A high efficiency 670 GHz x36 InP HEMT multiplier chain

In this letter, the first 670 GHz multiplier chain with integrated buffer amplifiers is reported. The x36 multiplier chain uses a 25 nm InP HEMT MMIC technology with > 1.5 THz fMAX. The chain consists of five packaged MMICs in three split-block waveguide housings with each multiplier incorporating an integrated output buffer. We report an output power of 1.8 mW at 680 GHz when measured at room temperature, with a total DC power consumption of only 1.7 W. This is believed to be the highest DC efficiency reported for a complete multiplier chain at this frequency range.