An Efficient Multipaction Analysis of an Output Multiplexer for Satellite Applications

Man Seok Uhm,Juseop Lee,In-Bok Yom,Jeong-Phill Kim 한국전자파학회JEES 2005 Journal of Electromagnetic Engineering and Science Vol.5 No.4

In this paper, an efficient multipaction analysis method of a manifold multiplexer for satellite applications is presented. While FEM(Finite Element Method) is used for the multipaction analysis of the lowpass filter, the equivalent circuit model is used for the analysis of the channel filters and the manifold. Employing equivalent circuit model for multipaction analysis takes less time than using EM(Electromagnetic) field analysis method while keeping the accuracy of the multipaction analysis. This present analysis method is applied to the manifold multiplexer for Ka-band satellite transponders and the results show that the present method is as accurate as the conventional EM field analysis method.

A study on the Engineering verification of RF Passive Equipment for Communication, Ocean and Meteorological Satellite (COMS)

Uhm, Man-seok,Lee, Ju-Seop,Yun, So-Hyeun,Noh, Youn-Sub,Park, Jong-Heung 통신위성우주산업연구회 2004 Joint Conference on Satellite Communications Vol.2004 No.-

본 논문에서는 2008 년에 발사될 통신해양기상위성용 RF 수동부품의 기술 검증을 보였다. 이들은 입력 광대역 필터, 협대역 채널 필터, 메니폴드 형태 멀티플렉서, 다이플렉서 등의 수동 부품들이다. 기술검증의 목적은 선정된 부품들이 그 동안 ETRI 에서 축적된 국내 기술로 개발이 가능한지 확인한 후 통신 위성에 사용하고자 하는 것이다. 입력 필터 어셈블리는 중계기의 입력 신호를 검사하기 위한 교차 방향성 시험 결합기와 상향 링크 대역 신호를 통과 시키는 입력 필터로 이루어져있다. IF 채널 필터로는 무게와 부피를 줄이기 위해서 4차 체비체프 combline 구조가 이용되었다. RF 채널 필터는 무게와 부피를 줄이기 위해서 8 차 타원형 필터와 2차 군지연 등화기를 이중모드 형태로 설계하였고, 출력 멀티플렉서는 저 손실 특성을 갖고, 무게 및 부피가 적은 메니폴드 형태가 이용되었다. 다이플렉서는 E 평면 T접합부에 아이리스를 두어 정합이 용이하도록 하였고, 송신부 필터는 용량성 아이리스를 수신부는 유도성 아이리스를 이용한 필터가 적용되었다. 모든 부품들의 성능 결과는 해석 결과와 일치하였고, 요구 규격을 만족하였다. 이번 기술 검증을 바탕으로 비행모델급 부품들이 개발되어 통신해양기상 위성에 사용될 예정이다. This paper presents the engineering verification of RF passive equipment for Communication, Ocean and Meteorological Satellite (COMS) to be launched in 2008. Those are the passive equipment for the input wide band filter, RF/IF channel filters, a manifold multiplexer, and a diplexer. The objective of this engineering verification is to study the feasibility of those equipment to be applied to communication satellite. The input filter assembly (IFA) consists of a cross directional test coupler to check the input signal level of the transponder and an input band pass filter to pass the uplink band signals. Four-pole Chebyshev combline structure is chosen for the IF channel filter to reduce the mass and volume. RF channel filter and output multiplexer (OMUX) is used for the channelization of the frequency band into a number of RF channels. Dual mode technique is adopted in both 8-pole elliptic channel filters and 2-pole external equalizers for mass and volume reduction for RF channel filters. For low insertion loss, mass, and volume reduction, manifold type is employed for output multiplexer. E-plane waveguide T-junction of the diplexer with the inductive iris is used for a matching elements to reduce the computation time for optimized performance. The inductive and capacitive irises are used for receiving and transmitting filter, respectively. The test results of all equipment show good agreement with the simulation results and are compliant th the requirement of each equipment. Followed by this verification, the flight model equipment will be developed for the COMS.

Synthesis of power pattern modifying only the phase distribution

Man Seok Uhm,Alexandre P. Popov,Kwang Ryang Park 대한전자공학회 1996 대한전자공학회 워크샵 Vol.1996 No.-

A study on Ka band Qualification Model Multiplexers for Communication, Ocean and Meteorological Satellite (COMS) Payload

Uhm, Man-Seok,Ahn, Ki-Burm,Yun, So-Hyeun,Kwak, Chang-Soo,Yom, In-Bok 통신위성우주산업연구회 2006 Joint Conference on Satellite Communications Vol.2006 No.-

