Synthesis without optimization of cascaded inline prototype filters with arbitrary transmission zeros

This work describes a novel synthesis technique of inline low pass prototype filters with arbitrary transmission zeros. The inline topology is constituted by the cascade of elementary building blocks extracting single or multiple transmission zeros. The novel synthesis method is based on the matrix rotation technique; starting from a recently proposed canonical prototype (wheel topology), general rules are introduced for determining the sequence of matrix rotations with the corresponding rotation angles which lead to the desired inline topology (which must satisfy the feasibility conditions for the given transmission zeros). The proposed technique does not require optimization procedures and it allows the association of a transmission zero to a specific block (such as the triplet, the quadruplet, the box section, etc) increasing the degree of freedom in the filter design process.