• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.515-518
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• 2002

This paper presents the iterative procedure with the concept of expanded waves in the spectral and spatial domains using the fast modal algorithm. We presents its applications to microwave integrated circuits on resistive substrate. The advantage is a reduction in computation time. These calculated results are checked by comparison with the experimental and simulated results by Sonnet and Momentum program.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권6호
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• pp.255-262
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• 2004

In this paper, a number of double-layered microwave integrated circuits (MIC) have been designed and analyzed based on a developed finite-difference time-domain (FDTD) solver. The solver was first validated through comparisons of the computed results with those previously published throughout the literature. Subsequently, various double-layered MIC printed on both isotropic and anisotropic substrates and superstrates, which are frequently encountered in printed circuit boards (PCB), have been designed and analyzed. It was found that in addition to protecting circuits, the added superstrate layer can increase freedoms of design and improve circuit performance, and that the FDTD is indeed a robust and versatile tool for multilayer circuit design.

• ETRI Journal
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• 제33권5호
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• pp.818-821
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• 2011

A D-band subharmonically-pumped resistive mixer has been designed, processed, and experimentally tested. The circuit is based on a $180^{\circ}$ power divider structure consisting of a Lange coupler followed by a ${\lambda}$/4 transmission line (at local oscillator (LO) frequency). This monolithic microwave integrated circuit (MMIC) has been realized in coplanar waveguide technology by using an InAlAs/InGaAs-based metamorphic high electron mobility transistor process with 100-nm gate length. The MMIC achieves a measured conversion loss between 12.5 dB and 16 dB in the radio frequency bandwidth from 120 GHz to 150 GHz with 4-dBm LO drive and an intermediate frequency of 100 MHz. The input 1-dB compression point and IIP3 were simulated to be 2 dBm and 13 dBm, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.245-248
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• 1997

The dielectric resonators(DRs) with dielectric properties are widely used in microwave integrated circuit(MICs) and monolithic microwave integrated circuits(MMICS). The variational method as numerical simulation scheme would be applied to calculate the resonant frequencies(fr) and Q-factors of microwave dielectric resonators. The dielectric resonator with a cylindrical “puck” structure of high dielectric material is modeled in this simulation. The parameters, such as the diameter, the height, and the dielectric constant of dielectric resonator, would determine the resonant frequency and the Q-factor. The relationship between these parameters would effect each other to evaluate the approximate resonant frequency. This simulation method by the variational formula is very effective to calculate fr, and Q-factor. in high frequency microwave dielectric resonator The error rate of the simulation results and the measured results would be considered to design the microwave dielectric resonators.

• Journal of information and communication convergence engineering
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• 제11권1호
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• pp.56-61
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• 2013

Modern integrated circuits (ICs) are becoming an integrated parts of analog, digital, and radio frequency (RF) circuits. Testing these RF circuits on a chip is an important task, not only for fabrication quality control but also for tuning RF circuit elements to fit multi-standard wireless systems. In this paper, RF test circuits suitable for embedded testing are introduced: RF power detectors, power control circuits, directional couplers, and six-port reflectometers. Various types of embedded RF power detectors are reviewed. The conventional approach and our approach for the RF power control circuits are compared. Also, embedded tunable active directional couplers are presented. Then, six-port reflectometers for embedded RF testing are introduced including a 77-GHz six-port reflectometer circuit in a 130 nm process. This circuit demonstrates successful calibrated reflection coefficient simulation results for 37 well distributed samples in a Smith chart. The details including the theory, calibration, circuit design techniques, and simulations of the 77-GHz six-port reflectometer are presented in this paper.

• Journal of electromagnetic engineering and science
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• 제12권2호
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• pp.171-175
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• 2012

In this work, a new microstrip-to-substrate integrated waveguide (SIW) transition using the parallel half-mode substrate integrated waveguide (HMSIW) is proposed. The proposed transition consists of three sections : a microstrip, parallel HMSIWs, and an SIW. By inserting the parallel HMSIWs section between the microstrip section and the SIW section, the proposed transition can improve the return loss characteristics of the near cut-off frequency because the HMSIWs section has a lower cut-off frequency than the SIW section (8.6 GHz). The lower cut-off frequency is achieved through gradual electromagnetic field mode changes for a low reflection. The measured return loss is less than 20 dB in the of 9.1~16.28 GHz freqeuncy range for the back-to-back transition. The measured insertion loss is within 1.6 dB for the back-to-back transition. The proposed transition is expected to play an important role in wideband SIW circuits fed by a microstrip.

• 대한전자공학회논문지
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• 제25권12호
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• pp.1582-1585
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• 1988

A cavity perturbation technique is employed to determine the dielectric property of thin samples. Substrates in microwave integrated circuits are fabricated in sheet form and are expected to have a dielectric constant less than 10 and a dielectric loss better than 10**-3. This research aimed to determine both dielectric constant and dielectric loss with good accuracy. The tecynique makes use of thin circular disk samples placed in a right circular cylindrical cavity. The accuracy of measurements is within \ulcorner% for dielectric constnat and 3x10**-4 for dielectric loss.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.319-322
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• 1998

A 20 GHz 2-stage MMIC (Monolithic Microwave Integrated Circuits) LNA(Low Noise Amplifiers) has been designed. The pHEMT with gate length of 1.15 um has been used to provide ultra low noise and high gain amplification. Series and Shunt feedback circuits were interted to ensured high stability over frequency range of DC to 60 GHz. The size of designed MMIC LNA is 2285um x 2000um(4.57mm2). The simulated noise figure of MMIC LNA is less than 1.7 dB over frequency range of 20 GHz to 21 GHz.

• E2M - 전기 전자와 첨단 소재
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• 제10권10호
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• pp.1056-1062
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• 1997

• 한국통신학회논문지
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• 제15권1호
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• pp.51-57
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• 1990

입, 출력 정합단에 타원여파기와 보조회로를 첨가하여 광대역증폭기의 마이크로파 집적회로(MIC)를 설계한다. 이 증폭기를 해석하기 위하여 GaAS MESFET의 입, 출력회로를 단방향성 등가회로로 변환한다. 입,출력 임피던스는 타원여파기로 정합하여 집적회로화 한다. 실험결과는 4~8GHz의 주파수내역에서 이득 10.5dB, 최대 정재파비 2.1:1 및 최대 잡음지수 2.5dB의 특성을 보인다.