• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.863-871
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• 2003

In this paper, we design a high stable Ku-band phase-locked dielectric resonant microwave oscillator with the gate voltage controls of p-HEMT. By adapting the nonlinear equivalent elements which affects phase noise of microwave oscillator, we optimize the nonlinear elements of p-HEMT to have low phase noise operation. Using the scattering parameters according to bias voltages, we designed the gate voltage control microwave dielectric resonant oscillator and phase-locked loop circuits is applied to have the high stable operations. Designed microwave oscillator as a local oscillator of digital microwave communication shows that output power is 9.17dBm at 10.75GHz and it's phase noise is -88dBc/Hz at 10KHz offset frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1417-1427
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• 2001

본 논문에서는 밀리미터파를 이용하여 사용자에게 양방향 무선 멀티미디어의 구현을 가능케 하는 LMDS 송수신 모듈을 설계, 구현하였다. 제작된 LMDS 송수신 모듈은 신서사이져, 혼합기, 저잡음 증폭기, 고출력 증폭기, 듀플렉서 등으로 구성하였으며, 전체적으로는 전원부와 제어부를 통하여 이상여부를 감시하며, 송수신 모듈에 이상이 발생했을 때 이를 보호할 수 있도록 구현하였다. 여기서 DAVIC 표준에 맞도록 IF부 대역은 0.95∼1.45GHz의 500MHz 대역폭에서 동작하도록 제작하였고, 상하향 혼합기는 격리도 특성을 최대화하였으며, 이를 위해 하이브리드 링형을 이용한 다이오드 평형 구조를 적용하여 설계하였다. 혼합기로 주입되는 Local 주파수는 안정도가 높아야 함으로 유전체 공진형 발진기로 구현하였다. 또한 저잡음 증폭기와 고출력 증폭기는 정보통신부에서 공고한 3사 주파수 대역을 모두 수용할 수 있도록 24GHz∼26.5GHz의 대역에서 정상적인 동작을 할 수 있도록 설계하였으며, 특히 저잡음 증폭기는 잡음 환경에서 작은 신호를 손실 없이 얻을 수 있도록 잡음지수를 최소화하고, 30dB 이상의 충분한 이득이 구현되도록 하였다. 고출력 증폭기는 15dBm 이상의 출력을 송신하면서도 선형성에 문제가 없도록 혼변조왜곡(IMD) 특성을 고려하여 설계하였다. 그리고 듀플렉서는 우수한 주파수 선택도와 낮은 삽입손실 특성을 갖도록 송수신 필터 모두 5개의 공진기를 포함한 Chebyshev형 구조를 갖으며 생산성이 뛰어난 모노리딕형으로 구현하여, LMDS 송수신 성능을 구현하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.13-19
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• 2004

The VCO(Voltage Controlled Oscillator) with low phase noise and high reliability is implemented using nonlinear design, and its phase noise characteristics are compared with that of Lesson's equation. The microstripline coupled with dielectric resonator is realized as a high impedance inverter to improve the phase noise, and the qualify factor of resonator circuit can be transferred to active device with the enhanced the loaded quality factor. The worst case and part stress analyses are achieved to obtain the high reliability of VCO. The developed VCO has the oscillating tuning factor of 0.56MHz/V for the control voltage range of 0$\~$12V This VCO requires the DC power of 160mW. The phase noise characteristics exhibit good performances of -96.51dBc/Hz @ 10KHz and -116.3dBc/Hz @ 100KHz, respectively. And, the output power of 7.33 dBm is measured.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.1-5
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• 2003

In this paper, the output power level and phase noise property of nine conventional push-push FET DROs (Dielectric Resonator Oscillator) have been experimentally investigated by adding one more identical DR at the drain port. The nine oscillators designed to generate 20 GHz from 10 GHz fundamental frequency, have been tested for each of three different power combiners at the output port. It has been observed that the output power level of the push-push FET DROs can be improved by placing the DR while maintaining their phase noise characteristics were approximately the same as before adding the DR.

• 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$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.38-47
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• 1995

An X-band highly frequency-stabilized MIC Gunn oscillator using a dielectric resonator is fabricated. Resonant frequency is obrained by a variational method and it is studied how the oscillating characteristics can be affected by several fators. By the optimizing these factors, we can realize the stabilited oscillator output of 250 mW with 5-7 percet efficiency at 10 GHz. It has the favorable characteristics with frequency variation of 70 KHz/$^[\circ}C$ and the ouput variation within 3 dB over the temperature range from 0 to 70$^[\circ}C$.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.145-149
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• 2003

The parallel feedback dielectric resonator oscillator (DRO) which is applicable to satellite communications and broadcasting has been investigated. In the design of oscillator, the phase noise is important parameter. In this paper, The proposed oscillator has good phase noise level because it suppressed harmonics. Measurement show the fabricated oscillator is output power of about 9 dBm at fundamental frequency of 12.0 GHz and fundamental frequency suppression of -47.5 dBc. The phase noise level is about -110 dBc/Hz at 100 KHz offset frequency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.174-177
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• 2009

In this paper, an oscillator using dielectric-rod loaded cavity resonators with HTS(High Temperature Superconductor) end-plates was presented. It was operated at X-band. A two port cavity resonator was incorporated into a basic feedback loop oscillator configuration. A rutile loaded cavity resonator with HTS thin film end-plates was used to provide the quality factor between $10^4$ and $10^6$. A parallel feedback oscillator was constructed with a dielectric loaded cavity resonator, an amplifier, and a directional coupler. At 300 K, the experimental results showed the phase noise of -108 dBc/Hz at a 100 kHz offset frequency. At 26 K, the results was -118.8 dBc/Hz at same offset frequency.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.79-85
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• 1999

In this paper, the resistive mixer for 5.86Hz wireless LAN, main part receiving system, was designed and implemented. The noise characteristics and the linearity in the base band was superior. For the use of local oscillator of mixer, dielectric resonator of stable output and temperature characteristics was designed. For the electrical tuning by the capacitance variation of varactor diode, the microstrip line and magnetic coupling characteristics of the dielectric resonance was used. It was obtained that gain of the proposed resistive mixer containing the RF cable loss, is -13.8dB, the conversion loss of frequency converter is -12 dB, and the output power of local oscillator is 1.67 dBm.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.28-35
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• 1993

The MESFET can be used as a three-terminal varactor by employing gate depletion capacitance Cg. In this paper, a novel VCDRO(voltage controlled dielecric resonator oscillator) is designed to apply VCDRO with this concept. The VCDRO produced 6.33dBm output power at a frequency of 11.058GHz and tunning bandwidth of 45MHz. The advantage of using the MESFET as a three-terminal varactor is to let the MESFET play both roles at the same time, thus simplifying the circuit configuration and fabrication. This finding demonstrates the potential of using both real and imaginary parts of the equivalent impedance of the active device.