A 2.4-GHz CMOS Efficiency-Enhanced Rectifier With a Differential-Feed Patch Antenna

This letter presents the codesign of a 2.4-GHz CMOS rectifier and an antenna for efficiency enhancement at low input power. The RF differential-driven rectifier architecture is used to lower the driving voltage required to turn on the transistors. The high-resistance feedback path with an offset voltage is added to the rectifier circuit to reduce the reverse leakage current for efficiency enhancement. The rectifier is connected directly to the differential-feed antenna to eliminate the need and loss of a balun. The measured power conversion efficiency (PCE) of the rectifier achieves 63% at the input power of −8 dBm.