A Novel Dual-Frequency Circularly Polarized Rectenna

A novel dual-frequency circularly polarized shorted ring-slot rectenna (rectifying antenna) for wireless power transmission at 2.45 and 5.8 GHz is proposed. Rectenna was composed of two nested microstrip-fed shorted annular ring-slot antennas and two rectifier circuits. Output dc voltage of over 2 V at the lower frequency band and over 1 V at the higher frequency band was achieved at a transmission distance of 2 m.