Ka-band pHEMT MMIC VCO with wide tuning range

Abstract

A Ka-bond MMIC VCO utilizing 0.15-mum T-gate GaAs P-HEMT technology is presented. The VCO exhibits a low-phase noise property with wide tuning range of up to 3 GHz. A balanced buffer amplifier is also developed to ensure that the output power is higher than 10 dBm. The best measured phase noise at 1 MHz offset is - 106 dBc/Hz. By varying the bias voltage of the on-chip varactor, the frequency can be continuously tuned from 33.3 to 36.3 GHz. In this frequency range, output power higher than 10 dBm has been measured without using the buffer amplifier. The buffer amplifier exhibits a typical gain of 5 dB with 15-dBm output power. A Lange coupler provides good matching between the VCO and the amplifier. (C) 2003 Wiley Periodicals, Inc.