Ultra-Wideband Frequency Doubler with Differential Outputs in SiGe BiCMOS

We present an ultra wideband push-push based frequency doubler with differential outputs and a 3 dB-bandwidth from 4.8 to 80 GHz. The maximum conversion gain is 1.7 dB at 25 GHz and -13dBm input signal. An on-chip active balun provides the differential drive signal enabling a good fundamental rejection over a wide bandwidth. Measurements up to 100 GHz verify the circuits functionality. The output bandwidth of 75 GHz combined with less than 3 dB output power variation exceeds the results of previous publications with differential outputs.