This letter presents the first CMOSFET RF-to-DC Rectifier IC which delivers more than 10 mW dc power at GHz frequency. This IC utilizes the single-ended In-phase Gate-boosting Rectifier (IGR) architecture, and its In-Phase Voltage Multiplier (IPVM) is derived from a λ/2 transmission line to boost in-phase VGS from the driving VDS. This simultaneously reduces the effective threshold voltage, forward resistance, and reverse leakage current of the rectifying transistors. To improve an IGR's performance, both RF source-pull and dc load-pull are carried out to find the optimal performance. The UHF IGR is implemented using thick-gate-oxide I/O transistors with 0.28 μm minimum gate length in TSMC 65 nm CMOS process. The implemented IC achieves a 20 mW output dc power with 31.8% peak efficiency at 900 MHz with 200 MHz 1 dB bandwidth.