# Plot a polar plot of an antenna array sensitivity (function)

    % with lines denoting the target direction and beamwidth.
    % This is a helper function used in the broadband antenna examples.
    %
    % Inputs:
    %    X:      an array of abs(y(theta)) where y is the antenna array pattern
    %    theta0: target direction
    %    bw:     total beamwidth
    %    label:  a string displayed as the plot legend
    %
    % Original code by Lieven Vandenberghe
    % Updated for CVX by Almir Mutapcic 02/17/06

    function polar_plot_ant(X,theta0,bw,label)

    % polar plot
    numpoints = length(X);
    thetas2 = linspace(1,360,numpoints)';

    plot(X.*cos(pi*thetas2/180), X.*sin(pi*thetas2/180), '-');
    plot(X.*cos(pi*thetas2/180), X.*sin(pi*thetas2/180), '-');
    hold on;
    axis('equal');

    plot(cos(pi*[thetas2;1]/180), sin(pi*[thetas2;1]/180), '--');
    text(1.1,0,'1');

    plot([0 cos(pi*theta0/180)], [0 sin(pi*theta0/180)], '--');
    sl1 = find(thetas2-theta0 > bw/2);
    sl2 = find(thetas2-theta0 < -bw/2);
    Gsl = max(max(X(sl1)), max(X(sl2)));
    plot(Gsl*cos(pi*thetas2(sl1)/180), Gsl*sin(pi*thetas2(sl1)/180), '--');
    plot(Gsl*cos(pi*thetas2(sl2)/180), Gsl*sin(pi*thetas2(sl2)/180), '--');

    text(-1,1.1,label);

    axis off;