Fast and efficient systematic procedure for and flexibility on the end coupling design in microwave filters

The end coupling of combline microwave cavity filters is designed to achieve the desired value of the external coupling. The interest in the subject is twofold: a) design parameters characterising the end coupling can be excluded by further optimizations; b) the end coupling requires neither post-manufacture adjustments nor tuning elements. A fast and efficient systematic procedure distinguishing between design and tuning parameters is used to solve the task and it enlightens the flexibility characterizing the design of the end coupling. Numerical results for the E1 Galileo band are provided and a sensitivity analysis is performed.