This paper presents the design and implementation of a highly efficient and stable electromagnetic wave energy harvesting circuit targeting ultra-high-frequency (UHF) RFID applications. The system consists of a rectifier, a reference circuit, and a voltage regulator, collectively providing a reliable power supply for other chip modules. Key achievements include: a differential rectifier achieving 67% power conversion efficiency (PCE) with 1.84 V output at -11 dBm input power; an ultra-low-power CMOS reference circuit with temperature coefficients of 34.9 ppm/°C (voltage) and 18.4 ppm/°C (current), and a power supply rejection ratio (PSRR) better than -93 dB at 100 Hz; and an LDO-based voltage regulator exhibiting a load regulation of 41.28 mV/mA under varying load conditions. Additionally, clock, reset, demodulation, and modulation circuits are integrated. The circuit is implemented in a 180 nm CMOS process, occupying a layout area of 341μm × 346μm. Post-layout simulations indicate a total power consumption of 6 μW. Silicon measurements confirm that all performance metrics meet the requirements for high conversion efficiency and power supply stability in UHF RFID chips.