gerpw.m

用传输矩阵的方法来计算光子晶体带隙

function field=gerPW(k,order,RoW,W,L)
% function field=gerPW(k,order,RoW,W,L)
% yhwsoft 2005.4.25

O=[W/4, L/2];
field=zeros(W,L);
for w=1:W,
    for l=1:L
        rr=sqrt(((w-O(1))*RoW)^2+((l-O(2))*RoW)^2);
        theta=pi-angle((w-O(1))*RoW+(l-O(2))*RoW*i);
        
        if order==1
            tt=1;
            t=cos(theta);
        end
        rho=1*k*rr;
        if rho<eps
            rho=eps;
        end
        
        preX=[t*besselh(order,1,rho),
            t*besselh(order,2,rho),
            tt*(besselh(order,1,rho)/rho+order/(2*order+1)*besselh(order-1,1,rho)-(order+1)/(2*order+1)*besselh(order+1,1,rho)),
            tt*(besselh(order,2,rho)/rho+order/(2*order+1)*besselh(order-1,2,rho)-(order+1)/(2*order+1)*besselh(order+1,2,rho))
            ];
        En=i^order*(2*order+1)/order/(order+1);
        field(w,l)=-En*sin(pi/2)*[1/2 1/2 -i/2 -i/2]*preX;
        
    end
end