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Measurement uncertainty for reverberation chambers - I. Sample statistics.

Arnaut, L R (2008) Measurement uncertainty for reverberation chambers - I. Sample statistics. NPL Report. TQE 2

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We define and derive expressions for the intrinsic uncertainty associated with random fields inside a reverberation chamber. Uncertainties are derived based on exact sampling theory for sample sets generated by N independent stir states. A hierarchy of expressions and results is presented that correspond to increasing levels of complexity and accuracy of the statistical models employed. In particular, closed-form expressions for the boundaries of confidence intervals for ensemble statistics of the power and field magnitude are derived. The expressions become asymptotically exact for increasingly large N and are based on the sample average value and standard error only. For emission measurements, the standard deviation for the average total radiated power is shown to be proportional to 1/vMN. By contrast, for the maximum received field in immunity measurements, the standard deviation is proportional to 1/[Mßln (N)] with parameter ß > 1/2. The theoretical results are illustrated with measured data on an emitting electronic device and with measured maximum levels of field strength estimated from chamber validation data. The methods and results can be used in chamber validation, EMC testing (including emission, immunity, shielding, absorption, and susceptibility measurement), antenna measurements, and numerical simulations.

Item Type: Report/Guide (NPL Report)
NPL Report No.: TQE 2
Keywords: measurement uncertainty, random electromagnetic vector fields, sampling distribution, confidence interval, hybrid stirring techniques
Subjects: Electromagnetics
Electromagnetics > RF and Microwave
Last Modified: 02 Feb 2018 13:15
URI: http://eprintspublications.npl.co.uk/id/eprint/4229

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