Synthesis of Simplified Cross Coupled Blocks with All Positive Couplings
In this work we present the synthesis of popular cross-coupled blocks used in the synthesis of filters with a cascaded topology to introduce transmission zeros in the response. The goal of the synthesis is to obtain the sign of all the couplings in the considered blocks positive (regardless of the position of the assigned transmission zeros). Furthermore, the elimination from the block topology of couplings that are difficult to implement is also realized. To solve this problem, we have exploited a recently introduced polynomial characteristic (namely the Reduced Chebycheff characteristic), which allows additional degrees of freedom with respect the classical Chebycheff response. The proposed synthesis technique has been validated by an experimental prototype, whose measured response is in good agreement with the theory prediction.