Artigos de revistas: "Aperture antennas"

1

Prof. Romi Morzelona. "Evaluation and Examination of Aperture Oriented Antennas". International Journal of New Practices in Management and Engineering 6, n.º 01 (31 de março de 2017): 01–07. http://dx.doi.org/10.17762/ijnpme.v6i01.49.

Texto completo da fonte

Resumo:

The exhaustive evaluation and analysis of aperture oriented antennas for different dimensions at two different frequencies (1800 MHz and 2.4 GHz) is presented in this paper. Design and comparison of the antennas for their performance is done through MATLAB. It is inferred that the circular aperture antenna has 95% higher directivity than rectangular aperture antenna. In addition, for the circular aperture antenna HPBW is 0.2849 degrees and for rectangular aperture HPBW is 1.0143 degrees. Also, circular patch antenna has less side lobe power than that of rectangular aperture antenna.

Estilos ABNT, Harvard, Vancouver, APA, etc.

2

Musa, Doaa Salim Mohammed, Ramazan Daşbaşı e Burak Polat. "Evaluation of Radiation Performances of Various Aperture and Horn Antennas over Sea Surface". European Journal of Research and Development 2, n.º 2 (7 de junho de 2022): 429–44. http://dx.doi.org/10.56038/ejrnd.v2i2.89.

Texto completo da fonte

Resumo:

Directional Currents Method (DCM) is applied to various aperture and horn antennas including rectangular aperture antenna, circular aperture antenna, dielectric loaded rectangular aperture antenna and E- and H-plane sectoral horn antennas to investigate their radiation performances analytically over sea surface in microwave bands. First, the expressions of the hypothetical directional currents of these antennas are derived in free space and the total radiation patterns are generated by MATLABTM. Then, the same antennas are simulated by the commercial electromagnetic simulation software CSTTM and compared to check the parametric accuracy of DCM numerically. In the second step, these directional currents are employed in deriving the analytical radiation fields of the antennas under investigation over sea surface by incorporating Green’s functions based on Norton’s formulation. This is followed by CSTTM simulations to observe the parametric accuracy of DCM expressions for microwave radiation over sea surface.

Estilos ABNT, Harvard, Vancouver, APA, etc.

3

Pang, Ke, Yongjun Xie, Legen Dai e Peiyu Wu. "Design of Ultra High Aperture Efficiency Surface Wave Antenna Array Based on the Three-Dimensional Aperture Principle". Electronics 11, n.º 21 (28 de outubro de 2022): 3515. http://dx.doi.org/10.3390/electronics11213515.

Texto completo da fonte

Resumo:

To overcome the conflict between limited space and the requirement for high gain antennas, a novel high aperture efficiency antenna array consisting of surface wave end-fire antennas is proposed based on the three-dimensional aperture principle. By introducing longitudinal dimension into the calculation of the regular aperture antenna gain, the two-dimensional aperture principle is expanded into the three-dimensional aperture principle. Meanwhile, the directivity and gain of the array could increase without increasing the aperture area. The aperture efficiency of the array could be more than 100% in this situation. The gain of the surface wave end-fire element antenna is 9.5 dBi. The proposed 3 × 3 square antenna array with the size of 1.5λ × 1.5λ × 2.24λ obtains a gain of 15.3 dBi and its aperture efficiency reaches 120%.

Estilos ABNT, Harvard, Vancouver, APA, etc.

4

Qu, Bingyue, Sen Yan, Anxue Zhang, Yongqiang Pang e Zhuo Xu. "Shared-aperture antennas based on mode modulation of a patch antenna and spoof surface plasmon polaritons". Journal of Physics D: Applied Physics 55, n.º 4 (25 de outubro de 2021): 045002. http://dx.doi.org/10.1088/1361-6463/ac2f69.

Texto completo da fonte

Resumo:

Abstract Light-weight shared-aperture antennas require the integration of multiple functions in separate frequency bands within the same physical aperture, having great potential use in remote sensing, radiometers, telemetry and communication, etc. In this letter, a method for designing light-weight shared-aperture antennas based on engineering of spoof surface plasmon polaritons (SSPPs) is presented. The proposed antenna consists of a feeding patch and a SSPP structure. Even and odd modes can be excited in different bands to realize different radiation performances. The simulated and measured results both corroborate that the presented shared-aperture antenna can achieveomnidirectional radiation at around 3.1 GHz and end-fire radiation at around 10.65 GHz, with peak gains about 1.90 dB and 6.24 dB, respectively. Without using several radiators and complex feeding networks, the antenna can work in two bands with different radiation patterns. This work provides an effective alternative design for shared-aperture antennas in light-weight and multi-functional wireless communication systems.

Estilos ABNT, Harvard, Vancouver, APA, etc.

5

Wang, Congsi, Haihua Li, Kang Ying, Qian Xu, Na Wang, Baoyan Duan, Wei Gao, Lan Xiao e Yuhu Duan. "Active Surface Compensation for Large Radio Telescope Antennas". International Journal of Antennas and Propagation 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/3903412.

Texto completo da fonte

Resumo:

With the development of radio telescope antennas with large apertures, high gain, and wide frequency bands, compensation methods, such as mechanical or electronic compensation, are obviously essential to ensure the electrical performance of antennas that work in complex environments. Since traditional compensation methods can only adjust antenna pointing but not the surface accuracy, which are limited for obtaining high surface precision and aperture efficiency, active surface adjustment has become an indispensable tool in this field. Therefore, the development process of electrical performance compensation methods for radio telescope antennas is introduced. Further, a series of analyses of the five key technologies of active surface adjustment is presented. Then, four typical large antennas that have been designed with active main reflector technology are presented and compared. Finally, future research directions and suggestions for reflector antenna compensation methods based on active surface adjustment are presented.

Estilos ABNT, Harvard, Vancouver, APA, etc.

6

Ding, Kaicheng, Lei Sun e Daqun Yu. "A Dual-Band Shared-Aperture Antenna Array Design". Journal of Physics: Conference Series 2419, n.º 1 (1 de janeiro de 2023): 012034. http://dx.doi.org/10.1088/1742-6596/2419/1/012034.

Texto completo da fonte

Resumo:

Abstract Aiming at solving the difficult problem of shared-aperture integration of dual-band antenna arrays, the research of P-band/S-band shared-aperture antenna arrays is carried out, focusing on the design of broadband wide-angle scanning, planarization, miniaturization, and low-profile of the two-band shared-aperture antenna arrays. And certain work is carried out for the shared-aperture antennas in terms of the improvement of isolation and suppression of the blocking effect. The simulation results of the antenna model show that this antenna works well and can meet the specification requirements.

Estilos ABNT, Harvard, Vancouver, APA, etc.

7

Washington, Gregory. "Smart aperture antennas". Smart Materials and Structures 5, n.º 6 (1 de dezembro de 1996): 801–5. http://dx.doi.org/10.1088/0964-1726/5/6/010.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

8

Xue, Yulong, Qihao Zhang, Yangming Ren, Yufang Lei, Xiaochen Sun e Lingxuan Zhang. "Two-dimensional single-lobe Si photonic optical phased array with minimal antennas using a non-uniform large spacing array design". Applied Optics 61, n.º 24 (15 de agosto de 2022): 7158. http://dx.doi.org/10.1364/ao.463542.

