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이동통신 환경에서의 표면 탄성파 노치를 이용한 저잡음 증폭기술 연구
안창엽(Chang-Yeup Ahn) 한국정보기술학회 2019 한국정보기술학회논문지 Vol.17 No.12
In this paper, the study of low noise amplification technology using surface acoustic wave notch in mobile communication environment was carried. Mobile network environments are using high-powered amplifiers for long-distance radio transmission. Thus, as radio noise between each network is generated and amplified through an antenna along with the main signal in the mobile communication service network, noise levels and main signal levels are rising together to increase the ratio of noise to the main signal. In this paper, to reduce these noise levels, signal noise can be selectively eliminated by using surface acoustic wave notch rather than implementing conventional loop method. The low noise amplification technique studied in this paper was designed to reduce noise level by more than 5 dB compared to existing TMA(Tower Mounted AMP) devices by blocking noise level to 5dB.
도파관 안테나를 이용한 3GHz 대역 소형 선박용 레이더 경보시스템 연구
안창엽(Chang-Yeop An),한영환(Young-Hwan Han) 한국정보기술학회 2021 한국정보기술학회논문지 Vol.19 No.4
Large ships operate radar for detecting sea, preventing collisions with other vessels during the voyage. In this paper, signals from these radars can be received to determine the location and distance of the ship. Large ships do not have navigation problems due to the installation of radar. However, it is common for small ships to sail without installing expensive radar. Therefore, small ships often do not have radar when sailing between large and small ships, so there are cases of frequent collisions, causing casualties. Therefore, we need a device that can tell us that a large ship is approaching from a small ship. In this paper, we proceed with A Study on the 3GHz Band Small Ship Radar Warning System Using Waveguide Antenna. The systems studied in this paper can receive radar signals from the coming ship to determine the location and distance of the coming ship, and subsequently increase reliability through the design of the new antenna design. It is designed with stationary 4-way antennas instead of large and expensive rotary radar systems.
지연 선로가 없는 Feedforward Loop를 이용한 선형화기의 설계 및 제작
정승환,조경준,김완종,안창엽,김종헌 한국전자파학회 2000 한국전자파학회논문지 Vol.11 No.1
This paper presents a linearizer using the feedforward loop which can be applied to PCS base-station applications. This linearizer used a IM amplifier and an auxiliary amplifier in order to remove delay lines used in the predistortor using the feedforward technique. The delay line in error loop is changed by the main power amplifier(PA) and the error amplifier is utilized to amplify the error signal which fed to the output of main amplifier. The linearizer was simulated by HP ADS ver 1.1 and fabricated on GML 1000 with thickness of 0.8 mm and dielectric constant of 3.2. Two-tone signals at 1.85 GHz and 1.851 GHz with -7dBm/tone from synthesizers are injected into the main PA. The main PA with a 27 dB gain and a $P_{1dB}$ of 29 dBm(two-tone) was utilized. The reduction of intermodulation distortion (IMD) is around 17 dB. 본 논문에서는 Delay line이 없는 Feedforward loop를 이용한 PCS 중계기용 선형화기룹 설계 및 제작하였다. 기존의 Feedforward 방식을 이용한 Predistortor에서 사용되는 지연 선로(Delay line)를 제거하기 위하여 기존의 선호 루프(Signal loop)의 주 경로에 보조 증폭기를 사용하고 보조 경로에 보조 증폭기와 비슷한 동작시간을 갖 는 혼 변조 증폭기(Inter-modulation am미ifier)를 사용하였다 또한, 주 증폭기를 에러 루프(Error loop)로 옮기 고 그와 비슷한 농작시간을 갖고 에러 선호를 증폭하기 위해서 에러 증폭기(Error amplifier)를 사용하여 지연 선로를 제거하였고 에러 선호를 주 증폭기 출력 단에 인가시켰다, 본 논문의 선형화기는 HP사의 EEsof ADS v ver.l.l을 사용해서 설계하였으며 유전율 3.2 .. 2 두께 0.8mm인 GML 1000 기판에 제작하였다. 측정 결과, 이득 27 d dB이고 $P_{1dB}$ 29 dBm인 주 전력 증폭기에 -7 dBm/tone을 갖는 1.85 GHz와 1.851 GHz의 2-tone 신호를 인가한 결과 전체 IMD가 약 17 dB 개선되었다.