• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1190-1197
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• 2013

AESA(Active Electronically Scanned Array radar) radar is able to instantaneously and adaptively position and control the beam, and such adaptive beam pointing of AESA radar enables to remarkably improve the multi-mission capability. For this reason, radar resource management(RRM) becomes new challenging issue. RRM is a technique efficiently allocating finite resources, such as energy and time to each task in an optimal and intelligent way. This paper deals with a design of radar resource management algorithms and simulator implemented main algorithms for development of airborne AESA radar. In addition, evaluation results show that developed radar system satisfies a main requirement about simultaneous multiple target tracking and detection by adopting proposed algorithms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.371-379
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• 2011

Active phased array antenna structure is used for modern multi-function radars. To search targets in high clutter environment, the radar receiver needs high dynamic range performance. Though active phased array antenna structure lead to increase of SNR, the SFDR is not increased. In this paper, high SFDR receiver of X-band active phased array radar was designed and manufactured. One channel digital receiver is connected to 32 T/R modules and one PCB assembly is composed to 2 channel digital receivers with RF part, ADC part, LO distribution part and digital down conversion part. A commercial FIFO board was used for digital receiver measurement about major performance in digital output signal condition. The measured digital receiver gain and SFDR is 33 dB and more than 81 dBc each.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.52-59
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• 2009

In modern radars, dynamic range requirements far severed due to high CNR(Clutter-to-Noise Ratio) environment operation scenario. ADC spurious signal restricted the required dynamic range. In this paper, receiver gain of active phased array radar dependent on ADC nonlinear characteristic was analyzed. Within limited scope of ADC SFDR which blocks required system dynamic range, ADC dynamic range reaches trade-off with ADC SNR loss. Comparing antenna stage output noise voltage to that of ADC input, receiver gain was mathematically analyzed. Finally the whole contents were explained from the application example.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.424-434
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• 2015

Adaptive beamforming algorithms have been widely used to remove interference and jamming in the phased array radar system. Advances in the field programmable gate array(FPGA) technology now make possible the real time processing of adaptive beamforming (ABF) algorithm. In this paper, the FPGA based real-time implementation method of adaptive beamforming system(beamformer) in the pre-processor module for active electronically scanned array(AESA) radar is proposed. A compact FPGA-based adaptive beamformer is developed using commercial off the shelf(COTS) FPGA board with communication via OpenVPX(Virtual Path Cross-connect) backplane. This beamformer comprises a number of high speed complex processing including QR decomposition & back substitution for matrix inversion and complex vector/matrix calculations. The implemented result shows that the adaptive beamforming patterns through FPGA correspond with results of simulation through Matlab. And also confirms the possibility of application in AESA radar due to the real time processing of ABF algorithm through FPGA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.1069-1076
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• 2014

This paper presents an efficient receive beam structure able to search and track the simultaneous bundle targets with the active electrically scanned array radar. One of the characteristic with the active phased array radar is to point toward wanted direction and to forming simultaneously the digital multi-beam. This paper proposes method to detect and track rapidly bundle targets coming to radar using the digital beam forming. The proposed the beam forming method in the paper is evaluated about the angle accuracy of targets via a computer simulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.825-832
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• 2011

In this paper, we described the design and measurement results of a Front-End Receiver for S-band active phased array radar. The Front-End Receiver has input P1dB of -4dBm and IIP3 of 7dBm. The measurement results show that gain is $24{\pm}0.7dB$, noise figure are less than 2.3dB over the frequency range of $fc{\pm}0.2GHz$. The Front-End Receiver can protect the receiver path from large input signals with a maximum peak power of multi-kW and recovery time is less than 0.8us. The measurement results satisfy all specifications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1243-1251
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• 2009

This paper presents design and test results of X-Band Transmit/Receive(T/R) module for active phased-array radar. Active phased array radars typically require solid state T/R modules with high output power, low noise figure, high Third Order Intercept(TOI), and sufficient gain in both transmit and receive. The output power of the module is 9 watts over a wide bandwidth. The noise figure is as low as 2.8 dB. Phase and amplitude are controlled by the 6-bit phase shifter and 5-bit attenuator, respectively. Highly integrated T/R module is achieved by using LTCC(Low Temperature Co-fired Ceramic) multiple layer substrate. The module incorporates a compact digital interface, requires only three supply voltages.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1155-1164
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• 2011

In this paper, we proposed the transmit beam measurement method of active phased array antenna, which is installed in Korea's first developed naval medium range radar, using near-field measurement facility. The pulse-mode high power characteristics of active phased array antenna's trasmit-beam make it difficult to measure with general near-field measurement facilities where low power continuous RF signals are used. Thus, in this paper, the measurement method of active phased array antenna's transmit beam in conjunction with the near-field measurement facility, which is suitable for the high-power transmit beam measurement, and PNA-X network analyzer(Agilent Technologies), which can support pulse-mode measurement, was proposed and measured by near-field measurement techniques. And the EIRP(Effective Isotropic Radiated Power), the transmit characteristic of active phased array antenna, was measured by the near field measurement techniques and compared to numerical estimation which was nearly equal with small difference of 0.1 dB.

• Information and Communications Magazine
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• v.16 no.9
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• pp.28-41
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• 1999

위상배열 안테나 시스템에서 빔 제어 기술은 이동통신 및 위성통신시스템, 비행하고 있는 임의의 비행체의 위치를 고도의 정확도를 가지고 추적하는 군사용 레이더 시스템이나 항공사의 통신 시스템, 선박이나 차량간의 충돌을 방지하기 위한 충돌방지 시스템 등에서 널리 사용되고 있다. 이러한 위상배열 안테나 시스템에서 위상천이기를 이용하는 방법이 널리 사용되고 있다. 이 방법은 원리적으로 간단하지만 실제 구현할 때 위상천이기를 제어하기 위한 제어 신호와 DC 바이어스 라인들 그리고 전력분배기로 구성되어 있기 때문에 전체 회로가 복잡해진다. 뿐만 아니라 현재로서는 위상천이기의 가격과 삽입 손실 때문에 저렴하고 높은 이을 갖는 위상 배열 안테나 시스템을 구현하기가 힘들다. 본 논문에서는 위상천이기를 사용하지 않고 발진기들의 결합을 이용함으로써 이와 같은 단점을 극복하면서 배열 안테나의 복사 빔을 제어할 수 있는 결합발진기 배열 안테나의 최근 기술동향을 분석하고 여러 기술들의 장단점을 기술한다.