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Trouble with UPML in FDTD - RF Cafe Forums
Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


metal
 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) THEN
DO J=1,Ny
DO 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.))*dexp(dble(-(Nt-200.)*(Nt-200.)/4000.))
ENDDO
ENDDO
ELSE
DO J=1,Ny
DO 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.))
ENDDO
ENDDO
ENDIF

You 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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