In this paper, a high-efficiency voltage doubler rectifier for radio frequency identification (RFID) applications is presented. The study focuses on a new internal VTh cancellation (IVC) technique which is a combination between conventional IVC circuit and proposed switches to improve power conversion efficiency (PCE) and voltage conversion efficiency (VCE). Proposed rectifier is designed using 0.13um CMOS technology for passive tags of high frequency (HF) applications. The proposed voltage doubler offers a maximum PCE of 80% and a DC output voltage of 900mV with a RF input voltage of 500mV at 13.56 MHz and a 10k load.