Texto completo da fonte

Resumo:

We report a two-dimensional Si photonic optical phased array (OPA) optimized for a large optical aperture with a minimal number of antennas while maintaining single-lobe far field. The OPA chip has an optical aperture of ∼ 200 µ m by 150 µm comprising a 9 × 9 antenna array. The two-dimensional spacings between these antennas are much larger than the wavelength and are highly non-uniform optimized by the genetic deep learning algorithm. The phase of each antenna is independently tunable by a thermo-optical phase shifter. The experimental results validate the design and exhibit a 0.39 ∘ × 0.41 ∘ beamwidth within the 3 dB steering range of 14 ∘ × 11 ∘ limited by the numerical aperture of the far-field camera system. The method can be easily extended to a larger aperture for narrower beamwidth and wider steering range.

Estilos ABNT, Harvard, Vancouver, APA, etc.

9

Ilnitskyi, Ludvig, Leonid Sibruk e Inna Mykhalchuk. "Considerations for Far-field Antennas Test". Electronics and Control Systems 2, n.º 68 (22 de novembro de 2021): 56–61. http://dx.doi.org/10.18372/1990-5548.68.16092.

Texto completo da fonte

Resumo:

The theoretical foundations of testing antenna parameters and characteristics in the far radiation field are presented. A two-beam model of radio wave propagation was used, including a direct wave and a wave reflected from the earth's surface. This model meets the conditions for carrying out measurements on a signals training areas or in an anechoic chamber. It is shown that for a given distance between the antennas, it is necessary to control the dimensions of the aperture transmitting and receiving antennas for the compliance with the maximum permissible values. Formulas for determining the permissible dimensions of the antenna aperture are obtained. The influence of the antenna hanging heights on the measurement accuracy was also investigated. Recommendations for reducing the level of electromagnetic waves reflected from the earth's surface are given.

Estilos ABNT, Harvard, Vancouver, APA, etc.

10

Gu, Chunwang, Hao Liu e Min Yi. "Lightweight Fan-Beam Microstrip Grid Antenna for Airborne Microwave Interferometric Radiometer Applications". Micromachines 14, n.º 1 (15 de janeiro de 2023): 228. http://dx.doi.org/10.3390/mi14010228.

Texto completo da fonte

Resumo:

The microwave interferometric radiometer (MIR) uses aperture synthesis technology to equate multiple small-aperture antennas into a large-aperture antenna to improve spatial resolution. At present, MIR antennas that operate at frequencies above the C-band mostly use horn antennas, waveguide slot antennas, etc., which have the disadvantages of a high profile and large mass. In this paper, a new type of miniaturized, low-profile, and lightweight K-band fan-beam microstrip grid antenna is designed for the airborne campaign of the K-band one-dimensional MIR of a Microwave Imager Combined Active and Passive (MICAP) onboard a Chinese Ocean Salinity Mission (COSM). With a limited size constraint (12.33 mm) on the antenna width, a fan-beam shape antenna pattern was achieved with a 5.34° 3-dB beamwidth in the narrow beam direction and up to a 55° 3-dB beamwidth in the fan-beam direction. A periodic structural unit is proposed in this paper to reduce the design complexity of Taylor weighting, achieving desirable performances on gain (19.1 dB) and sidelobe level (<−20 dB) in the H-plane. Four antenna elements were fabricated and arranged in a non-redundant sparse array. The performance of the four-element sparse array was evaluated with a simulation and real measurement in an anechoic chamber. The coupling between antenna elements was less than −25 dB, and the consistency of phase patterns was better than 3.4°. These results verify the feasibility of the proposed K-band microstrip grid antenna for airborne MIR applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

11

Moheb, H., J. Shaker e L. Shafai. "Numerical and experimental investigation of cavity-backed arbitrary slot antennas". Canadian Journal of Physics 74, n.º 3-4 (1 de março de 1996): 122–31. http://dx.doi.org/10.1139/p96-019.

Texto completo da fonte

Resumo:

The equivalence principle and the generalized network formulation are used to model the tangential electric field on arbitrary apertures, backed by a rectangular wave guide or cavity, in terms of equivalent magnetic currents. The coupling is through the aperture whose characteristics are expressed by the aperture admittance matrices of the cavity and half-space regions. The aperture coupling is then expressed as the sum of the two independent aperture admittances, with source terms related to the incident field. The result is an integral equation for the unknown aperture current. This integral equation is then reduced to a matrix equation using the method of moments. The formulation is then used to, investigate the electrical characteristics, i.e., aperture field distribution, aperture admittance, and radiation patterns of low-gain antennas such as H, cross, end-loaded, and centre-loaded slots backed by a cavity. Experimental results are also provided to verify the numerical results.

Estilos ABNT, Harvard, Vancouver, APA, etc.

12

Teniou, Mounir, Helene Roussel, Mohammed Serhir, Nicolas Capet, Gerard-Pascal Piau e Massimiliano Casaletti. "Tensorial metasurface antennas radiating polarized beams based on aperture field implementation". International Journal of Microwave and Wireless Technologies 10, n.º 2 (23 de novembro de 2017): 161–68. http://dx.doi.org/10.1017/s1759078717001222.

Texto completo da fonte

Resumo:

This paper presents a procedure for the design of tensorial metasurface antennas radiating polarized beams through aperture field synthesis. The aperture field is generated using the surface wave to leaky wave conversion resulting from metasurface modulation. The design procedure of the feeder is presented with a description of the geometrical parameters affecting the antenna matching. Numerical solutions for single beam and multi-beam metasurface antennas working respectively, at 12.25 and 20 GHz are presented. In addition, a metasurface prototype working at 12.25 GHz is manufactured and measured.

Estilos ABNT, Harvard, Vancouver, APA, etc.

13

Reichthalhammer, T., e E. Biebl. "Motion compensation of short-range, wide-beam synthetic aperture radar". Advances in Radio Science 9 (29 de julho de 2011): 61–66. http://dx.doi.org/10.5194/ars-9-61-2011.

Texto completo da fonte

Resumo:

Abstract. Up to now, SAR systems are a well known possibility for long-range detection. Applying them for short-range applications with wide-beam antennas, of course, does not increase the resolution but the probability to detect hidden targets with an anisotropic radar cross section significantly in comparison to other detection systems. Working with an appropriate wavelength even improves the possiblity to look through natural cover like grass. An application is detecting fawn while pasture mowing. The main issue in such applications is the antenna's motion in range direction as it is carried by cars or traction engines. If motion is not compensated, the phase cannot be reconstructed correctly, the resolution gets poorer and, in worst case, the target even disappears. Conventional methods for motion compensation either fail for wide beam antennas, since for contributions of wide angles the phase reconstruction is incorrect, or is not applicable for realtime data processing, because the processing time due to interpolation or similar steps is very high. We present a method of image reconstruction regarding motion of the antenna as well as wide beamwidth. This method is analyzed concerning processing time in comparison to the conventional image reconstruction. In our system we use a combination of algorithms. There is shown a comparison for different algorithms dependent of the antenna's motion and aperture angle.

