一种曲折型缺陷地结构超宽带滤波器的设计

针对超宽带滤波器插损较大、阻带较窄的问题,提出一种曲折型缺陷地结构小型超宽带滤波器的设计方法.首先,在金属地面上开曲折型缝隙,得到曲折型缺陷地结构；然后,依据曲折型缺陷地平行耦合线和传输线的结构特点,分别构造它们的等效电路模型,再结合HFSS仿真来验证电路模型的正确性,推导出结构尺寸与等效电路元件参数之间的对应关系,得出曲折型缺陷地平行耦合线具有超宽带特性和曲折型缺陷地传输线具有低通高选择性的结论.结合这两种结构的优点设计了一种结构简单、具有宽阻带的超宽带滤波器.测试结果表明,与传统缺陷地结构和复合左右手传输线(CRLH)结构的超宽带滤波器相比,该滤波器具有插损小的特点,其带内最大插损仅为0.88 dB,阻带抑制在11.75～20 GHz范围内均小于-30 dB.

Design of Ultra-Wideband Filter with Tortuously Defected Ground Structure

A novel design method for small ultra-wideband(UWB) filter is proposed by using tortuously defected ground structure(DGS) to solve the problem of larger insertion loss and narrower stop band in the design of UWB filter.Firstly,a tortuous DGS is obtained by using winding shaped slot in the metal ground,and then equivalent circuit models are established according to the structural features of the parallel coupled-line and the transmission line of the tortuous DGS.The correctness of the circuit models is verified by using software HFSS,and the relation between DGS size and equivalent circuit parameters is deduced.The UWB characteristic of the parallel coupled-line and the low-pass/high selective characteristic of the transmission line of tortuous DGS are demonstrated.A simple and high-selective UWB filter is then designed based on the advantages of the two lines.Test results show that the insertion loss of the proposed filter is lower than those of the conventional DGS and the CRLH UWB filters,and that the measured maximum insertion loss is about 0.88 dB and the rejection in the range of 11.75 to 20 GHz is less than-30 dB.