hex_centers.m

利用电磁场的源激发方法来计算光子晶体波导例如光子晶体光纤

function [vCx, vCy] = hex_centers(a, tri_size1, tri_size2, type)
% [xCenters, yCenters] = HEX_CENTERS(a, firstRing, lastRing, type)
% Calculates the coordinates of points on a hexagonal lattice
% a is the lattice pitch.
% firstRing is the number of points per hexagon side in the 
% first ring. lastRing is the number of points per hexagon side in
% the last ring.
% type is either 1 or 2, which determines which one of the two 
% types of lattices is calculated.
tri_size1 = tri_size1+1;
tri_size2 = tri_size2+1;
vCx = [];
vCy = [];
for row = tri_size1:tri_size2
        for col = 1:(row-1)
                for tri = 1:6
                        % calculate vein centers
                        x0 = -a/2*(row-1)+a*(col-1);
                        y0 = a*sqrt(3)/2*(row-1);
                        xc = cos(pi/3*(tri-1))*x0 + sin(pi/3*(tri-1))*y0;
                        yc = -sin(pi/3*(tri-1))*x0 + cos(pi/3*(tri-1))*y0;
                        R = xc + j*yc;
                        if type == 2
                                xc = real(abs(R)*exp(j*(angle(R)+pi/6)));
                                yc = imag(abs(R)*exp(j*(angle(R)+pi/6)));
                        end
                        vCx = [vCx xc];
                        vCy = [vCy yc];
                end
        end
end