过模基片集成波导腔体滤波器设计

Design of Oversized SIW Cavities Filters

提出了一种过模基片集成波导(SIW)腔体滤波器。介绍了只由单个过模SIW腔体构成的一阶滤波器的原理。利用过模SIW腔体中的基模实现模式交叉耦合,滤波器能产生一个位于通带任一边的传输零点(TZ)。设计了一个由两个过模SIW腔体级联成的二阶滤波器,该滤波器能产生两个传输零点。为了改善滤波器的阻带性能,使用了非相似谐振器技术来实现寄生抑制。此外,阻带性能也可以通过增加基模谐振器的数量来改善。设计并制造了含有两个过模SIW腔体的二阶和三阶滤波器,仿真与测试结果吻合。

In this paper, oversized substrate integrated waveguide （SIW） cavities filters are proposed. First, the the- ory of a first-order filter only constituted by an ,oversized SIW cavity is introduced. By using modal cross coupling provided by fundamental resonance mode in an oversized SIW cavity, one transmission zero （TZ） on either side of the passband is gener- ated. Then, we design a second-order filter with two TZs by cascading two oversized SIW cavities. To improve the stopband performance of the filter, the technique of using dissimilar resonators for spurious suppression is adopted. In addition, stop- band performance can also be improved by adding the number of fundamental mode resonators to the filter. A second-order and a third-order filter consisting of two oversized SIW cavities are designed and constructed. Good agreement is observed be- tween simulation and measurement.