一种基于正方环形谐振器的新型宽带带通滤波器

A Novel Wide-band Band-pass Filter Based on Square Ring Resonator

本文设计了一种紧凑型、宽通带、宽阻带的微带带通滤波器。该滤波器的设计是基于带有两个开路调节支节的正方谐振环。基于紧凑性的考虑，改变了传统方环谐振滤波器的馈电点和开路调节支节的位置，以便对谐振环进行折叠处理。这种改变并不影响谐振环的奇偶模特性。在输入和输出端口，通过两个叉指耦合结构对滤波器进行馈电，这种馈电方式增加了滤波器阻带的带宽和抑制度。滤波器的中心频率为4GHz，相对带宽为45％，通带内的回波损耗小于-12dB，群时延小于0．8ns，1-2．9GHz阻带抑制度大于12dB，5．3～7GHz阻带抑制度大于18dB。

A novel compact micro-strip band-pass filter with wide band-pass and wide stop-band is presented, it is designed based on a square ring resonator with two tuning open stubs. In order to achieve compact design, location of feeding point and tuning open stubs of the traditional square ring resonator filter are changed for easy folding processing to the square loop, and this change did not affect the even-odd mode characteristic of the ring resonator. Two interdigital couplers are introduced at input/output ports for feeding of the filter, which can increase bandwidth and rejection of stop-band of the proposed filter. The center frequency of proposed filter is 4 GHz and relative band- width is 45%, the return loss within passing band is less than-12dB, the group delay is less than O. 8 ns, rejection is better than 12dB within stop-band of 1 -2. 9 GHz, and better than 18 dB within 5.3 -7 GHz.