A novel wideband stepped-impedance rectangular-ring resonator bandpass filter with two notched bands

A new configuration of wideband bandpass filter (BPF) with notched bands is presented. Proposed BPF is based on stepped-impedance resonator. By utilizing dual stepped-impedance resonators in folded topology a rectangular-ring resonator is formed. Two notched bands in the passband are achieved without using asymmetrical coupled lines. In other words, the filter configuration is capable of producing notched bands.