dielectric loads in the enclosure creates situations with the potential of being a complicated resonant system with several coupled oscillations which can only be clarified by measurements. Modeling of the internal field structure based on given geometric and structural situations seems to be useful for related one- and two-dimensional cases to gain general insights into the true nature of a three-dimensional problem. In first approximation, the methods of geometric optics are to be applied. The exact distribution of internal radiation requires the application of field theory (Maxwell's equations) for a meaningful interpretation of interference patterns, standing wave fields, hot and dead spots, reactive zones, etc. Measurements of reflectivity levels in certain chambers will be required employing an isotropic field probe and a scanning mechanism. Such a probe responds equally to signals of any direction and polarization, but can also be switched to select orthogonal field components for the location of reflection sources which might cause a particular "hot spot" problem. Simple mitigative measures can effectively suppress the onset of hot spots. If reflections of the 2.45 GHz radiation at the outside are enhanced by metal sidings, awnings, and screening of apertures and dampened on the inside by lossy walls of low reflectivity, lossy furniture, avoidance of bare, opposing metal surfaces, etc., one can expect with some certainty that there is no HSP at all points of the inner space. If one has to be absolutely sure, then field uniformity can be attained by perturbing the field with a mode stirrer (e.g., rotating vane, pulsating reflector, moving body) or by random FM modulation of the SPS microwave power, which requires a certain bandwidth for the energy beam. In summary, in any type of habitable enclosure there will be a nonuniform field strength distribution due to reflected and scattered field components interfering with each other. Essential to field enhancements are multiple reflections in a resonance mode, which are then proportional to the product of a quality factor Q and a coupling coefficient q. For almost all practical purposes it was concluded that this product Eq. (16) will not exceed unity.
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