60–80 GHz frequency doubler operating close to fmax

A push-push frequency doubler, capable of delivering acceptable power to feed active mixers at frequencies close to fmax, is presented. Fabricated in an 80 GHz fT/fmax SiGe HBT technology, it achieves a maximum output power of −1.6 dBm at 60 GHz (with 0 dBm input power) and a 3 dB bandwidth of 18 GHz (30%). The suppression of the fundamental signal is better than 13 dB. The doubler has been integrated with a VCO in the same technology, demonstrating signal generation from 62.4 GHz to 78.1 GHz with a maximum output power of −1.9 dBm. The output power level and high operating frequency (compared to fmax) of the VCO/doubler combination is superior to that of typical push-push VCOs.