electronically steered away from the principal planes. Because the sufficient cross-polar isolation is difficult to achieve by the phased array antenna hardware and because the copolar as well as cross-polar patterns inevitably vary with each beam position, it is crucial to properly evaluate errors of estimates due to radiation patterns. Herein, a method that combines the measured or simulated radiation patterns and simulated time series is introduced. The method is suited for phased array and parabolic antennas, and it allows for evaluation of radiation-pattern-induced polarimetric variable biases and standard deviations specific to the antenna used to produce the patterns. The method can be used either as an alternative to a well-established approach using analytical derivations or as a tool for cross validation of the bias computations. For standard deviation evaluation in the presence of antenna cross-polar fields, the analytical approach becomes overly complex, which inexorably leads to the introduction of numerous approximations to obtain the results. These approximations inevitably compromise the accuracy of such computations. The method proposed herein avoids such approximations and therefore provides a valuable tool for accurate assessment of polarimetric measurement precision.

16

Пастернак, Ю. Г., В. А. Пендюрин, Д. К. Проскурин, and К. С. Сафонов. "ANTENNA ARRAY OF DOUBLE-WAY ARCHIMEDEAN SPIRALS EXCITED USING COMMUNICATION PINS IMMEDIED INTO A RECTANGULAR WAVEGUIDE." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА 19, no. 6(-) (December 20, 2023): 157–63. http://dx.doi.org/10.36622/vstu.2023.19.6.024.

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растущий спрос на широкополосные мультимедийные услуги побуждает авиационную отрасль в ближайшем будущем предоставлять услуги двунаправленной бортовой связи. Гражданские самолеты в настоящее время оснащаются терминалами высокоскоростной спутниковой связи. До настоящего времени терминалы спутниковой связи разрабатывались для L- и Ku-диапазонов частот. С учетом тенденций развития технологий широкополосных мультимедийных приложений возникла необходимость использования более высоких частот, в частности, частот Ka-диапазона, где может быть обеспечена требуемая пропускная способность. Исследования показывают, что для бортовой широкополосной спутниковой связи антенная система является одним из ключевых компонентов в конструкции аппаратуры. Из-за ограничений антенн с механическим управлением наиболее многообещающим решением представляется антенная решетка с электронным управлением, использующая цифровое формирование луча. Тем не менее, разработка подобных антенных решеток в Ka-диапазоне сталкивается с высокими требованиями в отношении производительности, интеграции и, что не менее важно, стоимости компонентов. Описан результат исследования антенной решетки, элементы которой запитаны с помощью синфазных и равноамплитудных делителей мощности в волноводном исполнении. Рассмотрены варианты конструкции излучателей; исследована возможность реализации элементов фазированной антенной решетки (ФАР) с использованием различных видов технологии. Проведена оценка потерь мощности в многоканальных волноводных делителях мощности the growing demand for broadband multimedia services is encouraging the aviation industry to provide bidirectional in-flight communication services in the near future. Civil aircraft are currently equipped with high-speed satellite communications terminals. Until now, satellite communication terminals have been developed for the L- and Ku-band frequencies. Taking into account the trends in the development of technologies for wide-band multimedia applications, there is a need to use higher frequencies, in particular Ka-band frequencies, where the required throughput can be provided. Research shows that for airborne broadband satellite communications, the antenna system is one of the key components in the hardware design. Due to the limitations of mechanically steered antennas, the most promising solution appears to be an electronically steered antenna array using digital beamforming. However, the development of such Ka-band antenna arrays faces high demands in terms of performance, integration and, last but not least, component cost. The result of a study of an antenna array, the elements of which are powered using in-phase and equal-amplitude power dividers in a waveguide design, is described. Design options for emitters are considered; The possibility of implementing phased array antenna (PAR) elements using various types of technology was investigated. An assessment of power losses in multichannel waveguide power dividers has been carried out

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He, Zhang, Yi, Jin, and Dong. "Suppressing Paired Echoes Caused by Stair-Step Antenna Steering in TOPS SAR Imaging." Remote Sensing 11, no. 21 (October 29, 2019): 2544. http://dx.doi.org/10.3390/rs11212544.