Estilos ABNT, Harvard, Vancouver, APA, etc.

14

Isakov, V. N., e V. S. Lankina. "Modeling of the electromagnetic field of radiating aperture". Russian Technological Journal 9, n.º 4 (26 de agosto de 2021): 56–67. http://dx.doi.org/10.32362/2500-316x-2021-9-4-56-67.

Texto completo da fonte

Resumo:

The article is devoted to the issues of numerical calculation of the characteristics of the electromagnetic field of radiating apertures. Тhe radiating aperture is a universal electrodynamic model used in the analysis of a special class of antennas, in particular, mirror and horn antennas, in the study of diffraction phenomena, in the planning of radio wave propagation paths, and when solving problems of wireless transmission of electric energy at a distance. The structure of the electromagnetic field of a radiating aperture in the intermediate and far zones is of the greatest interest according to the needs of practice. However, the theoretical solutions of these problems are usually difficult to obtain, except for some special cases related to the far zone. This leads to the development of appropriate computational models. This paper is aimed at generalization and systematization of experience in developing software for the simulation of electromagnetic field characteristics of radiating apertures in the intermediate and far zones. This paper considers an approach to developing a computational model of a radiating aperture that may be used to calculate the characteristics of electromagnetic field in the intermediate and far zones. Examples of results obtained for circular and ring apertures describing the structure of their electromagnetic field are given. Examples of flight diagrams of a circular aperture are given. The effect of “searchlight” localization of the electromagnetic field in the intermediate zone of a circular emitting aperture is demonstrated. The effect of mutual compensation of neighbouring Fresnel zones using the circular emitting aperture model is demonstrated. A program was developed for calculating the characteristics of the electromagnetic field of radiating holes in the intermediate and far zones. The results can also be used as illustration material for teaching the academic disciplines “Electrodynamics and radio wave propagation” and “Microwave devices and antennas”.

Estilos ABNT, Harvard, Vancouver, APA, etc.

15

Ohnimus, Florian, Uwe Maaß, Gerhard Fotheringham, Brian Curran, Ivan Ndip, Thomas Fritzsch, Jürgen Wolf, Stephan Guttowski e Klaus-Dieter Lang. "Design and Comparison of 24 GHz Patch Antennas on Glass Substrates for Compact Wireless Sensor Nodes". International Journal of Microwave Science and Technology 2010 (7 de fevereiro de 2010): 1–9. http://dx.doi.org/10.1155/2010/535307.

Texto completo da fonte

Resumo:

Three patch antennas suitable for integration and operation in a compact 24 GHz wireless sensor node with radar and communication functions are designed, characterized, and compared. The antennas are manufactured on a low loss glass wafer using thin film (BCB/Cu) wafer level processing (WLP) technologies. This process is well suited for 3D stacking. The antennas are fed through a microstrip line underneath a ground plane coupling into the patch resonator through a slot aperture. Linear polarization (LP), dual mode (DM) operation, and circular polarization (CP) are achieved through the layout of the slot aperture and rectangular patch dimensions. Antenna gain values of ∼5.5 dBi are obtained in addition to the 10 dB impedance bandwidths of 900 MHz and 1.3 GHz as well as 500 MHz CP bandwidth with a 3 dB axial ratio for the LP, DM, and CP patch antennas, respectively.

Estilos ABNT, Harvard, Vancouver, APA, etc.

16

Lukin, Konstantin, Anatoliy Mogila, Pavlo Vyplavin, Gaspare Galati e Gabriele Pavan. "Novel concepts for surface movement radar design". International Journal of Microwave and Wireless Technologies 1, n.º 3 (junho de 2009): 163–69. http://dx.doi.org/10.1017/s1759078709000233.

Texto completo da fonte

Resumo:

Traditional millimeter-wave surface movement radar (SMR) has been designed and tested. A novel concept for the design of a new SMR is suggested based on synthetic aperture antenna and noise radar technology. It enables designing SMR without mechanical rotation of an antenna, but applying several nonmoving synthetic aperture antennas instead. Application of noise radar technology is also considered in more detail to improve the expected performance of a new SMR.

Estilos ABNT, Harvard, Vancouver, APA, etc.

17

Kumar, Girish, e R. K. Kotapati. "Aperture Coupled Microstrip Antennas". IETE Technical Review 16, n.º 1 (janeiro de 1999): 85–88. http://dx.doi.org/10.1080/02564602.1999.11416808.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

18

Kim, Eunhee, Ilkyu Kim e Wansik Kim. "Non-Uniform MIMO Array Design for Radar Systems Using Multi-Channel Transceivers". Remote Sensing 15, n.º 1 (23 de dezembro de 2022): 78. http://dx.doi.org/10.3390/rs15010078.

Texto completo da fonte

Resumo:

Multiple-input multiple-output (MIMO) technology has recently attracted attention with regard to improving the angular resolution of small antennas such as automotive radars. If appropriately placed, the co-located transmit and receive arrays can make a large virtual aperture. This paper proposes a new method for designing arrays by adopting a structure with minimum redundancy. The proposed structure can significantly increase the virtual array aperture while keeping the transmit and receive antennas at the same size. We describe the application of the proposed method to subarray-type antennas using multi-channel transceivers, which is essential for arranging RF hardware in a small antenna operating at high frequency. Further, we present an analysis of the final beam pattern and discuss its benefits and limitations.

Estilos ABNT, Harvard, Vancouver, APA, etc.

19

Karami, Farzad, Halim Boutayeb, Ali Amn-e-Elahi, Alireza Ghayekhloo e Larbi Talbi. "Developing Broadband Microstrip Patch Antennas Fed by SIW Feeding Network for Spatially Low Cross-Polarization Situation". Sensors 22, n.º 9 (24 de abril de 2022): 3268. http://dx.doi.org/10.3390/s22093268.

