• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.513-514
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• 2008

A scalable satellite broadcasting system is designed to guarantee quality of multimedia service cooperatively utilizing both Ku Band and Ka band. In the system, video streams are separated into a base layer and an enhancement layer, and are transmitted over the two channels, Ku Band and Ka band, respectively. A basic quality of service using the base layer stream can be provided even when the enhancement layer stream over Ka band channel is unavailable by rain attenuation. A rain fall model is simulated using Barlett-Lewis Pulse model and is used in the operation test of the implemented sacalable satellite broadcasting system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8B
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• pp.1035-1040
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• 2001

SNU-ISRC 0.25$\mu\textrm{m}$ pHEMT 표준 공정을 사용하여 Ka-band에서 동작하는 0.2W급 MMIC CPW 전력증폭기를 설계, 제작하였다. 기존의 MMIC 공정에서 사용되는 마이크로스트립 전송선 대신 CPW 전송선을 사용함으로써 보다 간단하고 저가의 공정이 가능하였다. 전력증폭기의 설계에서는 보다 넓은 주파수 대역에서 원하는 출력전력을 얻기 위해서 출력단을 Wilkinson coupler를 사용하였는데, 일반적으로 Wilkinson coupler에 사용되는 50Ω 특성임피던스 전송선 대신에 25Ω 특성임피던스 전송선을 사용하여 좋은 출력단 전력 정합과 출력 반사손실을 동시에 얻을 수 있었다. 제작된 전력증폭기의 측정결과, 주파수 27GHz에서 출력전력 23.4dBm과 Power-added Efficiency 21.7%의 결과를 보였다.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.68-71
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• 2003

An output multiplexer of manifold type is widely employed in a recent satellite transponder due to its small size and mass. For correct operation, channel fillers in manifold multiplexer must be singly terminated. In this paper, a simple synthesis method fur a single terminated filter is described. From the given method, a 4-pole singly terminated elliptic function filter for Ka band satellite transponder is designed. The filter is shown to be suitable for satellite application and its measured results agrees well with computed ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.454-460
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• 2004

In this paper, we studied hierarchical channel coding scheme using unequal error protection method for consecutively broadcastingservice under the rain attenuation of Ka band satellite broadcasting. Unlike time-sharing methods, which are design for different channel coding scheme in according to different modulation, unequal error protection method is made in such way that minimum distance between signals are different for importance of signals with same modulation. Consequently we proposed optimal method according to performance analysis.

• Electronics and Telecommunications Trends
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• v.34 no.3
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• pp.65-74
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• 2019

The Earth Stations in Motion (ESIM) system is one of the most modern satellite systems, providing high-speed and high-capacity communication with mobility. To facilitate ESIM in the Ka band, operational, technical, and regulatory studies have been conducted in the International Telecommunication Union Radiocommunication Sector (ITU-R) since 2016. In this paper, we introduce the ESIM and discuss its system characteristics and frequency sharing issues with respect to existing services in the same frequency bands. Taking into account current standardization activity in the ITU-R, we provide the latest study results of ESIM operation based on the Conference Preparatory Meeting Report for the World Radiocommunication Conference-19.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.4
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• pp.335-344
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• 2004

A low phase noise EQM(Engineering Qualified Model) LO(Local Oscillator) has been developed for Ka-band satellite transponder. A VCDRO(Voltage Controlled Dielectric Resonator Oscillator) is also designed using a high impedance inverter coupled with dielectric resonator to improve the phase noise performances out of the loop bandwidth. The mechanical analysis fur housing and the thermal analysis fur circuit board are achieved. This EQM LO is applied to Ka-band satellite transponder of EQM level after environmental experiments for space application. The LO has the harmonic suppression characteristics above 52 ㏈c and requires low power consumption under 1.3 watts. The phase noise characteristics are exhibited as -101.33 ㏈c/㎐ at 10 ㎑ offset frequency and -114.33 ㏈c/㎐ at 100 ㎑ offset frequency, with the output power of 14.0 ㏈m${\pm}$0.17 ㏈ over the temperature range of -15∼＋65$^{\circ}C$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5B
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• pp.476-481
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• 2004

Since the bands 27.5 ∼ 28,350㎓ and 31.0 ~ 31.30Hz for existing fixed-satellite service were allocated to tile HAPS system in WRC-2000, the analysis on the interference effects between the existing FSS/GSO system and FS/HAPS system should be needed. To do study on the interference effects between above two systems, we can consider two frequency operational conditions, one is the Reverse mode, the other is Forward mode. In this paper, we analyzed the interference effects from airship of HAPS systems to satellite of the GSO system in the case of Reverse condition mode due to the C/I criterion, the latitude of HAPS and transmitting power of HAPS airship. In future, these results will be vital data to share between HAPS and GSO systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.6
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• pp.533-539
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• 2015

In this paper, we designed a reconfigurable mixer for microwave broadband receiver. The proposed mixer using a anti-parallel diode is operated as a fundamental mixer or sub-harmonic mixer with respect to a control voltage. A fundamental mixer with a control voltage show a conversion loss of -10 dB, 1 dB compression point of 2.0 dBm at X-band/ Ku-band. On the other hand, it is performed as a sub-harmonic mixer with a conversion loss of -17 dB, 1 dB compression point of 2.0 dBm at Ka-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.775-780
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• 2004

This paper describes the realization of the Ka-band group-delay equalized filter desisted with the help of a new hybrid method of Simulated Annealing(SA) and Conjugate Gradient(CG), to be employed by the multi-channel Input Multiplexer for a satellite use, each channel of which comprises a channel filter and a group-delay equalizer. The SA and CG find circuit parameters of an 8th order elliptic function filter and a 2-pole equalizer, respectively. Measurement results demonstrate that the performances of the designed component meet the specifications, and validate the design methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.158-165
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• 2000

In this paper, the transmission channels of L-band and Ka-band multi-media satellite communication systems for the land mobile satellite(LMS) communication service are modeled. Trellis coded(TC) 8PSK is proposed as a power and bandwidth efficient digital transmission scheme for the LMS system, and its error probability performance is analyzed. Block interleaving and deinterleaving are applied to the transmitter and receiver of LMS system respectively in order to compensate for the BER performance degradation of TC-8PSK caused by multipath fading. Viterbi equalizer is also employed in the receiver for channel equalization, and the corresponding BER performance improvement is analyzed.