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The use of electronically steered antennas in the azimuth dimension typically leads to a staircase-like antenna beam steering law in the Terrain Observation by Progressive Scan (TOPS) wide-swath synthetic aperture radar (SAR) data acquisition mode, which will introduce paired echoes in the focused images. This paper proposes a new approach for removing such paired echoes from TOPS SAR images based on the generalization of the ideal optimum filtering concept, which can be implemented easily in the SAR data processing. Modeling the amplitude-modulated azimuth signal shows that the absolute phase of the introduced paired echoes cannot be determined due to the random rotation angle jump time for each target, which will prevent the precise use of optimum filtering. An extended optimum filtering approach, which is originally proposed for suppressing the azimuth ambiguities in SAR images, is reintroduced in this particular case, and a new approximated and generalized form of the deconvolving filtering in the approach is redefined to accommodate the undetermined phase for both the strongest paired distortion peaks and the other peripheral peaks in the distorted impulse response function (IRF). Simulated data from a TOPS SAR mode with staircase-like beam steering are used to verify the improvement in image quality by using the new method.

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Karabey, Onur Hamza, Alexander Gaebler, Sebastian Strunck, and Rolf Jakoby. "A 2-D Electronically Steered Phased-Array Antenna With 2$\,\times\,$2 Elements in LC Display Technology." IEEE Transactions on Microwave Theory and Techniques 60, no. 5 (May 2012): 1297–306. http://dx.doi.org/10.1109/tmtt.2012.2187919.

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19

Oppermann, Martin, Joerg Schroth, and Felix Thurow. "Transmit/Receive (T/R) Modules – Key Elements for Phased Array Antennas." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, CICMT (September 1, 2013): 000054–58. http://dx.doi.org/10.4071/cicmt-2013-tp24.

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Modern Active Electronically Steered Antennas (AESA) are operating in different platforms and systems. Inside EADS/CASSIDIAN the focus on X-Band antennas today is in airborne and fighter nose radars, in satellite based SAR antennas (Synthetic Aperture Radar) for earth observation and ground surveillance and security radars. Active antennas are assembled with hundreds or even thousands of T/R modules. This paper will describe an example of a so called standardized module solution based on LTCC package technology. State-of-the-art modules are assembled with active components like MMICs realized in GaAs technology, e.g. Low Noise Amplifier (LNA) and High Power Amplifier (HPA), Silicon based devices and passives. Assembly technologies are optimized for high yield series production inside CASSIDIAN MicroWave Factory. New semiconductor technologies, like GaN (Gallium Nitride) are enablers for a new T/R module generation. GaN/SiC based MMICs with higher power density compared with GaAs based devices are technological challenges for innovative thermal management solutions and assembly alternatives. GaN power devices are soldered on modern heatsink materials with high thermal conductivity and matched CTE (between MMIC and heatsink). Results of thermal simulations comparing different heatsink materials in combination with soldering techniques will be discussed and an optimized solution will be shown. Another type of T/R Module technology based on RF-PCB and packaged MMICs will be discussed. Future applications of ground-based security radars, active antenna products with a one-dimensional array and needs for cost-effective solutions seem to be SMD-based products. Different packages, e.g. QFN (Quad Flat Pack no Lead) and ceramic based (HTCC), mainly for power devices will be shown and compared.

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Oppermann, Martin, Joerg Schroth, and Felix Thurow. "Transmit/Receive (T/R) Modules—Key Elements for Phased Array Antennas." Journal of Microelectronics and Electronic Packaging 10, no. 3 (July 1, 2013): 116–19. http://dx.doi.org/10.4071/imaps.381.

