平坦通带高频纵向耦合谐振滤波器的研制

Development of Longitudinal Coupling Resonator Filter with Flat Pass Band

应用耦合膜理论,重点研究了纵向耦合谐振滤波器耦合换能器与输入/输出换能器间距对纵向耦合谐振滤波器通带波纹的影响,探讨了制作纵向耦合谐振滤波器中金属铝的干法刻蚀工艺。基于理论模拟得出的结论,文中给出了中心频率为900MHz纵向耦合谐振滤波器频率响应的计算模拟结果和实验测试数据。测得1dB带宽25.9MHz,3dB带宽28.7MHz,阻带抑制达到50dB,插入损耗3.85dB,通带波纹小于0.7dB。实验结果与理论分析相吻合。

By using coupling of modes theory,the relation of pass band ripple and the gap between coupling IDT and input/output IDT is studied.The dry etching process for making mental Al in longitudinal coupling resonator filter is discussed.The Simulation results for experimental filter（center frequency 900 MHz） and experimental results corresponding to the filter are presented in the paper.Measured insertion loss is 3.85 dB;attenuation of stop band rejection to main pass band is 50 dB.The 1 dB pass band-width is 25.9 MHz;3 dB pass band-width is 28.7 MHz with pass band ripple of about 0.7 dB.Theoretical results agree well with experimental results.