A Push-Push VCO With 13.9-GHz Wide Tuning Range Using Loop-Ground Transmission Line for Full-Band 60-GHz Transceiver

Abstract

A 59-GHz push-push voltage-controlled oscillator (VCO)—based on 0.18- m SiGe BiCMOS technology—for a full-band 60-GHz transceiver w as developed. The VCO uses a loop-ground transmission line (LG-TML) compose do f signal lines (half wavelength at fundamental frequency) and secondary lines (quarter wavelength at second harmonic frequency). The LG-TML makes it possible to outp ut both a large signal at second harmonic frequency and an adequate signal at the fundamental frequency for driving a prescalar, while it prevents the Miller effect of the HBTs in th e VCO from increasing and negative conductance from being reduced. As a result, the VCO achieves high output power of +1.5 dBm, while maintaining wide tuning range of 13.9 GHz (26% of the ce nter oscillation frequency). Moreover, it exhibits a low phase noise of –108 dBc/Hz at a 1-MHz offset frequency and achieves a state-of-the-art figure of merit (FOM ) of –189.6 dB.