An Efficient Plane-Waves Superposition Method for Improved Spatial Correlation in Simulated Reverberation Chambers

Abstract

Accurate Rayleigh propagation environments within an ideal reverberation chamber (RC) are synthesized computationally using a superposition of plane-waves (PWs). Randomness in the electromagnetic (EM) field distribution is achieved by synthesizing many field realizations featuring slantpolarized PWs with randomly defined transverse field components. These PWs propagate along a large number of predefined and uniformly distributed directions determined only once via an efficient spiraling sampling scheme over the unit sphere. Comparisons with theoretical Rayleigh field statistics indicate that the proposed method yields random EM field distributions that in several cases follow more closely the field spatial correlation properties, for comparable numerical burden, than other available numerical techniques. Finally, a formula relating the number of PWs to the size of a desired RC analysis volume was provided.INDEX TERMS EM field statistics, equipment under test (EUT), numerical methods, plane-waves superposition, Rayleigh propagation, reverberation chambers, spatial correlation.

Monte-Carlo Based Numerical Dosimetry in Reverberation Chamber Exposure Systems Employed for in-Vivo Rodent Bioassays

“…Hence, the Rayleigh field modeling can be performed regardless of the actual RC geometry. To this end, a method yielding accurate Rayleigh field distributions within a predefined AV at the study frequency (900 MHz) was developed in [25] and is presently used to examine the statistical distribution of wbSAR over a large cohort of homogeneous rat models.…”

“…In the first one, the whole cohort of simplified, homogeneous rat models is determined via a random assignment of their weight, position, orientation and posture. In the second step, a random Rayleigh field realization is generated using the approach in [25] and enforced as a Huygens box equivalent source in the Finite-Difference Time-Domain (FDTD) simulation environment. In the last step, the FDTD simulation yields the wbSAR for each rat model, which is collected for post-processing.…”

“…In the present approach, the field in ideal Rayleigh fading environments is approximated using a semi-analytical method [25] borrowing from West et al [26], where a novel algorithm was developed to superpose an arbitrarily large number (N) of equal-amplitude PWs with randomly slanted linear polarizations and propagation directions, obtained via the uniform spherical spiral sampling scheme illustrated in Fig. 2.…”

“…In fact, the large RC working volume in [24] required about 1400 PWs for an accurate Rayleigh field representation (see Eq. ( 14) in [25]).…”

“…In this study, an efficient PW superposition method [25] has been employed to generate a near-ideal Rayleigh fading environment in an electrically-large RC analysis volume (AV) hosting a whole cohort of 96 animals. In this way, a Monte-Carlo approach that used many random inputs is proposed for the first time to provide a priori quantitative wbSAR statistics for the bioassay design (e.g., to define target exposure levels).…”