Design of triple-band bandpass filter using quad-mode stepped impedance resonator (SIR) with shorted stub

作者：Song, Yi; Xu, Yichen; Liu, Haiwen^*; Ma, Zhewang

来源：IEICE Electronics Express, 2018, 15(2): 20171219.

DOI：10.1587/elex.15.20171219

• triple-band filter
• quad-mode
• stepped impedance resonator

A compact microstrip triple-band bandpass filter (BPF) using an improved quad-mode stepped impedance resonator (SIR) with shorted stub is introduced in this letter. Distinct mode splitting characteristics of the quad-mode SIR are investigated by adopting even-and odd-mode theory. Two pairs of even-odd modes are utilized to design the former two passbands with the help of loop-loop coupling for splitting two identical modes. Then, a tapped side-coupled feed-lines construct an additional passband avoiding occupying extra size. The bandwidth of each passband can be controlled independently. To validate the approach, a triple-band BPF centered at 1.4/2.7/ 3.57 GHz has been implemented. Good agreement is obtained between simulated and measured results.

• 出版日期2018-1-25
• 单位西安交通大学; 华东交通大学