Pseudo-elliptic bandstop filter with 1:2:3 harmonic ratio stubs

Abstract

By employing open circuited stubs with a length ratio of 1:2:3 separated by three unit elements, it is shown that a pseudo-elliptic frequency response can be obtained with a compact structure. It has an electrical performance comparable to that of a Cauer filter, but is realizable in etched form for very wide bandwidths and very high rates of cutoff.