5.8-GHz Series/Parallel Connected Rectenna Array Using Expandable Differential Rectenna Units

This communication demonstrates series and/or parallel connection of the differential rectenna units. The differential rectenna unit provides high expandability of rectenna arrays due to its balanced structure. The proposed rectenna array produces higher voltage and/or more current by the series and/or parallel connection of the rectenna units. In the measurement, 30% RF-DC conversion efficiency at the power density of 0.03 W/m2was achieved in all the case of series and/or parallel four-units connected rectenna array. The maximum conversion efficiency was about 38% in the case of the series-parallel connection. As the proposed rectenna arrays can be easily expanded to large scale integrated rectenna arrays, it will be practically attractive for wireless power transmission.