I am not certain what you want or what your current data are. (I also do not have significant experience with the Antenna Toolbox.) The pol2cart function offers one option.
Try this —
h = helix;
[pat,azimuth,elevation] = pattern (h, 2e9, 0, 1:1:360); % Example from the 'pattern' Documentation
% figure
% plot(elevation, pat)
% grid
figure
polarplot(deg2rad(elevation), abs(pat))
[x,y] = pol2cart(deg2rad(elevation).', abs(pat));
figure
plot(x, y)
grid
axis('equal')
.
