High-Gain Simple Printed Dipole-Loop Antenna for RF-Energy Harvesting Applications

In this paper, a compact dual-band antenna for RF energy harvesting applications is presented. The basic antenna structure is formed using a combination between a dipole and a loop antenna to operate at 900 MHz and 1600 MHz, respectively. To enable the antenna to resonate at a dual- band within a compact substrate, two L-shaped vertical arms as a dipole connected with a trapezoidal slot loop. A meandered transmission line is connected to the coplanar slot line to act as a stub to match the input impedance of the dipole and the loop. On the back of the antenna, a reflector is positioned to enhance the forward to back ratio and provide a unidirectional radiation pattern. The antenna has a compact size 0.149λ
_o
×0.23λ
_o
(with respect to the wavelength at the lowest operating frequency), making it comparatively smaller than similar designs. It has a measured fractional bandwidth of 11% at 0.970 GHz at the lower band and 52.9% at the upper band from 1.5 to 2.58 GHz. The antenna performance has a peak gain of 6.5 dB. To prove the antenna normal operation, a prototype is fabricated, tested and the measurements are compared against the simulation results. This antenna is intended for the RF wireless energy harvesting applications.