figure(1)
theta = -pi/2:.01:pi/2;
% kdover2 = 2;
kdover2 = 12;

% kdover2 = N *pi; % need to set N

plot(theta / pi * 180, abs(sinc(1/pi * kdover2 * sin(theta))))
xlabel('theta (degrees)')
ylabel('abs(MATLAB sinc(1/pi * kdover2 * sin(theta)))')
v = axis;
v(1) = -90;
v(2) = 90;
v(3) = 0;
axis(v)
fix_axis
grid

figure(2)
rho = ones(size(theta));
polar(theta, abs(sinc(1/pi * kdover2 * sin(theta))))
fix_axis

% pressure release boundary

figure(3)
plot(theta / pi * 180, 20 * log10(abs(sinc(1/pi * kdover2 * sin(theta)))))
xlabel('theta (degrees)')
ylabel('20 * log10(sinc(.))')
v = axis;
v(1) = -90;
v(2) = 90;
% v(3) = 0;
% v(4) = 1;
axis(v)
fix_axis
grid