Synthesis of Fully Canonical Wideband Bandpass Filters With Complex Reflection Zeros

The paper presents a synthesis of fully canonical wideband bandpass filters with complex reflection zeros (RZs), which can realize the bandpass filters with the same number of transmission zeros (TZs) as the order of filters. Three functions are proposed to generate the general Chebyshev filtering function with complex RZs. A simple recursion technique is described for the generation of the polynomials for the filtering function with symmetrically or asymmetrically prescribed TZs. Then, a method for the direct extracting the elementary lumped elements of the modified inline topology circuit to yield a prescribed response is given. Two design examples demonstrating the soundness of the synthesis method are presented and one of them is implemented, fabricated, and measured.