Active Phased Array Antenna System Research Articles

A Study of Direction-of-Arrival Estimation with an Improved Monopulse Ratio Curve Using Beamforming for an Active Phased Array Antenna System

When constructing a wireless communication network, the line of sight of radio waves is limited by the terrain features in a ground communication network. Also, satellite communication networks face capacity limitations and are vulnerable to jamming. Aviation communication networks can solve the above-mentioned problems. To construct seamless aviation communication networks, fast counterpart location estimation and efficient beam steering performance are essential. Among various techniques used for searching the counterpart’s location, the monopulse technique has the advantage of quickly estimating the location through a simplified procedure. However, the nonlinear characteristics of the monopulse ratio curve, which are inevitably caused by the general antenna beam shape, both limit the location estimation range and reduce the estimated location accuracy. To overcome these limitations, a method that improves the estimation accuracy and extends the range by correcting the sum and difference patterns using the beamforming technique of active phased array antennas was proposed. An antenna system model suitable for aviation communication networks was presented, and the proposed model was experimentally proven to be effective. An average angle error of 0.021° was observed in the estimation of the accuracy of the antenna location.

무선통신링크용 다중빔수신 능동위상배열 안테나 시스템 개발

무선통신링크용 다중빔수신 능동위상배열 안테나 시스템 개발

A 39 GHz spatial division multiplex MU-MIMO using 256 element hybrid AAS for IAB application

AbstractThis paper describes the design and implementation of a 39 GHz 256-element hybrid active phased array antenna system with 16 individual digital transceivers, and its wireless multi-user, multi-input, multi-output verification. An earlier version of this paper was presented at the 2021 51st European Microwave Conference and was published in its Proceedings [1]. Using the prototype device, a single carrier transmission test assuming a mobile backhaul link and a MU-MIMO transmission test using a zero-forced orthogonal multi-beam based on channel reciprocity assuming an access link was performed. As a result, an EIRP of 43 dBm and a data rate of 5.5 Gbps in 1 GHz bandwidth single carrier 128QAM operation and an estimated total throughput of 2.4 Gbps by 3GPP TS38.214 [2] in 100 MHz bandwidth OFDM 8 MU-MIMO operation were achieved, respectively. As far as the author knows, this is the first demonstration for integrated access and backhaul (IAB) application that uses the 39 GHz band.

A 28 GHz 8 × 8 Gapwaveguide Phased Array Employing GaN Front-End With 60 dBm EIRP

A cost-efficient, high equivalent isotropic radiated power (60 dBm), large-bandwidth (26.5-29.5 GHz) active phased array antenna system has been designed and experimentally verified. The proposed design methodology results in a reduction of production costs by employing GaN-based radio frequency front-ends with 31 dBm output power allowing a reduced number of antenna elements. A fully metallic gapwaveguide technology has been employed achieving efficient heat dissipation per aperture area of the array as well as low-loss easy-to-manufacture antenna elements. The phased array is realized by subarraying an 8×8 slot array antenna with horizontal polarization. A ±60° analog beamforming in the E-plane is demonstrated. The presented antenna is a potential candidate for compact-size high-performance 5G base station antennas with excellent temperature stability.

Car Talk: Active Phased Array Antenna System Design for Vehicle-to-Everything Communication

Car Talk: Active Phased Array Antenna System Design for Vehicle-to-Everything Communication

Fast digital multi-beam search method for active phased array antenna system with full azimuth beam steering

This paper proposes a multi-beam search method based on an active phased array antenna system using digital beamforming. It includes initial beamforming, valid beam selection, and beam angle estimation using phase comparison mono pulses for multi-channel signals. To verify DoA estimation error, simulation and measurement are performed using the proposed antenna system. As a result, we confirm the performance of estimating each channel's angle and the beam directional error within 0.5°.

