Subterahertz Wireless Power Transmission Using 303-GHz Rectenna and 300-kW-Class Gyrotron

A subterahertz 303-GHz rectenna was developed and then assessed using a 300-kW-class gyrotron. Measurement of the antenna gain was conducted using finline, which is a waveguide-to-microstrip line (MSL) transducer: gain of 8.32 dBi was obtained. The input power was estimated by the application of the beam profile measured using an IR camera and the beam output power. Results show that the maximum dc output power and rectenna power density (dc output power per unit area) were 17.1 mW and 3.43 kW/ \text{m}^{2} , respectively. The diode breakpoint was observed. The RF-dc conversion efficiency was obtained as 2.17% with 342-mW input power and 130- \Omega dc load. This letter is the cutting edge of high-frequency operation in a microwave MSL-type rectenna.