Recent Progress on Design Method of Microwave Power Amplifier and Applications for Microwave Heating

Recently, GaN devices are often adopted in microwave power amplifiers to improve the performances. And many new design methods of microwave power amplifier were proposed. As a result, a highefficiency and super compact microwave signal source has become easily available. It opens up the way for new microwave heating systems. In this paper, the recent progress on design methods of microwave power amplifier and the applications for microwave heating are described. In the first, a device model of GaN transistor is explained. An equivalent thermal model is introduced into the electrical non-linear equivalent device model. In the second, an active load-pull (ALP) measurement system to design a highefficiency power amplifier is explained. The principle of the conventional closed-loop ALP system is explained. To avoid the risk of oscillation for the closed-loop ALP system, novel ALP systems are proposed. In the third, a microwave heating system is explained. The heating system monitors the reflection wave. Then, the frequency of the signal source and the phase difference between antennas are controlled to minimize the reflection wave. Absorption efficiency of more than 90% was obtained by the control of frequency and phase. In the last part, applications for a medical instrument is described. key words: GaN power amplifier, pulse-mode operation, active load-pull, microwave heating, frequency and phase control, medical instrument

[1]  H. Zirath,et al.  On the large-signal modelling of AlGaN/GaN HEMTs and SiC MESFETs , 2005, European Gallium Arsenide and Other Semiconductor Application Symposium, GAAS 2005.

[2]  S. Sano,et al.  A 100W Class-E GaN HEMT with 75% Drain Efficiency at 2GHz , 2006, 2006 European Microwave Integrated Circuits Conference.

[3]  S. Sano,et al.  A 500W Push-Pull AlGaN/GaN HEMT Amplifier for L-Band High Power Application , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.

[4]  Y. Hirano,et al.  Internally-matched GaN HEMT high efficiency power amplifier for Space Solar Power Stations , 2010, 2010 Asia-Pacific Microwave Conference.

[5]  Fadhel M. Ghannouchi,et al.  Introduction to load-pull systems and their applications , 2013, IEEE Instrumentation & Measurement Magazine.

[6]  Keigo Nakatani,et al.  A 2.4 GHz-Band 100 W GaN-HEMT High-Efficiency Power Amplifier for Microwave Heating , 2015 .

[7]  Andrea Ferrero,et al.  Recent Advances in Real-Time Load-Pull Systems , 2008, IEEE Transactions on Instrumentation and Measurement.

[8]  H. Zirath,et al.  A new empirical nonlinear model for HEMT and MESFET devices , 1992 .

[9]  K. Motoi,et al.  A 72% PAE, 95-W, single-chip GaN FET S-band inverse class-F power amplifier with a harmonic resonant circuit , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[10]  Ishizaki Toshio,et al.  Study on stability of Active Load-Pull Systems , 2017 .

[11]  A. Ferrero,et al.  Recent Improvements in Real-Time Load-Pull Systems , 2006, 2006 IEEE Instrumentation and Measurement Technology Conference Proceedings.

[12]  Koji Yamanaka,et al.  Internally matched GaN FET at C-band with 220W output power and 56% power added efficiency , 2012, 2012 Asia Pacific Microwave Conference Proceedings.

[13]  Ishizaki Toshio,et al.  Basic study on Open- and Closed-Loop Active Load-Pull System , 2017 .