Hello Sir/Madam

I uploaded the sample equation to find the aperture radar but this aperture follow on zero angle to 360 angle but i need the angle only follow on zero to 180? and i want the angle follow 0 to 180 and in even and odd angle ?

how can i change this equation?

To provide an example: first my are is 0 to 15 afterward my arc in turn to 1 to 16 afterward my arc turn to 2 to 17..... how can i change this equation in this way and when this arc reached to 180 this analysis is finished.

Thanks