Contents I. Introduction
Energy is always one of the most critical issues, especially in the modern society over-exploitation of resources lead to global environmental and energy crisis. According to the reports, at the current consumption rate the fossil fuel resources will be completely lost within 100 to 150 years[1]. So to pursue sustainable energy sources have become a research hotspot and catches more and more researchers' attentions in resent years. Solar power is a kind of sustainable and safe energy. Considering the atmospheric absorption, hours of sunshine, solar power station is higher efficiency in space than it's on the ground. The use of a microwave beam to transport solar power from space to the earth surface was proposed by Peter Glaser in 1968 [2]. This idea known as solar power satellite(SPS), which collects solar energy in space and transmits it to the ground. High power conversion efficiency is one of the primary considerations in SPS system. So a high PAE PA is an important part of SPS.
