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# waveguide20

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# waveguide20   {  WAVEGUIDE20.PDE

This problem solves for the Transverse-Electric modes of a T-septate

rectangular waveguide.  It is a copy of WAVEGUIDE.PDE with more modes.

}

title "TE Waveguide"

select

modes = 20       { This is the number of Eigenvalues desired. }

ngrid=20         { we need enough density to resolve higer modes }

variables

hz

definitions

L = 2

h = 0.5               ! half box height

g = 0.01             ! half-guage of wall

s = 0.3*L             ! septum depth

tang = 0.1           ! half-width of tang

Hx = -dx(Hz)

Hy = -dy(Hz)

Ex = Hy

Ey = -Hx

equations

Hz:  del2(Hz) + lambda*Hz = 0

constraints

integral(Hz) = 0 { since Hz has only natural boundary conditions,

we need to constrain the answer }

boundaries

region 1

start(0,0)

natural(Hz) = 0     line to (L,0) to (L,1) to (0,1) to (0,h+g)

natural(Hz) = 0

line to (s-g,h+g) to (s-g,h+g+tang) to (s+g,h+g+tang)

to (s+g,h-g-tang) to (s-g,h-g-tang) to (s-g,h-g) to (0,h-g)

line to close

monitors

contour(Hz)

plots

contour(Hz) painted

end