A Compact and Efficient RF Rectifier Using Series-Parallel LC Network for UHF Battery-Less RFIDs

This article proposes a wide-input power range compact and efficient rectifier for harvesting ambient radio frequency ( RF ) energy from 915 MHz ultra-high frequency ( UHF ). A L-match series and parallel topology have been designed and compared to not only boost the received input power but also to produce a highly efficient network to hold a broad input power range. This paper demonstrates theoretically and practically that a parallel network is more efficient than a series network due to greater harmonic suppression results in an improvement of 3% to 8% percent efficiency throughout a power range of −26 dBm to 12 dBm at a desired frequency. The design utilizes multi diode (SMS-7630, HSMS-2850, and HSMS-2862) approach to achieve higher efficiency over a wide input power range. From the measurements, the proposed series L match rectifier achieves peak power conversion efficiency of 75% at 4 dBm with 35 dB of wide input power range from −23 dBm to 12 dBm with > 20% respectively whereas the proposed parallel L match rectifier achieves peak power conversion efficiency of 79% at 4 dBm with 38 dB of wide input power range from −26 dBm to 12 dBm with > 20% in an area of 1.8 X 2 cm 2 respectively