Multilayered stripline interdigital-hairpin bandpass filters with small-size and improved stopband characteristics

In this paper, novel multilayered stripline interdigital-hairpin bandpass filters are proposed. The new structure can not only reduce the size of the filters, but also provide transmission zeros to improve the stopband characteristics. As design examples, a four-pole and an eight-pole bandpass filters using the proposed structures are provided. Moreover, the novel four-pole bandpass filter is fabricated and measured. The experimental results agree very well with the simulated data.