Design of the New MST Radar in Chinese Meridian Project

With the support of the second phase of the Chinese Meridian Project, a new mesosphere–stratosphere–troposphere observation radar (MST radar), called Qinzhou MST radar, located in Qinzhou City, Guangxi Province, China (22°7′55′′N,108°16′20′′E) is under construction. The Qinzhou MST radar is a large VHF monostatic pulse Doppler radar with an active phased array antenna system, mainly using Doppler beam swinging technique for observation. The capability of multibeam observation, space antenna observation, and frequency- and spatial-domain interferometry are also employed. The main scientific objective of this radar is to explore the atmosphere dynamical processes at low latitudes of China. The observation of ionospheric field-aligned irregularities (FAIs) is also an important function of the radar. The radar applies a circular array composed of 1261 3-element crossed Yagi antennas with a diameter of 153 m and an aperture of near 2×104 m2. Thereinto, 997 elements connect both transmitting and receiving channels and 264 elements distributed near the edge connect only receiving channels. The peak power of the transmitter in each transmitting/receiving (T/R) module is 2 kW. The central frequency and bandwidth of the output signal are 50 and 4 MHz, respectively. The peak power of the whole system will be close to 2 MW. This article presents the initial design of the Qinzhou MST radar, and the construction will be completed at the end of 2022.

능동위상배열안테나 시스템의 초기 빔 형성에 관한 연구

능동위상배열안테나 시스템의 초기 빔 형성에 관한 연구

Evaluation of EAR Spaced Antenna Performance Using Multiple Receiving Antennas Orientations

AbstractEquatorial Atmosphere Radar (EAR) is a very high frequency (VHF) Doppler radar with an active phased array antenna system operating at 47 MHz. It had originally been equipped with a single receiving channel system since its establishment in 2001 at the equator in Kototabang, West Sumatra, Indonesia (0.20°S, 100.32°E). Recent progress has enabled the implementation of a spaced antenna (SA) method on the EAR through the development of a multichannel receiver using Universal Software Radio Peripheral (USRP) and GNU Radio. However, this approach exhibits limited height observation and horizontal wind estimation accuracy. Here, we present comparison and analysis of EAR SA performance with five different orientations, taking into consideration the size of the receiving antennas and their separation distance. Experiments with the chosen configurations were carried out between April and September 2019, and the horizontal wind profiles were estimated using full correlation analysis (FCA) and compared with the EAR standard data. In addition, FCA with the least squares method is carried out for all configurations with the aim of improving the estimation accuracy. Based on the results, the configuration with the largest aperture shows a clear advantage over the other four configurations but with limited improvement in terms of maximum observable height.

Impedance-Dependent Wideband Digital Predistortion of Solid-State Radar Amplifiers

Spectral regrowth and waveform distortion caused by wideband signals input into active phased array antenna systems is the problem this paper addresses. The paper's unique contribution is the development of the impedance-dependent memory polynomial model, capable of solving nonlinear predistortion model parameters for a solid-state high power amplifier with varying load impedance resulting from active electronic beamsteering. Wideband load impedance mismatched tests demonstrate the effectiveness of this technique on a 2.7 GHz, 8 W amplifier.

