A Millimeter Wave Monolithic VCO with an Integrated Heterojunction FET as a Varactor

A millimeter wave monolithic voltage controlled oscillator (VCO) with a 0.15μm gate AlGaAs/InGaAs heterojunction FET as an active element and with a Schottky gate of a drain DC-biased HJFET as a variable reactance element has been developed. The drain DC-biased HJFET varactor has an improved Cg-Vg characteristics and is effective to realize a linear oscillation frequency control of 26MHz/V with 5.5dBm output power around 29GHz.