A Rectenna Design With Harmonic Suppression for RF Energy Harvesting Applications

In this paper, a compact rectenna is presented for radio frequency (RF) energy harvesting applications. The antenna also features a lowpass (LPF) structure to suppress unwanted harmonics. The LPF has a DC-pass characteristic and is designed with a 1.96 GHz cut-off frequency using a radial resonator. A zero bias and low-power Schottky diode SMS7630 is utilized as the rectifying element. A circular patch antenna is designed and optimized to resonate at 2.44 GHz. A microstrip matching network is placed between the proposed antenna and rectifier to maximize power conversion efficiency. The presented topology is designed using a high frequency FR4 substrate with a thickness of 62mil (1.6 mm), a dielectric constant of 4.4 and a loss tangent of 0.019 at 2.44 GHz. According to the results, by using the proposed LPF structure, the first and second harmonics have been suppressed with a rejection level of 10 dB. The proposed rectenna shows a maximum power conversion efficiency (PCE) and DC output voltage of approximately 39.24% and 2.17 V at 2.44 GHz for an optimum load resistance RL = 1.2 k Omega and an input RF power of +10 dBm.