5.8GHz circularly polarized rectennas using schottky diode and LTC5535 rectifier for RF energy harvesting

5.8 GHz circularly polarized single element patch antenna and 2 × 2 antenna array for RF energy harvesting were designed and fabricated. A comparison between Schottky diode and LTC5535 for RF energy harvesting rectenna (rectifying antenna) was analyzed at WLAN frequency of 5.8 GHz. Both rectennas are printed on Rogers 4003C substrate. Maximum gain at boresight tip was measured to be 3.4 dBi and 8.0 dBi for circular polarized single element patch antenna and array patch antenna respectively. And the measured return loss of the two types of antennas was measured to be -10.3 dB and -20.3 dB respectively. The maximum output DC voltage reading is 72.5 mV for Schottky diode and 428.3 mV for the LTC5535 rectifier, at a distance of 15 cm from the transmitting reference antenna.