Advanced Rectenna Technologies for Space Power Applications

This proposal describes innovative, low-cost design of a rectenna system capable of delivering a large amount of electric power to the military space-vehicles. The key innovations essential to the system include: (1) high efficiency dual polarized rectenna and array; (2) EMI noise reduction techniques, (3) failure and thermal analysis (4), device technology study for high frequency rectennas and (5) the bus-bar design for DC output power. High power transmitter sources such as high power tubes or quasi-optical power combiner in which a large number of low power devices combine their output powers quasi-optically in the free space are capable of converting available electrical energy (solar, nuclear, hydro, etc.) into an electromagnetic wave (microwave, millimeter-wave, laser), transmitting via an antenna, and the receiving the energy at a remote point, and converting back into a usable format (DC, 60 Hz, etc.). The rectenna (rectifier + antenna) that converts the received microwave power into DC power can be developed using printed antenna elements integrated with the solid-state devices such as Schottky devices. A high efficiency circularly polarized conformable rectenna design capable of delivering large amount of electric power for spacecraft and its payload system is needed. A modular approach will be developed for easy replacement and maintenance. The techniques to reduce the higher order harmonic radiation from the large rectenna structures and bus-bar design are also described.