Retrodirective Array Antenna System for the Microwave Power Transmission

The long and middle range MPT (microwave power transmission) is very important, which basically uses RF beamforming technology to efficiently provide the power at distance and requires the large dimension of array system to the far end power receiver. In this paper, we design an antenna and phase conjugate circuit for the retrodirective array antenna system. The beam directivity is improved by 0.2dBi, 0.45dBi and 0.3dBi at 0, 120 and 180 degree. Simulation results show that the phase conjugation is well performed. So, the proposed system can be useful for the middle range MPT system. Also, we have studied and discussed the system power efficiency for wireless power transmission and antenna array dimension. A design example shows the primary design of 5% power efficiency for microwave power transmission at the distance of 4 m. when the center frequency is 2.45GHz.