US Patent 7791557 Multiple antenna energy harvesting

Energy harvesting circuits and associated methods are provided that employ multiple antennas to optimize the amount of energy that is harvested while at the same time making efficient use of tag space. In some embodiments, matching networks are chosen in a manner that optimizes the DC energy that is created from the harvesting process. In other embodiments, phase shifts are introduced into the received signals to allow the signals to be more efficiently combined after they are rectified.