# 模拟电磁波和周期性结构

2014年 1月 17日

### 定义衍射级

m\lambda_0 = d(n_B \sin \beta_m - n_A \sin \alpha_1)

for: m=0,\pm 1, \pm 2,

#### 评论 (8)

##### wajid ali
2017-04-16

how to simulate chiral medium

##### 宇航 秦
2017-04-21

Hello wajid ali ,

Online support center: https://www.comsol.com/support
Email: support@comsol.com

##### Zhimin Jing
2018-07-15

Dear Walter Frei,
I am writing to you for your help. These days i have been simulating a 3-D model of a periodic structure with oblique incidenting circular polarized light. But I have encountered some problems that have been solved for a long time.
I want to define a circular polarized light with an Angle of theta between the k and z axes, and k is on the z-x plane. My settings are as follows：I choosed “periodic” in type of port and
I defined the polarization of circular polarized light at both input and output port : cos (theta) in x direction, a* i in y direction, and -sin(theta) in z direction. Then, i choosed “floquent periodicity” in x and y direction in periodic condition. And i choosed “from periodic port” in k-vector for floquent periodicity. However, the charge map derived from the calculation results is not continuous on the right and left side of the structure in x direction.
I don’t know if my periodic conditions are wrong. Any reply from you will be greatly appreciated

##### Zhimin Jing
2018-07-15

Dear Walter Frei,
I am writing to you for your help. These days i have been simulating a 3-D model of a periodic structure with oblique incidenting circular polarized light. But I have encountered some problems that have been solved for a long time.
I want to define a circular polarized light with an Angle of theta between the k and z axes, and k is on the z-x plane. My settings are as follows：I choosed “periodic” in type of port and
I defined the polarization of circular polarized light at both input and output port : cos (theta) in x direction, a* i in y direction, and -sin(theta) in z direction. Then, i choosed “floquent periodicity” in x and y direction in periodic condition. And I choosed “from periodic port” in k-vector for floquent periodicity. However, the charge map derived from the calculation results is not continuous on the right and left side of the structure in x direction.
I don’t know if my periodic conditions are wrong. If wrong, how should I revise. Any reply from you will be greatly appreciated.
Sincerely yours,
Zhimin Jing

##### Tengyue Gao
2018-10-19

Hi Zhimin ,

Online support center: https://www.comsol.com/support
Email: support@comsol.com

2019-01-16

##### 泳棵 王
2024-05-12

What is the purpose of using periodic ports

##### Min Yuan
2024-05-14 COMSOL 员工

Used to add excitation/absorption to the periodic element model, and when Periodic is selected, the Diffraction Order port subnode is available from the context menu, manual and automatic add Settings can refer to the model: https://cn.comsol.com/model/plasmonic-wire-grating-wave-optics-14705 、https://cn.comsol.com/model/hexagonal-grating-wave-optics-22331