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# Trouble with UPML in FDTD - RF Cafe Forums

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 Post subject: Trouble with UPML in FDTD Posted: Thu Mar 09, 2006 10:32 am
 Lieutenant

Joined: Thu Mar 09, 2006 10:27 am
Posts: 1
 Hi everyone,I am currently working on a 3d FDTD code using UPML to truncate the physical domain. Nevertheless, when generating a plane wave (wave vector linear to z), it appears that the wavefront in the UPML becomes quickly angled, which results in large errors at late times. The algorithm I use for source generation is : IF (Nt.LE.200) THENDO J=1,Ny DO ii=1,NxEx(ii,J,Nz/2)=Ex(ii,J,Nz/2)+(kappax(ii)-I*sigmax(ii)*30./(2.*Pi))/(kappay(j)-I*sigmay(j)*30./(2.*Pi))*(dcos(2.*pi*Nt/30.)+I*dsin(2.*pi*Nt/30.))*dexp(dble(-(Nt-200.)*(Nt-200.)/4000.)) ENDDOENDDOELSEDO J=1,NyDO II=1,Nx Ex(II,J,Nz/2)=Ex(II,J,Nz/2)+(kappax(ii)-I*sigmax(ii)*30./(2.*Pi))/(kappay(j)-I*sigmay(j)*30./(2.*Pi))*(dcos(2.*pi*Nt/30.)+I*dsin(2.*pi*Nt/30.)) ENDDOENDDOENDIFYou can notice that the electric field checks the conservation of the normal component of electric induction D at the interface with UPML. Nevertheless, this does not work well. Did someone experience similar problems with a FDTD code ? How did you solve them ? Thanks very much,M.

Posted  11/12/2012
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