新型的方形贴片双模微带带通滤波器

Novel square patch dual-mode microstrip bandpass filter

提出了一种新型的方形贴片双模微带带通滤波器。该滤波器结构有一个切角,并且在贴片中心处开了一个两臂等长的十字槽,采用正交直接馈电方式,并在每条馈线上引入了一节与谐振腔有一定耦合的开路短截线。该结构在上下阻带都产生衰减极点,馈线上引入的微带线有效地抑制了寄生通带,提高了阻带抑制特性。仿真结果表明,该滤波器在中心频率2.9 GHz处,回波损耗优于–30.9 dB,通带内最小插入损耗为–0.1 dB,与实测结果基本一致。

A new type square patch dual-mode microstrip bandpass filter was proposed. The structure of the filter had a corner cut, and a pair of equal crossed slots in the center of patch. Using orthogonal direct feed way, open-stubs were added on the feed-lines to suppress the spurious band and to improve the stopband rejection. The filter could produce attenuation poles in the passband on both sides. The simulating results show that the passband center frequency is 2.9 GHz, the max return loss surpasses -30.9 dB and the minimum insertion loss is -0.1 dB in the passband. The measured result is in good agreement with simulated result.