elliptica.m

经典书籍MIMO Signals And Systems的源代码

% Program file "elliptica.m"
% calculates and displays tip of electric
% field vector of elliptically polarized
% EM wave traveling along z axis.

N = 4000; % Number of E field samples 
P = 3; % Number of full (2pi) cycles to be drawn

t = [0:P*2*pi/(N-1):P*2*pi];
om = 1;

Exm = input('Enter amplitude of Ex = '); 
phi_x = input('Enter phase angle (in degrees) of Ex, phi_x = ');

Eym = input('Enter amplitude of Ey = '); 
phi_y = input('Enter phase angle (in degrees) of Ey, phi_y = ');
dphi = phi_x - phi_y
phi_x = phi_x*pi/180;
phi_y = phi_y*pi/180;
Ex = Exm*cos(om*t + phi_x);
Ey = Eym*cos(om*t + phi_y);
dphi = phi_x - phi_y;
%Calculation of magnitude of 2D elliptic vector
M = length(t);
Eabs = zeros(1,M);
for k = 1:M
Eabs(k) = sqrt(Ex(k)^2 + Ey(k)^2);
end

dex = 0.5*atan(2*Exm*Eym*cos(dphi)/(Exm^2 - Eym^2));
dex = dex*180/pi
OA = 0.5*sqrt(2*((Exm^2) + (Eym^2) + sqrt((Exm^4) + (Eym^4) + 2*(Exm^2)*(Eym^2)*cos(2*dphi))))
OB = 0.5*sqrt(2*((Exm^2) + (Eym^2) - sqrt((Exm^4) + (Eym^4) + 2*(Exm^2)*(Eym^2)*cos(2*dphi))))
subplot('Position',[0.13,0.55,0.27,0.4])
plot(Ex, Ey);
xlabel('Ex')
ylabel('Ey')
grid
subplot('Position',[0.53,0.55,0.4,0.4])
plot3(t/(2*pi), Ex, Ey)
xlabel('z');
ylabel('Ex');
zlabel('Ey');
grid
subplot('Position',[0.13,0.13,0.8,0.2])
plot(t/(2*pi), Eabs)
xlabel('z');
ylabel('magn(E)');
grid