Design of Rectennas at 7.30 GHz for RF Power Harvesting

Wireless power transfer is gaining interest in harvesting energy from radio frequency (RF) signals by rectennas. This paper proposes two rectenna systems for RF power harvesting at 7.30 GHz employing a half-wave rectifier and a three-stage Dickson rectifier. The development is carried out using the equivalent circuit of an antenna with Advance Design Software (ADS) and the proposed rectenna system is simulated with LTspice. Firstly, ADS is used to develop and optimize the dual-band antenna's equivalent RLC circuit at 7.30 GHz and 9.50 GHz. Next, the two rectifier topologies in the rectenna system are developed, and their performance is evaluated in terms of output power, load resistance, input and output voltage. It is found that the rectenna system using a three-stage Dickson rectifier provides 2.28 times higher output voltage than a half-wave rectifier while the input voltage is 250 mV and the load is 6.5 KΩ. Results also show that the output power level for the three-stage Dickson rectifier is -20 dBm to 9.24 dBm whereas the output power level for half wave is -20 dBm to 31.7 dBm.