Mounted Director Element on Dual-Band Vivaldi Antenna for Wireless Energy Harvesting Application

This paper presents radio frequency energy harvesting (RFEH) using a rectenna system for 3.1 and 5.75 GHz frequencies. The antenna used in this work is a Vivaldi antenna with a new structure. Mounting the newly designed parasitic element on the proposed Vivaldi antenna has improved the gain and directivity of the antenna. The parasitic element is introduced as the director element. The arms of the director element are expanded exponentially. We simulated the proposed antenna design in CST Studio Suite and simulated the proposed rectifier in an advanced design system (ADS). The substrates chosen for the antenna and rectifier are of low-cost type. We have used the voltage doubler technique for the rectifier. Good impedance matching using two stubs has made it possible to connect the rectifier to the antenna. We obtained RF to DC measurement results for the proposed design, which are 56.3% for 3.1 GHz at 8.5 dBm input power and 33.4% for 5.75 GHz at 6.5 dBm input power, respectively. After combining the antenna and the rectifier, the maximum efficiency measured for the power input of 5 dBm at the frequency of 3.1 GHz is equal to 50.8%, which is suitable for energy harvesting.