A tri-band filter using tri-mode stub-loaded resonators (SLRs)

Abstract

The tri-mode stub-loaded resonators (SLRs) are employed in the design of a tri-band bandpass filter (BPF), where a special coupling structure is used to provide enough design freedom, and a magnetic source-load coupling is introduced to improve the frequency selectivity with six transmission zeros. The good performance of our proposed filter is demonstrated by good agreement obtained between the simulated and measured S-parameters.