Near-field focusing properties of colinear dipole arrays

Antenna arrays are normally characterized in terms of their far-field radiation patterns, beam width and directive gain. However, for some applications the army is required to act as a lens and is focused in the near-field zone. The focusing is done by adjusting the phase of the array elements. In this study the focusing properties of a linear dipole array are investigated to determine the parameters that influence focusing efficiency. In particular, the effects of the array size, focusing distance, frequency of operation, and spacing between elements are studied. The simulations are carried out using the method of moments, and show that the array size and phase distribution play dominant roles in the focusing process. Other parameters have minimal effects