A novel self‐packaged DBBPF with multiple TZs for 5G sub‐6 GHz applications

Abstract

AbstractIn this article, we proposed a self‐packaged dual‐band bandpass filter (DBBPF) with high isolation and low insertion loss (IL) for 5G sub‐6 GHz applications. To get high stopband suppression, multiple and controllable transmission zeros (TZs) are introduced. A pair of quarter‐wavelength stepped‐impedance resonators (QSIRs) and half‐wavelength hairpin resonators (HWHR) are introduced to form a cross‐coupled five‐star topology to generate two passbands and multiple TZs analyzed by mixed electromagnetic couplings. A pair of U‐shape resonators are designed on G6 to fully excite the resonators and introduce source/load TZs at the same time. The generation of TZs by separate electric and magnetic coupling paths (SEMCP) is discussed. The DBBPF achieves a low IL of 0.85/1.13 dB with fractional bandwidths (FBW) of 11.0%/6.9% at center frequencies of 3.45 and 4.9 GHz for 5G sub‐6 GHz applications, respectively. The total size is only 0.32 λg × 0.45 λg.