Circularly Polarized Microstrip Patch Antenna with Tilted Patch and DGS for Ambient RF Energy Harvesting

A novel compact octagonal shape microstrip patch antenna with tilted patch is designed for radio frequency energy harvesting. A DGS technique in combination with tilted patch with respect to feed creates circular polarization at 6 GHz, 10.1 and 13.3 GHz having axial ratio bandwidth of 0.17 GHz, 1.88 GHz and 0.30 GHz respectively. The gain varies between 6.5 to 7.27 dB in the axial ratio bandwidth. The suggested antenna covers the entire frequency spectrum of UWB giving fractional impedance bandwidth of 141.7% (2.33 - 13.64 GHz). This compact, wideband and circularly polarized antenna can be utilized for ambient RF energy harvesting system. The results show that the antenna covers Wi-Fi and Bluetooth band (2.4 GHz, 5 GHz), WiMAX-band (3.5 GHz, 5.5 GHz), WLAN-band (5.2 GHz, 5.8 GHz) and X-band (8–12 GHz).