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표면 경계조건을 이용한 코러게이트 혼 안테나 특성 해석
엄만석,박광량,Alexander Shishlov 한국통신학회 1996 韓國通信學會論文誌 Vol.21 No.6
We obtained the predicted and measured results for the reflection coefficient and radiation pattern of Ka-band (20- GHz) corrugated horn, which is usually used for feeder of reflector antenna for satellite communication, using suface impedance condition. In order to predict the reture losses of corrugated horn, we analyzed propagation constant of hybrid mode in the corrugated waveguide and then obtained the total reflection coefficient using the circuti theory of multi-step transformer. We also got the radiation pattern of corrugated horn with small flare angle, considering the phase deviation and integrate transverse field on aperture. A test model of corrugated horn antenna for Ka-band designed using theory and program displayed performance and the results agree with the theoretical prediction.
이중모드 비대칭 Canonical 구조 필터의 합성에 대한 연구
엄만석,이주섭,염인복,이성팔 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.6
이중모드 비대칭 canonical 구조 필터는 일반적으로 위성 중계기의 입력 멀티플렉서에 주로 사용된다. 본 논문에서는 비대칭형 canonical 필터의 용이한 합성 방법에 대하여 언급하였다. 비대칭형 canonical 필터의 결합행렬은 대칭형 canonical 필터의 결합 행렬로부터 평면 회전(plane rotation)과 같은 similarity transformation을 이용하여 구하였다. 비대칭형 canonical 필터의 결합 행렬을 구하기 위한 similarity transformation 과정에 있어서 회전 순서, 피벗(pivot), 회전각을 제시하였다. 본 논문에서 제시한 방법을 이용하여 8차 및 10차 비대칭 canonical filter의 결합 행렬을 추출하였으며, 비대칭형 canonical 필터의 주파수 응답 특성은 대칭형 canonical 필터의 주파수 응답 특성과 동일한 특성을 나타내었다. A dual-mode asymmetric canonical filter is widely used in an input demultiplexer for satellite transponder. This paper deals with a simple synthesis method fur an asymmetric canonical filter. The coupling matrix of an asymmetric canonical filter is obtained by applying plane rotation technique to the coupling matrix of a symmetric canonical filter. This paper gives a list of pivots and rotation angles to obtain the coupling matrix of asymmetric canonical structure filters. The coupling matrix of 8th and 10th order asymmetric canonical filter is obtained by this proposed method. It is shown that the frequency response of asymmetric canonical filter is identical to that of symmetric canonical filter.
엄만석,장동필,이병선,Uhm, M.S.,Chang, D.P.,Lee, B.S. 한국전자통신연구원 2022 전자통신동향분석 Vol.37 No.3
This article presents an overview of the key technologies in the communications payload of broadband LEO satellite communications systems. In recent years, new developments have been realized for LEO satellite communications. SpaceX's Starlink, a technology leader in this field, offers premium services with satellites carrying in-house developed communications payloads. OneWeb, Amazon, Telesat, and Boeing are also developing LEO satellite communications payloads. The communications payload consists of user link antennas, inter-satellite link communications equipment, feeder link antennas, and a digital processor. Highly sophisticated technologies of compact active phased array antennas for generating multiple hopping beams and light laser communication equipment for ultra-high-speed inter-satellite communication will be applied to next- generation payloads.