Texto completo da fonte

Resumo:

A stacked multi-layer substrate integrated waveguide (SIW) microstrip patch antenna with broadband operating bandwidth and low cross-polarization radiation is provided. A complete study on the propagating element bandwidth and cross polarization level is presented to demonstrate the importance of the design. The proposed antenna includes three stacked printed circuit board (PCB) layers, including one layer for the radiating 2 × 2 rectangular patch elements and two SIW PCB layers for the feeding network. There are two common methods for excitation in cavity-backed patch antennas: probe feeding (PF) and aperture coupling (AC). PF can be used to increase the bandwidth of the antenna. Although this method increases the antenna’s bandwidth, it produces a strong cross-polarized field. The AC method can be used to suppress cross-polarized fields in microstrip patch antennas. As microstrip patch antennas are inherently narrowband, the AC method has little effect on their bandwidth. This paper proposes an antenna that is simultaneously fed by AC and PF. As a result of this innovation, the operating bandwidth of the antenna has increased, and cross-polarization has been reduced. Actually, the combination of probe feeding and aperture coupling schemes leads to achieving a broadband operating bandwidth. The arrangement of radiator elements and cavities implements a mirrored excitation technique while maintaining a low cross-polarization level. In both numerical and experimental solutions, a less than −30 dB cross-polarization level has been achieved for all of the main directions. A fractional impedance bandwidth of 29.8% (10.55–14.25 GHz) for S11 < −10-dB is measured for the proposed array. Simulated and measured results illustrate good agreement. Having features like low cost, light weight, compactness, broadband, integration capabilities, and low cross-polarization level makes the designed antenna suitable for remote-sensing and satellite applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

20

Karami, Farzad, Halim Boutayeb, Ali Amn-e-Elahi, Alireza Ghayekhloo e Larbi Talbi. "Developing Broadband Microstrip Patch Antennas Fed by SIW Feeding Network for Spatially Low Cross-Polarization Situation". Sensors 22, n.º 9 (24 de abril de 2022): 3268. http://dx.doi.org/10.3390/s22093268.

Texto completo da fonte

Resumo:

A stacked multi-layer substrate integrated waveguide (SIW) microstrip patch antenna with broadband operating bandwidth and low cross-polarization radiation is provided. A complete study on the propagating element bandwidth and cross polarization level is presented to demonstrate the importance of the design. The proposed antenna includes three stacked printed circuit board (PCB) layers, including one layer for the radiating 2 × 2 rectangular patch elements and two SIW PCB layers for the feeding network. There are two common methods for excitation in cavity-backed patch antennas: probe feeding (PF) and aperture coupling (AC). PF can be used to increase the bandwidth of the antenna. Although this method increases the antenna’s bandwidth, it produces a strong cross-polarized field. The AC method can be used to suppress cross-polarized fields in microstrip patch antennas. As microstrip patch antennas are inherently narrowband, the AC method has little effect on their bandwidth. This paper proposes an antenna that is simultaneously fed by AC and PF. As a result of this innovation, the operating bandwidth of the antenna has increased, and cross-polarization has been reduced. Actually, the combination of probe feeding and aperture coupling schemes leads to achieving a broadband operating bandwidth. The arrangement of radiator elements and cavities implements a mirrored excitation technique while maintaining a low cross-polarization level. In both numerical and experimental solutions, a less than −30 dB cross-polarization level has been achieved for all of the main directions. A fractional impedance bandwidth of 29.8% (10.55–14.25 GHz) for S11 < −10-dB is measured for the proposed array. Simulated and measured results illustrate good agreement. Having features like low cost, light weight, compactness, broadband, integration capabilities, and low cross-polarization level makes the designed antenna suitable for remote-sensing and satellite applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

21

Tkachenko, Sergey, Jürgen Nitsch e Moawia Al-Hamid. "High-Frequency Electromagnetic Field Coupling to Small Antennae in a Rectangular Resonator". International Journal of Antennas and Propagation 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/897074.

Texto completo da fonte

Resumo:

The integral-differential equation for the current of an electrically small antenna, inside a resonator, which is induced by given sources, is approximately solved by the so-called “Method of Small Antenna,” both for dipole and loop antennas. The current induced in the antenna is evaluated using the scattering characteristics of small antennas in free space and regularized Green’s function of resonator. As example of application of the theory, a transfer function (“external field→induced voltage”) for the coupling through aperture is calculated.

Estilos ABNT, Harvard, Vancouver, APA, etc.

22

Capozzoli, Amedeo, Claudio Curcio, Giuseppe D'Elia, Flaminio Ferrara, Claudio Gennarelli, Rocco Guerriero e Angelo Liseno. "A Probe-Compensated Helicoidal NF-FF Transformation for Aperture Antennas Using a Prolate Spheroidal Expansion". International Journal of Antennas and Propagation 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/753156.

Texto completo da fonte

Resumo:

A new probe-compensated near-field-far-field (NF-FF) transformation for aperture antennas in a cylindrical scanning geometry is presented. Such a technique takes the advantage of the NF data acquisition made according to a very efficient sampling strategy along a helix and exploits a proper aperture field expansion based on the use of the prolate spheroidal wave functions (PSWFs), accounting for the a priori information on shape and size of the antenna under test. The unknown aperture field expansion coefficients of the PSWFs are evaluated from the acquired voltage samples by an inversion process using a regularized version of the singular value decomposition method. Experimental results on connected and disconnected radiating aperture antennas, including sum and difference patterns, show the effectiveness of the approach and, in particular, how it enables a serious reduction of the measurement points without impairing the FF estimation accuracy.

Estilos ABNT, Harvard, Vancouver, APA, etc.

23

Kirpanev, A. V., e N. A. Kirpanev. "Methods of antenna and «antenna- radome» system analysis based on amplitude and phase measurements of their far field spherical components". Issues of radio electronics 1, n.º 1 (13 de março de 2021): 19–25. http://dx.doi.org/10.21778/2218-5453-2021-1-19-25.

Texto completo da fonte

Resumo:

The main principles of electric intensity recovery of electrical field in tested antenna aperture or in the «antenna radome» system radome-close aperture field (false aperture) by amplitude and phase long-range measurements are proposed. Measurements zone means a part of the spherical surface that envelopes analyzed antenna, the boarder of this surface are determined by the kinematic scheme of rotary joint of the scanner. Recovery of amplitude and phase distribution of the field in a flat aperture area or on the plane where array irradiators are located is used in case of wave diagnostics of such type of antennas. It is proposed to use the recovered phase distribution in a false aperture for a phase correction on phased array irradiators in order to compensate phase errors appeared because of the radome. The method of radome dielectric permittivity is discussed.

Estilos ABNT, Harvard, Vancouver, APA, etc.

24

Wang, Wen-Qin. "Virtual Antenna Array Analysis for MIMO Synthetic Aperture Radars". International Journal of Antennas and Propagation 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/587276.

Texto completo da fonte

Resumo:

Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) that employs multiple antennas to transmit orthogonal waveforms and multiple antennas to receive radar echoes is a recently proposed remote sensing concept. It has been shown that MIMO SAR can be used to improve remote sensing system performance. Most of the MIMO SAR research so far focused on signal/data models and corresponding signal processing algorithm. Little work related to MIMO SAR antenna analysis can be found. One of the main advantages of MIMO SAR is that the degrees of freedom can be greatly increased by the concept of virtual antenna array. In this paper, we analyze the virtual antenna array for MIMO SAR high-resolution wide-swath remote sensing applications. The one-dimensional uniform and nonuniform linear antenna arrays are investigated and their application potentials in high-resolution wide-swath remote sensing are introduced. The impacts of nonuniform spatial sampling in the virtual antenna array are analyzed, along with a multichannel filtering-based reconstruction algorithm. Conceptual system and discussions are provided. It is shown that high operation flexibility and reconfigurability can be obtained by utilizing the virtual antenna arrays provided by the MIMO SAR systems, thus enabling a satisfactory remote sensing performance.

