A dual-band CMOS VCO for automotive radar using a new negative resistance circuitry

A novel structure of negative resistance circuit is presented. Using this structure, we develop a dual-band differential voltage controlled oscillator (VCO) for automotive radar. The proposed negative resistance circuit allows the use of the bias tail resistor that increases the oscillation voltage headroom, and improves the phase noise performance of the VCO. Moreover, this structure shows low parasitic capacitance resulting in a wide frequency tuning range. The proposed VCO is implemented in TSMC 65 nm CMOS technology. Post-layout simulation results show tuning ranges of 22-27 GHz and 74-81 GHz for the 24 and 77 GHz bands, respectively. The phase noises at the offset of 1 MHz are less than -127 and -114dBc/Hz for 24 and 77 GHz bands, respectively.