77/154 GHz push–push VCO with phase-noise- and output-power-enhanced off-state parallel transistors in 90 nm CMOS

A 77/154 GHz push–push voltage-controlled oscillator (VCO) with tail double-frequency (f02) output (VCO1) and a 70/140 GHz push–push VCO with head f02 output (VCO2) are demonstrated in 90 nm CMOS. Off-state transistors are included in parallel with the cross-coupled transistors of VCO1 to enhance its nonlinearity-based second-harmonic frequency tone. This leads to its phase noise (PN) and output power (Pout) enhancement. VCO1 consumes 14.4 mW from a 1 V power supply and achieves decent results. At the fundamental (f01 = f02/2) port, VCO1 achieves single-ended Pout of -6.8 dBm, tuning range of 76–77.6 GHz, and a PN of −109.2 dBc/Hz at 10 MHz offset from the carrier frequency. The corresponding figure-of-merit (FOM) is −175.41 dBc/Hz. At the double-frequency port, VCO1 achieves single-ended Pout of −11.1 dBm, tuning range of 152–155.2 GHz, and a PN of −83.6 dBc/Hz at 1 MHz offset from the carrier frequency. The corresponding FOM is −175.83 dBc/Hz. Moreover, at the fundamental port, VCO2 achieves single-ended Pout of −3.7 dBm, tuning range of 66.3–70.2 GHz, and a PN of −113.8 dBc/Hz at 10 MHz offset from the carrier frequency. The corresponding FOM is −180.01 dBc/Hz. The result indicates VCO1 is suitable for dual-band millimeter-wave transceivers.