Dual-band Bandpass Filters using Inverted Stepped-Impedance Resonators

Abstract

This paper presents a new dual-band bandpass filter (BPF) using inverted stepped impedance resonators. In the proposed filter configuration, the conventional half-wavelength open-circuited stub single-frequency resonators are replaced with dual-band simple two-section stepped impedance configurations. Simple equations to design the dual-band stepped impedance resonators are derived using transmission line analysis. The filter structure is investigated using a full wave electromagnetic (EM) simulator and then realized at 2.5 GHz and 3.55 GHz bands. Experiments have also been done to validate the design concept. The distinguished dual-band performance of the proposed design is verified by the simulation and measurement results.