Microwave High-Power Four-Posts Auto-Matching System

One of the most important problems of microwave energy in industry is the need to perform a customized design, since applicator behavior is very dependent on the material. Little modifications in size or shape can make the applicator energy inefficient, since microwave cavities are usually very sensitive, which can result in a wasted high-reflected power. We have developed an auto-matching system based on a four-post matching network. It can be used to improve the energy performance on most systems, and is able to decrease the S₁₁ parameter to less than -30dB. It implies that reflected power is less than 0.1% from the incident one. The developed system is built on WR340 waveguide and consists of four motorized metallic posts, whose penetration depth inside the waveguide is varied. This penetration depth is calculated from the reflection coefficient measurement performed by a six-port reflectometer at the start. Then the system is monitored and fine-adjusted all along the process