Measurement Based Indoor Radio Channel Modeling and Development of a Fading Optimized Circular Polarized Patch Antenna for Smart Home Systems within the SRD Band at 868 MHz

Abstract

Radio based smart home systems become more widespread over the next years. The reason for that is that the demands of home builders and homeowners are tending to green homes with high energy efficiency. Additionally smart homes deliver interoperability of home electronics and control panels in ways that enhance security, convenience, comfort and overall quality of life.A drawback of radio based systems is the difficult predictability of signal quality, especially in indoor propagation scenarios due to the high variance in signal strength introduced by fading. So a priori knowledge of the expected path loss is crucial for an efficient dimensioning of the necessary radio network. This paper presents the results of an extensive measurement campaign to deduce realistic radio channel models for short range devices (SRD) applications at 868 MHz. Additionally, a concept to reduce fading effects is presented. This concept is based on the idea to mitigate fading caused by depolarization losses by using a circular polarized antenna in interaction with a linear polarized antenna. A proof of concept of this method was embedded in the previous mentioned measurement campaign.