• Title, Summary, Keyword: Varactor 다이오드

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A Study on Varactor Tuning Gunn Oscillator for X Band (Varactor 튜닝 X 밴드 Gunn 발진기에 관한 연구)

  • 박한규;천장호
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.15 no.5
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    • pp.39-45
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    • 1978
  • This paper described on the varactor tuning Gunn oscillator for X band. Analyzed the coplanar 2 post case using the dyadic Green's function then derived the obstacle network for the incident TE10 mode. For the electronical tuning, used the tuning varactor diode which has a high speed dynamic response characteristic and high Q. Oscillation frequency, switching mode, and stable oscillation point were calculated by the computer simulation. In the expriments, switching mode was occurred at 18 mm, 32.5 mm of the short tcircuit position, respectively. The general characteristics of the varactor tuning Gunn oscillator were abruptly changed by the moving of the short circuit and the variation of the bias voltage.

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Development of the High Performance 94 GHz Waveguide VCO (우수한 성능의 94 GHz 도파관 전압조정발진기의 개발)

  • Ryu, Keun-Kwan;Kim, Sung-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.5
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    • pp.1035-1039
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    • 2012
  • In this paper, we developed a 94 GHz waveguide VCO(voltage controlled oscillator) using a GaAs-based Gunn diode and a varactor diode. The cavity is designed for fundamental mode at 47 GHz and operated at second harmonic of 94 GHz. Bias posts for diodes operate as LPF(low pass filter) and resonator. The fabricated waveguide VCO achieves an oscillation bandwidth of 760 MHz. Output power is from 12.61 to 15.26 dBm and phase noise is -101.13 dBc/Hz at 1 MHz offset frequency from the carrier.

X-band Voltage Controlled Oscillator using Varactor Diode (바랙터 다이오드를 이용한 X-밴드 전압제어 발진기)

  • Park, Dong-Kook;Yun, Na-Ra;Choi, Yean-Ji;Kim, Yea-Ji
    • Journal of the Korean Society of Marine Engineering
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    • v.33 no.5
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    • pp.756-761
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    • 2009
  • In this paper, a X band voltage controlled oscillator is proposed. The oscillator uses a transistor as an oscillating element and its oscillating frequencies are controlled by the tuning voltage of varactor diode. Using the circuit simulation tools, the matching circuits between the transistor and varactor diode, its input and output matching circuits, and a feedback circuits are designed. The measured results of the fabricated oscillator show that its oscillation frequencies are from 10.50GHz to 10.88GHz according to the turning voltages of 1V to 18V, its output power levels are about 4.3dBm, and its phase noise is around -43.5dBc/Hz at 100kHz offset frequency of 10.5GHz.

Varactor-Diodeless VCO for Radar Signal Detection Applications (레이더 신호감지용 Varactor-Diodeless 전압 제어 발진기)

  • Go, Min-Ho;Oh, Su-Hyun;Park, Hyo-Dal
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.7
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    • pp.729-736
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    • 2011
  • In this paper, we propose a varactor-diodeless voltage-controlled oscillator operating at X-band, and verify the possibility of applying to a receiver for microwave radar signal detection applications. The proposed VCO is realized by only single RF BJT device as a varactor diode is substitued by a intrinsic collector-base PN-junction of the active device which is used to generate negative resistance. The fabricated VCO meets the specification of the receiver, which has a 11.20~11.75 GHz tuning bandwidth with respect to the tuning voltage, 1.0~7.0 V, output power of 9.0~12.0 dBm and linear frequency tuning performance.

Design and Implementation of VCO for Doppler Radar System (도플러 레이더 시스템용 VCO 설계 및 제작)

  • Kim Yong-Hwan;Kim Hyun-Jin;Min Jun-Ki;Yoo Hyung-Soo;Lee Hyung-Kyu;Hong Ui-Seok
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.4 no.2
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    • pp.81-87
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    • 2005
  • In this paper, a VCDRO(Voltage Control Dielectirc Resonator Oscillator) for signal source of doppler radar system is designed and fabricated. The proposed VCDRO is made with new tuning mechanism using CPW line. The coplanar waveguide of $\lambda_{g}$/2 in length with varactor diode is placed on the metallization side under the dielectric resonator and coupled to it. Tuning varactor diode is mounted at one end of the CPW. The proposed circuit tuned by a CPW allows one more varactor diode to be mounted on the optimized CPW, where a greater sensitivity of frequency tuning is needed. With varying the biasing voltage for the varactor diode from 0 V to 15 V, output frequency tuning of 12 MHz is obtained. The PLDRO exhibits output power of 16.5 dBm with phase noise in the phase locked state characteristic of -115 dBc/Hz at 100 Hz, -105 dBc/Hz at the 10 kHz, and -102 dBc/Hz at 1 Hz offset from 10.525 GHz , respectively.