기판집적 도파관(SIW)을 기반으로 하는 고효율 능동 위상 배열안테나

저손실, 전자기 완전차폐, 고전력 특성을 갖는 기판집적 도파관(SIW)을 이용하여 X-band <TEX>$8{\times}16$</TEX> 이중편파 능동 위상배열안테나 시스템을 구현하였다. 16-way SIW 전력분배 네트워크의 측정된 순수 삽입손실(0.65 dB)은 마이크로스트립 경우보다 1 dB 감소하였으며, SIW 부배열(<TEX>$1{\times}16$</TEX>) 안테나 소자의 측정된 방사효율(73 %)은 약 2배(3 dB) 향상되었다. 이러한 SIW를 이용한 분배손실과 방사효율의 상당한 개선은 능동 위상 배열안테나 시스템에서 고전력 증폭기의 최대출력(P1 dB)을 저감하고, 총 전력소모를 약 30 % 절감할 것이다. SIW 기반으로 제작된 X-band <TEX>$8{\times}16$</TEX> 이중편파 능동 위상 배열안테나 시스템을 이론적인 제어벡터만을 생성하여 0도, 5도, 9도, 18도의 정밀한(최대편차 2도) 빔 조향을 측정하였으며, 열주기/진공 시험에서 우주환경 적합성을 확인하였다. 고효율 SIW 배열안테나 시스템은 고성능 레이더는 물론 차세대 무선통신(5G)을 위한 Massive MIMO와 다양한 밀리미터파 통신시스템(60 GHz WPAN, 77 GHz 자동차 레이더, 초고속 디지털 전송시스템 등)에 매우 유용할 것으로 기대한다. An X-band <TEX>$8{\times}16$</TEX> dual-polarized active phased array antenna system has been implemented based on the substrate integrated waveguide(SIW) technology having low propagation loss, complete EM shielding, and high power handling characteristics. Compared with the microstrip case, 1 dB less is the measured insertion loss(0.65 dB) of the 16-way SIW power distribution network and doubled(3 dB improved) is the measured radiation efficiency(73 %) of the SIW sub-array(<TEX>$1{\times}16$</TEX>) antenna element. These significant improvements of the power division loss and the radiation efficiency using the SIW, save more than 30 % of the total power consumption, in the active phased array antenna systems, through substantial reduction of the maximum output power(P1 dB) of the high power amplifiers. Using the X-band <TEX>$8{\times}16$</TEX> dual-polarized active phased array antenna system fabricated by the SIW technology, the main radiation beam has been steered by 0, 5, 9, and 18 degrees in the accuracy of 2 degree maximum deviation by simply generating the theoretical control vectors. Performing thermal cycle and vacuum tests, we have found that the SIW array antenna system be eligible for the space environment qualification. We expect that the high efficiency SIW array antenna system be very effective for high performance radar systems, massive MIMO for 5G mobile systems, and various millimeter-wave systems(60 GHz WPAN, 77 GHz automotive radars, high speed digital transmission systems).

A Compact Active Channel Module Design for Active Phased Array Antenna System

This paper introduces the T/RX combined compact active channel module which is a key unit of the active phased array antenna(APAA) system. This module is mainly compoased of two parts for TX and RX fabricated on both sides of the active module for size reduction. The TX-part is primarily composed of a 3-stage amplifier, a microstrip phase shifter, a thermal compensation and a power detection circuit. The RX-part is composed of LNAs a microstrip phase shifter and BPFs for TX power rejection. Using the proposed design structure we can realized a compact active channel module having high performance.

A C - Ku-Band RF Module Transmitter Including an RF Signal Generator for a Flexible Phased-Array System

This paper presents a new concept of an active phased array antenna (APAA) system with RF modules, including an RF signal generator. The proposed APAA realizes multi-frequency and multi-modulation beam forming simultaneously by generating an RF signal independently in each module and sharing them among the antenna arrays. This configuration is effective in a distributed array radar system because the interconnect equipments of modules can be simplified by not transmitting an RF signal on the cables. Moreover, the proposed APAA can compensate the performance variation between output signals of RF modules. These features contribute a flexible and precise APAA operation. Key features of the proposed APAA are verified by measurements. A transmitter block of the RF module with three silicon-germanium integrated circuits is fabricated to validate the proposed functions and performances. The fabricated RF module generates the various modulated signals of 1 Gs/s and operates in C- Ku-bands. It is achieved that the measurement accuracy of timing error, phase error, and amplitude error of RF output signals are 56 ps · rms, 0.6° · rms, and 0.6 dB · rms, respectively.

평면형 능동 위상 배열 레이더용 안테나 시스템 개발

본 논문에서는 레이더용 평면형 능동 위상 배열 안테나 시스템의 설계 및 제작 그리고 측정 결과를 소개한다. 설계된 안테나는 X-대역에서 대역폭 10 %를 만족하며, 이중 슬롯 급전 마이크로스트립 패치 안테나와 편파 스위치의 사용으로 이중 편파 사용이 가능하다. 배열 구조는 <TEX>$16\times16$</TEX>의 삼각 배열 구조이고, 각 배열은 출력 40 dBm 이상의 TR(Transmit & Receive) 모듈로 구성된다. TR 모듈은 디지털 감쇄기와 위상 변위 기를 포함하고 있어서 임의의 빔 형성/빔 조향을 할 수 있으며, 전자적 빔 조향 범위는 방위각/고각 방향으로 각각 <TEX>${\pm}60^{\circ}$</TEX> 범위에서 가능하다. 또한 수신 구조는 부배열로 구성하여 수신 패턴은 각 채널로부터의 RF 빔 합성으로 얻어진다. 안테나의 성능 검증을 위해서 근접 전계 측정 시설에서 안테나 패턴을 측정하였으며, 패턴 측정 결과는 예측된 빔 패턴과 거의 일치하였고, 이로부터 제어에 의한 빔 조향/빔 형성이 가능함을 확인할 수 있었다. The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is <TEX>$16\times16$</TEX> triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle<TEX>$({\pm}60^{\circ})$</TEX>. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

