• 대한전자공학회논문지SD
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• 제37권10호
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• pp.11-16
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• 2000

회로설계 엔지니어들이 쉽게 RF IC 설계에 사용할 수 있는 나선형 인덕터의 SPICE 모델을 개발하였다. 이 모델은 나선형 인덕터의 등가회로 소자 값들을 SPICE의 user-defined function 및 subcircuit 기능을 이용하여, 레이아웃 변수, 공정 변수, 실리콘 기판 변수로부터 정의하였다. 특히 인덕턴스는 임의의 회전에 대한 인덕턴스 Li 및 임의의 두 회전에 대한 상호 인덕턴스 Mij를 subcircuit으로 정의하여 전체 인덕턴스 값을 계산하였다. 모델의 정확성을 검증하기 위하여 CMOS 0.8${\mu}m$ 공정으로 제작된 나선형 인덕터의 측정 s-파라미터, 총 인덕턴스 및 quality-factor 결과를 시뮬레이션 데이터와 비교한 결과 일치함을 확인하였다. 본 논문에서 제시된 SPICE를 이용한 나선형 인덕턴스 모델은 scalable하며, 실리콘 기판의 영향등을 포함하기 때문에 레이아웃 최적화에 쉽게 사용할 수 있는 장점을 가진다.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.202-207
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• 1997

Design and fabrication issues for an L-band GaAs Monolithic Microwave Integrated Circuit(MMIC) Voltage Controlled Oscillator(VCO) as a component of Personal Communications Systems(PCS) Radio Frequency(RF) transceiver are discussed. An ion-implanted GaAs MESFET tailored toward low current and low noise with 0.5mm gate length and 300mm gate width has been used as an active device, while an FET with the drain shorted to the source has been used as the voltage variable capacitor. The principal design was based on a self-biased FET with capacitive feedback. A tuning range of 140MHz and 58MHz has been obtained by 3V change for a 600mm and a 300mm devices, respectively. The oscillator output power was 6.5dBm wth 14mA DC current supply at 3.6V. The phase noise without any buffer or PLL was 93dB/1Hz at 100KHz offset. Harmonic balance analysis was used for the non-linear simulation after a linear simulation. All layout induced parasitics were incorporated into the simulation with EEFET2 non-linear FET model. The fabricated circuits were measured using a coplanar-type probe for bare chips and test jigs with ceramic packages.

• 한국광학회지
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• 제15권4호
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• pp.349-354
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• 2004

XFP(10 Gb/s Small Form Factor Pluggable) 트랜시버 모듈에 사용되는 광송신 서브어셈블리(TOSA: Transmitter Optical Sub-assembly)를 열적, 전기적 측면에서 설계, 제작 및 평가하였다. 저가격이며 소형인 TOSA를 제작하기 위해서 바이어스 티 및 정합저항등을 AlN서브마운트 위에 집적하였다. 10 Gb/s의 초고속 전기 신호의 입력을 위해 CPW형 마이크로파 전송로를 스템 구조체내에 도입하였다. 소자의 전기적 특성 분석을 위해 서브마운트내에 실장되는 각종 전기광학 부품들과 스템 구조체들을 고속회로 모델링 하였다. 제작한 TOSA의 특성평가를 통해, 85$^{\circ}C$에서 11 GHz 이상의 -3 dB 대역폭을 얻을 수 있었다.

• 대한전자공학회논문지SD
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• 제42권12호
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• pp.1-8
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• 2005

본 연구에서는 측정된 S-파라미터로부터 추출된 Nano-scale MOSFET 등가회로 파라미터의 scaling 방정식을 사용하여 차단주파수의 게이트 길이 종속성을 모델화하였다. 모델된 차단주파수는 게이트 길이가 줄어듬에 따라서 크게 증가하다가, 점점 증가율이 크게 감소하는 경향을 보였다. 이는 게이트 길이가 감소함에 따라 내부전달시간은 크게 줄어들지만, 외부 기생 충전시간은 상대적으로 조금씩 감소하기 때문이다. 이와 같은 새로운 게이트길이 종속 모델은 Nano-scale MOSFET의 RF성능을 최적화시키는 데 큰 도움이 될 것이다.