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Modern active electronically steered antennas (AESA) operate in different platforms and systems. Inside EADS/CASSIDIAN, the focus on X-band antennas today is on airborne and fighter nose radars, in satellite based SAR antennas (synthetic aperture radar) for earth observation, and ground surveillance and security radars. Active antennas are assembled with hundreds or even thousands of transmit/receive modules. This paper will describe an example of a so-called standardized module solution based on LTCC package technology. State-of-the-art modules are assembled with active components such as MMICs realized in GaAs technology, for example, the low noise amplifier (LNA) and the high power amplifier (HPA), silicon based devices, and passives. Assembly technologies are optimized for high yield series production inside CASSIDIAN MicroWave Factory. New semiconductor technologies, such as GaN (gallium nitride) are enablers for a new transmit/receive module generation. GaN/SiC based MMICs with higher power density compared with GaAs-based devices are technological challenges for innovative thermal management solutions and assembly alternatives. GaN power devices are soldered on modern heat sink materials with high thermal conductivity and matched CTE (between the MMIC and the heat sink). The results of thermal simulations comparing different heat sink materials in combination with soldering techniques will be discussed and an optimized solution will be shown. Another type of transmit/receive module technology based on RF-PCB and packaged MMICs will be discussed. Future applications of ground-based security radars, active antenna products with a one-dimensional array, and the need for cost-effective solutions seem to be a good fit for SMD-based products. Different packages, for example, QFN (quad flat pack no lead) and ceramic based (HTCC), mainly for power devices will be shown and compared.

21

Munoz-Martin, Joan Francesc, Raul Onrubia, Daniel Pascual, Hyuk Park, Miriam Pablos, Adriano Camps, Christoph Rüdiger, Jeffrey Walker, and Alessandra Monerris. "Single-Pass Soil Moisture Retrieval Using GNSS-R at L1 and L5 Bands: Results from Airborne Experiment." Remote Sensing 13, no. 4 (February 22, 2021): 797. http://dx.doi.org/10.3390/rs13040797.

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Global Navigation Satellite System—Reflectometry (GNSS-R) has already proven its potential for retrieving a number of geophysical parameters, including soil moisture. However, single-pass GNSS-R soil moisture retrieval is still a challenge. This study presents a comparison of two different data sets acquired with the Microwave Interferometer Reflectometer (MIR), an airborne-based dual-band (L1/E1 and L5/E5a), multiconstellation (GPS and Galileo) GNSS-R instrument with two 19-element antenna arrays with four electronically steered beams each. The instrument was flown twice over the OzNet soil moisture monitoring network in southern New South Wales (Australia): the first flight was performed after a long period without rain, and the second one just after a rain event. In this work, the impact of surface roughness and vegetation attenuation in the reflectivity of the GNSS-R signal is assessed at both L1 and L5 bands. The work analyzes the reflectivity at different integration times, and finally, an artificial neural network is used to retrieve soil moisture from the reflectivity values. The algorithm is trained and compared to a 20-m resolution downscaled soil moisture estimate derived from SMOS soil moisture, Sentinel-2 normalized difference vegetation index (NDVI) data, and ECMWF Land Surface Temperature.

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Anderson, Betty Lise, James G. Ho, William D. Cowan, Olga Blum-Spahn, Allen Y. Yi, Delton J. Rowe, Martin R. Flannery, David L. McCray, Peter Chen, and David J. Rabb. "Hardware Demonstration of Extremely Compact Optical True Time Delay Device for Wideband Electronically Steered Antennas." Journal of Lightwave Technology 29, no. 9 (May 2011): 1343–53. http://dx.doi.org/10.1109/jlt.2011.2124444.

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23

Oppermann, Martin, Felix Thurow, and Ralf Rieger. "RF Sensor Modules – Needs for Multifunctional Architectures." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, CICMT (May 1, 2016): 000207–10. http://dx.doi.org/10.4071/2016cicmt-tha25.

