Rotor Blade with an Integrated Radar Absorber for a Wind Power Plant

Abstract

A rotor blade comprising fiber-reinforced plastic for a wind power plant is provided with a radar absorber embedded into the fiber-reinforced plastic. The rotor blade includes a layer close to the surface with a defined electrical sheet resistivity of 100 to 800 ohm/square, which is located at a depth of 2 to 5 mm below the surface. The rotor blade also includes a layer far removed from the surface with a defined electrical sheet resistivity of at a maximum 50 ohm/square at a distance to the layer close to the surface of 5 to 16 mm. The integrated radar absorber covers one or several discrete surface sections of the rotor blade, without covering the entire surface of the rotor blade.

What is claimed: 
     
         1 . A method, comprising the steps of:
 receiving, by a radar system, reflections of a plurality of rotor blades of a wind power plant, wherein at least one of the plurality of rotor blades comprises at least one radar absorber embedded in the rotor blade so that a reflected signal from the radar system generates a defined chronologically dependent intensity of reflection during rotation of the rotor blade   processing, by the radar system, the received reflections of the plurality of rotor blades;   identifying, by the radar system, the defined chronologically dependent intensity of reflection as being a wind power plant; and   filtering out, by the radar system, reflections of the identified wind power plant.   
     
     
         2 . The method of  claim 1 , wherein the at least one radar absorber and surfaces used by the at least one radar absorber damp reflections during rotation of the rotor blade. 
     
     
         3 . The method of  claim 2 , wherein a dimension and speed of rotation of the rotor blade generate a defined chronologically dependent intensity of the reflection characteristic. 
     
     
         4 . The method of  claim 1 , wherein a dimension and speed of rotation of the rotor blade generate a defined chronologically dependent intensity of the reflection characteristic.