• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1393-1394
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• 2008

본 논문은 사람의 호흡과 심박 수를 0.5 m 의 거리에서 원격 측정하는 레이더 시스템 설계에 관한 내용을 기술한다. 기존에 많이 사용되었던 능동 주파수 혼합기 회로를 파형 간섭 효과를 이용한 6 -포트 회로로 대치하여 설계하였으며 특히 전력 검출기 성능에 따라 낮은 국부 발진기 전력을 사용할 수 있다는 장점을 가짐을 보였다. 본 논문에서는 수신신호 감지를 위한 최적의 국부 발진기의 전력을 제시하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.380-387
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• 2002

In this paper, the effect of the phase noise of a local oscillator on the ACPR of a transmitter and the reception sensitivity of a receiver to meet the TIA/EIA/IS-98-D for the CDMA mobile station was analyzed. And the optimum condition for performance of the local oscillator was suggested. It was found that the phase noise level of the local oscillator in a receiver and a transmitter should be below -138.3dBc/Hz and -120dBc/Hz, respectively, at 900kHz offset. It was confirmed that the reception sensitivity and ACPR efficiency were satisfactory when the signal of the local oscillator to the down-converter of a receiver with the phase noise level of less than -138.3dBc/Hz is supplied to the up-converter of the transmitter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.9-12
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• 2004

A numerical simulation is presented for investigating the effects of pressure ratio of $D_2$ injector to supersonic nozzle on the Population inversion in the DF chemical laser cavity, while a latins concurrently takes place. In this study, these phenomena are investigated by means of analyzing the distributions of the DF excited molecules, while simultaneously estimating the maximum small signal gains and power in the DF chemical laser cavity. Major results reveal that the higher $D_2$ injection pressure provides a favorable condition for $DF^{(1)}$-$DF^{(0)}$ transition to generate the higher power laser beam.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.906-911
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• 2004

In this paper, a VCDRO(Voltage Control Dielectric Resonator Oscillator) applied to FMCW(Frequency Modulated Continuous Wave)Radar as stable source is implemented and constructed with a MESFET(Metal-semiconductor Field-Effect Transistor) for low noise, a dielectric resonate. of high frequency selectivity, and high Q varator diode to obtain a good phase noise performance and stable sweep characteristics. The designed circuits is simulated thrash harmonic balance simulation technique to provide the optimum performance. The measured result of a fabricated VCDRO shows that output is 2.22㏈m at 12.05GHz, harmonic suppression -30㏈c, phase noise -130㏈c at 100KHz offset, and sweep range of varator diode $\pm$18.7MHz, respectively. This oscillator will be available to FMCW Radar.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.471-482
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• 2015

In this paper, design and implementation of the 94 GHz Gunn oscillator and the evaluation of the maximum power of the Gunn diode used in the oscillator are presented. The 94 GHz Gunn oscillator is used InP Gunn diode and designed employing a WR-10 waveguide. The designed oscillator is fabricated through machining and its performance is measured. The fabricated oscillator shows an oscillation frequency of 95 GHz, output power of 12.64 dBm, and phase noise of -92.7 dBc/Hz at 1 MHz offset frequency. To evaluation the maximum power of the InP Gunn diode used in oscillator, the oscillator structure is modified to a structure having a diaphram. The height of thick diaphram which is used in the oscillator is varied. As a result, an oscillator has several different load impedances, which makes it possible to plot $G_L-V^2$ plot at the post plane. Using the $G_L-V^2$ plot, the maximum power of used Gunn diode including post is computed to be 16.8 dBm. Furthermore using the shorted and zero bias Gunn diode, the post loss used for DC biasing can be computed. Using the two losses, The maximum power of a InP Gunn diode is computed to be 18.55 dBm at 95 GHz. This result is close to a datasheet.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.235-238
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• 2001

단일 단말기로부터 멀티 통신이 가능하게 됨에 따라 광대역 또는 듀얼대역에서 사용되는 RF 소자 개발이 중요시되고 있다. 그러므로 소형, 저 비용의 멀티대역 VCO(Voltage Controlled Oscillator)개발이 요구된다. 본 논문에서 GSM/DCN 대역에서 사용 가능한 듀얼밴드 VCO을 설계하였다. 하나의 발진부, 듀얼 공진부, 완충증폭기, 스위치회로로 구성되었으며, 위상 보정 기법을 이용하여 각 밴드에 대한 발진 조건을 만족시키므로 사용 부품의 수를 줄일 수 있어 저 비용, 소형화, 낮은 위상잡음(phase noise)을 얻을 수 있다. 설계된 듀얼 VCO는 GSM 대역에서 -110dBc/Hz(100kHz offset) 이하의 위상 잡음과 DCN 대역에서 -108dBc/Hz(100kHz offset)의 위상 특성을 보인다. 출력전력은 0$\pm$3dBm이며 소비전력 7mA로 만족할만한 성능을 보인다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.857-862
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• 2008

This paper evaluate the performance using a simulated 490KHz narrow band filter based on characteristic parameters appropriately extracted from 490KHz band-pass filter after considering each characteristic, which is modeled on equivalent circuit and applied to NAVTEX receiver using crystal oscillator. The evaluation results show that the value of a series capacitor of crystal oscillator has only little capacity by Cs=21.094fF and the bandwidth characteristics of filter go worse as the capacity value of crystal oscillator grow increase. Moreover, the series inductance value of crystal oscillator has a relatively big value by L=5H, therefore the bandwidth characteristic according as inductance's capacity shows more little effect than the capacity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.71-76
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• 2010

In this paper, a 120 GHz local oscillator(LO) for the sub-harmonic mixer in the THz transceiver with a carrier frequency of 240 GHz was designed and fabricated. A 120 GHz local oscillator was composed of 40 GHz PLL(Phase Locked Loop), 40 GHz BPF(Band Pass Filter), frequency tripler and 120 GHz BPF. The commercial model of the frequency tripler was used. The measured result of the 40 GHz PLL showed the phase noise of -105 dBc/Hz at the 100 kHz offset frequency. The measured result of 120 GHz BPF showed the insertion loss of 1.3 dB at center frequency of 119 GHz with bandwidth of 5 GHz. The output power of 120 GHz LO was measured to 6.6 dBm.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.57-65
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• 2004

In this paper, keeping pace with light weight, pocket-size, lower-price, we design VCO(Voltage Controlled Oscillator) X/Ku band for using at public RD(Radar Detector) to apply to controlled voltage on base in transistor which used as a oscillator, without using varactor diode in part of VCO tuner. As a result of simulation, we conclude VCO could be have 110 MHz by controlled voltage 4.25 V to 4.80 V and show its output 9.63 dBm at operating frequency, 11.46 GHz, and its phase noise -107.2 dBc at 1 MHz offset frequency. So it turned out suitable performance for commercial use.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.437-443
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• 2004

Aperture has been employed on the ground plane in the hairpin resonator. Aperture has been fabricated by etching the part of the ground effected coupling coefficient and then quality factor of hairpin resonator has been increased. When the hairpin oscillator using aperture has been compared with the conventional hairpin oscillator using microstrip, it has been improved the phase noise about 19 ㏈c @100 ㎑. As a result of PBG connecting to the output of the employing aperture hairpin oscillator, the second and third harmonics are suppressed. In this paper, oscillator has been designed and fabricated in operating 5.8 ㎓ band. The output power has been obtained 0,67 ㏈m and the second harmonic has been suppressed about -53,67 ㏈c.