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Abstract Next generation of RF sensor modules, mainly for airborne applications, will cover a variety of multifunction in terms of different operating modes, e.g. Radar, EW and Communications / Datalinks. The operating frequencies will cover a bandwidth of > 10 GHz and for realisation of modern Active Electronically Steered Antennas (AESA) the Transmit/Receive (T/R) modules have to match with challenging geometry demands, and RF requirements, like switching and filtering between different operational frequencies in transmit and receive mode. New GaN technology based MMICs, e.g. LNA, HPA are in development and multifunctional components (MFC MMICs) cover more than one RF function in one chip. Different front end demonstrators will be presented, based on multilayer ceramic (LTCC) and RF-PCB and associated assembly technologies, like chip&wire and SMD reflow soldering. These TRM front ends include a Low Noise Amplifier with an integrated Switch (LNA/SW) and for characterisation the measured Noise Figure (NF), a key characteristic for receive performance, will be compared. The need for high integration on module level is obvious and therefore specific demands for low loss ceramic and PCB based modules, packages and housings exist.

24

Boyarsky, Michael, Timothy Sleasman, Mohammadreza F. Imani, Jonah N. Gollub, and David R. Smith. "Electronically steered metasurface antenna." Scientific Reports 11, no. 1 (February 25, 2021). http://dx.doi.org/10.1038/s41598-021-83377-9.

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AbstractMobile devices, climate science, and autonomous vehicles all require advanced microwave antennas for imaging, radar, and wireless communications. We propose a waveguide-fed metasurface antenna architecture that enables electronic beamsteering from a lightweight circuit board with varactor-tuned elements. Our approach uses a unique feed structure and layout that enables spatial sampling at the Nyquist limit of half a wavelength. We detail the design of this Nyquist metasurface antenna and experimentally demonstrate electronic beamsteering in two directions. Nyquist metasurface antennas can realize high performance without costly and power hungry phase shifters, making them a compelling technology for future antenna hardware.

25

Ka’bi, Amin H. Al. "Effect of Polarization on the Performance of Adaptive Antenna Arrays." Journal of Communications, 2020, 661–68. http://dx.doi.org/10.12720/jcm.15.9.661-668.

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The polarized electromagnetic waves impinging on adaptive antenna arrays have significant impact on their performance. In this paper we investigate the effect of polarized desired and undesired signals on the performance of electronically steered beam adaptive antenna arrays in terms of their output SINR’s (Signal to Interference plus Noise Ratios). To achieve this goal, we compare the performances of adaptive antenna arrays composed of single dipole antenna elements with those composed of cross-dipole antenna elements to illustrate the effect of polarized signals on their performance. Based on the experimental and simulation results, it will be shown that the adaptive antenna arrays using cross-dipole antennas provide better performance compared to those using single-dipoles, in presence of randomly polarized signals. However, if the desired signal polarization is well known, single-dipole antenna arrays exhibit better performance.

26

Gupta, Monish. "Electronically Steered MIMO Patch Antenna with Conformal Feeding for 5G Applications." Wireless Personal Communications, January 21, 2022. http://dx.doi.org/10.1007/s11277-021-09444-6.

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27

Carlson, C. M., T. V. Rivkin, P. A. Parilla, J. D. Perkins, D. S. Ginley, A. B. Kozyrev, V. N. Oshadchy, et al. "30 GHz Electronically Steerable Antennas Using BaxSr1−xTiO3-Based Room-Temperature Phase Shifters." MRS Proceedings 603 (1999). http://dx.doi.org/10.1557/proc-603-15.

