A Compact 0.9-/2.6-GHz Dual-Band RF Energy Harvester Using SiP Technique

A compact dual-band radio frequency (RF) energy harvester (EH) composed of matching networks, bandpass and band-stop filters (BPF/BSF), and rectifiers, using a system-in-package technique is proposed in this letter. The matching networks and BPF/BSF are realized on a low-loss integrated-passive-device (IPD) carrier while the rectifiers are implemented in a 0.18-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology. The CMOS chip is flipped and bonded onto the IPD carrier through low-loss gold bumps. The proposed BPF/BSF can provide zeros and poles to pass and stop signals, respectively, allowing dual-band operation. Moreover, high-Q IPD passive components are employed to design the matching networks and the filters. This not only gives a compact solution but higher impedance transformation ratio between the source resistance and the rectifier input impedance also becomes feasible, which provides higher voltage gain to greatly enhance the RF-to-dc conversion efficiency. The proposed RF EH can give measured output voltage of 1.35 and 1 V with RF-to-dc conversion efficiency of 12.6% and 7% at 0.93 and 2.63 GHz, respectively, as the input power is −15.4 dBm and the load resistance is 500 <inline-formula> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula>. The EH only occupies an area of 11.6 mm².