带宽恒定的电调带通滤波器

Tuned Bandpass Filter with Constant Bandwidth

为了减小电调带通滤波器结构的复杂度,该文设计了一种基于阶梯阻抗谐振器的电调滤波器。以变容二极管作为电调元件,贴片电感作为输入、输出耦合元件。采用ADS和HFSS软件分析了耦合系数和外部品质因数随频率的变化关系。仿真结果表明,在0.45~1.0 GHz,耦合系数和外部品质因数保持恒定。采用相对介电常数为2.2的Rogers 5880(tm)介质基板制作实物,并用网络分析仪进行测试,实测结果与仿真结果基本一致。

In order to reduce the complexity of the structure of electrically tuned bandpass filters,an electrically tuned filter based on step impedance resonators is designed in this paper.The varactor diodes are used as tuning elements and the chip inductors are used as input-output coupling elements.The ADS and HFSS software were used to analyze the relationships between the coupling coefficient and the external quality factor with frequency.The simulation results show that the coupling coefficient and external quality factor keep constant from 0.45~1.0 GHz.The proposed filter was manufactured on a Rogers 5880(tm)dielectric substrate with relative dielectric constant of 2.2 and measured by network analyzer.The measured results are basically consistent with the simulation results.