Analysis and design for Ka-band doubler with CAD technology

This paper presents theoretical analysis and circuit design of a Ka-band frequency doubler using two beam-lead Schottky barrier diodes as varistors. Characteristics and applications of non-linear components are researched. CAD technology is applied to design the doubler, which includes an anti-parallel diode pair and a microstrip circuit. The influence of the cavity on the microstrip circuit is fully considered during the CAD process and an accurate model is set up. The input circuit and output circuit of a frequency doubler are realized using low loss suspended striplines (suspended LPF, SCPW) and fin lines. Input and output signals are isolated and harmonic components of the output signal are found to be very low by using a unique planar balanced circuit structure. Input frequency is 13/spl sim/20 GHz. Output frequency is 26/spl sim/40 GHz. Conversion loss is 11.2/spl plusmn/1.8 dB. A microwave signal source can thus extend to Ka-band.