Synthesis of Extracted-Zero Filters

We present here an exact synthesis procedure for the low-pass prototype of extracted-zero filters. This type of filter has been recently introduced and it allows the realization of a true in-line topology with up two transmission zeros. Compared to other in line (or quasi-inline) solutions, the one here considered is the simplest to dimension and fabricate (the same techniques used for all-pole filters can be adopted).The procedure here presented has been applied to the synthesis of various prototypes and the results confirms the effectiveness of the proposed concept. A filter previously realized in a quasi-inline configuration has been re-designed in the new topology and the results obtained with the two topologies are compared and discussed