Novel Design for a Rectenna to Collect Pulse Waves at 2.4 GHz

A novel rectifying circuit topology is proposed for converting electromagnetic pulse waves (PWs), that are collected by a wideband antenna, into dc voltage. The typical incident signal considered in this paper consists of 10-ns pulses modulated around 2.4 GHz with a repetition period of 100 ns. The proposed rectifying circuit topology comprises a double-current architecture with inductances that collect the energy during the pulse delivery as well as an output capacitance that maintains the dc output voltage between the pulses. Experimental results show that the efficiency of the rectifier reaches 64% for a mean available incident power of 4 dBm. Similar performances are achieved when a wideband antenna is combined with the rectifier in order to realize a rectenna. By increasing the repetition period of the incident PWs to 400 ns, the rectifier still operates with an efficiency of 52% for a mean available incident pulse power of -8 dBm. Finally, the proposed PW rectenna is tested for a wireless energy transmission application in a low-Q cavity. The time reversal technique is applied to focus PWs around the desired rectenna. Results show that the rectenna is still efficient when noisy PW is handled.

I. Introduction

Wireless power transfer (WPT) using microwaves is one of the most attractive solutions aiming at extending the battery life of sensors or sometimes even to avoid the need for a battery. In the past three decades, much development has been made in the direction of designing the receiving part of the WPT systems, namely, the rectenna, with the aim of collecting the incident waves and realizing the conversion from RF into dc. The main focus has revolved around the development of devices designed for a narrow band around 2.4 or 5.8 GHz [1]; some authors have also proposed rectennas capable of operating over a wide frequency band in order to harvest the ambient RF energy contained in different telecommunication bands [2], [3].