본 논문에서 2008 년에 발사될 통신해양기상 위성탑재용 Ka 대역 멀티플렉서의 인증모델 결과를 보였다. 이들은 위성통신에서 주파수 자원을 효율적으로 사용하기 위한 위성중계기용 입력 및 출력 멀티플렉서와 반사판 안테나를 송수신 대역에서 공용으로 사용하기 위한 급전용 다이플렉서이다. 4 개의 주파수 채널을 지닌 중계기 입력부에서 사용되는 입력 멀티플렉서는 높은 주파수 선택도 특성을 지닌 협대역 8 차 타원형 필터와 2 차 군지연 등화기를 갖는 독립 채널 필터들로 이루어져 있다. 출력 멀티플렉서는 저손실 특성을 갖고, 무게 및 부피가 적은 매니폴드 형태가 이용되었다. 입력 및 출력 멀티플렉서에 이용되는 채널 필터들의 무게와 부피를 줄이기 위해서 이중모드 공진기가 사용되었다. 그리고 공진기는 온도 변화에 민감하지 않도록 인바 재질이 사용되었고, 품질계수를 높이고자 은도금을 실시하였다. 급전부에 사용되는 다이플렉서의 송수신 포트는 E 평면 T 접합부를 이용하여 분기되었고, 송신부 필터는 용량성 아이리스를 수신부는 튜닝이 용이하도록 비대칭 유도성 아이리스를 이용한 필터가 적용되었다. 제작된 인증모델 멀티플렉서들은 요구 규격에 맞도록 전기적 성능시험, 진동시험, 기계적 충격시험, 열진공 시험, EMC 시험 등이 실시되었고, 시험결과 비행모델에 적용 가능한 성능을 보였다. This paper presents the test results of Ka band qualification model multiplexers for Communication, Ocean and Meteorological Satellite (COMS) Payload to be launched in 2008. These are the input and output multiplexers of the satellite transponder to use available frequency resources effectively and the diplexer of the satellite antenna to use the same reflector for both transmitting and receiving frequency bands, respectively. The input multiplexer of the transponder with four frequency channels has four(4) independent channel filters which consist of a narrow 8-pole elliptic band-pass filter for high frequency selectivity and a 2-pole equalizer for group delay equalization. For low insertion loss, mass and volume reduction, manifold type is employed for output multiplexer. Dual mode technique is adopted in the cavities of channel filters for both input and output multiplexers for mass and volume reduction. The cavities are made of Invar with low thermal expansion coefficient that provides a stable RE performance over the specified temperature range and plated with silver to obtain the high unloaded quality factor. E-plane waveguide T-junction is used for either splitting or combining a frequency band into two sub-bands. Asymmetric inductive irises and capacitive irises are used to tune the receiving filter easily and to avoid the unwanted harmonic band for the transmitting filter, respectively. The electrical performance and environmental test such as vibration test, mechanical shock test, thermal vacuum test and EMC test are performed and the results of all qualification model multiplexers are compliant to the requirement of each multiplexer. Followed by this qualification, the flight model equipment will be developed for the COMS.

고이득 및 고 효율 2W Ka 대역 MMIC 고출력 증폭기

엄만석(Man-Seok Uhm),장동필(Dong-Pil Jang),염인복(In-Bok Yom) 대한전자공학회 2000 대한전자공학회 학술대회 Vol.2000 No.11

A dual-mode waveguide pseudo-elliptic filter with zero-shifting properties

Lee, Juseop,Uhm, Man Seok,Yom, In-Bok,Kim, Jeong Phill Wiley Subscription Services, Inc., A Wiley Company 2005 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.47 No.4

<P>This paper describes the design and realization of dual-mode waveguide filters with zero-shifting properties. The transmission zero can be shifted from one side of the passband to the other by simply changing the resonant frequencies of the resonators. Without changing the physical dimensions of the resonators and coupling irises, transmission zeros can be shifted by adjusting the tuning and coupling screws. The filters are realized and the measured results show good agreement with the simulated ones. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 357–359, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21169</P>

Design and Realization of the Dual-mode Channel Filter and Group-Delay-and-Amplitude Equalizer for the Ka-band Satellite Transponder Subsystem

Sungtek Kahng,Man Seok Uhm,Seong Pal Lee 한국전자파학회JEES 2003 Journal of Electromagnetic Engineering and Science Vol.3 No.2

In this paper, the design of a channel filter and its group-delay-and-amplitude equalizer is carried out for the Ka-band satellite transponder subsystem. The 8th order dual-mode filter is employed for high selectivity around the band-edges with an elliptic-integral function response and has an in-line configuration. The 2-pole, reflection-type, group-delay equalizer is designed and manufactured to reduce the group-delay and amplitude variation, which can be large for such a high order filter. It is noted that in both the filter and equalizer, adopting the dual-mode coupling mechanism leads to less mass and volume. Through measurement, the performance of the realized group-delay-equalized filter is shown to meet the equipment requirements and to be appropriate for the satellite input multiplexer.

Network Parameters of 6-Pole Dual-Mode Singly Terminated Elliptic Function Filter

Lee, Juseop,Uhm, Man-Seok,Yom, In-Bok,Lee, Seong-Pal 한국통신학회 2003 韓國通信學會論文誌 Vol.28 No.7A

An output multiplexer of manifold type is widely used in a recent satellite transponder for its mass and volume reduction. For correct operation, the filters of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly-terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling coefficients are obtained easily without complicated matrix algebra such as orthogonal projection and similarity transformation. Two different-structure filters are taken into consideration and the network parameters of each filter have been extracted from the same transfer function. It is shown that the responses of two filters are same to each other since their network parameters are obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.

Synthesis of a self-equalized dual-passband filter

Lee, Juseop,Uhm, Man Seok,Park, Jong Heung IEEE 2005 IEEE microwave and wireless components letters Vol.15 No.4

This letter describes synthesis method for a self-equalized dual-passband filter. Compared to a conventional dual-passband filter, the self-equalized dual-passband filter can reduce bit-error rate (BER) in digital data communications and does not need an external equalizer for group delay equalization. To validate the synthesis method described in this letter, a 10-pole dual-passband filter which has two self-equalized five-pole elliptic-response passbands is synthesized.

위성 중계기용 단일종단 이중모드 타원응답 필터에 관한 연구

이주섭(Juseop Lee),엄만석(Man Seok Uhm),서준석(Joon-Suk Suh),염인복(In-Bok Yom),이성팔(Seong Pal Lee) 한국통신학회 2003 한국통신학회 학술대회논문집 Vol.2003 No.7