Active Stabilization of Vehicle-Mounted Phased-Array Antennas

In this paper, a novel hybrid tracking method for mobile active phased-array antenna systems is developed. The proposed technique consists of a mechanical stabilization loop and a direction-of-arrival (DOA) estimation algorithm, which is based on electronic beamforming. Compared with other tracking methods, the proposed method requires only one low-cost yaw rate sensor. The method utilizes electronic feedback from the phased-array antenna to compensate for the low-cost sensor irregularities. The effectiveness of the proposed tracking method is demonstrated by measured performance of a fast-moving ultra-low-profile phased-array satellite terminal, which uses the proposed approach. The field test results confirm that the hybrid tracking mechanism can nullify the base vehicle yaw disturbances up to 60deg/s and 85deg/s2 and keep the azimuth angle error at less than the permissible bound of [-1deg, +1deg]. Although performance of the proposed tracking system is verified in the context of a mobile satellite television reception system, the basic principles can be applied to any tracking system that employs phased-array antennas. The mobile satellite Internet terminal is an important example.

At the core of complex microwave system design

Powerful 3-D electromagnetic field solvers have long been used by engineers to design complex microwave components. In this article, we explored the powerful capabilities and comprehensive analyses that can be performed when electromagnetic field simulation is tightly and bi-directionally coupled to nonlinear circuit analysis. Simulations of an active phased-array antenna system were performed using coupled harmonic balance and finite element simulation. The effect of the nonlinearities of the transmit power amplifiers was observed to degrade the far-field radiation pattern as the input power was increased.

Equatorial Atmosphere Radar (EAR): System description and first results

A VHF Doppler radar with an active phased‐array antenna system, called the Equatorial Atmosphere Radar (EAR), was established recently at the equator near Bukittinggi, West Sumatra, Indonesia (0.20°S, 100.32°E, 865 m above sea level). The EAR is a large monostatic radar which operates at 47.0 MHz with peak output power of 100 kW. The EAR uses a circular antenna array, approximately 110 m in diameter, which consists of 560 three‐element Yagi antennas. Each antenna is driven by a solid‐state transmitter‐receiver module. This system configuration allows the antenna beam to be steered electronically up to 5,000 times per second. The scientific objective of the EAR is to advance knowledge of dynamical and electrodynamical coupling processes in the equatorial atmosphere from the near‐surface region to the upper atmosphere. The equatorial atmosphere over Indonesia is considered to play an important role in global change of the Earth's atmosphere. This paper presents the system description of the EAR, including observational results of the equatorial atmosphere made for the first time with altitude resolution of 75–150 m.

Active acoustic phased array antenna system

A hyper-sound detection and ranging system for remote wind measurements that provides all three orthogonal components of a three dimensional wind field on a single transmission pulse utilizing simultaneous beams of acoustic waves. The present invention measures atmospheric wind by transmitting a broad beam acoustic pulse to illuminate a zone of the atmosphere, and then measuring the Doppler shifts in the backscatter signals arrived at the system from various directions along the broad beam projection utilizing simultaneous receiving beams of narrow beamwidth. The simultaneous receiving beams are obtained by means of a hybrid of analog and digital beamforming technologies that enables simultaneous formation of a programmable number of beams in any direction within the designed fields-of-view.

Carrier power to intermodulation-distortion power-ratio-increasing technique in active phased-array antenna systems

This paper describes a novel technique to compensate for the intermodulation (IM) distortion components of high-power amplifiers in an active phased-array antenna system. This technique uses IM phase control to break the strong association between carriers and IM components, and can make the radiation patterns of carriers and IM components different on active phased-array antenna systems. As a result, carrier power to IM power ratio (CAM) is increased in the carrier-beam direction. A newly developed IM controller can increase the C/IM of near-saturated solid-state power amplifiers and, therefore, achieve high power efficiency. This paper shows experimental results confirming this technique using a six-element linear array.