An Octave-Wide Planar Microwave Frequency Doubler

A simple frequency doubler circuit is presented, which is based on the bridge rectifier scheme with a quad of Schottky diodes and a new planar balun configuration joining a microstrip and a coplanar line. Measurement results of the frequency doubler for the output frequency in the Ku-band prove the practical usefulness of this low-cost and small-sized circuit. It is characterized by a high and nearly frequency independent conversion efficiency and a good suppression of the fundamental frequency.