• Journal of electromagnetic engineering and science
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• 제16권1호
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• pp.44-51
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• 2016

A commercial $0.25{\mu}m$ GaN process is used to implement 6-18 GHz wideband power amplifier (PA) monolithic microwave integrated circuits (MMICs). GaN HEMTs are advantageous for enhancing RF power due to high breakdown voltages. However, the large-signal models provided by the foundry service cannot guarantee model accuracy up to frequencies close to their maximum oscillation frequency ($F_{max}$). Generally, the optimum output load point of a PA varies severely according to frequency, which creates difficulties in generating watt-level output power through the octave bandwidth. This study overcomes these issues by the development of in-house large-signal models that include a thermal model and by applying distributed L-C output load matching to reactive matched amplifiers. The proposed GaN PAs have successfully accomplished output power over 5 W through the octave bandwidth.

• 한국진공학회지
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• 제8권3B호
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• pp.368-375
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• 1999

The Maxwell equation and the transformer equivalent-circuit model are applied to a radio frequency planar inductively coupled plasma. The spatial distribution of the vector potential, the magnetic field, and the electric field are obtained analytically. As a result, the plasma current, the mutual inductance between the coil and the plasma, and the self inductance of plasma are found to increase with increasing skin depth. The spatial distribution of absorbed power has maximum where the antenna coil exists, and has a similar profile to that of the induced electric field. The power transfer efficiency is found to increase with increasing gas pressure before a saturation around p+ 20mTorr, while it shows an increase with the plasma density before a slight decrease around a density of $5\times10^{11}/\textrm{cm}^3$.

• Journal of Biosystems Engineering
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• 제24권3호
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• pp.235-242
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• 1999

This study was conducted to develop a grain moisture meter using microwave free space transmission technique at X-band frequency. The 10.5GHz microwave oscillator using a dielectric resonator was designed and fabricated to transmit electromagnetic wave through standard horn antenna to a sample holder with the wetted Hwasung and Chuchung rough rice(12.00∼26.25%). To detect the output voltage of transmitted wave from receiving horn antenna, the detector was composed of shottkey diode and RF impedance matching circuit. The regression model for measurement of grain moisture content was developed. Its correlation coefficient and standard error of prediction (SEP) were found to be 0.9882 and 0.657 respectively between measure and predicted moisture contents.

• Advances in nano research
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• 제1권1호
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• pp.13-27
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• 2013

Carbon nanotube characterized by additional inductive effect as compared with the traditional conductors like copper wires of the same size. Consequently, carbon nanotubes have high characteristic impedance and slow wave propagation in comparison with traditional conductors. Due to these characteristics, carbon nanotubes can be used as antenna. In view of this, we describe and review the present research progress on carbon nanotube antennas. We present different analysis models and results which are developed to investigate the characteristics of CNT antennas. Then we conclude by summarizing the characteristics of CNT antennas and specifying the operating frequency limit.

• 전기학회논문지
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• 제57권12호
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• pp.2269-2275
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• 2008

This paper examined the simulation results after applying not only spiral inductor's 3D EM simulation but also de-embedding technique to reduce the pad's RF effects. When calculating standard deviation with measurement results not only the gain at 0.5GHz${\sim}$4GHz but also noise figure at 1.8GHz${\sim}$4GHz, the simulation results includes de-embedded inductor' model improved gain deviation by 0.171 and noise figure deviation by 0.151 than the results from simulation with foundry inductor equivalent circuit models.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.439-443
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• 1987

$PbTiO_3$ thin film is prepared by rf sputtering method to implement the pyroelectric infrared detector at room temperature. Annealing of $PbTiO_3$ thin film is done from $400^{\circ}C$ to $550^{\circ}C$ each for 2 hours in furnace. The spectral response to recrystallization process of $PbTiO_3$ thin film is measured by IR photospectro meter. Pyroelectric detector Modeling is studied for implementing device using electrical equivalent circuit model. It is found that $PbTiO_3$ thin film has two IR absorption band within $1000-400\;cm^{-1}$ (10um-25um) and it's spectral response is improved as annealing temperature increase. As a result of pyroelectric detector modeling, we find the possibility of implementing optimum device structure.