Radiation from finite microstrip patch arrays using infinite array approach

A DFT-based technique is presented for efficient analysis of large finite phased array antennas that can handle arbitrary complex excitations of the individual elements. Numerical results are presented to demonstrate the versatility of the present approach for handling non-uniform excitations. The results of the study are reported for a representative example of a 7 × 7 microstrip patch array, and good agreement has been found between the results derived by the DFT technique and the conventional MoM-based approach. For practical array antennas comprising of hundreds if not thousands of elements, it is not possible to use the direct MoM approach because of the extremely heavy burden on the computational time and the memory size, which can be estimated by extrapolating the corresponding requirements for the relatively small case of 7 × 7 array reported here. In contrast to this, the proposed approach does not suffer from this limitation, since its computational complexity is almost independent of the number of elements in the finite structure.