A common-gate boot strapped CMOS rectifier dedicated for VHF (very high frequency) isolated DC –DC converter is proposed . It uses common-gate bootstrapped technique to compensate the power loss due to the threshold voltage, and to solve the reflux problem in the conventional rectifier circuit . As a result , it improves the power conversion efficiency (PCE) and voltage conversion ratio (VCR). The design saves almost 90% of the area compared to apreviously reported double capacitor structure . In addition, we compare the previous rectifier with the proposed common-gate bootstrapped rectifier in the case of the same area; simulation results show that the PCE and VCR of the proposed structure  are superior to other structures. The proposed common-gate bootstapped rectifier was fabricated by using CSMC 0.5 μm BCD process .The measured maximum PCE is 86% and VCR achieves 77% at the operatingfrequency of 20 MHz. The average PCE  is about 79% and average VCR achieves 71 % in the frequency range of 30- 70 MHz . Measured PCE and VCR have been improved compared to previous results .