The effects of wide-band signals on radar antenna design

The amount of information about the angle of arrival of a plane wave incident on a line aperture is shown to depend on the bandwidth of the incident signal as well as on the extent of the aperture. Conventional antenna theory assumes the angular resolution of an antenna depends only on the aperture extent and illumination. However, by autocorrelation techniques further angular resolution can be obtained. This additional directivity depends on the extent of the signal bandwidth. It is shown for line arrays that the obtainable directivity information depends on the aperture illumination function and the autocorrelation function of the incident signal. In view of the vast amount of information available concerning conventional antennas, the results of this paper have been related to conventional antenna theory. The antenna designer can specify the desired directivity pattern in terms of a conventional single-frequency aperture illumination function. The effects of this single frequency illumination function can then be achieved for wide-band signals by a simpler illumination function. Some examples of the theory are given.