The emission patterns from electrically large objects are complex and require time consuming spherical scans to determine the emissions maximum. A planar cut from the spherical pattern is a relatively easy measurement to make and resembles the techniques used in present EMC emissions and immunity standards. However, a planar cut is likely to miss the maximum emissions of a test object. This paper explores how planar cut data can be used to estimate the spherical emissions maximum. Simulated data for a random emitter are presented, both the full spherical radiation pattern and planar cut estimates. The key result is that, if planar cut data can be used to accurately approximate the mean radiation power, the directivity estimates for electrically large emitters can be used to accurately predict the maximum emissions. The results presented here have application to emissions and immunity measurements at frequencies above 1 GHz where most objects will be electrically large and and have complex emissions and receiving patterns.
Conference Dates: August 19-23, 2002
Conference Location: Minneapolis, MN
Conference Title: 2002 Intl. EMC Symp.
Pub Type: Conferences
emission testing, planar cut, spherical scan, unintentional emitter, directivity