Impact of Different Concrete Types on Radio Propagation: Fundamentals and Practical RF Measurements

Wireless Friendliness Evaluation and Optimization for Sandwich Building Materials as Reflectors

“…Building materials used for walls, ceilings, floors, windows, and interior objects differ widely in ingredients. Traditional ingredients include: concrete, brick, plasterboard, wood, glass [24]- [29]. Concrete and brick are the typical components in building facades and the walls between rooms [24], [25].…”

“…Traditional ingredients include: concrete, brick, plasterboard, wood, glass [24]- [29]. Concrete and brick are the typical components in building facades and the walls between rooms [24], [25]. Plasterboards are often used in interior walls to separate two rooms [26], [27].…”

“…Practical building materials are generally multi-layer composite materials [27]. A typical concrete exterior wall of a residential building is a fabricated sandwich-like panel composing of two outlying concrete layers and a heat insulation layer between them [24], [25]. The interior structures of office buildings commonly adopt two wall types: a 3-layered structure with the air layer sandwiched between two plasterboard layers; or a 4-layered structure consisting of a plasterboard layer, an air layer, a heat insulator layer, and a concrete layer [27].…”

“…Taking concrete as an example, the three main components are cement, aggregate and water with a rough proportion of 1:7:2 [24, Table 1], while additional chemical admixtures are usually added to accelerate or slow down the hydration process and/or to increase the resistance against frost of hardened concrete. It has been shown, through measurements in [24], that the relative permittivity varies significantly among different concrete samples of various water-cement ratio, response to moisture, type and frequency band. For instance, comparing the S100B and SB45B concrete type [24,Table 2] with the same water-cement ratio of 0.7, the real parts of the relative permittivities are 4.89 and 5.72 in 4.5-19 GHz, respectively, and are 4.77 and 5.6 in 26-40 GHz band, respectively, while the imaginary parts of the relative permittivities are 0.22 and 0.22 in 4.5-19 GHz, respectively, and are 0.3 and 0.26 in 26-40 GHz band, respectively.…”

“…It has been shown, through measurements in [24], that the relative permittivity varies significantly among different concrete samples of various water-cement ratio, response to moisture, type and frequency band. For instance, comparing the S100B and SB45B concrete type [24,Table 2] with the same water-cement ratio of 0.7, the real parts of the relative permittivities are 4.89 and 5.72 in 4.5-19 GHz, respectively, and are 4.77 and 5.6 in 26-40 GHz band, respectively, while the imaginary parts of the relative permittivities are 0.22 and 0.22 in 4.5-19 GHz, respectively, and are 0.3 and 0.26 in 26-40 GHz band, respectively. As shown in [25,Fig.…”