Development of A Compact 915-MHz Push-Pull Power Amplifier for Use in Oxidation Process of PAN Fiber

Cheng-Hsuan Chan^1*, Tsung-Chi Yu², Tsun-Hsu Chang¹

¹Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
²Radio Frequency Group, National Synchrotron Radiation Research Center, Hsinchu, Taiwan

* Presenter:Cheng-Hsuan Chan, email:fearfulstring@gmail.com

We develop a 915-MHz continuous-wave push-pull power amplifier for high power materials processing. The developed amplifier is currently being used for researching the microwave-assisted oxidation process of PAN fiber, which is one of the precursor of carbon fiber. The developed amplifier module consists of planar baluns, input/output matching circuits, a transistor and a high-directivity directional coupler. The amplifier achieves 740 W output power with 63 % drain efficiency and 19.5 dB power gain. The development of such long wavelength source aims to provide a more uniform and phase-controllable large-area microwave processing, reducing unwanted effect brought by hot spots and non-uniform temperature distribution in large-area microwave heating.

Keywords: carbon fiber, directional coupler, microwave processing, planar balun, power amplifier