Multiphysics Design of Dielectric-Coated S-Band Filter with a Screw-Free Tuning Method

This paper designs a fourth-order combline filter with a screw-free tuning method to enhance power capability. To satisfy the power demands, the top part of resonant columns in the filter are covered with spheres made of Teflon. The top wall of each cavity is correspondingly designed as a hemisphere to guarantee a uniform distance from the resonant columns, which avoids vulnerable points that may be broken down by high voltage. Besides, mechanical deformation is introduced as a special post-process tuning method to the filter instead of traditional tuning screws for better performance. Multiphysics analysis is applied to achieve the relationship between electromagnetic and mechanical parameters, thus providing a guideline for practical tuning structures. The coincidence between the simulation and measurement verified the proposed filter and the tuning method.