A 180-GHz Schottky Diode Frequency Doubler With Counter-Rotated $E$ -Fields to Provide In-Phase Power-Combining

This letter reports on the first demonstration of a power-combined Schottky diode frequency doubler that uses counter-rotated E-fields at the output of two frequency doublers to enable in-phase H-plane power-combining. The single chip integrated circuit comprises of a four-anode structure on a 20-μm-thick GaAs substrate that when used individually demonstrates a peak efficiency of 34% and the maximum output power of 109 mW at 180 GHz. In a power-combined configuration, the frequency doubler with counter-rotated E-fields exhibits a 3-dB bandwidth of 10% and a peak conversion efficiency of 37% for input powers between 150 and 200 mW. This doubler delivers 130-mW output power and 26% conversion efficiency for 500-mW input. The novel H-plane power-combined frequency doubler is compared with the single-chip doubler to show the combining efficiency and the chip-to-chip variation for multiple circuit builds.