600-GHz High-Power Signal Sources Based on 250-nm InP HBT Technology

Two 600-GHz radiation signal sources, a single- and 4-element oscillators, have been developed based on a 250-nm InP heterojunction bipolar transistor (HBT) technology. The single-element unit oscillator adopts the common-emitter cross-coupled structure with reactive emitter degeneration, which enables 2^nd harmonic oscillation around 600 GHz with enhanced output power. Based on the unit oscillator, the 4-element coupled oscillator with cascaded 2-way shunt power combiners was developed to further increase the output power. Both oscillators are integrated with on-chip patch antennas with simulated antenna gain of 3.5 dBi and directivity of 8.0 dBi at 600 GHz. The measured oscillation frequencies of the two signal sources are 580 - 586 GHz and 583 - 591 GHz, respectively, varied with the base bias. They exhibited measured peak EIRP of 1.1 and 2.7 dBm, respectively, which correspond to the radiated output power of -7.5 and -5.9 dBm. The total dc power consumptions are 34.5 and 129.6 mW, which lead to estimated dc-to-RF efficiencies of 0.52 and 0.2% for the two sources. The measured phase noises are -88.6 and -90.1 dBc/Hz at 10-MHz offset frequency for the single- and 4-element oscillators, respectively.