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AbstractWe report the performance of 16-element phased array antennas operating at 30 GHz and ambient temperature. These antennas use BaxSr1−xTiO3(BST)-based phase shifters to produce the beam steering. Ferroelectric phase shifters offer advantages over current semiconductor and ferrite devices including faster switching speeds and lower costs. Also, ferroelectric phase shifters offer higher power handling capability than semiconductor devices and also have high radiation resistance. We made phase shifters from laser-ablated epitaxial BST films as well as from polycrystalline BST-oxide composite films. Although neither the devices nor the materials themselves are fully optimized, phase shifters have shown > 360° of phase shift with < 350 V DC bias (E < 9 V/µm) and ∼8 dB insertion loss. With ferroelectric phase shifters incorporated, antennas show radiation patterns with central-lobe half-power widths of ∼13° and side lobe intensities down by more than 10 dB. Using the phase shifters, the central lobe can be shifted, or “steered,” by ±18° in either direction. These results demonstrate a first step toward a prototype steerable antenna for 20–30 GHz satellite communications as well as other applications.

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Annapurna Sogunuru, P. Vikram, and Suma Varughese. "A Novel Approach Towards Rain Test on an Airborne Aesa." Journal of Aerospace Sciences and Technologies, July 28, 2023, 56–62. http://dx.doi.org/10.61653/joast.v73i1.2021.89.

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Centre for Airborne Systems (CABS) has designed, developed and successfully qualified Active Array Antenna Unit (AAAU) - a state-of-art technology system for airborne applications and mounted on Indigenous Airborne Early Warning and Control (AEW & C) aircraft. AAAU houses Active Electronically Steered Antenna (AESA) of Primary and Secondary Radar and front end electronics of the radar. These electronics positioned inside AAAU use ram air cooling. To comply with the all-weather conditions, an important test is the Rain test in which the radar effectiveness is verified. This paper presents a novel, cost effective and tailor made methodology adopted to suit the requirements for qualification of the AAAU. On successful completion of the test, AAAU is certified by Centre for Military Airworthiness and Certification (CEMILAC) authorities for flying under rainy conditions and has been accepted by the Indian Air Force.

29

Schurwanz, Max, Jan Mietzner, and Peter Adam Hoeher. "Improving estimation performance of compressive sensing‐based multiple‐input multiple‐output radar using electronic beamsteering." IET Radar, Sonar & Navigation, January 11, 2024. http://dx.doi.org/10.1049/rsn2.12535.

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AbstractTwo‐dimensional direction‐of‐arrival (DoA) estimation in azimuth and elevation via radar systems equipped with uniform rectangular arrays (URAs) will play an important role in various application areas—most distinctively in future urban air mobility settings with unmanned aerial vehicles. A key factor is the fast and reliable provision of target detections in terms of range and DoA for safe autonomous operation of the vehicle using on‐board antenna arrays with compact installation size. The authors present a technique for improving the performance of DoA estimation using compressive sensing in conjunction with multiple‐input multiple‐output arrays with electronically steered beams in the transmit direction. The simulation study investigates the impact of different design considerations on radar signal processing performance. An optimisation of a radar system using electronic beamsteering in the transmit domain is presented numerically. Based on the architecture of the URAs used, performance and detection accuracy can be improved.

30

Trott, Cathryn M. "Comparison of Observing Modes for Statistical Estimation of the 21 cm Signal from the Epoch of Reionisation." Publications of the Astronomical Society of Australia 31 (2014). http://dx.doi.org/10.1017/pasa.2014.23.

