Energy efficient microwave processing is important for enhanced material processing. The microwave processing of a material is non-trivial due to the highly nonlinear process dynamics associated with the occurrence of constructive and destructive interferences, based on the sample dimension and material dielectric properties. Destructive interferences may lead to wasteful microwave heating which, however, can be avoided by suitable alteration of the interference pattern via sample dimensions and material dielectric properties. Thus, an energy efficient processing requires a priori information on the interference patterns as a function of sample dimension and material dielectric properties, in order to minimize the destructive interferences and maximize the heating rate with minimal hot spot formation. The current work is an attempt to establish the generalized microwave power absorption characteristics within circular samples of varying sizes and materials. The analysis has been performed based on three dimensionless parameters, N-w, f(p) and f(w), where f(p) and f(w) capture the effect of dielectric properties, and N-w, captures the effect of the sample dimension, It has been shown that the entire spectrum of power absorption characteristics can be classified into (i) thin (N-w <= 0.1), (ii) intermediate (0.1 < N-w < 3/(2 pi f(p))), and thick (2 pi N(w)f(p) ( N-p) >= 3) regimes based on their unique features. Two real-time scenarios of static and rotating samples have been analyzed, and the effect of various parameters in each regime has been presented in detail It has been shown that time dependent simulations of the wave propagation within rotating samples can be avoided, by devising an "equivalent static representation", which has been established for the first time in this work The current work also highlights the possible identification of efficient microwave processing via forecasting of heating dynamics (heating rates and hot spot formations) for a few test materials, based on the material invariant analysis as a function of N-w, f(p), and f(w). (C) 2014 Elsevier Ltd. All rights reserved.