Estilos ABNT, Harvard, Vancouver, APA, etc.

25

Kirpanev, A. V., e A. N. Mikhailov. "Dual-frequency offset transreflector antennas". Issues of radio electronics, n.º 8 (7 de agosto de 2019): 71–78. http://dx.doi.org/10.21778/2218-5453-2019-8-71-78.

Texto completo da fonte

Resumo:

The paper presents the results of computer simulation of the developed dual‑frequency antennas with a common radiating aperture, operating in the millimeter and centimeter wavelength range. The operation of antennas in the Kaand W‑bands is based on the well‑known dual reflector polarization rotating antennas constructing principles. The twistreflector of the considered antennas is combined with the radiation surface of the centimeter wavelength range (X‑band) waveguide‑slot array. Transreflector is made by offset scheme. For the Kaand X‑bandsantenna, the transreflector is a paraboloid of rotation part. In the case of the Wand X‑band antenna, the transreflector has a flat Fresnel zoned antenna structure. Computer simulation is based on the method of finite integrals, which provides a reliable result at an appropriately chosen sampling step. The calculated characteristics confirm the operability of the considered antenna options.

Estilos ABNT, Harvard, Vancouver, APA, etc.

26

Wang, Sungsik, Hyunsoo Kim, Dongyoon Kim e Hosung Choo. "Multi-Band Array Antenna Sharing a Common Aperture with Heterogeneous Array Elements". Applied Sciences 12, n.º 18 (18 de setembro de 2022): 9348. http://dx.doi.org/10.3390/app12189348.

Texto completo da fonte

Resumo:

This paper proposes a multi-band array antenna that shares a common aperture with heterogenous array elements. The multi-band array antenna includes one printed dipole antenna for the S-band and 3 × 3 array E-shaped patch antennas for the X-band. The current directions of the printed dipole and E-shaped antenna are orthogonal to each other, which properly diminishes the mutual coupling interference. To decrease the mutual coupling interference among the X-band components, we placed cavities using multiple vias surrounding the X-band components. To check the validity of the proposed design, the unit-cell was expanded to a 12 × 12 X-band array configuration, and then the beam steering properties were examined. The proposed antenna’s average gains are 5.2 dBi in the S-band and 5.2 dBi in the X-band. The bore-sight gain of the extended array configuration on the ship mast is 35.6 dBi. The results confirm that the proposed design is suitable for MFR applications even in a shared aperture.

Estilos ABNT, Harvard, Vancouver, APA, etc.

27

Kojima, Seishiro, Naoki Shinohara e Tomohiko Mitani. "Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region". Wireless Power Transfer 4, n.º 2 (setembro de 2017): 120–31. http://dx.doi.org/10.1017/wpt.2017.10.

Texto completo da fonte

Resumo:

We address transmission between array antennas in the Fresnel region, where there is a difference between the theoretical and actual transmission efficiencies. In particular, we focus on the effect of synthesis loss in the receiving antenna's power combiner circuit caused by amplitude and phase differences among the signals received by the elements. We designed 24 GHz array antennas and investigated the effect of synthesis loss on transmission efficiency via simulation. The synthesis loss was found to increase for smaller transmitting antenna sizes and larger receiving antenna sizes. In addition, to clarify the origin of the discrepancy between the theoretical and actual efficiency values and accurately estimate the efficiency, we defined four other loss factors and calculated them via simulation. Based on the results obtained, we propose an approximate equation for transmission efficiency in terms of synthesis loss and aperture efficiency. Finally, we calculate the efficiency with the effect of the loss factors included and confirm that the calculated and measured efficiencies are almost identical.

Estilos ABNT, Harvard, Vancouver, APA, etc.

28

Dong, Jian, Ronghua Shi, Wentai Lei e Ying Guo. "Minimum Redundancy MIMO Array Synthesis by means of Cyclic Difference Sets". International Journal of Antennas and Propagation 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/323521.

Texto completo da fonte

Resumo:

Antenna array synthesis is an important issue in MIMO radars. By judiciously designing antenna positions, one can create a very long virtual array steering vector with a small number of antennas and therefore achieve very high spatial resolution at a small cost. This paper presents a combinatorial methodology based on cyclic difference sets (CDSs) for minimum redundancy (MR) MIMO array synthesis which seeks to maximize the virtual array aperture for a given number of antennas. First, the key features of CDSs and the CDS-based MR-MIMO layouts are described. Then, the analytical expression of the maximum contiguous virtual array aperture is derived. Further, based on this expression, an enumerative shifting procedure is developed for identifying the optimal CDS-based MR-MIMO layout. Selected examples are analyzed to point out the computational effectiveness of the CDS-based MR-MIMO array synthesis.

Estilos ABNT, Harvard, Vancouver, APA, etc.

29

Zhou, Li, e Ming Hou. "Research and Analysis about Array Antennas in Mobile Communications". Advanced Materials Research 760-762 (setembro de 2013): 628–33. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.628.

Texto completo da fonte

Resumo:

Because the direction of a single antenna is limited, and for strengthening the direct radiant ability of the antenna, we will put the weaker direction antennas together in some way to constitute an antenna array system. The antenna array is also called the array antenna or a disperse antenna array. The antenna cell can be the symmetry center-fed dipole, the aperture antenna, the circle antenna or other forms of the antennas whose direction are limited. In practice, the antenna array is almost constituted of similar antenna cells. I have mainly completed the antenna array direction diagram in conditions of some kinds of parameters. And at last, I get the useful results for practice. This also provides theories basis for the analysis of smart antenna.

Estilos ABNT, Harvard, Vancouver, APA, etc.

30

Cao, Yunqing, Menglong Wang, Daoyuan Sun e Dan Shan. "A Novel Miniaturized Four-Ridged Horn Antenna with Enhanced Gain". International Journal of Antennas and Propagation 2021 (7 de agosto de 2021): 1–7. http://dx.doi.org/10.1155/2021/8143395.

Texto completo da fonte

Resumo:

Miniaturization of wideband antennas has attracted much attention for its wide application in modern society. This article proposes a novel broadband miniaturized four-ridged horn antenna (FRHA) with high gain operating from 2.6 to 8.4 GHz. By filling the FRHA with the epoxy-laminated glass cloth board, the side length of the aperture realizes 48% reduction comparing to a traditional ridged horn antenna. The cuboid-shaped polyethylene lens provides good impedance matching between the antenna and the air at low frequencies and decreases the aperture phase error at high frequencies, which optimizes the radiating characteristics in the whole operating band.

Estilos ABNT, Harvard, Vancouver, APA, etc.