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AbstractNoise considerations for experiments that aim to statistically estimate the 21 cm signal from high redshift neutral hydrogen during the Epoch of Reionisation (EoR) using interferometric data are typically computed assuming a tracked observation, where the telescope pointing centre and instrument phase centre are the same over the observation. Current low frequency interferometers use aperture arrays of fixed dipoles, which are steered electronically on the sky, and have different properties to mechanically-steered single apertures, such as reduced sensitivity away from zenith, and discrete pointing positions on the sky. These properties encourage the use of two additional observing modes: (1) zenith drift, where the pointing centre remains fixed at the zenith, and the phase centre tracks the sky, and (2) drift + shift, a hybrid mode where the telescope uses discrete pointing centres, and the sky drifts during each fixed pointing. These three observing modes view the sky differently, and therefore yield different uncertainties in the power spectrum according to the balance of radiometric noise and cosmic variance. The coherence of measurements made by the instrument in these modes dictates the optimal reduction in thermal noise by combination of coherent modes, and the reduction in cosmic variance by combination of incoherent modes (views of different patches of the sky). Along with calibration and instrument stability considerations, the balance between these noise components provides one measure for the utility of these three modes for measuring a statistical signature of the EoR signal. We provide a general framework for estimating the uncertainty in the power spectrum for a given observing mode, telescope beam shape, and interferometer antenna distribution. We then apply this framework to the Murchison Widefield Array (MWA) using an analysis of the two-dimensional (2D) and one-dimensional (1D) power spectra for 900 hours of observing. We demonstrate that zenith drift scans can yield marginally lower uncertainty in the signal power compared with tracked scans for the MWA EoR experiment, and that moderately higher signal-to-noise ratio (S/N) estimates of the amplitude (3%) and slope (1%) of the 1D power spectrum are accessible, translating directly into a reduction in the required observing time to reach the same estimation precision. We find that the additional sensitivity of pointing at zenith, and the reduction in cosmic variance available with a zenith drift scan, makes this an attractive observing mode for current and future arrays.

31

Stefano Salvi, Cristiano Tolomei, John Peter Merryman Boncori, Giuseppe Pezzo, Simone Atzori, Andrea Antonioli, Elisa Trasatti, Roberta Giuliani, Simona Zoffoli, and Alessandro Coletta. "Activation of the SIGRIS monitoring system for ground deformation mapping during the Emilia 2012 seismic sequence, using COSMO-SkyMed InSAR data." Annals of Geophysics 55, no. 4 (October 17, 2012). http://dx.doi.org/10.4401/ag-6181.

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<p>On May 20, 2012, at 02:03 UTC, a moderate earthquake of local magnitude, Ml 5.9 started a seismic sequence in the central Po Plain of northern Italy The mainshock occurred in an area where seismicity of comparable magnitude has neither been recorded nor reported in the historical record over the last 1,000 years. The aftershock sequence evolved rapidly near the epicenter, with diminishing magnitudes until May 29, 2012, when at 07:00 UTC a large earthquake of Ml 5.8 occurred 12 km WSW of the mainshock, starting a new seismic sequence in the western area; a total of seven earthquakes with Ml >5 occurred in the area between May 20 and June 3, 2012. Immediately after the mainshock, the Italian Department of Civil Protection requested the Italian Space Agency to activate the Constellation of Small Satellites for Mediterranean Basin Observation (COSMO-SkyMed) to provide Interferometric Synthetic Aperture Radar (InSAR) coverage of the area. COSMO-SkyMed consists of four satellites in a 16-day repeat-pass cycle, with each carrying the same SAR payload. In the current orbital configuration, within each 16-day cycle, image pairs with temporal baselines of 1, 3, 4 and 8 days can be formed from the images acquired by the four different sensors. Combined with the availability of a wide range of electronically steered antenna beams with incidence angles ranging from about 16˚ to 50˚ at near-range, this capability allows trade-offs between temporal and spatial coverage to be exploited during acquisition planning. A joint team involving the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA-CNR) was activated to generate InSAR-based scientific products to support the emergency management. In this framework, the ASI and DPC requested that INGV activated the Space-based Monitoring System for Seismic Risk Management (SIGRIS). SIGRIS consists of a hardware/software infrastructure that is designed to provide the DPC with value-added information products in the different phases of the seismic cycle. During earthquake emergencies, its goal is to rapidly provide decision-support products, such as validated ground-displacement maps and seismic source models. This study reports the details of the activation of the SIGRIS system in the case of the Emilia sequence. It provides a description of the COSMO-SkyMed datasets and processing procedures, as well as selected interferometric results for the coseismic and post-seismic ground deformation. […]</p>

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