Cascded Triplet and Quadruplet filter design using cascade syntesys approach

A unified review of design of Cascaded Triplet (CT) and Cascaded Quadruplet (CQ) filters are presented. Cascade synthesis approach with pole placement is used to synthesize the filter and then Norton transformations are used to put the circuit into a standard form for conversion into CT ar CQ form. Sections of the filter containing one FTZ can be converted into Bridge Tees forming the CT sections and sections of filters containing two finite transmission zeros are converted into CQ sections. An example is given showing development of equivalent alternative CT and CQ filter structures having all-inductive, all capacitive or mixed cross-couplings, depending on the location of FTZs with respect to passband