Design of Extracted-Pole Filters: an Application-Oriented Synthesis Approach

In this paper a novel design approach for a general configuration of extracted-pole filters is presented. The proposed solution is based on the synthesis of a prototype network, followed by the evaluation of the generalized coupling coefficients. The prototype is then de-normalized into a form suitable for implementation, i.e. characterized by parameters recoverable from the physical structure implementing the filter. The main advantage of the proposed design approach is that the dimensioning of the overall filter structure is broken into the dimensioning of elementary blocks, whose equivalent parameters are available after the synthesis (their value can be controlled exploiting the degrees of freedom offered by the use of the generalized coupling coefficients). Some design examples in different technologies are presented to illustrate the generality and effectiveness of the proposed approach.