How can I change this code to use it for a Circular aperture instead of the Rectangle Aperture?Thank you

How can I use the circ instead of the rect below?

% sqr_beam propagation example

 L1=0.5*10^-3; %side length
 M=256; %number of samples
 dx1=L1/M; %src sample interval
 x1=-L1/2:dx1:L1/2-dx1; %src coords
 y1=x1;
 lambda=0.5*10^-6; %wavelength
k=2*pi/lambda; %wavenumber
 w=0.051*10^-3; %source half width (m)
 z=10.0*10^-4; %propagation dist (m)

 [X1,Y1]=meshgrid(x1,y1);
 u1=rect(X1/(2*w)).*rect(Y1/(2*w)); %src field
 I1=abs(u1.^2); %src irradiance

 figure(1)
 imagesc(x1,y1,I1);
 axis square; axis xy;
colormap('gray'); xlabel('x (m)'); ylabel('y (m)');
 title('z= 0 m');
 u2=propIR(u1,L1,lambda,z); %propagation

 x2=x1; %obs coords
 y2=y1;
 I2=abs(u2.^2); %obs irrad

 figure(2) %display obs irrad
 imagesc(x2,y2,I2);
 axis square; axis xy;
 colormap('gray'); xlabel('x (m)'); ylabel('y (m)');
 title(['z= ',num2str(z),' m']);
 %
 figure(3) %irradiance profile
 plot(x2,I2(M/2+1,:));
 xlabel('x (m)'); ylabel('Irradiance');
 title(['z= ',num2str(z),' m']);
 %
 figure(4) %plot obs field mag
 plot(x2,abs(u2(M/2+1,:)));
 xlabel('x (m)'); ylabel('Magnitude');
 title(['z= ',num2str(z),' m']);
 %
 figure(5) %plot obs field phase
 plot(x2,unwrap(angle(u2(M/2+1,:))));
 xlabel('x (m)'); ylabel('Phase (rad)');
 title(['z= ',num2str(z),' m']);

************************************** I have a function for a circle but how can I iclude it in the code above? the circle function is:

function my_circ(imageSize, center,radius)

%UNTITLED Summary of this function goes here % Detailed explanation goes here imageSizeX=imageSize(1); imageSizeY=imageSize(2); [columnsInImage rowsInImage]=meshgrid(1:imageSizeX,1:imageSizeY); centerX=center(1); centerY=center(2); circlepixels=(rowsInImage - centerY).^2+(columnsInImage - centerX).^2<=radius.^2; image(circlepixels); colormap([0 0 0;1 1 1]); title('Binary image of a circle');

end