A Tunable 220 GHz Comb Generator Realized With an Ultrawideband Mixer in an InP HBT Technology

We present a novel approach to millimeter-wave electrical comb generators with frequency-adjustable tone spacing and a tunable RF center frequency. We upconvert the spectrum of a series of repetitive pulses with an ultrawideband (UWB) mixer to demonstrate a stable electrical comb from 140 GHz to 220 GHz, with 500 MHz and 2 GHz frequency spacings. This upconverted comb can be used as a phase reference at millimeter-wave frequencies once an accurate characterization of the phase of its spectrum is available.