Radar cross section from small wind turbines on top of radio cellular pylons

Abstract

International audienceHybrid-powered base stations have become an effective solution to reduce fossil fuel consumption, when power demand for future mobile networks (LTE/4G, 5G) dramatically increases. Such base stations are powered by small wind turbines (SWTs) having nominal power in the range of 1.5-7.5 kW. Due to the close proximity between SWTs and BTSs, questions have been raised about possible radio interference. In the context of the OPERA-Net2 European project, the main objectives of this original work concern cellular radio / SWT compatibility as well as recommendations to mitigate possible related disturbances. Compared to megawatt WTs, SWTs have a variety of shapes, materials and orientations (horizontal / vertical). Thus, a simple representative model (RSWT-u) was first designed. It is fully metallic to correspond to the worst radio case and its dimensions are scalable to SWT nominal power. The RSWT-u dimensions have since been optimized to improve the RCS match between the RSWT and realistic SWT models having the same nominal power. To verify, comparisons have been made between the RSWT and 3.5 kW Nheowind-100 model (IDSUD ENERGIES). A scaled prototype of the 3.5 kW RSWT with a 1:10 ratio was manufactured. Its RCS was measured in an anechoic chamber at 9 GHz and 17 GHz. A comparison between simulation and measurement at these frequencies shows good agreement. Taking into account the frequency and dimension scale factors, the results obtained at radio cellular frequencies are validated