基于频率选择表面的三通带太赫兹滤波器的设计与分析

Design and Analysis of Three-Band Terahertz Filter Based on Frequency Selective Surface

目前三通带太赫兹滤波器存在通带带宽差异大的问题。为了提高太赫兹滤波器三通带的带宽均匀性,设计了一款基于频率选择表面的三通带太赫兹滤波器,其结构由三个嵌套式“十”字环金属贴片、“十”字金属贴片和聚酰亚胺衬底三层结构组成。当太赫兹波垂直入射到滤波器表面时,在0.1~0.862 THz范围内形成三个滤波通带,各通带的峰值透射系数约为0.9,具有较好的通带性能,并且通带之间的传输零点的透射系数都在0.07以下,带外抑制良好。各通带的3 dB带宽的最大通带比约为1.29,10 dB带宽的最大通带比约为1.13,具有较好通带均匀性。三个工作通带的矩形系数均大于1.7,通带边沿陡峭,频率选择性良好。该滤波器具有透射系数高、带宽差异小、结构简单和易于加工等特点,其在太赫兹的多信道通信领域具有广阔的应用前景。

The current three-band terahertz filter have a problem of large difference in passband bandwidth.In order to improve the bandwidth uniformity of terahertz filter,a frequency-selective surface based terahertz filter is designed,which consists of three nested "cross" ring metal patches,"cross" metal patches and polyimide substrate.When the terahertz wave is vertically incident on the filter surface,three filter passbands are formed in the range of 0.1~0.862 THz,and the peak transmission coefficient of each passband is about 0.9,which has good passband performance,and the transmission coefficient of transmission zero between the passbands is below 0.07,and the out-of-band suppression is good.The maximum bandpass ratio of 3 dB bandwidth is about 1.29,and the maximum bandpass ratio of 10 dB bandwidth is about 1.13,which has good passband uniformity.The rectangular coefficients of the three working passbands are greater than 1.7,the passband edges are steep,and the frequency selectivity is good.The filter has the characteristics of high transmission coefficient,small bandwidth difference,simple structure and easy processing.It has broad application prospects in the field of terahertz multi-channel communication.