基于交指结构和双模谐振器的双频微带滤波器

Dual-band Microstrip BPF Based on the Interdigital Structure and Dual-mode Resonator

提出了一种应用于宽带系统和窄带系统的双频微带滤波器,其宽带通带和窄带通带分别通过三阶交指型滤波结构和双模微带谐振器来控制。两部分的相互加载效应可进一步增强源-负载耦合,提高通带的选择性。在50Ω馈线上加载两个不同尺寸的反向四分之一波长谐振器(QWR)耦合短路枝节,可以在通带之间及上下边缘处产生多个传输零点,提高了通带选择性和隔离度。最终,本文设计了一个工作于3.2GHz(宽带)和5.8GHz(WLAN)的双频滤波器用以验证上述设计方法,测试和仿真结果吻合良好。

A dual-band microstrip bandpass filter( BPF) is proposed for wideband and narrow band applications,which are controlled by the third-order interdigital structure and the short-stub-loaded resonators,respectively. The loading effect of the two different resonators can further enhance the source-load coupling,which can enhance the selectivity of the passbands. To further improve the selectivity and isolation of the passbands,two short stubs with different size which is coupled to an quarter wavelength resonator( QWR) are loaded in the 50Ω feedlines. Finally,a dual-band BPF located at 3.2GHz( wideband application) and 5. 8GHz( WLAN application) is designed and fabricated to verify the aforementioned design method. The measured results agree well with the simulated ones,which verifies the validity of the design.