Compact Dual-Band Bandpass Filter Using Single Perturbed Rectangular Patch Resonator with Stubs

In this paper, a compact dual-band bandpass filter (BPF) using a single perturbed rectangular patch resonator with two stubs is presented. Four resonant modes in the single rectangular patch are used to design this filter. Without changing the size and construction of the initial patch, only two simple metallic via-holes are used to realize desired perturbed structure in this filter. In addition, the perturbation metallic via-holes can be utilized to adjust the bandwidths of passbands. To improve the design freedom degree of the dual-band filter, two stubs are applied in this design and they can be utilized to flexibly adjust desired centre frequencies and bandwidths of two passbands. The filter is fabricated, and measured results agree well with simulated ones.