Dear professor Johnson and Meep users,
It has been mentioned multiple times that a capacity similar to variable mesh
size can be emulated in meep by applying the coordinate transformation
technique formulated in "Coordinate Transformation &
Invariance in Electromagnetism".
However my attempts in applying the technique to a scaling factor larger than
one always resulted in field divergence.
This script tried to scale the whole computation domain, filled with air, by a
factor of 2 in all directions. According to the article, that would corresponds
into an s factor of 2, or an epsilon and mu of 0.5.
(set-param! resolution 200)
(define-param fcen 1.0)
(define-param df 1.0)
(set! geometry-lattice (make lattice (size 0.2 0.2 0.2)))
;(set! pml-layers (list (make pml (thickness 0.5))))
(set! geometry (list
(make block (center 0 0 0) (size infinity infinity infinity)
(material (make dielectric
(epsilon 0.5)
(mu 0.5)
)))))
(set! sources (list
(make source
(src (make gaussian-src (frequency fcen) (fwidth df)) )
(component Ez) (center 0 0 0)
)))
(define (field-Ez)
(print "Field:" (get-field-point Ez (vector3 0 0 0)) "\n"))
(run-until 100
;(after-sources
(at-every 0.1 field-Ez)
;)
)
Field however quickly diverges.
Any attempt to stretch the coordinates would involve stretching the air
surrounding the devices, which will make the field diverge.
Could anyone provide assistance? Thank you so much.
Yours sincerely,
Tran Quyet Thang.
Ajou University.
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