Dependence of radio wave reflection and transmission characteristics of reinforced concrete slabs on frequency and angle of incidence

For effective use of mobile communication systems within a building, it is crucial to know the electromagnetic properties of the materials composing t he floors, ceilings, walls, and so on. This paper considers RC (reinforced concrete) slabs, a major component of large buildings, and attempts to deve lop techniques for predicting and for measuring radio wave reflection and t ransmission characteristics in various environments. The frequency range co nsidered in the analysis is approximately from 0.3 to 3.5 GHz, which is oft en used in mobile communications. As the first step, a slab with single-pla ne iron bar mesh buried in the concrete is assumed as the basic model for t he analysis. A simulation experiment is performed with a 1/10 scale model, using microwaves or millimeter waves. A simulation calculation is also perf ormed with a multiply stratified model, in which the iron mesh plane is rep laced by an equivalent dielectric layer. The reflection and transmission ch aracteristics are investigated as functions of the frequency and angle of i ncidence of the radio waves. The calculation results and measurements agree well, and the effectiveness of the method is verified. The characteristics of the basic analytical model are elucidated. A real floor consisting of m etal mesh embedded in concrete is examined. The reflection characteristics for 2.0-GHz incident waves are examined by simulation calculation and by me asurement with a network analyzer. The measurement technique is established and the dependence of the reflection characteristics on the incident polar ization and angle of incidence is elucidated. (C) 2001 Scripta Technica.