scholarly journals Vivaldi Antenna Arrays Feed by Frequency-Independent Phase Shifter for High Directivity and Gain Used in Microwave Sensing and Communication Applications

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6091
Author(s):  
Jiwan Ghimire ◽  
Feyisa Debo Diba ◽  
Ji-Hoon Kim ◽  
Dong-You Choi
Keyword(s):  
Antenna Arrays ◽  
Phase Shifter ◽  
Antenna System ◽  
Phase Shifters ◽  
Ultra Wideband ◽  
Feed System ◽  
Power Splitter ◽  
Frequency Independent ◽  
Vivaldi Antenna ◽  
The Right

This paper describes a novel feed system for compact, wideband, high gain six-slot Vivaldi antenna arrays on a single substrate layer using a unique combination of power splitters based on binary T-junction power splitter topology, frequency-independent phase shifter, and a T-branch. The proposed antenna system consists of six Vivaldi antennas, three on the left, and three on the right arm. Each arm connects with T-junction power divider splitter topology, given that the right arm is linked through a frequency-independent phase shifter. Phase shifters ensure that the beam is symmetrical without splitting in a radiating plane so that highly directive radiation patterns occur. The optimal return losses (S-parameters) are well enriched by reforming Vivaldi’s feeding arms and optimizing Vivaldi slots and feeds. A novel feature of our design is that the antenna exhibits the arrangements of a T-junction power splitter with an out-of-phase feeding mechanism in one of the arms, followed by a T-branching feeding to even arrays of proper Vivaldi antenna arrangement contributing high realized gain and front-to-back ratio up to 14.12 dBi and 23.23 dB respectively applicable for not only ultra-wideband (UWB) application, also for sensing and position detecting. The high directivity over the entire UWB frequency band in both higher and lower frequency ranges ensures that the antenna can be used in microwave through-wall imaging along with resolution imaging for ground penetration radar (GPR) applications. The fabricated antenna parameters are in close agreement with the simulated and measured results and are deployed for the detection of targets inside the voids of the concrete brick.

scholarly journals 3D Metallic Plate Lens Antenna based Beamspace Channel Estimation Technique for 5G Mmwave Massive MIMO Systems

2021 ◽  
Vol 13 (1) ◽  
pp. 1-16
Author(s):  
Prosenjit Paul ◽  
Md Munjure Mowla
Keyword(s):  
Channel Estimation ◽  
Massive Mimo ◽  
Phase Shifter ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Antenna System ◽  
Phase Shifters ◽  
Lower Amount ◽  
Metallic Plate ◽  
Lens Antenna

Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of information from mobile devices. However, this estimation is required to ensure the perfect channel state information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase shifter (PS) components used in this estimation need high power to select the beam in the desired direction. To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD) based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate and a switch in our model which compensates the limitation of phase shifters. Simulation results show that the proposed RSSD based channel estimation surpasses traditional technique and SD based channel estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive MIMO systems.

scholarly journals Potential of Liquid-Crystal Materials for Millimeter-Wave Application

2018 ◽  
Vol 8 (12) ◽  
pp. 2544 ◽  
Author(s):  
Toshiaki Nose ◽  
Ryota Ito ◽  
Michinori Honma
Keyword(s):  
Liquid Crystal ◽  
Millimeter Wave ◽  
Microstrip Line ◽  
Phase Shifter ◽  
Substrate Surface ◽  
Antenna System ◽  
Phase Shifters ◽  
Phased Array Antenna ◽  
Electric Circuits ◽  
Line Type

In this study, we reviewed three topics regarding the application of liquid-crystal (LC) materials to millimeter-wave (MMW) devices. It is essential to develop useful measurement methods for refractive indices of LC materials in the MMW region. Herein, a novel measurement method using optical short is demonstrated using a Si semiconductor substrate. There are two approaches to develop MMW LC devices. One is the quasi-optical approach, which involves scaling up the optical components, and the other approach involves integrating the LC materials into high-frequency electric circuits. A three-dimensional (3D) printer is used to fabricate the Fresnel lens, which is a typical quasi-optical device useful in the MMW region, where we can develop the tunable lens by introducing LC materials. A planar-type MMW waveguide is advantageous for integrating the LC materials to develop LC MMW devices using the second approach. We investigated a useful microstrip-line-type LC phase shifter by developing a novel conversion circuit to introduce the LC material onto the dielectric substrate surface. A phase shifter is an important MMW component that is used to attain a phased array antenna system, and a minimal twin antenna array is demonstrated using the microstrip-line-type LC phase shifters.

