Circuit Model for Diffuse Multipath and Electromagnetic Absorption Prediction in Rooms

Abstract

Abstract-We present a room electromagnetics based theory which primarily models the Diffuse Multipath Components (DMC) power density with a simple circuit model, and afterwards includes the Line-Of-Sight (LOS) component to predict the total exposure in a realistic environment. Given a human absorption cross section (ACS) and its location from a transmitter (Tx), the whole-body absorption rate (SAR wb ) can be determined by the proposed circuit model for Ultra Wide Band (UWB) and Wireless Local Area Network (WLAN) systems. The SAR wb in humans in a realistic office environment for both UWB and WLAN systems is investigated as part of application. The theory is simulated with the Advanced Design System (ADS) software, and excellent agreement between theoretical and simulated values are obtained in terms of relative errors (<2%). The model may be very useful for SAR wb prediction in realistic complex indoor environments.

Assessing Whole-Body Absorption Cross Section For Diffuse Exposure From Reverberation Chamber Measurements

“…The first step towards the experimental assessment of the wholebody ACS wb is to determine the reverberation time τ i , which is actually the decay rate of the DMC and is proportional to the slope of the decaying tail of the PDP [18]. The total absorbing area in the chamber and its reverberation time are related via the following equation [17], [18], [25], [26]:…”

Reverberation Time and Power Model in Indoor Wireless Scenarios

“…Over the last decade, studies based on room electromagnetics manage to provide more insightful physical understanding for indoor wireless channels [1][2][3][4][5][6][7]. The room electromagnetics theory [1] points out that the electromagnetic waves in indoor wireless scenarios and the acoustic waves in room acoustics share similar behaviors in various aspects.…”

“…The index describes the decaying of primary component in reverberation models, and it can get closer to 2 than in traditional models [4]. Reverberation time is a key parameter in reverberation models [5][6][7], [9], [10]. It originates from room acoustics, where it is defined as the time in which the total energy falls to one millionth of its initial value [11][12][13].…”

“…Hence, the modeling of reverberation time is of great importance, as it is a basis of reverberation models. Most reported electromagnetic reverberation time models are based on either Sabine's or Eyring's equation [1], [4][5][6][7], [11], [12]. In analogy with acoustics, it is proposed in the two equations that electromagnetic reverberation time in an indoor wireless scenario is solely dependent on three parameters that are fixed by propagation geometry and materials: volume, surface and average absorption coefficient of the environment [11][12][13][14].…”

“…Also, the small scale fading characteristics including the modeling of PDP are rarely investigated. Meanwhile, most of these studies are limited in enclosed environments like conference rooms and classrooms [1][2][3][4][5][6][7], but semi-enclosed scenarios are rarely studied. Therefore, it is highly desired to develop a novel, accurate and more general reverberation model for indoor wireless scenarios.…”