A simple, low reflection, and highly-efficient pilot-plant scale microwave irradiation reactor for woody biomass pretreatment was fabricated. Pretreatment is an essential process for effective bioethanol production. The fabricated reactor consists of 8 microwave irradiators which are attached to a metal pipe. The woody biomass mixture which contains water and organic acid flows through the metal pipe and is heated by microwaves at a total power of 12,kW. To design the microwave irradiators, we used a 3D Finite Element Method (FEM) simulator, which was based on the measured complex permittivity data of the woody biomass mixture. The simulation results showed that the reflection coefficient $|S_{11}|$ from the reactor was less than -30,dB when the woody biomass mixture temperature was between 30$^{circ}$C and 90$^{circ}$C. Finally, we experimentally confirmed that the fabricated irradiation reactor yielded a microwave absorption efficiency of 79%.

We developed a phase controlled magnetron (PCM) with high DC-RF conversion efficiency and with phase control to steer a microwave beam in order to realize the final space Solar Power Station (SPS) system. For the PCM, we use injection locking technique and PLL feedback to anode current. We can stabilize and control a frequency and a phase of a microwave of the PCM. However, we have a power loss after the PCM for the SPS use because of a size of the antenna (> km) and of a microwave power (> GW). In order to decrease power loss after PCM, we newly propose a concept of "sub phase shifter" which can change only 1 or 2 bits of a phase and has low loss. We can keep high beam collection efficiency when we control a beam to a twice larger direction in the SPS system. With this concept, we developed a PCM array called SPORTS (Space Power Radio Transmission System) in FY2000 and FY2001 in Kyoto University.