毫米波微带带通滤波器的设计

一种毫米波微带带通滤波器的设计

内容简介：基于小反射理论,引入Klopfenstein阻抗渐变线对传统发夹型谐振器结构进行改进,设计了一种相对带宽为8%的结构紧凑型毫米波带通滤波器。采用S参数的多项式综合方法得到耦合矩阵电路模型,利用三维电磁场全波仿真软件HFSS拟合出耦合系数与谐振器间距、外部品质因数与抽头位置的关系曲线,进而提取出耦合矩阵对应滤波器的物理尺寸。实测结果表明：在28.8 GHz~31.2 GHz频带内,该滤波器的插损小于3.0 dB,回波优于-17 dB,带外抑制大于40 dB@33 GHz,测试结果与计算结果吻合较好。

Abstract：A millimeter-wave microstrip bandpass filter of a 8% fraction bandwidth is presented here. It is developed from the traditional hairpin resonator structure with introducing the Klopfenstein impedance taper which is based on the theory of small reflection. First,coupling matrix model is derived with synthesis methods of Chebyshev transfer and reflection polynomials. Then the curve of coupling coefficient versus coupling spacing and the curve of external quality factor versus tap location are calculated and plotted with HFSS. Finally,the physical dimensions of the corre-sponding filter can be extracted from the results above. The test result shows that the insertion loss is less than 3 dB and the return loss is better than -17dB in the frequencies of 28. 8 GHz to 31. 2 GHz,besides the out-of-band rejection level is larger than 40 dB at the frequency of 33 GHz. The result matches with the simulations very well.

作者：王文才, 陈昌明, 杨刚,

关键词：滤波器, 发夹谐振器, 耦合矩阵, 外部品质因数