微带交指滤波器抽头的结构改进  

Structure improvement of tapped-line in microstrip interdigital filter

作　　者：文数文 高杨[2] 张大鹏 WEN Shu-wen;GAO Yang;ZHANG Da-peng(School of Information Engineering,Southwest University of Science and Technology,Mianyang 621010,China;Institute of Electronic Engineering,CAEP,Mianyang 621999,China;State Key Laboratory of Particle Detection and Electronics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]西南科技大学信息工程学院,四川绵阳621010 [2]中国工程物理研究院电子工程研究所,四川绵阳621999 [3]中国科学院高能物理研究所核探测与核电子学国家重点实验室,北京100049

出　　处：《光学精密工程》2018年第9期2261-2268,共8页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.61574131);中国工程物理研究院超精密加工技术重点实验室基金资助项目(No.2014ZA001);核探测与核电子学国家重点实验室开放课题基金资助项目(No.2016KF-02)

摘　　要：使用耦合谐振电路理论设计微带交指滤波器具有较好的灵活性,然而当衬底厚度和中心频率增加到一定程度时,由传统的50Ω抽头线得到的外部品质因数Qe达不到理论值。为了增大实际设计中的Qe,同时匹配源和负载,本文将传统的抽头结构改进为一段50Ω微带线与一段较细微带线组合的类SIR抽头;此外,为了减小微带线阶跃变化带来的回波损耗,将类SIR抽头改进为一段50Ω微带线与一段较细微带线渐变式过渡的抽头。最终,分别采用类SIR抽头和渐变式抽头设计了一个Ka波段微带交指滤波器。仿真表明:使用类SIR抽头和渐变式抽头得到的Qe都能与理论值相匹配,且带渐变式抽头的滤波器相比于带类SIR抽头的滤波器,其回波损耗减小8.31dB,插入损耗减小0.16dB。从而验证了所提出的两种抽头结构改进的可行性。According to the theory of coupled resonant circuits,the design of the microstrip interdigital filter is quite flexible.However,when the substrate thickness and the center frequency increase to a certain value,the external quality factor Q e cannot reach the theoretical value when using the traditional 50Ωtapped-line.In order to increase the Q e in the actual design and match the source and load,the traditional tapped-line structure was improved to an SIR-like tapped-line,with the combination of a 50Ωmicrostrip line and a narrower microstrip line.To reduce the return loss caused by the step change of the microstrip line,the SIR-like tapped-line was improved to a gradual tapped-line with the combination of a 50Ωmicrostrip line and a narrower microstrip line.Then,taking a Ka-band filter as an example,the microstrip interdigital filter was designed by using the SIR-like tapped-line and the gradual tapped-line,respectively.The simulation indicates that both the Q e of the SIR-like tapped-line and the gradual tapped-line can match the theoretical values.In addition,compared with the filter with the SIR-like tapped-line,the return loss of the filter with a gradual tapped-line is reduced by 8.31 dB,and its insertion loss is reduced by 0.16 dB.The feasibility of the proposed two kinds of tapped-line structure improvement is verified.

关 键 词：微电子机械系统 耦合谐振电路理论 微带滤波器 交指 抽头线 结构改进 

分 类 号：TN631.2[电子电信—电路与系统] TN713