31

Love, A. W. "Equivalent circuit for aperture antennas". Electronics Letters 23, n.º 13 (1987): 708. http://dx.doi.org/10.1049/el:19870504.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

32

Povolotsky, F. K., e T. P. Sydorova. "Linear-phase aperture distribution antennas". IEEE Transactions on Antennas and Propagation 44, n.º 6 (junho de 1996): 874–78. http://dx.doi.org/10.1109/8.509891.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

33

Hagen, Jon B., e Hans A. Baumgartner. "Backscatter gain of aperture antennas". Radio Science 31, n.º 4 (julho de 1996): 693–99. http://dx.doi.org/10.1029/96rs01095.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

34

Lin, Yecong, e Sai-Wai Wong. "Coplanar Dual-Band Dual-Polarized Shared-Aperture Antenna Array For 4/5G Base Station Applications". Journal of Physics: Conference Series 2245, n.º 1 (1 de abril de 2022): 012020. http://dx.doi.org/10.1088/1742-6596/2245/1/012020.

Texto completo da fonte

Resumo:

Abstract A novel dual-band dual-polarized shared-aperture antenna array is presented for fifth generation wireless communication application. This novel antenna array is a combination of a low-band antenna and four high-band antennas. In order to simplify the design model while achieving broadband, antenna working on low-band (from 0.68 to 0.99 GHz) and antenna working on high-band (from 3.3 to 5.1 GHz) are both loop-shape radiator fed by Y-shape feed. Coplanar, dual-band and shared-aperture are resolved by embedding four HB antenna elements in the LB antenna. From simulation, the proposed coplanar antenna array respectively achieves 43% (from 0.68 to 0.99 GHz) and 37% (from 3.3 to 5.1 GHz) impedance bandwidth in the low-band and high-band.

Estilos ABNT, Harvard, Vancouver, APA, etc.

35

Li, Ming-Jian, Meng Li, Yu-Fei Liu, Xin-Yu Geng e Yuan-Yuan Li. "A Review on the Development of Spaceborne Membrane Antennas". Space: Science & Technology 2022 (7 de março de 2022): 1–12. http://dx.doi.org/10.34133/2022/9803603.

Texto completo da fonte

Resumo:

The membrane antenna technology is a very promising approach to obtain large aperture with light weight and low stowed volume. In the past decades, extensive studies have been carried out on active and passive membrane antennas. However, the practical spaceborne applications are rare due to many challenges, e.g., the surface accuracy maintenance, the on-orbit reliability, and the environmental compatibility. This paper summarizes the history and state-of-art progresses on spaceborne membrane antennas. Curved surface reflectors, conformal active membrane antennas, planar array membrane antennas, and planar reflectarray membrane antennas have been introduced, respectively. Radiofrequency design, deploying mechanism, material, experiment, application, and analysis method have been presented. By concluding the advantages and challenges of the current membrane antennas, this paper is aimed at providing a perspective of the existing problems and future trend of spaceborne membrane antennas.

Estilos ABNT, Harvard, Vancouver, APA, etc.

36

Park, Daesung, e Jaehoon Choi. "A Dual-Band Dual-Polarized Antenna with Improved Isolation Characteristics for Polarimetric SAR Applications". Applied Sciences 11, n.º 21 (26 de outubro de 2021): 10025. http://dx.doi.org/10.3390/app112110025.

Texto completo da fonte

Resumo:

A dual-band dual-polarized antenna with high isolation characteristics is proposed for polarimetric synthetic aperture radar (PolSAR) applications. The antenna consists of four dipole antennas and 2 × 2 patch antenna arrays operating at the P-band (450–730 MHz) and Ka-band (34–36 GHz), respectively. The dipole antennas and the patch antenna arrays need dual-linear polarization characteristics to acquire PolSAR data. Improvements in the isolation characteristics at the P-band are achieved by inserting a metamaterial absorber with a fractal geometry between the transmitting (Tx) and receiving (Rx) dipole antennas. Without the absorber, the simulated isolation characteristics between the Tx and Rx antennas are lower than 19.2 dB over the target band. On the other hand, with the absorbers, the simulated isolation characteristics are higher than 23.44 dB over the target band, and remarkable improvement is achieved around the resonance frequency of the absorber. The measured results are in good agreement with the simulated ones, showing that the proposed antenna can be a good candidate for PolSAR applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

37

Csathó, Botond Tamás, Bálint Péter Horváth e Péter Horváth. "Modeling the near-field of extremely large aperture arrays in massive MIMO systems". Infocommunications journal 12, n.º 3 (2020): 39–46. http://dx.doi.org/10.36244/icj.2020.3.6.

Texto completo da fonte

Resumo:

Massive multiple-input multiple-output (MIMO) is a key technology in modern cellular wireless communication systems to attain a very high system throughput in a dynamic multi-user environment. Massive MIMO relies on deploying base stations equipped with a large number of antenna elements. One possible way to deploy base stations equipped with hundreds or thousands of antennas is creating extremely large aperture arrays. In this paper, we investigate channel modeling aspects of massive MIMO systems with large aperture arrays, in which many users are located in the near-field of the aperture. Oneand two-dimensional antenna geometries, different propagation models, and antenna element patterns are compared in terms of inter-user correlation, condition number of the multi-user channel matrix, and spectral efficiency to identify key design parameters and essential modeling assumptions. As our analysis reveals by choosing spectral-efficiency as a design objective, the size of the aperture is the critical design parameter.

Estilos ABNT, Harvard, Vancouver, APA, etc.

38

Hannan, Hu. "Impulse responses of aperture antennas with arbitrary aperture distributions". Journal of Electronics (China) 3, n.º 3 (julho de 1986): 211–19. http://dx.doi.org/10.1007/bf02778883.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

39

Karmakar, N. C., e S. K. Padhi. "Very small aperture terminal broadband shared-aperture planar antennas". International Journal of RF and Microwave Computer-Aided Engineering 13, n.º 3 (maio de 2003): 180–93. http://dx.doi.org/10.1002/mmce.10078.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

40

Dolzhikov, V. V. "Longitudinal distribution of the field intensity of a circular focused aperture". Radiotekhnika, n.º 205 (2 de julho de 2021): 118–28. http://dx.doi.org/10.30837/rt.2021.2.205.13.

Texto completo da fonte

Resumo:

Microwave and millimeter-wave antennas focused in their Fresnel zone, which are usually named as near-field focused (NFF) antennas, are becoming increasingly popular. Indeed, when compared to conventional far-field focused antennas, they can guarantee performance improvement at a relatively limited implementation cost, in short-range communication systems, wireless power transfer arrangements, remote nondestructive sensing setups, and radiofrequency identification apparatus, among many others. In this paper, analytical expressions are obtained for calculating the main parameters characterizing the longitudinal distribution of the circular focused aperture field intensity with a relatively large diameter (2R/λ≥10) : the displacement of the intensity maximum relative to the focal point, focusing gain and depth of focus. Cases of uniform and decreasing amplitude distributions of the excitation field are considered. The found approximate relations make it possible to determine the values of the above parameters for any values of the longitudinal coordinate of the focal point, lying both in the Fresnel zone and in the far zone. Comparison with numerical calculations showed that the error in the obtained parameter values does not exceed 5%. The results of this paper will be useful when calculating the field of antennas in the form of a circular focused aperture, as well as focused antenna arrays operating in the Fresnel zone.

