Dual-Core mm-Wave VCO with Enhanced Second Harmonic Extraction by Mode Separation

The voltage-controlled oscillator is the heart of every mm-wave radar or communication system and it needs to attain stringent requirements such as low phase noise and a wide tuning range. In this work, we extend our previous work on dual-core VCO by proposing an enhanced common-mode coupling device for the second harmonic extraction from the VCO resonator using the mode separation principle. he proposed coupling device targets the elimination of eddy currents to reduce power losses and ensure better phase noise. The proposed VCO in measurements exhibits the phase noise of -105.72dBc/Hz at lMHz offset from a 58 GHz carrier and a -ldBm of the output power spectrum. It was tunable up to the tuning range of 26.41 % centered at 58.48 GHz frequency. The VCO along with the butter and 4-stage divide-by-8 fundamental frequency divider consume 112mA from a 1. 8V supply.