TRANSIT TIME EFFECTS IN PHASED ARRAYS
Abstract
Large linear arrays, when excited by pulses of very short duration, in the order of a few cycles, with all elements excited simultaneously, give rise to radiation patterns which have a very non-uniform side lobe structure, and result in degradation of the main lobe if the pulses are too short. This report presents a set of pulses produced at given points in space as a result of exciting an array of 49 elements, with half-wave spacing, by pulses of five cycles and less, the phase of the excitation was varied to cause the main lobe to scan through 20 degrees off boresight. The techniques for applying the results to excitations of more than five cycles were given. A family of radiation patterns are given, to show the variations in the patterns as a function of time, for the several pulse durations studied. The curves clearly show the build-up and decay of the patterns; the fluctuations in the side lobe structure, and the growth and decay of the main lobe both in width and amplitude. It was concluded that this method of excitation and lobe switching is feasible provided minimum pulse duration is determined for the given array size and desired scan angle, based upon specified limits in main lobe degradation. Side lobe suppression could be provided by appropriate selection of amplitude distribution.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1963
- Accession Number
- AD0405974
Entities
Organizations
- Syracuse University