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항공기 탑재 AESA 안테나의 이득 대 잡음온도비 계산 및 측정
박홍우(Hongwoo Park) 한국전자파학회 2021 한국전자파학회논문지 Vol.32 No.2
본 논문에서는 항공기 탑재 능동전자주사식 위상배열(active electronically scanned array, AESA) 안테나의 주요 특성인 이득 대 잡음온도비(gain over temperature, G/T)에 대한 계산 및 측정방법을 제시하며, 실제 사례에 대한 계산 및 측정을 통해 제안한 계산 및 측정방법이 유효한 수준임을 확인하였다. 이를 위해 기존 논문에서 제시된 계산방법을 활용하여 AESA 안테나의 G/T를 계산하고, 제작된 2대의 동일한 AESA 안테나를 활용하여 무반향실에서 G/T를 측정하였다. 계산된 G/T는 −9.2 ㏈/K, 측정된 G/T는 −10.1~−8.2 ㏈/K로, 예측한 결과와 비교하여 1 ㏈ 이내의 차이를 보이며, 이를 통해 제안된 G/T의 계산 및 측정방법이 유효한 수준임을 확인하였다. 제안된 방법은 비슷한 개념으로 설계된 다른 위상 배열 안테나에도 적용이 가능할 것으로 판단된다. This paper describes the calculation and measurement method of gain over temperature (G/T), which is the main characteristic of an airborne active electronically scanned array (AESA) antenna. Accordingly, we calculated the G/T of an AESA antenna based on earlier approaches. Then, we measured the G/T of two same AESA antennas in an anechoic chamber. The calculated and measured G/T of the AESA antenna were −9.2 ㏈/K and in the range of −10.1 to −8.2 ㏈/K, respectively. Based on the analysis and measurement, we proved that the proposed method was valid. The proposed method can also be used for other types of phased array antenna systems.
Non-Foster 회로를 이용한 FM 안테나의 신호 대 잡음비 개선
박홍우(Hongwoo Park),강승택(Sungtek Kahng),김홍준(Hongjoon Kim) 대한전기학회 2016 전기학회논문지 Vol.65 No.2
In this paper, we demonstrate a Non-Foster matching method for an electrically small antenna to improve the signal-to-noise ratio (SNR) of communication link. For the experiment, we used a general FM antenna whose resonance frequency is about 52–57 MHz and a floating type Linvill negative impedance converter(NIC)-based circuit as a Non-Foster matching element. By implementing the Non-Foster circuit to cover FM band, we can achieve a wide bandwidth matching covers 40–200 MHz. Our measurement shows 3–7 dB improvement of SNR for the same bandwidth though there are several spikes which means no improvement of SNR in the band.
RHTL과 LHTL 형태의 위상변위기를 이용한 주파수 변환기 성능비교
한희제(Heejae Han),박홍우(Hongwoo Park),김홍준(Hongjoon Kim) 대한전기학회 2014 전기학회논문지 Vol.63 No.3
In this paper, we compared the performances of the Right Handed Transmission Line (RHTL) and the Left Handed Transmission Line (LHTL) phase shifters as a frequency translator. Unlike other phase shifters, both phase shifters show a 0°-360° phase variation for a broadband frequency and compact in size which are ideal to use as a frequency translator. For the performance comparison, we fabricated both a RHTL and a LHTL phase shifter to cover 1.5 GHz - 2.4 GHz range with the whole 360° phase variation. For the frequency range, a LHTL based frequency translator showed a much better performance whose Spurious Free Dynamic Range (SFDR) is 4dB - 17dB higher than the RHTL based frequency translator when the sawtooth modulation freqncy is 11 kHz. This is due to the linear phase-voltage variation of LHTL phase shifter. Furthermore, the LHTL phase shifter shows a less insertion loss and a insertion loss variation than the RHTL phase shifter. Overall, the LHTL based frequency translator outperformed RHTL based freqency translator.