单轴各向异性左手平板波导的导模特性研究

Investigation on guided mode characteristics of a uniaxially anisotropic left-handed material slab waveguide

为了研究单轴各向异性左手材料波导的传输性能,对单轴各向异性左手平板波导的导模特性进行了研究.推导了该波导的导模特征方程,对导模的快慢波特性进行了研究,发现单轴各向异性左手平板波导的非表面波模与各向同性左或右手材料平板波导的不同,它既可以成为快波模,也可以成为慢波模;非表面波偶模存在一个截止频率;表面波模都是慢波模.对表面波模特征方程有或无解的情况进行了研究.详细讨论了该波导的电磁参量与表面波模特征方程解的关系,发现有些情况下,对于同一频率,表面波可以存在两种模式.证明了波导的导模之间具有正交关系.

In order to investigate the transmission performance of a uniaxially anisotropic left-handed material waveguide, the characteristics of the guided modes of a uniaxially anisotropic left-handed material slab waveguide were studied. The characteristic equations of the guided modes in this waveguide were derived. The fast and slow wave characteristics of the guided modes were investigated. It was found that the nonsurface wave modes of the uniaxially anisotropic left-handed material slab waveguide are different from that of the right- or left-handed waveguide. These modes can be either fast wave mode or slow wave mode; there is a cut-off frequency for the non-surface wave even modes; and the surface wave modes are all slow wave modes. The conditions that the characteristic equation of the surface wave has a solution was also explored. The relationship between the electromagnetic parameters of the waveguide and the solution of the characteristic equation of the surface wave modes was discussed. It was found that the surface waves with the same frequency sometimes can have two modes. The orthogonality of guided modes was proven.