Design of a Wideband Frequency Synthesizer with Low Varactor Control Voltage

낮은 바렉터 제어 전압을 이용한 광대역 주파수 합성기 설계

  • Won, Duck-Ho (Department of Electronic Engineering, Sogang University) ;
  • Choi, Kwang-Seok (Department of Electronic Engineering, Sogang University) ;
  • Yun, Sang-Won (Department of Electronic Engineering, Sogang University)
  • Published : 2010.01.31


In this paper, with using the clapp type VCO(Voltage Controlled Osillator) configuration a wideband frequency synthesizer in UHF band is proposed. In order to design a wideband frequency synthesizer, the variation of phase in the negative resistance circuit as well as the load circuit was analyzed. Based on this result we propose a method to widen the operation range of the VCO. A frequency synthesizer using the proposed wideband VCO was designed and fabricated. It is shown that the synthesizer has the operating frequency range of 740~1,530 MHz by 0~5 V varactor tuning voltage, and it had the output power of 2~-6 dBm. Moreover, the phase noise measured as -77 dBc/Hz at 10 kHz offset, and as -108 dBc/Hz at 100 kHz offset from the oscillation frequency.


Clapp Type VCO;Varactor;Wideband;Tuning Voltage;Phase


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