• Title/Summary/Keyword: Array Antenna Calibration

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Performance Analysis of Smart Antenna Base Station Implemented for CDMA2000 1X (CDMA2000 1X용으로 구현된 스마트 안테나 기지국 시스템의 성능분석)

  • 김성도;이원철;최승원
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.9A
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    • pp.694-701
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    • 2003
  • In this paper, we present a hardware structure and new features of a smart antenna BTS (Base Transceiver Station) for CDMA2000 1X system. The proposed smart antenna BTS is a composite system consisting of many subsystems, i.e., array antenna element, frequency up/down converters, AD (Analog-to-Digital) and DA (Digital-to-Analog) converters, spreading/despreading units, convolutional encoder/Viterbi decoder, searcher, tracker, beamformer, calibration unit etc. Through the experimental tests, we found that the desired beam-pattern in both uplink and downlink communications is provided through the calibration procedure. Also it has been confirmed that the adaptive beamforming algorithm adopted to our smart antenna BTS is fast and accurate enough to support 4 fingers to each user. In our experiments, commercial mobile terminals operating PCS (Personal Communication System) band have been used. It has been confirmed that the smart antenna BTS tremendously improves the FER (Frame Error Rate) performance compared to the conventional 2-antenna diversity system.

Calibration Method of Channels' Initial Phase Shift in Active Phased Array Antenna (능동 위상배열 안테나 채널의 초기위상 천이 보정 방법)

  • Mun, Yeong-Chan;Park, Chan-Gu;Pyo, Cheol-Sik;Jeon, Sun-Ik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.7
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    • pp.18-23
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    • 2000
  • An active phased away antenna consists of many channels including radiator and active circuitary that contains low noise amplifiers and phase shifters. Each channel has different initial phase shift and gain because of inequality in active circuitary itself, interface between radiator and active circuitary, beam forming network and other antenna configurations. This is an inherent problem in active phased away antenna, therefore each channels' initial phase shifts and gains should be calibrated for obtaining the designed radiation pattern and antenna gain. In this paper, an efficient calibration method for the active phased array antenna is presented. By performing the above method, thhe antenna gain is increased more than 2.0 dB after calibrating considerably unequal 12 channels' initial phase shifts and gains.

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Study on TRX Channel Amplitude and Phase Calibration Method for a Radar Wind Profiler Based on 256 Active Phased Array (256 능동위상배열 기반 연직바람 관측장비의 송수신 채널 크기 및 위상 보정 방법 연구)

  • Jung, Woo-Jae;Lee, Jong-Chul
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.21 no.5
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    • pp.162-170
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    • 2022
  • In this paper, the phased-array transceiver (TRX) channel amplitude and phase calibration method for a radar wind profiler (RWP) based on the 256 active phased array is discussed. Without the additional module, the TX and RX calibration paths were secured using couplers and switches in the TRX front ends and the TRX switching duplexers, and the amplitude and phase of the 256 TRX were calibrated using a gain and phase detector. The beam widths and side lobes of five beams (vertical, east, west, south, and north) of the calibrated 256 active phased array antenna were confirmed by a near-field which agreed well with the simulation results. The proposed calibration method can be easily applied to a system based on an active phased array operated in an outdoor environment.

A Calibration Technique for Array antenna based GPS Receivers (배열 안테나 기반 GPS 수신기에서의 교정 방안)

  • Kil, Haeng-bok;Joo, Hyun;Lee, Chulho;Jeong, Eui-Rim
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.4
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    • pp.683-690
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    • 2018
  • In this paper, a new signal processing technique is proposed for calibrating gain, phase, delay offsets in array antenna based anti-jamming minimum variance distortionless response (MVDR) global-positioning-system (GPS) receivers. The proposed technique estimates gain, phase and delay offsets across the antennas, and compensates for the offsets based on the estimates. A pilot signal with good correlation characteristics is used for accurate estimation of the gain, phase and delay offsets. Based on the cross-correlation, the delay offset is first estimated and then gain/phase offsets are estimated. For fine delay offset estimation and compensation, an interpolation technique is used, and specifically, the discrete Fourier transform (DFT) is employed for the interpolation technique to reduce the computational complexity. The proposed technique is verified through computer simulation using MATLAB. According to the simulation results, the proposed technique can reduce the gain, phaes and delay offset to 0.01 dB, 0.05 degree, and 0.5 ns, respectively.

A Survey of Essential Considerations in the Desist of Downlink Beamforming of Smart Antenna System (순방향 빔형성 스마트 안테나 시스템 설계의 필수 고려 사항에 대한 연구)

  • 이원철;최승원
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.6
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    • pp.627-633
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    • 2004
  • Downlink beamforming is very important in recent mobile communications which requires wireless internet, VOD(Video-On-Demand), multimedia services. This paper addresses and analyzes the essential considerations fur downlink beamforming of smart antenna system to provide wanted characteristics. Major considerations in this paper are HPA power allocation for downlink beamforming, received power at mobile terminal, concept and performance of auxiliary pilot channel, importance and moth of array calibration, and throughput comparison of downlink and uplink. All above mentioned items are investigated in this paper.

