光子晶体微波加速结构的计算与设计

用有限差分法计算了由金属棒分别按方形和三角形晶格分布的二维光子晶体的色散曲线, 得出了带隙图．计算结果表明: 对于三角形晶格, 当金属棒半径和棒间距比值小于0.2时, 由该种光子晶体构成的微波加速结构可约束主模、抑制高次模; 用Microwave Studio软件模拟计算了三角形晶格分布的二维光子晶体加速结构, 研究了新加速结构的RF参数与结构尺寸的关系, 优化出一组RF频率为9.37GHz时此种加速腔的结构尺寸, 计算还表明该种新加速结构具有较高的分路阻抗和品质因数.

Simulation and Design of the Photonic Crystal Microwave Accelerating Structure

We have derived the global band gaps for general two-dimensional (2D) photonic crystal microwave accelerating structures formed by square or triangular arrays of metal posts. A coordinate-space, finite-difference code was used to calculate the complete dispersion curves for the lattices. The fundamental and higher frequency global photonic band gaps were determined numerically. The structure formed by triangular arrays of metal posts with a missing rod at the center has advantages of higher-order-modes (HOM) suppression and main mode restriction under the condition of a/b < 0.2. The relationship between the RF properties and the geometrical parameters have been studied for the 9.37GHz photonic crystal accelerating structure. The Rs, Q, Rs/Q of the new structure may be comparable to the disk-loaded accelerating structure.