A 100–180-GHz Coaxial Frequency Tripler Based on Copper Additive Manufacturing

This article presents a wideband coaxial D-band frequency tripler fabricated by copper additive manufacturing (AM). The central part of the tripler consists of two waveguide–coaxial transitions, a coaxial low-pass filter, an antiparallel Schottky diode chip, and an output impedance matching network. Most constitutions, except for the diode chip, are monolithically fabricated in one piece. The diode chip with additional thermal paths is specially designed to obtain a good thermal performance and better power handling. To facilitate the measurement, a waveguide fixture is also designed to convert the ports to standard waveguide ports (WR-19 and WR-6.5). The measurements show that the maximum output power of the tripler is 9.44 mW with about 182 mW of input power at 147 GHz and its 3-dB bandwidth is 45.2% from 108 to 171 GHz. Additionally, the tripler delivers $>$ 1.87 mW of output power and better than 10 dB of return loss over the 100–180-GHz range. To the best of authors’ knowledge, this is the first AM coaxial ultra-wideband frequency multiplier reported in the open literature.