5.8-GHz circularly polarized dual-diode rectenna and rectenna array for microwave power transmission

This paper reports a new circularly polarized rectenna whose rectifying circuit includes two diodes. The rectenna consists of a coplanar stripline (CPS) truncated patch antenna and CPS bandpass filter, which can block harmonic signals up to the third order reradiating from the rectifying circuit. The recterma is printed on Rogers Duroid 5880 substrate with epsilon(r) = 2.2 and a thickness of 20 mil. The new dual-diode recterma can provide at least twice the dc output voltage than the traditional recterma with only a single diode, which has the same layout dimension as the single-diode rectenna. The dual-diode recterma achieves an RF-to-dc conversion efficiency of 76% at 5.8 GHz. The proposed rectermas can be interconnected to form the recterma arrays by series, parallel, and cascaded connections. It is found that a cascade connected recterma array can provide the highest output voltage. The antenna element can be easily extended to become a traveling-wave antenna or array suitable for high output voltage or current in wireless power transmission applications.