Dual‐band CPW rectenna for low input power energy harvesting applications

Abstract

A dual-frequency band low input power rectenna is proposed in this study. The rectenna is comprised of a co-planar waveguide (CPW) rectifier integrated with a rectangular split ring antenna loaded by a spiral strip line. A single diode series connection topology is used to miniaturise the losses at low input power. A spiral coil in addition to two short circuit stubs are used as a matching network for maximum power transfer between the antenna and the rectifying circuit. The proposed rectenna operates at low input power with relatively high measured RF-DC conversion efficiency up to 74 % at input power of − 6.5 dBm at the first resonant frequency f 1 = 700 MHz and 70 % at − 4.5 dBm at the second operating frequency f 2 = 1.4 GHz with a resistive load of 1.9 k Ω . The measured rectenna sensitivity (the rectenna ability to receive low power with acceptable conversion efficiency) reaches up to − 20 dBm with a conversion efficiency of 47 and 36 % at f 1 and f 2 , respectively, and a DC output voltage of 0.18 V . The measured efficiency is over 50 % from − 18 to − 3.5 dBm and from − 15 to − 1.5 dBm at f 1 and f 2 , respectively.