221 lines
7.4 KiB
Matlab
221 lines
7.4 KiB
Matlab
function [E_theta,E_phi,Prad,Dmax] = AnalyzeNF2FF( Sim_Path, nf2ff, f, theta, phi, r )
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% [E_theta,E_phi,Prad,Dmax] = AnalyzeNF2FF( Sim_Path, filenames_E, filenames_H, f, theta, phi, r )
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%
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% calculates the farfield via a near field to far field transformation
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%
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% input:
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% Sim_Path: simulation directory
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% nf2ff: structure on filenames etc. as created by CreateNF2FFBox
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% f: frequency (Hz) for far field calculation
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% theta: (degrees) vector of discrete theta values to calculate the far field for
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% phi: (degrees) vector of discrete phi values to calculate the far field for
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% r: (optional) Radius (m) at which the E-fields are calculated (default: 1 m)
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%
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% output:
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% E_theta: E_theta(theta,phi); theta component of the electric field strength at radius r
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% E_phi: E_phi(theta,phi); phi component of the electric field strength at radius r
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% Prad: time averaged radiated power
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% Dmax: maximum directivity
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%
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% example:
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% see examples/NF2FF/infDipol.m
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%
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% See also CreateNF2FFBox
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%
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% (C) 2010 Sebastian Held <sebastian.held@gmx.de>
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% (C) 2011 Thorsten Liebig <thorsten.liebig@gmx.de>
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% check arguments
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error( nargchk(6,6,nargin) );
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if ~isscalar(f)
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error 'Currently only one frequency is supported. Call this function multiple times.'
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end
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filenames_E = nf2ff.filenames_E;
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filenames_H = nf2ff.filenames_H;
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if (~isrow(nf2ff.directions))
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nf2ff.directions = nf2ff.directions';
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end
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% read time domain field data and transform into frequency domain
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for n=find(nf2ff.directions==1)
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[Ef{n}, E_mesh{n}] = ReadHDF5Dump( [Sim_Path '/' filenames_E{n}], 'Frequency', f );
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%clear out time domain data
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Ef{n} = rmfield(Ef{n},'TD');
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[Hf{n}, H_mesh{n}] = ReadHDF5Dump( [Sim_Path '/' filenames_H{n}], 'Frequency', f );
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%clear out time domain data
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Hf{n} = rmfield(Hf{n},'TD');
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% reshape mesh into row vector
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mesh{n}.x = reshape( E_mesh{n}.lines{1}, 1, [] );
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mesh{n}.y = reshape( E_mesh{n}.lines{2}, 1, [] );
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mesh{n}.z = reshape( E_mesh{n}.lines{3}, 1, [] );
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end
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% create a normal vector for every plane
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% FIXME!!! this is dependent upon the order of filenames_*
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n = {};
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for a=1:6
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temp = [(a<=2), ((a>=3)&&(a<=4)), (a>=5)];
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n{a} = temp - 2*mod(a,2)*temp;
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end
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physical_constants
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k = 2*pi*f/c0;
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center = [0 0 0];
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Umax = 0;
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phi_idx = 0;
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for phi_deg_aufpunkt = phi
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phi_rad_aufpunkt = phi_deg_aufpunkt/180*pi; % radiant
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phi_idx = phi_idx + 1;
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theta_idx = 0;
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for theta_deg_aufpunkt = theta
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theta_rad_aufpunkt = theta_deg_aufpunkt/180*pi; % radiant
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theta_idx = theta_idx + 1;
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N_theta = 0;
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N_phi = 0;
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L_theta = 0;
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L_phi = 0;
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for a=find(nf2ff.directions==1)
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[N_theta_,N_phi_,L_theta_,L_phi_] = process_plane( k, n{a}, center, mesh{a}, Ef{a}.FD.values{1}, Hf{a}.FD.values{1}, theta_rad_aufpunkt, phi_rad_aufpunkt );
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N_theta = N_theta + N_theta_; N_phi = N_phi + N_phi_;
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L_theta = L_theta + L_theta_; L_phi = L_phi + L_phi_;
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end
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% E-fields
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erg_E_theta = -1i*k*exp(-1i*k*r) / (4*pi*r)*(L_phi+Z0*N_theta);
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erg_E_phi = 1i*k*exp(-1i*k*r) / (4*pi*r)*(L_theta-Z0*N_phi);
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% output
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E_theta(theta_idx,phi_idx) = erg_E_theta;
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E_phi(theta_idx,phi_idx) = erg_E_phi;
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% directivity
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U = r^2/(2*Z0) * sum(abs([erg_E_theta erg_E_phi]).^2);
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Umax = max( [Umax U] );
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end
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end
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% power
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Prad = 0;
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for a=find(nf2ff.directions==1)
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[~,~,~,~,P] = process_plane( k, n{a}, center, mesh{a}, Ef{a}.FD.values{1}, Hf{a}.FD.values{1}, theta_rad_aufpunkt, phi_rad_aufpunkt );
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Prad = Prad + P;
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end
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% directivity
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Dmax = 4*pi*Umax / Prad;
