提出了一种双层半圆介质加载表面等离子激元波导新结构，并利用有限元方法对该新型波导结构在工作波长1550 nm下的传输特性进行了数值仿真和优化分析，得到了波导传播特性的主要参数。结果表明：在波导总面积保持不变的情形下，当双层半圆介质的折射率分别取为n1=1.4和n2=1.473时，波导的传播特性最佳；在此折射率参数基础上，波导的内外介质半径比r1/r2为0.5时，波导的传播长度最大、衰减系数最小并且模式面积和品质因数的取值都非常理想，可以获得最优的波导传输效果。

A new structure of double-layer semi-circular dielectric-loaded surface plasmon polariton (SPP) waveguide is proposed. By using the finite element method (FEM) on the waveguide structure at the telecom wavelength of λ=1550 nm, the transmission characteristics are simulated and analyzed to get the fundamental parameters of this kind of waveguide. The results show that the optimal transmission characteristics of the waveguide propagation can be achieved with the same total area for the waveguide and the refractive index of n1=1.4 and n2=1.473 for the double semi-circular dielectric layers. When the ratio of the inner and outer semi-circular dielectric radii is r1/r2 = 0.5, the maximum propagation length, minimum attenuation coefficient, ideal waveguide mode area and figure of merit can be achieved with the same refractive index parameters, so the optimal transmission results can be obtained.