Directional Multiport Ambient RF Energy-Harvesting System for the Internet of Things

Ambient radio-frequency (RF) energy harvesting can extract from RF signals in the ambient environment and has potential for applications Internet of Things. However, power density is low therefore methods to maximize average output direct current (dc) are required. In this work we show that dc nonlinearly dependent on antenna directivity linearly port number. To it necessary utilize directional multiport rectennas. demonstrate enhancements possible, design a 4-port pixel patch rectenna system harvest GSM-1800 frequency band provided. The an size each 0.3?×0.3?, realized gains 5.5 dBi. Measurement results proposed increase by up 6.2 4.5 dB compared omnidirectional single-port designs similar size, respectively. real also conducted, showing achieve 11.2 ?W which five times higher than two reference