920MHz band high sensitive rectenna with a small loop antenna

In this paper, the 920MHz band rectenna on ambient energy harvesting is discussed for high efficient rectification in low RF power region. For high RF output voltage of the antenna, extreme high antenna impedance of 29 k Ω can be achieved with resonance between the small loop antenna and the SOI-CMOS rectifier IC. Physical dimensions of the antenna is optimized to improve high rectification efficiency. As results, top-level efficiency of 25% and output voltage of 0.35 V can be obtained at input power of-30 dBm.