A novel technique for automated post production filter tuning

A novel technique for automated post production filter tuning is presented. The characteristic parameters of a de-tuned or roughly pre-tuned filter under test are extracted from an initial S- parameter measurement. The extracted parameters can be directly compared to the parameters of a tuned (ideal) filter known from filter synthesis. Frequency shifts of individual resonators with respect to the operating frequency or detuned coupling elements between the resonators are immediately obvious. A sensitivity analysis determines the electrical characteristics of the tunable elements as a function of position or penetration depth (e.g. tuning screws), respectively. In a final optimization, the optimal positions of the tuning elements (screws) are found.