The only Matlab toolbox i know about to simulate an antenna is Comsol Mulitphysics. It has an Rf-module where that can be done. Comsol was original Femlab, which was a toolbox for Matlab, which later got so big that it went off on its own. You can set up the simulation with Comsol then export it as an m-file.
Yes Matlab is the best tool for simulating antenna arrays; Below i have typed some MATLAB code to simulate liner antenna array.
change the different variable and see the results.
%********************************
clc
clear all
f=2000;
c=340;
d=.08;
N=10;
theta= 45 * (pi/180);
si=0i/100i;
for k=1:101
peak(k)=(sin(N*f*d*pi*(cos(si(k))-cos(theta))/c))/(N*sin(pi*f/c*d*(cos(si(k))-cos(theta))));
end
figure(1)
plot(si*180/pi,20*log10(abs(peak)))
grid on