Experimental and theoretical study on 35 GHz rf-to-dc power conversion receiver for millimeter-wave beamed power transmission

Abstract

35 GHz power conversion receivers were developed through theoretical analyses and experiments. The theoretical analyses included the derivation o f a mathematical model for conversion efficiency, the calculation o f diode parameters from the semiconductor material properties, nonlinear circuit simulations o f 35 GHz rectennas, and full-wave analyses o f dipole and patch antennas. The three constituents of a rectenna--diode, rectifying circuit, and antenna-- were optimized to maximize the power conversion efficiency. The maximum conversion efficiency o f a 35 GHz dipole rectenna with a currently available diode was estimated to be approximately 60%. The maximum efficiency o f a 35 GHz patch rectenna with the same diode was estimated to be 50% due to the surface wave loss. A full-wave rectifying bridge diode was evaluated as having the advantages o f a small harmonics generation and a relaxed optimum circuit condition in rectenna applications. Three types of rectennas were fabricated and tested for conversion efficiency. Most rectennas showed a conversion efficiency o f less than 40% . A rectangular patch rectenna had a power conversion efficiency o f 60% with a 213 £2 dc load and a 25 mW input power. Power transmission to a high altitude communication relay platform was analyzed as an application o f 35 GHz beamed power transmission. The output dc power at the platform was estimated to be 41 kW using a 25 m diameter transmitter radiating 200 kW. The output dc powers at the platform were estimated for various transmitter sizes and weather conditions.