新型交叉耦合双模宽带带通滤波器设计

Novel Cross-coupled Dual-mode Wideband Bandpass Filter

采用变形的阶梯阻抗谐振器(SIR)设计了一款小型化、高性能新型宽带带通滤波器。通过对经典的SIR进行弯折,在高阻抗线之间引入交叉耦合构成交叉耦合多模谐振器。该谐振器具有与经典SIR相同的谐振模式,由前两个谐振模式构成通带,并且在上下阻带产生两对对称的传输零点。该带通滤波器结构紧凑、带内差损非常小,同时由于带外传输零点的存在,一阶杂散得到有效抑制,带外特性明显改善。

A novel miniaturized and high performance wideband bandpass filter using a single modified stepped impedance resonator （SIR） is presented. By bending the classical SIR, cross-coupling is introduced between the high-impedance lines to construct cross-coupled multiple-mode resonator. The resultant resonator can not only provide the first double resonances of a classical SIR for building a passband, but also produce two pairs of symmetrical transmission zeros at the lower and upper stopbands simultane- ously. The filter has compact size and very low insertion loss. Meanwhile, the first stray is also suppressed by the transmission ze- ros, leading to the significantly improved out-of-band performance.