Abstract
Measuring antenna patterns costs time and money. Therefore effort is placed where necessary: only in the cardinal i.e. the azimuth and elevation planes. EMC engineers are interested in the intercardinal values, since an interfering system may be placed off boresight, both in azimuth and elevation. This paper suggests a method to estimate the intercardinal gain, G(/spl phi/,/spl theta/), based solely on the cardinal patterns, G(/spl phi/) and G(/spl theta/). The common approach is to assume that the gain at an intercardinal angle, (/spl phi/,/spl theta/), is equal to the sum (in dB): G(/spl phi/,/spl theta/)=G(/spl phi/)+G(/spl theta/). This is a rather simple way of estimation. It has, however, no mathematical proof or physical basis. The approach suggested in this article adopts an opposite line of logic. Rather than trying to estimate G(/spl phi/,/spl theta/) based on G(/spl phi/) and G(/spl theta/), we will estimate one equivalent angle, /spl phi/' or /spl theta/' to be used with one of the cardinal patterns, G(/spl phi/) or G(/spl theta/). The basic idea is to look for the geometric locus in space, of pairs of angles /spl phi/ and /spl theta/, having an iso-gain. The assumption is that these loci are circles drawn on a sphere if BW/sub AZ/=BW/sub EL/ and ellipses drawn on a sphere, in the general case, when BW/sub AZ//spl ne/BW/sub EL/. Also, a way to reduce estimation errors is suggested. Finally, a quantitative comparison between the suggested equations and a simulated spherical antenna pattern, illustrates the small error of the new technique.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call