A compact wideband bandpass filter (BPF) with a broad stopband (4.1 f0) based on a triple-mode stub-loaded resonator (SLR) is presented in this article. Using even/odd mode analysis, the proposed SLR is found to have the ability to introduce three transmission poles in the passband. By appropriately adjusting the frequencies of these transmission poles and using a 0 tapped feed structure, the BPF can provide a wide passband and a sharp rejection over a broad stopband without using other lowpass or bandstop networks. The predicted results on S-parameters are compared with measured ones and good agreement is achieved.
- bandpass filter
- stub-loaded resonator