scholarly journals Mathematical description of imaging processes in ultra-wideband active aperture synthesis systems using stochastic sounding signals

2021 ◽  
pp. 166-182
Author(s):  
Valeriy Volosyuk ◽  
Simeon Zhyla ◽  
Volodimir Pavlikov ◽  
Eduard Tserne ◽  
Anton Sobkolov ◽  
...  
Keyword(s):  
Spectral Density ◽  
Antenna Arrays ◽  
Mathematical Description ◽  
Phase Distribution ◽  
Coherence Function ◽  
Antenna System ◽  
Aperture Synthesis ◽  
Ultra Wideband ◽  
Radio Image ◽  
Wideband Signals

Mathematical models of the fields of stochastic ultra-wideband signals that are necessary for solving problems of aperture synthesis of images using active radar methods are presented. The expediency of using V-transformations in these problems has been substantiated, the effectiveness of which has already been proven for the mathematical description of ultra-wideband spatio-temporal fields in the methods of passive and active radar, as well as remote sensing, that are used to solve problems of radio astronomy, medicine, navigation. Using modern methods of mathematical analysis and the theory of ultra-wideband systems, the physical essence of radio images obtained with the help of algorithms for coherent and incoherent signal processing is investigated. According to these algorithms, it is proposed to divide images into coherent and incoherent. Coherent images include those in which its amplitude and phase are recorded separately. In the case of an incoherent image, only its amplitude (power or related characteristic) is recorded. To describe of the obtained radio image structure, new concepts of the spectral density of the complex spatial coherence function (SDCSCF) and the spectral density of the spatial autocorrelation function of the amplitude-phase distribution (SDFSAF APD) are introduced. Application-use of functions is expedient and fundamentally necessary for solving problems of aperture synthesis using stochastic ultra-wideband signals. A mathematical description of the structures obtained by aperture synthesis of radio images is given. Here, studies are conducted for the general case of using a continuous (idealized) aperture, and for using an antenna system with spatially separated receiving elements. Simulation of the heuristic synthesized algorithm for constructing incoherent radio images is conducted. The possibility of using antenna arrays and synthesized aperture synthesis algorithms for solving problems of image formation in a survey located directly under the aircraft (at sounding angles close to vertical) are substantiated.

scholarly journals Verification of Phase Shifter Measurements of a Reflective Array Antenna

2021 ◽  
Vol 24 (2) ◽  
pp. 18-26
Author(s):  
M. D. Parnes
Keyword(s):  
Measurement Error ◽  
Radiation Pattern ◽  
Antenna Arrays ◽  
Measurement Errors ◽  
Phase Shifter ◽  
Error Function ◽  
Phase Error ◽  
Optical Excitation ◽  
Phase Shifters ◽  
Reference Plane

Introduction.  Large-size phased antenna arrays (PAA) frequently incorporate optical excitation schemes, whose main elements include the feed and the reflective aperture. In turn, the reflective aperture consists of several tens of thousands of radiators and phase shifters. Major distortions of the radiation pattern in reflective arrays occur due to phase errors, leading to a decrease in the gain and an increase in the side lobes of the radiation pattern. In the millimeter wavelength range, ferrite phase shifters can have an initial phase from 0 to 360 °, thus requiring measurements of the array elements following their assembly.Aim.  To develop a method for evaluating errors in measurements of the parameters of phase shifters incorporated in an antenna array by comparing theoretical and experimental data.Materials and methods.  A convenient method for determining the parameters of phase shifters is probing, in which a movable probe is connected in series with each array element. In cases where a PAA element represents a single structure consisting of a ferrite segment and a dielectric radiator, measurements are carried out using a probe in the form of a segment of a round waveguide moving towards the radiator. In order to evaluate the measurement error of such a scheme, a mechanically controlled reference phase shifter was used.Results. Measurement errors for the probe structure used were calculated based on the assumption of the phase error arising from the vector addition of the controlled and uncontrolled reflected signals at the input of the PAA element, in the section of the reference plane at the input of the probe. In addition, the S-parameters of the superposition section were calculated. The extrema of the error function were used to determine the maximum errors in measuring the phase and amplitude.Conclusion. The performed analysis confirmed the validity of the proposed method for measuring the parameters of phase shifters using a waveguide probe. The measurement error of the PAA elements according to the proposed scheme was found to be about 3 o, which is commensurate with that of recording devices.

