Miniaturized dual‐mode sector patch bandpass filter using a single via‐hole

Abstract A miniaturized dual‐mode sector patch bandpass filter using a single via‐hole is presented in this article. Only a single 11.25° sector patch resonator, which is one‐thirty‐second of the complete circular patch resonator, is utilized to miniaturize the filter for the first time. Without changing the size and construction of the initial patch, a simple via‐hole is used to perturb the patch resonator, thus the novel dominant mode, which provides further compactness is generated. In addition, the change of via‐hole position is utilized to expand the bandwidth and significantly enhance the flexibility of the filter. Moreover, the proposed filter possesses two transmission zeros and it has obvious advantages of low insertion loss, compact size, and wide passband.