An Iterative MUSIC-Based DOA Estimation System Using Antenna Direction Control for GNSS Interference

  • Seo, Seungwoo;Park, Youngbum;Song, Kiwon
    • Journal of Positioning, Navigation, and Timing
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    • v.9 no.4
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    • pp.367-378
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    • 2020
  • This paper introduces the development of the iterative multiple signal classification (MUSIC)-based direction-of-arrival (DOA) estimation system using a rotator that can control the direction of antenna for the global navigation satellite system (GNSS) interference. The system calculates the spatial spectrum according to the noise eigenvector of all dimensions to measure the number of signals (NOS). Also, to detect the false peak, the system adjusts the array antenna's direction and checks the change's peak angles. The phase delay and gain correction values for system calibration are calculated in consideration of the chamber's structure and the characteristics of radio waves. The developed system estimated DOAs of interferences located about 1km away. The field test results show that the developed system can estimate the DOA without NOS information and detect the false peak even though the inter-element spacing is longer than the half-wavelength of the interference.

On the Control of Initial Phases in Optical Phased Array Based LADAR Systems: Hill-Climbing Based Approach (광위상배열 기반 LADAR의 초기 위상 제어 기법 연구: 언덕 오름 기반 접근법)

  • Kim, Taehoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.4
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    • pp.467-474
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    • 2019
  • Recently, optical phased array(OPA) based laser detection and ranging(LADAR) has gained great interest to replace the traditional mechanical light detection and ranging technique(LiDAR). In OPA-based LADAR, it is well known that phases of laser pulses traveling through each of channels should be the same to obtain a narrow free-space single beam without noise-like ripples in the far field. However, it is difficult to provide such ideal condition due to the fabrication errors. To tackle this problem, any algorithms should be necessary to compensate the initial random phases of each channel in OPA antenna. In this paper, we propose a hill-climbing based phase calibration algorithm and evaluate the performance of the proposed algorithm.

Design of Sub-array Receiver for Active Phase Array Radar (능동위상배열 레이더 부배열 수신기 설계)

  • Yi, Hui-min;Kim, Do-hoon;Han, Il-tak
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.5
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    • pp.568-573
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    • 2019
  • Modern Radars are evolving into MFRs which can search multiple targets simultaneously and then track them. Additionally they should be able to avoid some external jamming signals. Applying to these MFRs, Antennas should be able to perform DBF including to not only real-time beam steering but also multi-beam forming simultaneously. And they can cancel the beam at the specific direction. In this paper, we describe the implementation of sub-array type antenna hardware which can be applying DBF. Also we propose the modified amplitude aperture distribution for suppressing the side lobe level and explain the sub-array receiver design with amplitude tapering. It consists in making the amplitude weighting in 2 steps. In order to compare two weighting cases, we investigate the G/T performance for the array antenna. At the conclusion, we make a comparative study for the dynamic range of every sub-array receiver and present the hardware implementation that is more advantageous for sub-array alignment and calibration in DBF.

Near-Field Rx-Measurement for Active Phased Array of Digital Radar Using Calibration Path (보정 경로를 활용한 디지털 레이더의 능동 위상 배열 근접전계 수신시험)

  • Yu, Je-Woo;Chae, Heeduck;Park, Jongkuk;Lim, Jae-Hwan;Kim, Duckhwan;Jin, Hyoung-Seog;Kim, Han-Saeng
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.6
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    • pp.504-511
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    • 2016
  • In this paper, the method is proposed that the equivalent result can be obtained by compensating the variation of gain and phase in the comparison with the result of near-field measurement which is obtained in the steady state, although the gain and phase variation of rx-channels occurred in the near-field rx-measurement of digital active phased array antenna. The proposed concept has the time section for monitoring the state of the rx-channels through the calibration path in the measurement timeline, and is the method for compensating the variation of state. For validating the proposed method, the fabricated X-band digital active phased array antenna and the planar near-field measurement facility is utilized. The proposed method is validated in the comparison with the compensated pattern which the unstable state of rx-channels is calibrated and the reference pattern obtained under the steady state of the rx-channels.

Analysis of the Required Limit on APAA Aperture using Statistical Simulation for HAPS

  • Ku, Bon-Jun;Park, Jong-Min;Kim, Yang-Su;Ahn, Do-Seob
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.1335-1338
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    • 2002
  • This paper presents the analysis of the required limit on a multibeam active phased array antenna (APAA) aperture using the statistical simulation for a High Altitude Platform Station (HAPS). The simulation takes into account the random errors caused by the non-identity of the array elements and the inaccuracy of the antenna calibration. The results of our statistical simulation show that the strict requirements on the sidelobe envelope for HAPSs can be met when the amplitude and phase distribution errors are minor, a condition which may be achieved by using digital beam forming.

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