Design of a 110 GHz broadband frequency tripler using planar varistor Schottky diodes

This paper presents the design and demonstration of a 110GHz broadband varistor tripler utilizing two commercial gallium arsenide Schottky diodes from United Monolithic Semiconductor (UMS) Inc. Anti-parallel configuration eliminates even harmonics and thus no additional output filtering is needed. An accurate threedimensional electromagnetic (3D-EM) model is established to characterize the high-frequency parasitic effect of diodes. Linear and nonlinear simulations are performed iteratively to design the embedding circuit for high efficiency conversion. The whole circuit of the tripler is fabricated on RT/Rogers 5880 substrate with thickness of 0.127mm, housed in split waveguide blocks. The measured results show that with 20~22dBm input power at Ka-band, the tripler reaches maximum 9 dBm output power at 106 GHz and achieves 2.3%~5.5% efficiency across 90~120 GHz frequency band.