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% integrate over one plane
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function [N_theta,N_phi,L_theta,L_phi,Prad] = process_plane( k, n, center, mesh, E_field, H_field, theta_rad_aufpunkt, phi_rad_aufpunkt )
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% [N_theta,N_phi,L_theta,L_phi,Prad] = process_plane( k, n, center, mesh, E_field, H_field, theta_rad_aufpunkt, phi_rad_aufpunkt )
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%
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% k: wave number
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% n: normal vector of the plane
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% center: correction coordinates for the center of the antenna
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% mesh: mesh info
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% E_field: E field array ?x?x?x3
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% H_field: H field array ?x?x?x3
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% speed up
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sin__theta_rad_aufpunkt = sin(theta_rad_aufpunkt);
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cos__theta_rad_aufpunkt = cos(theta_rad_aufpunkt);
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sin__phi_rad_aufpunkt = sin(phi_rad_aufpunkt);
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cos__phi_rad_aufpunkt = cos(phi_rad_aufpunkt);
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if abs(n(1)) == 1
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% x-plane
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x = mesh.x(1);
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[y z] = ndgrid( mesh.y, mesh.z );
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coord1 = mesh.y.';
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coord2 = mesh.z.';
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Ex = squeeze( E_field(1,:,:,1) );
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Ey = squeeze( E_field(1,:,:,2) );
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Ez = squeeze( E_field(1,:,:,3) );
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Hx = squeeze( H_field(1,:,:,1) );
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Hy = squeeze( H_field(1,:,:,2) );
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Hz = squeeze( H_field(1,:,:,3) );
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elseif abs(n(2)) == 1
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% y-plane
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y = mesh.y(1);
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[x z] = ndgrid( mesh.x, mesh.z );
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coord1 = mesh.x.';
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coord2 = mesh.z.';
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Ex = squeeze( E_field(:,1,:,1) );
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Ey = squeeze( E_field(:,1,:,2) );
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Ez = squeeze( E_field(:,1,:,3) );
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Hx = squeeze( H_field(:,1,:,1) );
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Hy = squeeze( H_field(:,1,:,2) );
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Hz = squeeze( H_field(:,1,:,3) );
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elseif abs(n(3)) == 1
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% z-plane
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z = mesh.z(1);
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[x y] = ndgrid( mesh.x, mesh.y );
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coord1 = mesh.x.';
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coord2 = mesh.y.';
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Ex = squeeze( E_field(:,:,1,1) );
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Ey = squeeze( E_field(:,:,1,2) );
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Ez = squeeze( E_field(:,:,1,3) );
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Hx = squeeze( H_field(:,:,1,1) );
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Hy = squeeze( H_field(:,:,1,2) );
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Hz = squeeze( H_field(:,:,1,3) );
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end
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Jx = n(2) .* Hz - n(3) .* Hy;
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Jy = n(3) .* Hx - n(1) .* Hz;
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Jz = n(1) .* Hy - n(2) .* Hx;
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Mx = -n(2) .* Ez + n(3) .* Ey;
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My = -n(3) .* Ex + n(1) .* Ez;
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Mz = -n(1) .* Ey + n(2) .* Ex;
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r_cos_psi = x*sin__theta_rad_aufpunkt*cos__phi_rad_aufpunkt + y*sin__theta_rad_aufpunkt*sin__phi_rad_aufpunkt + z*cos__theta_rad_aufpunkt;
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e_fkt = exp( +1i*k*r_cos_psi );
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N_theta = dbltrapz( ( Jx*cos__theta_rad_aufpunkt*cos__phi_rad_aufpunkt + Jy*cos__theta_rad_aufpunkt*sin__phi_rad_aufpunkt - Jz*sin__theta_rad_aufpunkt) .* e_fkt, coord1, coord2 );
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N_phi = dbltrapz( (-Jx*sin__phi_rad_aufpunkt + Jy*cos__phi_rad_aufpunkt) .* e_fkt, coord1, coord2 );
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L_theta = dbltrapz( ( Mx*cos__theta_rad_aufpunkt*cos__phi_rad_aufpunkt + My*cos__theta_rad_aufpunkt*sin__phi_rad_aufpunkt - Mz*sin__theta_rad_aufpunkt) .* e_fkt, coord1, coord2 );
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L_phi = dbltrapz( (-Mx*sin__phi_rad_aufpunkt + My*cos__phi_rad_aufpunkt) .* e_fkt, coord1, coord2 );
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if nargout > 4
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% Prad requested
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% this is crap! recode it!
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EH = zeros(size(Ex));
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for i1 = 1:numel(coord1)
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for i2 = 1:numel(coord2)
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E = [Ex(i1,i2) Ey(i1,i2) Ez(i1,i2)];
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H = [Hx(i1,i2) Hy(i1,i2) Hz(i1,i2)];
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EH(i1,i2) = real( dot(cross(E,conj(H)),n) );
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end
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end
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Prad = 0.5 * dbltrapz( EH, coord1, coord2 );
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end
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function Q = dbltrapz(matrix,a,b)
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%DBLTRAPZ Trapezoidal numerical integration in two dimensions.
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% Z = DBLTRAPZ(MATRIX,A,B) computes an approximation of the double integral
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% of MATRIX via the trapezoidal method (with respect to A and B). A and B must be
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% column vectors of the same length.
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% index like this: MATRIX(A,B)
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if nargin < 3, error('MATLAB:dblquad:NotEnoughInputs',...
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'Requires at least three inputs.'); end
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if size(a,2) ~= 1, error('column vectors required'); end
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if size(b,2) ~= 1, error('column vectors required'); end
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temp = zeros(size(b));
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for i = 1:length(b)
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temp(i) = trapz( a, matrix(:,i) );
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end
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Q = trapz( b, temp );
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