一种新偏压结构的BST电容梳状滤波器设计

介绍了一种五阶可调抽头式梳状线滤波器,设计采用共面方式接地,使用Ba0.6Sr0.4TiO3 (BST)铁电薄膜平板电容作为可调部件,并分析了平板电容结构的影响.针对梳状电调滤波器需单阶加压和外接大电阻繁琐的情况,提出利用集成在衬底上的大容量BST电容作为隔离电容,将各阶谐振器的偏压线互连来简化加压过程.运用高频电磁仿真软件HFSS进行验证,设计出的滤波器中心频率可调范围为842～960 MHz(14％),3 dB带宽为9％～10％.

Design of BST Capacitor Comb line Filter with a New Bias Structure

A new type of five order tunable tapped comb line filter has been presented in this paper.The designed device uses the coplanar ground and uses the ferroelectric film Ba0.6Sr0.4TiO3(BST) parallel plate capacitors as the tunable component.The effect of the plate capacitor on the device has been analyzed.Aiming at the condition that a DC bias and high resistance for isolation are required for the comb line filter,a method which uses the high capacity BST capacitor integrated on the substrate as the isolation capacitor and interconnects the bias lines of each order resonator to simplify the pressure procedure has been proposed the first time in this work. The design is simulated and verified by software of HFSS.The designed filter has the center frequency tuning range of 842~960 MHz(14%) and 3 dB bandwidths of 9%~10%.