Compact and Broadband RF Rectifier With 1.5 Octave Bandwidth Based on a Simple Pair of L-Section Matching Network

This letter proposes a novel wideband rectifier circuit for RF energy harvesting. The proposed circuit can collect signals efficiently over broad bandwidth spanning from 0.87 to 2.7 GHz which includes UHF ISM 900 MHz, GSM 900 and 1800 MHz, wireless communication, PCS, and ISM 2.4 GHz. In order to obtain sufficiently large rectifier bandwidth, a matching circuit based on high-pass type L-section for lower band impedance matching and inductive L-section for higher band impedance matching is proposed. The rectifier circuit is constructed using voltage doubler configuration with Schottky diode SMS7630-005LF. The circuit is optimized and refabricated to compensate the undesired parasitic and obtain the required rectifier performance. Two prototypes were simulated, fabricated, and characterized. The rectifier has a measured conversion efficiency exceeding 30% from 870 MHz to 2.5 GHz at 0 dBm input power and a load terminal of 2 k Omega and a dc output voltage equal to 1 V. The circuit sensitivity may reach up to -20 dBm with dc output voltage 40 mV and 8% conversion efficiency. The maximum measured efficiency is 63% from 1.1 to 1.35 GHz.