Investigation of the electromagnetic field distribution in an undermoded reverberation chamber
Publish date: 2003-01-01
Report number: FOI-R--0823--SE
Written in: English
Electromagnetic radiation with high intensity can cause disturbance and destruction of electronic systems. The electromagnetic threat can be intentional, e.g. High Power Microwaves (HPM) weapons, or unintentional, e.g. radiation from radar stations. A Reverberation Chamber (RC) is a test facility that can be used to perform susceptibility tests of electronic systems. The properties of the electromagnetic field in the chamber have to be well known to be able to use the RC. A deterministic model of the field would be very complex, and therefore field statistics are used to describe the field. Normally the RC is used for applications at high frequencies, where the chamber is over-moded, but low frequency measurements are also of great practical and economical interest. For high frequencies it exist a commonly accepted statistical model for the field in the chamber, the X (chi) distribution. In this Master of Science thesis some newly proposed theoretical distribution functions are compared to experimental data at low frequencies where the X-model breaks down. The examined distributions are a Bessel K distribution, a Gamma distribution, and a so-called Compound Exponential distribution. An improvement is shown in the agreement with measured data compared to the X-distribution function at lower frequencies.