Microwave power transmission system with phase and amplitude controlled magnetrons

Since the first proposal of a space solar power system (SSPS) in 1968, many different types of SSPS have been proposed. The SSPS reference system, the SPS2000, the Sun Tower and recent Japanese models are among them. Some of them are designed with microwave power transmission (MPT) technology based on a microwave power transmitter with microwave tubes. Electronic tubes, such as klystron or magnetron, have high efficiency (>70%) and high power output (over kW). The other MPT system is a microwave power transmitter with semiconductor amplifiers. However, the efficiency of the semiconductor amplifier is still below 40% and still much more expensive compared with the microwave tubes. The power-to-weight ratio of the semiconductor amplifier is over 50g/W, and heavier than that of a microwave tube (below 30g/W). The higher the efficiency, the less launching weight and size required. We show a new concept of a microwave power transmission system using phase and amplitude controlled magnetrons (PACM) with high efficiency and we propose a new phased array system with PACMs for the SSPS.