hello, can anybody hello me solve the problems?

I wanna define a circular phased array ultrasound with 16 elements and the focus point is at center of the circle.

I have two methods to approach problem.

the below is Matlab code.

1:define one element of the transducer.

source_shape1 = makeCircle(Nx, Ny, 0, 0, 100, pi/8);

2:Rotate source_shape1 about pi/8 as the second element

source_shape2 = imrotate(source_shape1, pi/8)

2:Rotate source_shape1 about pi/8 as the third element

source_shape3 = imrotate(source_shape2, pi/8)

..........................

16:source_shape16 = imrotate(source_shape2, pi/8);

add all the source_shape together

but Matlab generate:

Error using +

Matrix dimensions must agree.

The second approach:Nx = Ny = 360

define the first elements

source_shape1 = makeCircle(Nx, Ny, 0, 0, 100, pi/8);

define the second element

source_shape2 = makeCircle(Nx, Ny, 0, 0, 100, pi/4);

cut the unwanted element of the source_shape2

source_shape2(180-50sin(pi/8:360, :);

source_shape3 use the same method as source_shape2;

add all the source_shapes together

source.p_mask = zeros(Nx, Ny);

source.p_mask(:, :) = source_shape1 + source_shape2 + ...........source.shape16 ;

but output of the matlab only come out the largest element, why?