High selectivity wideband 180° phase shifters with the functionality of vertical transition

2020 ◽  
pp. 1-7
Author(s):  
Yu Zhu ◽  
Kaijun Song ◽  
Yong Fan
Keyword(s):  
Design Theory ◽  
Phase Shifter ◽  
High Selectivity ◽  
Phase Shifters ◽  
Ground Layer ◽  
Equivalent Circuits ◽  
Transmission Zeros ◽  
Vertical Transition ◽  
Frequency Independent

Abstract In this paper, a high selectivity wideband 180° phase shifter (PS) with the functionality of vertical transition is presented. The whole circuit is realized based on the hybrid microstrip/slotline (SL) structure. By introducing the short-circuited microstrip stepped-impedance resonators, two transmission zeros are created to improve the selectivity of the PS. With the SL in the center ground layer, a frequency independent 180° PS can be obtained. The even/odd-mode equivalent circuits of the proposed PS are analyzed to guide the design. Finally, a practical wideband 180° PS with high filtering selectivity is designed and fabricated to verify the design theory.

ULTRA WIDEBAND RADIATOR WITH A STABLE PHASE CENTER FOR A REFLECTOR ANTENNA

2020 ◽  
Author(s):  
Д.В. БОСОМЫКИН ◽  
А.П. ВОРОНЦОВ ◽  
И.В. ПРИЩЕПА ◽  
А.А. ГАВРИЛОВ ◽  
А.В. ПРОРЕШКИН ◽  
...  
Keyword(s):  
Frequency Ratio ◽  
Reflector Antenna ◽  
Antenna System ◽  
Ultra Wideband ◽  
Stable Phase ◽  
Orthogonal Polarization ◽  
Phase Center ◽  
Directional Characteristics ◽  
Hybrid Coupler ◽  
Vivaldi Antenna

Предложен широкополосный излучатель со стабильным фазовым центром (ФЦ) для использования в составе облучателя зеркальной антенны. Излу ортогональных поляризациях и круговой поляризации при использовании квадратурного питания. Рабочая полоса по уровню КстU ≤ 2 обеспечивается при коэффициенте перекрытия по частоте более 1:16. Исследованы характеристики направленности облучателя зеркальной антенны на базе антенны типа Вивальди, представлены результаты расчетов и измерений его параметров. Обоснована пригодность для использования в составе облучателя сверхширокополосной зеркальной антенной системы в режиме суммарного и разностного формирования диаграммы направленности (ДН). It is presented the wideband irradiator with a stable phase center for use in a reflector antenna irradiator. The irradiator is based on a smoothly expanding slot. It has two coaxial feeds to form dual linear orthogonal polarization. Circular polarization radiation can be achieved with an additional hybrid coupler. The VSWR≤2 bandwidth is obtained for a frequency ratio of more than 1:16. The directional characteristics of the irradiator of a reflector antenna based on a Vivaldi antenna are investigated, the results of calculations and measurements of its parameters are presented. The suitability of the irradiator for use as a part of the irradiator of the ultra-wideband reflector antenna system is justified.

Use of graphics processors to cardinally acceleration the calculation procedure of large subaperture active phased antenna arrays radiation pattern

2021 ◽  
Author(s):  
A.S. Petrov ◽  
V.A. Chikov
Keyword(s):  
Statistical Analysis ◽  
Real Time ◽  
Radiation Pattern ◽  
Antenna Arrays ◽  
High Performance ◽  
Phase Shifter ◽  
Phase Distribution ◽  
Phase Shifters ◽  
Triangular Grid ◽  
Graphics Processors

