基于开口谐振环上加载变容二极管设计可调谐滤波器,很好地实现了电磁波带隙的可调。在单环开口谐振环缝隙处或者双环开口谐振环的两环之间加载变容二极管,改变加载变容管上得的电压,改变该结构的分布参量而达到滤波器可调性能。同时通过数值计算分析了该滤波器结构对电磁波的频率响应函数,指出其形成电磁波带隙的物理机制,为了消除开口谐振环的磁谐振效应而关闭开口谐振环的缝隙实验进行了验证。研究表明基于变容管开口环的可调谐滤波器所形成的电磁波带隙中,有的带隙是源于磁谐振机制,有的带隙是源于电谐振机制。对该滤波器形成带隙物理机制的研究,可以更好地理解开口谐振环,有助于其在光学和微波波段器件的设计。

Tunable filters with varactor-loaded spilt-ring resonant structure have been fabricated and the electromagnetic bandgap tuning is achieved. The varactor is positioned in a gap of a single split-ring resonator or between two split-ring resonators, and the filtering is tuned through capacitances modulation of the structure by adjusting the bias voltage applied to the varactor. The frequency response function of the filter to electromagnetic wave is numerically analyzed, and the physical principle of electromagnetic bandgap formation is explained. In order to eliminate the magnetic resonant effect and close the gap of split-ring resonator, experiments are carried out. It is found that the some bandgaps are resulted from magnetic resonance and some are resulted from electric resonance.