Circularly polarized strips integrated microstrip antenna for energy harvesting applications

A circularly polarized (CP) microstrip antenna with four strips is proposed for wide beamwidth and RF energy harvesting applications. Four strips along the diagonal directions are integrated symmetrically onto a square patch radiator for CP radiation with wide beamwidth. To improve the impedance matching of the antenna, a stub is integrated along the orthogonal direction of the patch radiator. The antenna is designed on FR4 substrate and an antenna prototype shows a measured 10-dB return loss bandwidth of 120 MHz (2.53–2.65 GHz) with a maximum gain of 4.6 dBic. The measured 3-dB axial ratio (AR) bandwidth is 65 MHz (2.540–2.605 GHz) with a 3-dB AR beamwidth of around 180° across the band. Overall antenna volume is 0.475λo× 0.475λo × 0.013λo at 2.5 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1044–1049, 2016