Design of rectenna array panel taking into account mutual coupling for RF energy harvesting

A study of a rectenna (rectifying anntena) array on a 1×1-m substrate for RF energy harvesting is presented. Square loop antennas are laid out on the given substrate size assuming to harvest 500-MHz Digital TV radio waves. The optimum number of elements is determined from the obtainable DC power and its angle characteristics taking into account mutual coupling between antenna elements and the non-linear RF-to-DC conversion efficiency of the rectifier. Mutual coupling effects can be exploited to control the angle characteristics to some extent. In this particular consideration, a 4×3 rectenna array was optimum in the harvesting of 500-MHz radio waves from a broad angle range in the horizontal dimension.