• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5116-5131
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• 2017

This paper studies the radio frequency to direct current (RF-DC) conversion efficiency of rectennas applicable to wireless power transfer systems, where multiple receive antennas are arranged in serial, parallel or cascaded form. To begin with, a 2.45 GHz dual-diode rectifier is designed and its equivalent linear model is applied to analyze its output voltage and current. Then, using Advanced Design System (ADS), it is shown that the rectifying efficiency is as large as 66.2% in case the input power is 15.4 dBm. On the other hand, to boost the DC output, three composite rectennas are designed by inter-connecting two dual-diode rectifiers in serial, parallel and cascade forms; and their output voltage and current are investigated using their respective equivalent linear models. Simulation and experimental results demonstrate that all composite rectennas have almost the same RF-DC conversion efficiency as the dual-diode rectifier, yet the output of voltage or current can be significantly increased; in particular, the cascade rectenna obtains the highest rectifying efficiency.