Cavity-backed slot antennas and arrays with simple geometry adapted to microwave energy transmission

摘要

We give simple design rules for antenna elements and large-scale array antennas for an energy-transmission antenna system for the solar power satellite. Finite-Difference Time-Domain (FDTD) techniques are employed to evaluate the impedance characteristics of a single element and of elements in the antenna array, as well as to estimate values of mutual coupling. The large-scale array antenna under consideration consists of numerous cavity-backed slot antenna elements, operating at a frequency of 2.45 GHz. The cavity-backed slot antenna is superior to other types of antenna elements in mechanical strength and heat dissipation. The conventional antenna structure is a rectangular conductive cavity with a slot. Hence, it is difficult to fabricate an antenna array, due to the conductive sidewall assembly and its electrically perfect connection with the upper and bottom conductive plates. Instead of using conductive sidewalls in the cavity, we propose a new type of slot-antenna element, consisting of parallel conductive plates separated by metal posts, and excited by a shorted probe or an inverted-F element. Such a new configuration makes it easy to fabricate low-profile antenna elements, as well as array antennas.