A 110 GHz Comb Generator in a 250 nm InP HBT Technology

We report a monolithic microwave integrated-circuit (MMIC) comb generator capable of producing a repetitive narrow pulse (7.1 ps pulse duration) with sharp edges (4.2 ps falling time). The circuit was designed in a 250 nm indium phosphide (InP) heterojunction bipolar transistor (HBT) technology using differential pairs. We characterized the output signal with a 110 GHz sampling oscilloscope and de-embedded the band-limited frequency spectrum of the pulse in the circuit reference plane. We measured a pulse duration of 7.1 ps and a peak amplitude of −0.333 V. In the frequency domain, the comb generator provided −48.7 dBm of output power at 110 GHz when the circuit is fed with a 1 GHz input signal.