arithmetic operations with arrays of unequal size in matlab

I am attempting to calculate a 2D polar plot of the power pattern of an Archimedean spiral array of isotropic antennas in MATLAB. This requires a theta and phi array that are both different sizes.

The code I am using is as follows:

clear all
close all
clc
r=27000;  
phi=0:.02:2*pi;
theta=0:.02:pi/2;
px=r.*cos(phi);
py=r.*sin(phi);
wL=1;
k=(2*pi)/wL;
d=px.*sin(theta).*cos(phi)+py.*sin(theta).*sin(phi);
phase=0;
psi=k.*d+phase;

N=27;
PowPatt=(sin(N.*(psi./2))./(N.*sin(psi./2))).^2;
polar(psi,PowPatt)

Naturally I get the following error:

??? Error using ==> times
Matrix dimensions must agree.

Error in ==> powerpattern at 11
d=px.*sin(theta).*cos(phi)+py.*sin(theta).*sin(phi);

Is there anyway to change my code to perform the arithmetic operations on the theta and phi arrays? Thank you.

Patrick

Answer 1

[Matt J]

What should be happening at the line that is generating the error message? Are you trying to compute d for all combinations of phi(i) and theta(j) ? If so, generate phi and theta using ndgrid

   [phi,theta]=ndgrid(0:.02:2*pi,  0:.02:pi/2);

[Patrick]

Hi Matt. The code definitely executes now. Thank you for the fast the response. However, the plot is no longer normalized, i.e. does not have a maximum value of 1. Actually, nothing appears on the plot figure when I execute the code. My new code is below. What might be causing this?

clear all
close all
clc
r=27000;

[phi,theta]=ndgrid(0:.02:2*pi,  0:.02:pi/2);
px=r.*cos(phi);
py=r.*sin(phi);
wL=1;
k=(2*pi)/wL;
d=px.*sin(theta).*cos(phi)+py.*sin(theta).*sin(phi);
phase=0;
psi=k.*d+phase;

N=27;
PowPatt=(sin(N.*(psi./2))./(N.*sin(psi./2))).^2;
polar(psi,PowPatt)

[Matt J]

However, the plot is no longer normalized, i.e. does not have a maximum value of 1.

What do you mean "no longer"? The error prevented you from ever having a plot.

Anyway, what exactly is supposed to have a maximum value of 1? PowPatt? I see nothing in the code to indicate that it should.