In this paper, a CMOS cross-coupled RF rectifier improved the reverse leakage current by using a thick-oxide MOSFET with a high threshold voltage as a rectifying device is proposed to improve the power conversion efficiency (PCE). As a result of reducing the reverse leakage current, peak PCE of up to 75.2 % is achieved at an RF input of -13 dBm.
Furthermore, a rectifier that operates adaptively in two modes to improve PCE performance at low input is described. Through the operation in the serial mode and the parallel mode, the two peak PCE performance is achieved 61.6 % at a low input of -20 dBm and 65.8 % at a high input of -13 dBm.
The proposed rectifier circuit is designed for 900 MHz UHF band applica-tion and implemented using 0.18 μm CMOS technology. This rectifier circuit has an input sensitivity of -16.5 dBm and achieves an input power range to achieve an optimal PCE of 9 dB.
