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%.

The expansion of the communication area is expected for Beyond-5G/6G networks using the High Altitude Platform Station (HAPS), Internet of Things (IoT), and sensor devices. Beyond-5G/6G networks constitute the vast amounts of devices that require the latest power utilization system. We expect Microwave Power Transfer (MPT) plays a role in the wireless power supply to HAPS, IoT, and sensors in this network. This work discusses the link design and techniques of MPT for the newest power utilization system required on Beyond-5G/6G networks.

The high performance GaN power amplifier circuit operating at 7.1 GHz was demonstrated for potential use such as in a space ground station. First, the GaN HEMT chips were investigated for the high power amplifier circuit design. And next, the designed amplifier circuits matching with the load and source impedance of the non-linear models were fabricated. From measurement, the AB-class power amplifier circuit with the four-cell chip showed the power added efficiency (PAE) of 42.6% and output power with 41.7dBm at -3dB gain compression. Finally, the good performance of the power amplifier was confirmed in a 20-way radial power combiner with the PAE of 17.4% and output power of 52.6 dBm at -3dB gain compression.