Occasionally harminv will miss modes (or find spurious ones)...you
have to remember that it is solving a rather tricky signal-processing
problem. So, when you compute band structures by running harminv at
lots of k points, occasionally you will get missing data points. For
example, you can see a few missing points in the band structure of the
tutorial:
http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial/Band_diagram%2C_resonant_modes
When this happens, I usually just ignore the missing points -- the
bands are continuous, so it is obvious that the points are there, and
you can just interpolate. If you really care, what you can do is give
harminv an easier signal-processing problem: run it with a narrower-
band source centered right on the frequency where you think the point
must be. Then it should find the point. (This is also a good way to
check for spurious modes, and in general to verify the harminv results.)
Steven
On Jul 14, 2009, at 10:47 PM, 刘荣鹃 wrote:
I'm using meep to calculate the band structure of waveguide band
stucuture in
3D photonic crystal. When the resolution or cell size increase, I
can't get the
complete band structure any more(when resolution=8, I can get a
complete band).
The mode points at high K-point are alway lost. what's the reason
for that？ I
changed the run time after the source is turned off. And I also set
eps-
averaging true or false to try. It seems that run time and eps-
averaging have
certain influence on it. But I still can't find the exact run time
to get a
complete band structure for eps-averaging being true or false. How
can I get a
complete band structure?
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