Comparison of the recorded RCS and spectra of three different wind turbines on L- and S-band

Renewable energy sources, of which wind energy is one of the main sources, are increasingly being preferred over fossil fuels. Megawatts of power can be generated by a single wind turbine, but unfortunately these large rotating structures pose a challenge when coexistence in the surveillance volume of civilian and military radar systems is required. This is due to the very large static RCS from the turbine tower and nacelle and the significant Doppler spread of the echoes from the moving blades. This paper presents the results from a measurement campaign that investigated the observed radar cross section (RCS) on L- and S-band on both VV and HH polarizations from a variety of aspect angles and turbine rotation rates. As expected, the results indicate that the RCS and spectrum is different for different aspect angles and different turbine rotation rates. The results also indicate significant differences in the echoes from turbines from different manufacturers. The turbine model should therefore also be taken into consideration during radar performance modelling.