EMF-Measurements of Rooftop Attenuation of Cellular Radio Base Stations Deployed on Gable Roofs

In this paper, we present measurements of the electromagnetic rooftop attenuation of gable roofs and tiles as corresponding building material. For cellular radio base stations which are mounted on such roofs the rooftop attenuation, being a combination of reflected and absorbed signal power by the rooftop, plays a crucial role in the EMF-assessment of the compliance boundary. The measurements presented are based on two methods. First, a self-constructed sample roof is characterized using a 2-port network analyzer together with broadband antennas. The measured attenuation ranges from 1.5 dB to 7.5 dB for frequencies between 700MHz and 3.6 GHz. In field measurements, the roofs of five cellular sites were measured in-situ by using the reference signals of existing cellular radio base stations, confirming the measurements of the sample roof.