各向异性左手材料劈形平面波导传输特性

Propagation Properties of the Guided Modes in a Taper Slab Waveguide with Anisotropic Metamaterials

从Maxwell方程组出发,得到三层各向异性左手材料对称平面波导TM模的色散方程及功率流方程;利用多台阶近似法得到该类劈形平面波导TM0振荡模的反射系数和传输系数方程;根据TM模的色散方程、反射系数和传输系数方程画出相应的特性曲线.分析表明:随着电磁波的传输,TM振荡模传输系数ct2逐渐减小,但在零附近出现振荡,同时出现双模反射特性;随着波导长度的增加,第一类反射系数ar12从零开始逐渐增加,最终趋于恒定;第二类反射系数ar22单调增加,最大可接近于1.增加多层结构左手材料中金属填充比或电磁波频率,传输特性曲线下移,传输能力下降;第一类反射特性曲线下移,反射能力下降,但第二类反射特性曲线上移,反射加强.

The propagation properties of the guided modes were studied in a taper slab waveguide with anisotropic metamaterials.For TM oscillating guided modes,the dispersion and power flux equations were obtained from the Maxwell＇s equations.The transmission and reflection coefficients of TM0 mode in a taper slab waveguide with anisotropic metamaterials were investigated.Through the dispersion,transmission and reflection equations,some related characteristic curves were received.These curves show that the transmission coefficient ct2 decrease as the electromagnetic wave transmission,it begins oscillating near zero,and appears double-mode reflection.The first reflection coefficient ar12 increases from zero,then it approaches a fixed value.And for the second reflection coefficient ar22,it increases from zero to near 1monotonously.Besides,with the increase of the frequency of electromagnetic waves or metal filling ratio in the multi-layer structure,the curves of transmission coefficient move down,which reveals that the transmission in the waveguide decreases.For the first reflection,the curves moving down means the reflection for electromagnetic waves decrease.However,for the second reflection,the curves moving up means the reflection for electromagnetic waves increase.