Practical Aspects of the Transmission Line Stub Matching in Microstrip

Abstract

While designing microwave circuits with microstrip lines using open or shorted stubs for matching or realization of filters, the actual circuit can be substantially mismatched when the length of the open stub is below 30 degrees of electrical length, or shorted stub is over 60 degrees of electrical length. Realization of such stubs could lead to practical difficulties because the normal etching accuracy does not support the exact lengths required for such stubs.