For traditional APAA with a rectangular and triangular grid of nodes, in which partial emitters are installed, simple analytical formulas are known that express the dependence of the array radiation pattern (ARP) on the angular coordinates. If the grid of nodes is irregular, or in a regular grid there are failures of individual digits in the control elements (phase shifters, attenuators, delay lines) or in power amplifiers, then these formulas are not applicable. Therefore, it is necessary to address to general relations of additive summation of the specific contribution to the ARP of the field generated by each emitter separately. In large arrays, their number can range from several to many tens or even hundreds of thousands. Further, if it is necessary to synthesize a given type of array RP, it is necessary to form special types of the amplitude-phase distribution of the signal on the emitters. The procedures for synthesizing such distributions require hundreds or even thousands of repeated calculations of the array RP, which may require several million angular points to analyze in the upper hemisphere of radiation. The article shows that using parallel computing with the help of programming technology on graphics processors (GPU), produced by NVIDIA and CUDA technology in a system designed to quickly create high-performance codes in the extended C language, C++ is able to speed up the calculations of the large antenna ARP by 2…3 orders of magnitude, even on standard office computers. When using modern CPUs (AMD Ryzen Threadripper PRO 3995 WX) and GPU (NVIDIA GeForce 3090), the acceleration in calculations can additionally increase by hundreds of times. At such computing speeds, even the problems of antenna synthesis and statistical analysis of the characteristics of the array RP will be solved almost in real time. An example of a statistical estimation of the ARP parameters of a large subaperture array with 1280 emitters, used in the COSMOSkyMed system, when random failures of the inverse type occur in the phase shifter digits. The use of graphics processors allows us to solve problems such as the synthesis of an array RP having a prescribed shape, and the statistical analysis of the characteristics of the array in the event of various failure options in its elements, as well as mechanical distortions of the aperture shape, in almost real time.

scholarly journals ANALOG PHASE SHIFTERS OF THE DECIMETER RANGE FOR INCREASED POWER LEVEL

2020 ◽  
Vol 8 (2) ◽  
pp. 89-93
Author(s):  
Konstantin Ya. Aubakirov ◽  
Alexander V. Makeev
Keyword(s):  
Phase Shifter ◽  
Bandpass Filter ◽  
Power Level ◽  
Control Device ◽  
Phase Shifters ◽  
High Frequency Power ◽  
Relative Bandwidth ◽  
Frequency Independent ◽  
Decimeter Range ◽  
Frequency Power

The results of designing a phase control device in the decimeter wavelength range in the form of a tunable bandpass filter are presented. Tuning such a filter by 1/2 of the relative bandwidth, not exceeding 40 - 50%, provides a frequency-independent controlled phase shift. The minimization of parasitic amplitude modulation, along with an increase in the high-frequency power transmitted by the phase shifter, is achieved by optimizing the switching factor of the varicap into the quasi-polynomial bandpass filter circuit.

scholarly journals Antipodal Vivaldi Antenna Arrays Fed by Substrate Integrated Waveguide Right-Angled Power Dividers

2018 ◽  
Vol 8 (12) ◽  
pp. 2625 ◽  
Author(s):  
Sara Salem Hesari ◽  
Jens Bornemann
Keyword(s):  
Antenna Arrays ◽  
Phase Distribution ◽  
Single Layer ◽  
Substrate Integrated Waveguide ◽  
Feed System ◽  
Waveguide Section ◽  
Power Dividers ◽  
Operating Bandwidth ◽  
Vivaldi Antenna ◽  
Better Than

This paper describes a novel feed system for compact antipodal Vivaldi antenna arrays on a single layer of substrate integrated waveguide (SIW) by using SIW H-plane right-angled power dividers. The proposed antenna systems are composed of a Vivaldi array and an H-plane right-angled corner power divider which includes an over-moded waveguide section. Based on the number of antennas in the Vivaldi array, mode converter sections at K-band and Ka-band frequencies are designed, fabricated, and measured when feeding Vivaldi antenna arrays with two, three, and four antennas. Right-angled SIW power dividers are employed to obtain controllable phase distribution over the output ports which consequently controls the beam shapes of the systems. The phase relationships in the output ports are varied to obtain different pattern directions for different applications. The two-way divider system with 180-degree phase difference and three-way divider system are fabricated and measured; simulation results are presented for other designs. The measured results are in good agreement with simulations which confirms the design approach. All systems achieve good performance and meet all design goals including a return loss better than 10 dB in the operating bandwidth, gain higher than 8 dB for all systems, and radiation and polarization efficiencies higher than 80% and 98%, respectively.

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