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Code to produce v1

This code takes the input of the Y1 matrix and the initial impedance to produce a vector of v1 values, using equations discovered in previous research. This code also produces v2 as well as yin which is not needed for our purposes.

%function to produce values for v1 given a Y1 and S0 function v1 = nfc(Y1,S0)n = 41; Z0 = 50;A = S0; S = zeros(n,n);for k = 1:n, for l = 1:n,S(k,l)=A(k,2*l-1)*cos(A(k,2*l)*pi/180)+i*A(k,2*l-1)*sin(A(k,2*l)*pi/180); endend Zparam = Z0*inv(eye(n)-S)*(eye(n)+S); % Zparameters of n-port systemYparam = inv(Zparam); W = Yparam; % Ys matrixm = 20; % Number of receivers r = n-1; % Maximum n-1W11 = W(1:m,1:m); W12 = W(1:m,(m+1):r);W13 = W(1:m,r+1); W21 = W((m+1):r,1:m);W22 = W((m+1):r,(m+1):r); W23 = W((m+1):r,r+1);W31 = W(r+1,1:m); W32 = W(r+1,(m+1):r);W33 = W(r+1,r+1); Yc = inv(W22 - W21*inv(W11)*W12 + Y1); % Complex Y matrixY = real(Yc); % Matrix M in paper YY = imag(Yc); % Matrix N in paperP = W22-W21*inv(W11)*W12; %*****W11+Y1 changed to W11 P1 = W31*inv(W11)*W12-W32; %*****W11+Y1 changed to W11M = real(P); M = 0.5*(M+M');v2 = P1*(Y+YY*i); % Voltages as input to Y1 v1 = -v2*W21*inv(W11)-W31*inv(W11); % Voltages not connected to Y1 %*****W11+Y1 changed to W11yin = v1*W13+v2*W23+W33; return

Using this code, we could feed the function a variety of Y1 values to try and determine a pattern between the Y1 and the v1. This way, we were able to modify Y1 in whichever fashion we liked to see if there were visible patterns that could be seen within the v1 values. The code that calls this function then uses the value of v1 and Y1 to plot graphs and look at specific values.

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Source:  OpenStax, Near field communication simulation & Identification. OpenStax CNX. Dec 19, 2011 Download for free at http://cnx.org/content/col11398/1.1
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