1- A 4-element unform linear array with interelement spacing of λ/2 is operated as a broadside array , find the beamwidth betwen nulls and the side lobe level in dB .
2- in the above problem , it is required to re-design the 4 element array so as to locate the nulls at : ( φ=0, 45.135 ,and 180 ) degrees , find the required current amplitudes (Hint : use the polynomial representation of the array factor ) .
3- find the phasing of the elements in order to rotate the direction of the peak in the above array in (problem 1) to the 60° direction.