A Millimeter Wave Schottky-Varactor Doubler with a Wide Tunable Frequency Range

Abstract

The efficiency of mm-wave doublers with a wide tunable frequency range was studied. The efficiency depends on the varactor parameters and the embedding impedances seen by the diode at fundamental and harmonic frequencies. Mm-wave doublers were simulated with a computer to find optimum embedding impedances for a given diode. A scaled model was constructed in order to search for optimum impedances for wide-band doublers in practice. For experimental verification a doubler from 40-60 GHz to 80-120 GHz was constructed. An efficiency > 30 % was obtained at the output frequency range from 75 to 96 GHz at various input power levels between 2 and 20 mW. The highest efficiency measured was 42 % at 88.6 GHz with 10 mW input power.