D-Band Frequency Tripler Module Using Anti-Parallel Diode Pair and Waveguide Transitions

Abstract

In this paper, D-band (110–170 GHz) frequency tripler module is presented using anti-parallel GaAs Schottky diode pair and waveguide-to-microstrip transitions. The anti-parallel diode pair is used as a nonlinear device generating harmonic components for Q-band input signal (33–50 GHz). The diode is zero-biased to eliminate the bias circuits and thus minimize the number of circuit components for low-cost hybrid fabrication. The anti-parallel connection of two identical diodes effectively suppresses DC and even harmonics in the output. Furthermore, the first and second harmonics of Q-band input signal are cut off by D-band rectangular waveguide. Input and output impedance matching networks are designed based on the optimum impedances determined by harmonic source- and load-pull simulations using the developed nonlinear diode model. Waveguide-to-microstrip transitions at Q- and D-bands are also designed using E-plane probe to package the frequency tripler in the waveguide module. The compensation circuit is added to reduce the impedance mismatches by bond-wires connecting two separate substrates. The fabricated frequency tripler module produces a maximum output power of 5.4 dBm at 123 GHz under input power of 20.5 dBm. A 3 dB bandwidth is as wide as 22.5% from 118.5 to 148.5 GHz at the input power of 15.0 dBm. This result corresponds to the excellent bandwidth performance with a conversion gain comparable to the previously reported frequency tripler operating at D-band.