Wideband Circularly Polarized High-Efficiency Rectenna With Large-Angle Wireless Power Capture Capability

This letter proposes a wideband, high-efficiency, circularly polarized (CP) semi-transparent rectenna with large-angle wireless power capture capability. It consists of a wideband and broadbeam CP receiving antenna and a highly efficient rectifier. The wideband and broadbeam CP characteristics are achieved by combining a grounded stub with a coplanar waveguide (CPW) slot antenna. The antenna is meshed and fabricated on a glass substrate to realize a certain degree of optical transparency (OT). For the rectifier, a fan-stub impedance matching network is designed to broaden the impedance bandwidth and improve the ac to dc conversion efficiency. The measured results show that the receiving antenna achieves a wide usable CP bandwidth of 21.55% [(2.07 to 2.57) GHz]. Broad-measured CP beams of over 119° in the two planes are also obtained at 2.45 GHz. When the receiving antenna is cascaded with the high-efficiency rectifier, the proposed rectenna realizes a wide over-60%-efficiency bandwidth of 21.55% [(2.07 to 2.57) GHz] with a peak efficiency of 72.47% at an input power of 10 dBm, showing great potential for wireless energy harvesting and wireless power transfer applications.