In some antenna applications, having high directivity while keeping the antenna dimensions small is desired, which can be obtained by use of superdirective arrays. Superdirective arrays have been popular in academic world since a superdirective array provides higher directivity than the uniformly excited antenna array of same length. In this thesis, superdirective arrays are investigated by making high precision numerical computations. Superdirective array element excitations, array factors and directivities are inspected for different number of elements. Superdirective array pattern and directivity features are compared to uniformly excited array pattern and directivities. Superdirective array tolerance is investigated by examination of array element excitation sensitivities. Bandwidth of superdirective arrays is also inspected. Multiple Precision Toolbox is used during numerical computations in Matlab.