We have an exciting announcement about badges coming in May 2025. Until then, we will temporarily stop issuing new badges for course completions and certifications. However, all completions will be recorded and fulfilled after May 2025.

Ansys Innovation Space

FREE STUDENT SOFTWARE

关于用公式计算MODEEXPANSION中N和P与仿真得到结果不一致的问题

- July 5, 2024 at 4:22 am
  1634281772
  Subscriber
  '); set('index',10); addfdtd; set('mesh type',"custom non-uniform"); set('define x mesh by',"maximum mesh step"); set("dx",0.008*um); set('define y mesh by',"maximum mesh step"); set("dy",0.008*um); set('define z mesh by',"maximum mesh step"); set("dz",0.05*um); set('x',0); set('x span',1*um); set('y',0); set('y span',1*um); set('z',2*um); set('z span',6*um); addmode; set("injection axis","z"); set("wavelength start",1.55*um); set("wavelength stop",1.55*um); set("x",0); set("x span",2*um); set("y",0); set("y span",2*um); set("z",-0.1*um); addpower; set("name","T"); set('x',0); set('x span',2*um); set('y',0); set('y span',2*um); set('z',3.5*um); set("output Px",1); set("output Py",1); set("output Pz",1); addmodeexpansion; set("name","modeexpansion"); set("monitor type","2D Z-normal"); set('x',0); set('x span',2*um); set('y',0); set('y span',2*um); set('z',3.5*um); setexpansion("T","T"); run; clear; T_fund=getresult('modeexpansion','expansion for T'); Pin=T_fund.getattribute('P'); Nm=T_fund.getattribute('N'); Exin=pinch(getresult('T','Ex')); Eyin=pinch(getresult('T','Ey')); Hxin=pinch(getresult('T','Hx')); Hyin=pinch(getresult('T','Hy')); dx=getdata('source','delta_x'); dy=getdata('source','delta_y'); chang=getresult("source","mode profile"); Exm=pinch(chang.getattribute("Ex")); Eym=pinch(chang.getattribute("Ey")); Hxm=pinch(chang.getattribute("Hx")); Hym=pinch(chang.getattribute("Hy")); matlabsave("modeexpansion 结果验证"); 导入matlab后的代码 Pin1=Exin.*conj(Hyin)-Eyin.*conj(Hxin); Pin1=sum(Pin1); Pin1=Pin1'; Pin1=sum(Pin1); Pin1=0.5.*dx(1,1).*dy(1,1).*Pin1; Nm1=Exm.*conj(Hym)-Eym.*conj(Hxm); Nm1=sum(Nm1); Nm1=Nm1'; Nm1=sum(Nm1); Nm1=0.5.*dx(1,1).*dy(1,1).*Nm1; 得到结果： Nm=4.33941221933428e-16 + 1.41321061678239e-29i; Pin=4.33926030958045e-16 - 1.62136768260574e-18i; Nm1=1.09206140594385e-16; Pin1=1.08481507739623e-16 + 4.05341920671331e-19i; 注意到modeexpansion得到的Pin和Nm与公式计算得到的Pin1和Nm1有一个4倍关系，但我仍然不清楚为什么两者不一样。">尊敬的老师：最近我在用公式验证MODE EXPANSION中的P和N；我查得信息得 Nm = 0.5. ∗ R Em × H∗ m · dS P in = 0.5. ∗ R Ein × H∗ m · dS 那么我化简得到 Nm = 0.5. ∗ dx. ∗ dy P (Exm ∗ Hym∗ − Eym ∗ Hxm∗ ) Pm = 0.5. ∗ dx. ∗ dy P (Exin ∗ Hyin∗ − Eyin ∗ Hxin∗ ) FDTD代码： selectall; delete; um=10^(-6); addrect; set('x',0); set('x span',0.22*um); set('y',0); set('y span',0.5*um); set('z min',-3*um); set('z max',10*um); set('material','