Effective loss design of double-passband filters

Two methods, valid for antimetric and symmetric (or ametric) networks, respectively, are developed for the insertion-loss synthesis of the double-passband filters having an equiripple amplitude response in the passbands. One unfavorable relation connects limit frequencies of the passbands to the frequencies of the attenuation poles, but this relation might disappear with parametric and ametric filters and that gives a great interest to these filter types.