Square electrically small EAD antenna array for RF energy harvesting from TV broadcast tower

This paper presents a square antenna array for TV broadcast RF energy harvesting. The antenna array consists of four square electrically small Egyptian-axe dipole (EAD) antennas. And each element comprises parasitic dipoles and exciting dipoles both with the right-angle arrow-shaped loadings, separately on two square-shaped substrates, which are smaller than previous work. Meander lines are used on 5-port Wilkinson power combiner for size reduction. Results show that simulated gain reaches 5.2 dBi at 515 MHz and measured 10-dB bandwidth is 1.96 %, from 509 MHz to 520 MHz, which is three times broader than previous 0.67 % and is enough for TV band in Suzhou, China. Measured voltage harvested by test system from TV broadcast tower is 1 V. Proposed antenna array has advantages such as electrically small size, 11 MHz measured 10-dB bandwidth, high gain, good radiation direction, high efficiency which is appropriate for RF energy harvesting from TV broadcast tower.