An Analysis of a Slotted Waveguide, Frequency Scanned, Antenna Near Cutoff

摘要

Two major concerns in the designs of X-Band precision approach radars are their cost and their ability to detect and track aircraft in heavy rain clutter. The objective of this investigation was to study a particular limited scan, linearly polarized antenna which could be used in conjunction with a digital filter for the suppression of clutter and thereby provide a low cost system concept. This antenna uses the inherent dispersion of slotted waveguide near cutoff for frequency scan in elevation. However, such antennas are sensitive to waveguid dimensional errors. This report presents an analysis of the effect of such errors on the formation of the frequency scanned beam. Basic design equations are developed for a narrow scan angle application. The effect of statistical errors is analyzed and average radiation patterns are presented which indicate the degree of degradation.