• JOURNAL OF ELECTRICAL WORLD
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• s.257
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• pp.70-77
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• 1998

21세기를 지향하여 음성뿐만 아니라 데이터, 나아가서는 화상까지도 쌍방향전송을 가능케하는 고도정보통신, 소위 멀티미디어의 세계가 구현되어 가고 있다. 이 멀티미디어의 세계는 (1)고속$\cdot$대용량, (2)글로벌, (3)모바일(퍼스널)의 키워드로 특징지을 수 있는데, 여기에는 화합물반도체를 베이스로하는 광$\cdot$마이크로파디바이스가 깊이 관련되어 있다. 마이크로파디바이스를 살펴보면 소위 ''텔레데식'' 계획으로 대표되는 다량의 인공위성을 이용한 글로벌한 고속$\cdot$대용량통신에는 30 GHz라는 초고주파기술이 필수이며, HEMT등의 고성능화합물 반도체디바이스가 반드시 필요하다. 또 2.5~10Gbps, 나아가서는 40Gbps의 고속$\cdot$장거리 통신에는 광 디바이스가 결정적인 역할을 하고 있다. 한편 지수 함수적으로 증대하고 있는 정보의 축적은 광디스크의 진보에 힘입은 바가 크다. 보다 많은 대용량 화상데이터의 축적과 읽기$\cdot$쓰기를 할 수 있는 DVD(Digital Versatile Disc)-ROM, DVD-RAM에 대하여도 시장 조성이 목전에 다가오고 있다. 이와 같이 광$\cdot$마이크로파디바이스는 정보$\cdot$통신의 프런트 엔드를 걸머진 중핵디바이스로서 앞으로 멀티미디어를 근간으로 하여 성장해 갈 것으로 생각된다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.222-224
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• 1996

This paper treats the stream phenomena of high frequency current on the solid-loop coil of which consists the hollow conductor. The governing equation is derived from electromagnetic field theory and the characteristics are analyzed by FEM with 2-D and 3-D. The results may be available data on designing the optimum shape of the coil for the improved pinch effect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.682-684
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics over the temperature range of 300K and 77K. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1814-1819
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• 2007

A new active resonator using defected ground structure with islands (DGSI) is proposed. The proposed resonator is composed of the conventional microstrip line with DGSI and negative resistance of active devices. The negative resistance part is realized by field effect transistor (FET) series feedback circuits. The characteristic of the proposed resonator with DGSI is improved by combining the negative resistance part with the parallel microstrip line structure with islands, where the electric field is formed the most strongly. The measured improvement of the proposed active resonator with DGSI are 4.55dB and 0.32dB in S21 and S22, respectively, at the resonant frequency whorl it is compared to the existing passive resonator having DGSI only.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.158-161
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• 2006

The purpose of this research is to establish the crosstalk characteristic of mm-wave Coplanar structure. The components in mm-wave CPW are classified to transmission devices, EM devices, and quasi - TEM devices. After design of these devices, we analyzed these CPW s electromagnetically using FDTD method, and suggested the corsstalk characteristic of mm-wave CPW. In oder to realize a CPW module up to 30 GHz-100 GHz band, we research on a technology of 3-dimensional mm-wave CPW, and GaAs substrate with ohmic lossy layer. As a result this research, we suggested the optimum crosstalk characteristic of mm-wave CPW, and improved the crosstalk quality of mm-wave CPW.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.919-923
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• 2003

In this paper, a double-sided planar balun using Microstrip-to-CPW coupled structure is fabricated and measured. The measured amplitude and phase imbalance are, respectively, less than 0.2 dB and 2.1$^{\circ}$ in a wide frequency range from 2.44 GHz to 4.33 GHz. It is expected that the proposed balun can improved the performance of balanced mixer, amplifier and feeding network of antennas. Also, it can be used in many microwave multilayer structures due to its structural characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.474-477
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics over the temperature range or 300K and 77K. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1129-1132
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• 2005

The purpose of this reserch is to establish the new design technology for microwave Coplanar structure. The components in microwave circuit are classified to transmission devices, EM devices, and quasi-TEM devices. After design of these devices, we analyzed these CPWs electromagnetically using FDTD method, and suggested optimum CPW structure. In oder to realize a CPW module up to 30 GHz-100 GHz band, we research on a technology of 3-dimensional microwave CPW, and GaAs substrate with Si layer for ohmic loss. As a result this research, we suppressed the leakage, resonance, coupling, and radiation of CPW EMI, and improved resonance quality of CPW.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.18-23
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• 1992

Recently, SSPAs(Solid-State Power Amplifiers) with high linearity and efficiency replace TWTAs (Traveling-Wave-Tube Amplifiers) in satellite transponders. In this paper, a power amplifier with maximum output power is designed and constructed using GaAs FET(MGF-1302) as a test model for the development of SSPAs. For conjugate matching of input and output network, transimission lines and stubs are optimized using microwave CAD program, LINMIC+. Power amplifier is realized on the teflon substrate($\in$S1rT=2.45) with a bandwidth of 1GHz at a center frequency of 8GHz. Maximum stable gain of simulation and simulation and experimental result is obtained 9.23, 7.65 dB, respectively.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.3
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• pp.24-29
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• 1978

A new mode of operation is observed in this paper which involves the tractive wave interaction between a cyclotron ways and a synchronous electron beam. The wave interaction is analysed by using both electron dynamics and coupled-mode methods. The gain expression derived from the analysis prognoses a new type of improved uhf amplifier with low noise and high power. Based on the theoretical analysis, experimental tubes have been designed, constructed arid exporimented. As a result, a low noise amplifier is anticipated well into millimeter lave region.