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A study on Design and Fabrication of Tunable Microstrip Ring Band Pass Filter using Varactor Diode (Varactor 다이오드를 이용한 가변 만이크로스트립 링 대역통과 필터의 설계 및 제작에 관한 연구)

  • 강원석;권성수;김진섭;남윤관;나극환
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.83-86
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    • 2000
  • 가변 필터는 송수신기에서 회로를 간단히 하여 특히 멀티채널을 사용하는 송수신기에서 중추적 역할을 담당하게 된다. 본 논문에서는 소형경량이고, 구조가 단순하여 제작이 간단하며, MMIC화하기 쉬운 실용적인 가변필터를 설계 및 제작하여 그 사용가능성을 제안하였다. 본 논문에서는 중심주파수 1.95GHz, 통과대역이 100MHz인 대역통과 링 필터를 Split 모드 방식으로 구현하고 이를 바탕으로 300MHz의 가변대역폭을 갖는 필터를 제작하였다. 이 필터의 대역폭을 가변하기 위하여 바이어스전압에 따라 커패시턴스가 변화하는 Varactor 다이오드를 사용하였다.

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A Continuously Frequency Tunable Electromagnetic Wave Absorber Using Varactor Diodes and Multiple Slits (버랙터와 다중 슬릿들을 결합한 광대역 주파수 가변 흡수체)

  • Cho, Soo-Bean;Jo, Eon-Seok;Kim, Dongho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.4
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    • pp.399-402
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    • 2016
  • We propose a thin electromagnetic wave absorber using varactor diodes combined with intentionally introduced multiple slits, which enables continuous sweep of an absorption frequency band throughout relatively wide frequencies. The absorption frequency range of conventional electrically tunable absorbers has been restricted by high capacitance of varactor diodes. In order to overcome the problem, we introduce parasitic capacitance and connect them with varactors in series, which reduces the total capacitance dramatically. As a result, we can raise the operating absorption frequency up to the X-band region. Moreover, we can also control the operating frequencies by modifying the number of slits with little change in an entire frequency sweep range. Good agreement between simulated and measured results show the validity of our proposal.

77 GHz Waveguide VCO for Anti-collision Radar Applications (차량 충돌 방지 레이더 시스템 응용을 위한 77 GHz 도파관 전압 조정 발진기)

  • Ryu, Keun-Kwan;Kim, Sung-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.7
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    • pp.1652-1656
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    • 2014
  • In this work, we demonstrated a 77 GHz waveguide VCO with transition from WR-12 to WR-10 for anti-collision radar applications. The fabricated waveguide VCO consists of a GaAs-based Gunn diode, a varactor diode, a waveguide transition, and two bias posts for operating as a LPF and a resonator. The cavity is designed for fundamental mode at 38.5 GHz and operated at second hormonic of 77 GHz. The waveguide transition has a 1.86 dB of insertion loss and -30.22 dB of S11 at the center frequency of 77 GHz. The fabricated VCO achieves an oscillation bandwidth of 870 MHz. Output power is from 12.0 to 13.75 dBm and phase noise is -100.78 dBc/Hz at 1 MHz offset frequency from the carrier.

Design and fabrication of Ka-Band Analog Phase Shifter using GaAs Hyperabrupt Junction Varactor Diodes and Reactance Matching (GaAs Hyperabrupt Junction 바랙터 다이오드와 리액턴스 정합을 이용한 Ka-Band 아날로그 위상변화기의 설계)

  • ;Seong-Ik Cho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.5
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    • pp.521-526
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    • 2003
  • This paper describes performance data and design information on a reflection-type analog phase shifter used in Ka-band. Arranging a couple of GaAs hyperabrupt junction varactor diode parallel in a circuit, and applying reactance matching method accordingly, it is possible to 831 a large the phase shift. Design equation is formulated theoretically. Since the assembly process is important in Ka-band, this paper also includes the assembly process that is essential to minimize the generation of parasitic elements during the assembly process. It is obtained variable phase shift 220$^{\circ}$${\pm}$7$^{\circ}$ and insertion loss 5 dB${\pm}$1 dB as a measured result larger than the existing figure in Ka-band.

A Design of Tunable Band Pass Filter using Varactor Diode (버렉터 다이오드를 이용한 가변 대역통과여파기 설계)

  • Ha, Jung-Hyen;Shin, Eun-Young;Kang, Min-Woo;Gwon, Chil-Hyeun;Park, Byung-Hoon;Lim, Jong-Sik;Choi, Heung-Taek;Ahn, Dal
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.6
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    • pp.1196-1200
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    • 2009
  • This paper proposed a tunable band pass filter. It is two-poles direct capacitive coupled resonator band pass filter which the capacitors of parallel resonators are changed by varactor diodes. The DC bias controls to change the value of capacitance in the parallel resonator for tunning the pass band. To validate the proposed design method, we fabricated the band pass filter which has tunable center frequency from 200MHz to 245MHz.