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Design of the K/Ka band waveguide duplexer with an E-plane T-junction
Sungmin Han,Daeig Chang,Hojin Lee 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
In this paper, the design and performance of the K/Ka-band (20/30㎓) waveguide duplexer with an Eplane T-junction is described. The waveguide duplexer consists of a transmit band pass filter and a receive band pass filter combined to the antenna port via an E-plane Tjunction. The reason why E-plane T-junction structure was selected which is to reduce PIM (Passive Inter-Modulation) level. The manufactured duplexer has good pass band return loss (>15㏈) and high isolation (>55㏈) for both transmit and receive frequency bands. The duplexer does not need any post fabrication tuning. Those mean the analysis results of the waveguide duplexer are verified through the electrical performance test.
The Analysis of New Generation S-DMB system
InKi Lee,DaeIg Chang 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
Current S-DMB service in the Korea, one of such personal mobile multimedia services, provides broadcasting with 11 video and 26 audio channels. To provide this service more differently from other multimedia services, enhancement in transmission quality or increase in transmission bandwidth is requested. But this enhancement(or increase) should be Backwards Compatible(BC) to the legacy system for saving system migration expenses. In this paper, we propose a method for enhancing transmission quality or bandwidth, using H- 16APSK for BC and LDPC for powerful channel code. As the enhancement in transmission rate can be allowed as far as the resulted performance degradation and the resulted increase in transmission rate have been simulated and analyzed.
재난현장 적용을 위한 CSS 기반 위성 IoT 신호 검출확률 개선효과 분석
이상민(Sangmin Lee),임경래(Gyeongrae Im),유준규(Joongyu Ryu),장대익(Daeig Chang) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.2
본 논문에서는 재난현장에서 필요한 정보 수집에 활용될 수 있는 후보기술 중 하나인 LoRa (Long Range) 기술을 위성환경을 고려한 IoT 에 적용하기 위해 신호검출 확률을 분석한다. 여기서 P2P 통신환경을 가정하였으며, 송신기에서는 LoRa 전송방식을 통하여 데이터 패킷을 생성하고 수신기에서는 LoRa 프리앰블을 탐색하여 패킷을 검출한다. 이 때 프리앰블 길이에 따른 패킷 검출 성능 변화를 분석하였고 컴퓨터 시뮬레이션 결과를 통해 본 논문이 주장하는 프리앰블 심볼 수와 검출확률 간의 상관관계를 입증하였다.