Tapered Distributed Filters

Abstract

The study of distributed networks has been prompted by the trend in electronic equipment toward smaller and smaller physical structures. Various investigators have determined the network characteristics of rather complex distributed RC structures. It is the purpose of this paper to point out the effects of geometrical tapering on the characteristics of distributed RC structures. Uniform (untapered), exponential, and linear tapers are analyzed for the distributed RC line and for a distributed narrow-band-rejection filter. It is shown that tapering is useful for sharpening the cutoff of gain vs frequency for the RC line and it is also useful for narrowing the rejection band of the "notch" filter. Transient behavior of the RC line is also investigated. Analytical expressions are presented for the network parameters and for the unit step response of both types of tapered RC structures.