Journal of Xidian University

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Design and implementation of a low-phase-noise GaAs HBT VCO

WU Yue;LV Hongliang;ZHANG Yuming;ZHANG Yimen   

  1. (School of Microelectronics, Xidian Univ., Xi'an 710071, China)
  • Received:2017-07-12 Online:2018-06-20 Published:2018-07-18

Abstract:

In order to reduce the effect of diodes in the bipolar process on the phase noise, a fully integrated K-band differential voltage controlled oscillator (VCO) is proposed. The VCO is realized based on gallium arsenide (GaAs) hetero-junction bipolar transistor (HBT) technology with a cutoff frequency fT of 75GHz and a maximum oscillating frequency fMAX of 80GHz. To reduce the phase noise of the VCO, the modified π-feedback networks are employed and applied to compensate the 180°phase shift. The oscillation frequency of this chip is from 23.123GHz to 23.851GHz. At the dc power consumption of 72mW from a -6V power supply,the measured maximum output power is -1.68dBm. The phase noise is about -103.12dBc/Hz at 1MHz offset and the chip area is 0.49mm2. It is shown that the circuit structure can reduce the effect of diodes in the bipolar process on the phase noise and achieve low phase noise without sacrificing the tuning range of the VCO.

Key words: K-band, phase noise, modified π-feedback network, gallium arsenide (GaAs) hetero-junction bipolar transistor (HBT), voltage controlled oscillator(VCO)


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