Broadband Rectenna Arrays for Randomly Polarized Incident Waves

This paper presents a new approach to efficient rectenna arrays for arbitrarily polarized incident waves with broad spectral content. The approach is validated experimentally on a dense grid array that rectifies two orthogonal linear polarizations, and on a self-similar spiral array with alternating right-hand and left-hand circular polarizations. The two arrays operate from 4.5to 8GHz and 8.5to 15GHz and have maximum open circuit voltages of 3.5 and 4.0 V, respectively. Their efficiencies increase above 35% and 45%, respectively, for higher incident powers.