{"id":363687,"date":"2024-04-23T10:40:36","date_gmt":"2024-04-23T10:40:36","guid":{"rendered":"\/forum\/forums\/topic\/fdtdjisuanguangzijingtinengdaijiegouwenti\/"},"modified":"2024-04-23T10:40:36","modified_gmt":"2024-04-23T10:40:36","slug":"fdtdjisuanguangzijingtinengdaijiegouwenti","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fdtdjisuanguangzijingtinengdaijiegouwenti\/","title":{"rendered":"FDTD\u8ba1\u7b97\u5149\u5b50\u6676\u4f53\u80fd\u5e26\u7ed3\u6784\u95ee\u9898"},"content":{"rendered":"

\u8001\u5e08\u60a8\u597d\uff0c\u5728\u6848\u4f8b“Bandstructure of planar photonic crystal with a hexagonal lattice<\/span>”\u4e2d\uff0c\u6211\u4f7f\u7528\u4e86\u5982\u4e0b\u811a\u672c\u6765\u8ba1\u7b97\u80fd\u5e26\u7ed3\u6784\uff0c\u4f46\u7cfb\u7edf\u62a5\u9519\u3002<\/p>\n

#############################################################################<\/p>\n

# This script combines the results from the Gamma-M-K-Gamma sweep<\/p>\n

# and plots the frequency spectrum fs from the bandstructure object<\/p>\n

# results over k, and the bandstructure.<\/p>\n

# The bandstructure information is extracted using tolerance and num_band<\/p>\n

# specified by the user at the beginning of the script.<\/p>\n

#<\/p>\n

# Properties:<\/p>\n

# a: period used to normalize the frequency (f_norm=f*a\/c)<\/p>\n

# f_band: Frequencies of bands in units of Hz<\/p>\n

# f_band_norm: Frequencies of bands in units of Hz * a \/ c<\/p>\n

#############################################################################<\/p>\n

# User Defined properties:<\/p>\n

tolerance = 1e-3; #tolerance for finding peaks and accepting bands<\/p>\n

# setting this too low will result in noisy data where sidelobes of<\/p>\n

# peaks are interpreted as new bands<\/p>\n

# setting it too high will mean that some bands are not found<\/p>\n

num_band = 10; #number of bands to search for in the bandstructure<\/p>\n

#<\/p>\n

#############################################################################<\/p>\n

 <\/p>\n

runsweep; # run all sweeps<\/p>\n

 <\/p>\n

# get a from model<\/p>\n

a = getnamed(“::model”,”a”);<\/p>\n

 <\/p>\n

# get fs data from the sweeps<\/p>\n

sweepname=”Gamma-M”;<\/p>\n

spectrum=getsweepresult(sweepname,”spectrum”);<\/p>\n

f=c\/spectrum.lambda;<\/p>\n

fs_all=matrix(length(f),30); # initialize matrix to store fs data in<\/p>\n

fs_all(1:length(f),1:10)=spectrum.fs;<\/p>\n

 <\/p>\n

sweepname=”M-K”;<\/p>\n

spectrum=getsweepresult(sweepname,”spectrum”);<\/p>\n

fs_all(1:length(f),11:20)=spectrum.fs;<\/p>\n

 <\/p>\n

sweepname=”K-Gamma”;<\/p>\n

spectrum=getsweepresult(sweepname,”spectrum”);<\/p>\n

fs_all(1:length(f),21:30)=spectrum.fs;<\/p>\n

 <\/p>\n

# simple imaging of fs vs k<\/p>\n

image(1:30,f,transpose(fs_all),”k (Gamma-M-K-Gamma)”,”f (Hz)”,”bandstructure, logscale”,”logplot”);<\/p>\n

image(1:30,f,transpose(fs_all),”k (Gamma-M-K-Gamma)”,”f (Hz)”,”bandstructure, linearscale”);<\/p>\n

 <\/p>\n

setplot(“colorbar min”,0);<\/p>\n

setplot(“colorbar max”,max(fs_all)*1e-4);<\/p>\n

 <\/p>\n

# plot bandstructure<\/p>\n

bandstructure=matrix(num_band,30); # initialize matrix in which to store band frequency information<\/p>\n

 <\/p>\n

# loop over sweep results<\/p>\n

for (i=1:30){<\/p>\n

#use findpeaks to find num_band number of peaks<\/p>\n

temp = findpeaks(fs_all(1:length(f),i),num_band);<\/p>\n

 <\/p>\n

#collect data for any peaks that are more than ‘tolerance’ of the maximum peak (to avoid minor peaks like sidelobes)<\/p>\n

minvalue = fs_all(temp(1),i)*tolerance;<\/p>\n

f_band=matrix(num_band);<\/p>\n

for(bandcount = 1:num_band) {<\/p>\n

if( fs_all(temp(bandcount),i) > minvalue) {<\/p>\n

f_band(bandcount) = f(temp(bandcount));<\/p>\n

}<\/p>\n

}<\/p>\n

 <\/p>\n

f_band_norm = f_band*a\/c; # normalize the frequency vector<\/p>\n

bandstructure(1:num_band,i)=f_band_norm;<\/p>\n

}<\/p>\n

 <\/p>\n

bandstructure=transpose(bandstructure);<\/p>\n

plot(1:30,bandstructure,”k (Gamma-M-K-Gamma)”,”f (Hz*a\/c)”,”bandstructure”,”plot points”);<\/p>\n

<\/p>\n

\u8bf7\u95ee\u8001\u5e08\u662f\u6211\u8bbe\u7f6e\u6709\u4ec0\u4e48\u95ee\u9898\u5417\uff1f<\/p>\n","protected":false},"template":"","class_list":["post-363687","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t