Statistical measurements of fast changing electromagnetic fields
The present works aims at describing important statistical indexes such as the field uniformity, the field inhomogeneity and the statistics near the cavity walls for a special case of fast changing random electromagnetic
fields. We generate this kind of electromagnetic environment by means of a vibrating intrinsic reverberation chamber. The use of several, fast, in-house, 3-axis field sensors allows for extensive, "real-time" measurements inside such a chamber.
Introduction of randomness in deterministic, physically-consistent descriptions of reverberation chambers and experimental verification
Reverberation chambers extensive knowledge up to now results from a somehow partial juxtaposition of four different approaches: the deterministic models, the statistical models, the empirical techniques and the computer/numerical methods. It is not possible to leave one of these approaches behind, as each one of them stands as a nonexhaustive, but necessary part of reverberation chamber description. Therefore, there is an obvious gap in knowledge which makes us change our methodology depending on what kind of result we seek. Our work focuses on building fairly simple yet physically appropriate one-, twoand three-dimensional models for a reverberation chamber which claim to be able to analytically predict the statistical behavior of such a chamber, without forsaking to the benefits of deterministic models. Several validation analysis mainly focused on the deviation of the field statistics from ideal reverberation operation (i.e. undermoded regime, vicinity to the cavity walls, loading) show agreement with other theories and measured results on real reverberation chambers. Some contributions to the field statistics under imperfect reverberation is also provided in this thesis by the derivation of novel probability density functions.
Calculation of and Errors in the Susceptibility
The measurement of the susceptibility requires three measurements, two of which have to be performed with a substance of known susceptibility. The difference of these last two measurements furnishes the proportionality constant of the apparatus, always employing the same volume, while the difference with the unknown substance gives the required susceptibility.