Roll-off Improvement of Open-circuited Stub Bandstop Filter

Abstract

This paper presents an alternative implementation of a shunt open-circuited stub bandstop filter for microwave circuit.  By making use of the proposed implementation, a simple and compact bandstop filter with distinct bandstop characteristics  is  designed at 1.25 cutoff frequency and FBW of 1.2. This paper also focuses on how to increase the roll-off of bandstop filter by increasing the number of the shunt stub. A shunt open-circuited stub is the simplest band stop structure for microwave circuit design, and roll-off is a term commonly used to describe the steepness of a transmission function with frequency.