基于U型双平面电磁带隙结构的小型化低通滤波器

提出了新型的微波低通滤波器结构,利用人工电磁谐振结构的基本特性,当谐振单元的结构尺寸满足一定条件时,会产生带隙特性,阻带的频率宽度和抑制深度随着谐振器的阶数而变化,由此也会增大电路的结构尺寸。为了改善电磁带隙结构的频率响应特性,将周期性谐振单元在基板两侧对称分布,并通过在传输线上添加开路枝节谐振器和马刺线结构来增加传输零点,从而增大阻带频率宽度和带内抑制深度。同时,将渐变理论应用于电磁带隙结构以改善通带波纹系数。与传统电磁带隙结构相比,所设计的改进型电磁带隙结构既可以改善频域传输特性,又可以减小电路尺寸。

A Miniaturized Lowpass Filter Based on U-Type Dual Plane Electromagnetic Bandgap Structure

In this paper, a miniaturized lowpass filter is designed based on U-type dual plane electromagnetic bandgap (EBG) structure. A bandgap behavior is shown when the periodic structure is satisfied with Bragg reflection condition. The bandwidth and suppression level is increased with the order of the EBG structure, but the size of the structure is enlarged correspondingly. In order to improve the transmission behaviors, open stub and spurline are added on the transmission line of the dual plane EBG structure. Then, two additional transmission zeros are introduced to increase the bandwidth and deepen the rejection level. Furthermore, the periodic resonators are distributed with U-type structure, which can make the EBG structure compact. In comparison with the traditional EBG structure, compact size, wide stopband and steep mitigation level are achieved with the presented EBG structure.