Current and near field calculations for cellular base-station collinear array antennas

In this paper, we present a new formulation for the evaluation of the electromagnetic field levels in the near zone of a cellular radio base-station collinear array antenna. The algorithm allows to determine the real current distribution along each half-wave dipole forming the array for a given exciting function and it enables to take into account the effects of mutual coupling among array elements. Once the antenna current distribution has been determined, the radiated field in the near zone is reconstructed using the integro-differential equation relating field and current. The developed algorithm, tested respectively on a 4-element and S-element collinear array antenna operating at 900 MHz, allows to accurately analyze the response of dipole arrays with a computational cost significantly lower than that of a classical method of moments.