A Two-Way Power Combined Ka-Band Rectifier for Low Input Power Energy Harvesting

In this letter, we propose an RF power combining approach for energy harvesting at Ka-band frequencies. A two-way 28-nm CMOS rectifier is presented, utilizing ultralow threshold voltage (ULVT) transistors for efficient rectification of low voltage swing input signals. The power combiner is a compact voltage summation design that minimizes the losses associated with transformer-based power combiners at mm-Wave frequencies. The rectifier achieves a record 13% power conversion efficiency (PCE) for $-$ 20 dBm input power per port, and peak PCE of 24% for $-$ 14 dBm input power per port.