Estilos ABNT, Harvard, Vancouver, APA, etc.

41

Vatutin, S. I. "Synchronous Addition of Antenna Signals with a Shift of Sampling Pulses in Idealized Mode of Spacecraft Tracking by Target Designations". Rocket-Space Device Engineering and Information Systems 7, n.º 4 (2020): 22–37. http://dx.doi.org/10.30894/issn2409-0239.2020.7.4.22.37.

Texto completo da fonte

Resumo:

The method of synchronous addition of signals of separate antennas was proposed previously for the aggregation of relatively small-scale aperture antennas into a single digital antenna array (digital antenna field) with a combined area for receiving telemetry signals from spacecraft. In this case, the antennas are mutually spaced by a big enough distance in order to not shade one another. The method is based on the idea of compensating the mutual delays between the antennas of the received signal by a corresponding shift of the sampling pulses of the signals of different antennas. This article demonstrates the method’s workability in idealized mode of spacecraft tracking by target designations on orbits of global navigation systems. It is shown that with the up-to-date level of impulse technology development the method of synchronous addition of antenna signals with a shift of sampling pulses is potentially capable of ensuring the reception of telemetry information from deep-space spacecraft at rates approximately 6 times higher than those of the classic Delta-DOR method.

Estilos ABNT, Harvard, Vancouver, APA, etc.

42

Vatutin, S. I., e P. A. Kozin. "Synchronous Addition of Antenna Field Signals with a Shift of Sampling Pulses during Spacecraft Tracking by Target Designations with Allowance for the Inertia of Antenna Motion". Rocket-space device engineering and information systems 8, n.º 4 (2021): 52–57. http://dx.doi.org/10.30894/issn2409-0239.2021.8.4.52.57.

Texto completo da fonte

Resumo:

The method of synchronous addition of signals of separate antennas was proposed previously for the aggregation of relatively small-scale aperture antennas into a single digital antenna array (digital antenna field) with a combined area for receiving telemetry signals from spacecraft when antennas are mutually spaced by a distance big enough for them not to shade one another. The method is based on the idea of compensating mutual delays between the antennas of the received signal by a corresponding shift of the sampling pulses of the signals of different antennas. The present paper demonstrates the efficacy of the method in the mode of spacecraft tracking by target designations in orbits of global navigation systems with allowance for the inertia of antenna motion. It is shown that in spacecraft tracking mode, which is close to the real one, this method gives a signal-to-noise ratio and bit-error probability closer to the theoretical limit than the values obtained for the idealized mode (analyzed earlier), which equates the angular coordinates and velocities of the antennas to the calculated angles and velocities of spacecraft in target designation nodes.

Estilos ABNT, Harvard, Vancouver, APA, etc.

43

Heo, Jin Myeong, Jongwon Yoon, Hyun Kim, Youngwan Kim e Gangil Byun. "A Cross-Correlation-Based Approach to Pattern Distortion and Mutual Coupling for Shared-Aperture Antennas". Applied Sciences 11, n.º 20 (15 de outubro de 2021): 9652. http://dx.doi.org/10.3390/app11209652.

Texto completo da fonte

Resumo:

This paper proposes a pattern distortion coefficient as a new figure of merit to quantitatively evaluate both mutual coupling and pattern distortions in multi-antenna systems. The proposed coefficient is defined as a cross correlation between unaffected and affected far-field patterns of antennas under test, and the input patterns are weighted using a Gaussian function to consider the target operation angle. The feasibility of the proposed approach is validated using a two-antenna system composed of an inverted-F antenna and a microstrip patch antenna, and the amount of mutual coupling is adjusted by changing the distance between the two antennas. The evaluation is further extended to a single-antenna system with a conducting wall that produces strong platform effects with serious pattern distortions. The results demonstrate that the proposed figure of merit provides quantitative insight into the amplitude and phase distortions of far-field patterns that can be caused by both mutual coupling and platform effects.

Estilos ABNT, Harvard, Vancouver, APA, etc.

44

Zhang, Yongwei, e Anthony K. Brown. "Design of wide-band dual–polarized aperture array antennas". International Journal of Microwave and Wireless Technologies 4, n.º 3 (3 de abril de 2012): 373–78. http://dx.doi.org/10.1017/s1759078712000256.

Texto completo da fonte

Resumo:

This paper describes the design of high-performance compact aperture array antennas for radio astronomy and other applications. Three recent antenna developments for square kilometer array design study (SKADS) have been investigated and the performances are compared. In addition to the radio frequency (RF) performance, an essential requirement for the square kilometer array application is the cost per square area. Based on initial large–scale finite array studies, prototypes with different geometries have been fabricated and measured. Guidelines are derived for large–scale wide–band dual-polarized array designs in applications where low cross-polarization and a wide range of scan angles are required.

Estilos ABNT, Harvard, Vancouver, APA, etc.

45

Kashyap, Neeru, Geetanjali ., Dhawan Singh e Neha Sharma. "Comprehensive Study of Microstrip Patch Antenna Using Different Feeding Techniques". ECS Transactions 107, n.º 1 (24 de abril de 2022): 9545–57. http://dx.doi.org/10.1149/10701.9545ecst.

Texto completo da fonte

Resumo:

For modern wireless communication systems, miniaturized multiband antennas with enhanced bandwidth and gain are desired to achieve optimum system performance. A planar microstrip patch antenna is preferred because of its small size, low cost, and ease of fabrication. For impedance matching, a conductive metallic patch can be fed by different techniques to deliver the maximum power to the microstrip antenna. The various configurations of inset feed, co-axial feed, aperture feed, and proximity feed, and CPW feed, which are used to excite micro-strip patch antennas, are reviewed in this research paper. Different feeding mechanisms are discussed to improve antenna performance in terms of S11 parameter, bandwidth, gain, and radiation pattern suitable for different wireless communication applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

46

García-Pino, Antonio. "An analytical simplified model to characterize focused aperture antennas". International Journal of Microwave and Wireless Technologies 8, n.º 1 (5 de setembro de 2014): 41–49. http://dx.doi.org/10.1017/s1759078714001196.

Texto completo da fonte

Resumo:

This paper presents an analytical model to characterize the radiation pattern of focused aperture antennas. The model is based on the classic parabolic on pedestal distribution for amplitude, but in this work the focusing phase term is considered and applied in the Fresnel region. The model is useful for millimeter and submillimeter wave imaging radar systems that usually work in the Fresnel region of the antenna. Analytical closed expressions are developed to predict the available resolution (transversal beamwidth) and operating range (axial beamwidth) of such systems. The effects of the first- and second-order phase distributions on the aperture have also been also studied in order to show the scanning effect, the axial refocusing, and the astigmatic beam degradation.

Estilos ABNT, Harvard, Vancouver, APA, etc.

47

Rusov, Yu S., e S. S. Krapivina. "Research of the Possibilities of Matching the Multi-element Receiving-Transmitting Irradiator Aperture". Radio Engineering, n.º 1 (30 de maio de 2021): 1–13. http://dx.doi.org/10.36027/rdeng.0121.0000168.

