摘要
提出了一种结构简单的新型太赫兹带阻滤波器。滤波器结构为内表面刻有方型槽阵列的平行平板波导。太赫兹波入射时,在周期结构表面激发出只与表面几何结构有关的表面等离子波。有限元法仿真结果表明:平行平板波导中波导模式的基模转换为表面等离子模式,该模式和高阶波导模式之间产生能带间隙,频率在该间隙频段内的太赫兹波将无法在波导内传播,从而实现带阻滤波功能。通过错位法,可以对该结构进行改进,使该阻带与较高频阻带间的通带增大,使结构更符合带阻滤波器的要求。通过改变两板间距,槽宽和槽深各参数可以得到不同带宽和中心频率的阻带。
A new type of terahertz band-stop filter is presented. The filter consists of two parallel metallic plates with rectangular groove arrays on their inside surfaces. Surface plasmon polaritons controlled entirely by the surface geome- try can be excited in a metallic periodical surface when terahertz wave is injected. The finite element method simula- tion results show that the fundamental wave guide mode of the parallel metallic plates is changed into surface plasmon wave mode, and a band gap between this mode and other wave guide modes is produced. The band-stop filtering func- tionality is realized by rejecting all frequencies in the gap. Transmission spectra also show zero transmission within the band gap region. By slightly shifting one of the parallel plates, the structure can be improved, it makes the passband between this band-stop and higher frequency band-stop to increase, and satisfy the demand of band-stop filter. By var- ying the distance of two plates, groove width and groove depth, the band-stop with different filtering bandwidth and dif- ferent center frequency can be achieved.
出处
《激光与红外》
CAS
CSCD
北大核心
2013年第7期803-808,共6页
Laser & Infrared
基金
国家自然科学基金(No.60671006
No.60971059)资助
