UHF Power Transmission System for Small and Mobile Targets

Abstract

This paper presents a method of wireless-power transmission to devices which move from close distance to far area from transmitting antenna. UHF range, specifically 430 MHz, was selected in this study so that both of the near-field and the electro-magnetic energy would exist in the applicable distance and the rectenna would be small enough. The resulting hardware is compact and light enough to be installed on a moving target with only minor sacrifices in size and weight. As a demonstration of this concept, a rectenna and two driving motors were embedded in each of the four rotors of a quadcopter. The rotor assembly (rotor, antenna, rectifier, two motors) is powered by UHF waves and rotates around a mechanically fixed shaft. Successful test flights of the quadcopter demonstrate the feasibility of wireless power transmission to mobile targets.