A compact 2×2 circularly polarized antenna array for energy harvesting

In this paper, a compact 2.45GHz circularly polarized (CP) antenna and a 2×2 antenna array are designed and fabricated. A new rectifier circuit which can increase the output voltage by N times will be designed and simulated. The CP is achieved using the unbalanced slots on the circular patch which subsequently makes the antenna compact. A 2×2 antenna array is designed using sequential rotation feeding scheme with a simulated axial ratio (AR) of more than 100MHz and gain of 13dBi. The measured return loss for antenna element is greater than 20dB and the minimum axial ratio (AR) of 0.21dB. The measured return loss for 2×2 array is 28.8dB and the measured minimum axial ratio is 0.15dB with a 3dB AR bandwidth of 140MHz.