Texto completo da fonte

Resumo:

Currently, aperture antennas with spatial excitation, such as reflector antennas and phased array antennas, are widely used in radar. The composition of such an antenna includes an irradiator, which can be made in the form of a small-element array of radiators to form a set of necessary radiation patterns. Monopulse irradiators are often used, which form both total and difference directional patterns. When performing an irradiator based on waveguide parts, radiators in the form of horns or open ends of waveguides are installed in its aperture. Waveguide irradiators with four and twelve horns are widely used. One of the main electrical characteristics of such an irradiator when used as part of a receiving-transmitting antenna is the isolation of the transmitting and receiving paths. Matching the aperture of the transmitting and receiving irradiator has a significant effect on the isolation of its waveguide channels. With small transverse dimensions of the radiators in the form of open ends of waveguides, it is not possible to obtain high isolation of waveguide channels without the use of additional matching elements. The task of research the effect of matching the aperture of a waveguide multi-element irradiator on the isolation of its transmitting and receiving channels, as well as the ways of matching its radiators, is set.The article considers a four-horn irradiator, the aperture of which contains radiators in the form of open ends of a square waveguide. Each radiator has the radius rounding required for the manufacture of the product using the available technological processes. To match the emitter, a dielectric plate is installed inside it. During the research the thickness of the plate and its location relative to the aperture plane changed. The characteristics of matching the radiators with a plate made of teflon, polyethylene and ST-4 material based on polymers filled with titanium dioxide are presented.The proposed method of matching the opening of a multi-element irradiator with a transverse emitter size of 0,68λ (λ is the wavelength in free space corresponding to the average frequency of the operating band) makes it possible to improve the isolation of the receiving and transmitting waveguide channels by at least 4 dB in the frequency band of up to 3%.

Estilos ABNT, Harvard, Vancouver, APA, etc.

48

Comoretto, Gianni, Riccardo Chiello, Matt Roberts, Rob Halsall, Kristian Zarb Adami, Monica Alderighi, Amin Aminaei et al. "The Signal Processing Firmware for the Low Frequency Aperture Array". Journal of Astronomical Instrumentation 06, n.º 01 (março de 2017): 1641015. http://dx.doi.org/10.1142/s2251171716410154.

Texto completo da fonte

Resumo:

The signal processing firmware that has been developed for the Low Frequency Aperture Array component of the Square Kilometre Array (SKA) is described. The firmware is implemented on a dual FPGA board, that is capable of processing the streams from 16 dual polarization antennas. Data processing includes channelization of the sampled data for each antenna, correction for instrumental response and for geometric delays and formation of one or more beams by combining the aligned streams. The channelizer uses an oversampling polyphase filterbank architecture, allowing a frequency continuous processing of the input signal without discontinuities between spectral channels. Each board processes the streams from 16 antennas, as part of larger beamforming system, linked by standard Ethernet interconnections. These are envisaged to be 8192 of these signal processing platforms in the first phase of the SKA so particular attention has been devoted to ensure the design is low cost and low power.

Estilos ABNT, Harvard, Vancouver, APA, etc.

49

Indrianti, Rizka Kurnia. "Build a Rectangular Patch Single Microstrip Antenna with Aperture Coupled for Wifi Application 2.4 Ghz". JOURNAL OF INFORMATICS AND TELECOMMUNICATION ENGINEERING 3, n.º 1 (25 de julho de 2019): 8. http://dx.doi.org/10.31289/jite.v3i1.2464.

Texto completo da fonte

Resumo:

<p><span>Wifi technology is a means of obtaining information in a fast way, to strengthen the signal, for that it is required that the functioning antenna emit and receive electromagnetic waves in which contained the information signal. A wide range of antennas have been developed for a wide range of applications, one of which is a microstrip antenna. Microstrip antennas have small characteristics, are lightweight, thin, easy to fabricate, and can be used at very long distances. The results of single rectangular patch microstrip antenna measurements indicate that the antenna can work optimally with a frequency of 2,440 GHz, has a return loss-22,182 dB value, VSWR 1,169 value, 0.3452 dB bandwidth value, LOS-45.6 dBm power value with Percentage upload is 97% higher than the reference antenna and the download percentage is 88% higher than the reference antenna, NLOS-79 dBm value with a percentage upload of 33% compared to the reference antenna and the download percentage 12% higher than the Reference antenna, for the range of distances capable of receiving signals up to 120 meters with a percentage of percentage of is 16% higher than the reference antenna.</span></p>

Estilos ABNT, Harvard, Vancouver, APA, etc.

50

Meshcheriakov, Viktor V., Natalia V. Markova e Pavel D. Iurmanov. "Modeling and Practical Implementation of a Broadband Double-Ridged Horn Antenna with an Operating Range More Than an Octave and a High Level of Cross-Polarization Discrimination". Journal of the Russian Universities. Radioelectronics 22, n.º 5 (4 de dezembro de 2019): 42–51. http://dx.doi.org/10.32603/1993-8985-2019-22-5-42-51.

Texto completo da fonte

Resumo:

Introduction. The resolution of the problem of radio polarimetry in multiposition microwave screening systems (MMSS) with aperture synthesis requires the use of antennas with a high level of cross-polarization discrimination (XPD) in a wide spatial angle. The radio images are reconstructed in MMSS at distances commensurate with the aperture of the antenna structures. Therefore, the value of the spatial angle, at which high XPD is required, can reach 30°. This leads to a new problem of creating an antenna configuration of the X and Ku band, the application of which in MMSS will resolve the problem of constructing a radio image of depolarized microwave radiation scattered on the human body in the form of hidden dangerous objects.Aim. To develop a double-ridged receiving antenna for long-term operation in MMSS with an XPD level of 28 dB at a spatial angle of 30° and operating frequencies of 8…20 GHz.Materials and methods. The requirements for the receiving antenna in MMSS were determined. Theoretical justifications were proposed for the choice of antenna design. Aperture synthesis was used to construct microwave images in MMSS. The stages and results of modelling broadband double-ridge antennas were presented using the CST Studio software broadly applied for three-dimensional electro-magnetic field modelling. The results of modelling pyramidal and conical double-ridged antennas, as well as those in circular and elliptical waveguides, were analyzed. The designed antenna was tested in an anechoic chamber. The measurement results were compared with those obtained during simulation.Results. An elliptical double-ridged horn antenna with a VSWR of no more than 2 and cross-polarization discrimination in a spatial angle of 30° of no less than 28 dB for the frequency range that covers an octave was designed and constructed.Conclusion. The developed antenna can be used in MMSS for the purpose of detecting the effect of micro-wave radiation depolarization as hidden dangerous objects on a human body. Such characteristics of the antenna as its high XPD value in a wide spatial angle will allow the future introduction of microwave polarimetry in MMSS.

Estilos ABNT, Harvard, Vancouver, APA, etc.

Artigos de revistas sobre o tema "Aperture antennas"

Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos