Creating multiple polar plot graphs for different frequencies

Essentially trying to use a loop to generate multiple plots for different values of f.

I get this error message:

Index exceeds the number of array elements (1).

Error in PistonDirectivity_2_11 (line 21)

f = f(n);

f = [125 250 500 1000 2000 4000 8000];
%f = 3.3820e+03;               %frequency
c = 340;             %speed of sound at 20 degrees
rho0 = 1.2;          %Acoustic impedance at 20 degrees
r = 100;                  %radius
a = 0.16;               %piston radius
u0 = 1;                 %particle velocity
theta = linspace(-pi/2+1.e-16,pi/2-1.e-16,181)'; %range of theta values from 90 to -90 degrees

%p = (1j*rho0*c*k*a^2*u0/(2*r) .* 2.* besselj(1,kasintheta)./kasintheta) * exp(-1j*k*r);
n = 1;
%% loop to make multiple plots
%while n < length(f)
for n = 1 : length(f)
    f = f(n);
    k = 2*pi*f./c;          %wavenumber
    p = besselj(1, k*a.*sin(theta))./(k*a.*sin(theta));

    db = 20*log10(abs(p));              %calculate dB and plot polar response
    mx = max(db);
    dynamic_range = 40;
    db = db + dynamic_range - mx;
    db = max(db,zeros(size(db)));
 
    polar(theta,db);   %plot polar response

    figure             %plot flat response
    plot(theta,db)
    xlabel('Theta (rads)')
    ylabel('Level (dB)')
    hold on
    
    n = n+1;
end

[Daniel M]

You're overwriting f in your loop. Don't do that.

[Cameron Latta]

Ahh, thank you! That seems to have fixed it! Cheers

Answer 1

[Daniel M]

I'm writing the same thing here so this question can be answered.

The issue is you are overwriting your variable f when you write f = f(n). I suggest changing it inside your loop, to fn = f(n).