Pseudo-elliptic function bandstop filter with shunt foster sections

Abstract

Filters with transmission zeros in the stopband have been shown to have superior rates of cutoff. Conventional Cauer filters give excellent performance but are relatively large and not always practically realizable. In this article, the design of a pseudo-elliptic bandstop filter which employs only shunt Foster sections and unit elements is presented. The filter is of the same size as a Chebyshev filter of the same order, but has a performance comparable to a Cauer filter.