This paper investigates the aperture optimization method of transmitting antennas for microwave power transmission (MPT) systems to obtain the maximum DC-DC (direct current to direct current) efficiency at a low budget. Two topological models, quasi-rhombus (QR) and quasi-circle (QC) are proposed and compared to the common square (SQ) model. The numerical results show that the QR and QC models can transmit much more power at a little higher beam collection efficiency than SQ one with the same total element number under certain condition.