A wind turbine comprising a support structure and one or more turbine blades is disclosed, that incorporates means for reducing the radar cross section (RCS), wherein the support structure is notionally divided into an upper section in the shadow of the blade sweep area, and a lower section beneath the upper section, wherein the upper section is adapted to have the means for reducing the RCS, and the lower section does not have the said adaptation. The invention makes use of the realization that the blade masking the tower as it rotates (or the blade being masked by the tower if facing away from a radar), contributes significantly to interference to radar systems, and so localized application of e.g. RAM can give good RCS reduction at a lower cost than treating the whole structure.

A method begins by one or more processing modules of one or more computing devices of a radar system determining whether a radar signature varies cyclically with time, and when the radar signature varies cyclically with time the method continues with the one or more processing modules collecting state telemetry information for the radar signature, along with a signal representation for the radar system. The state telemetry information includes rotation angle, yaw angle and rotation rate for the object responsible for the observed radar signature and the signal representation for the radar system includes data sufficient to determine an I/Q signal for the radar system. The method then determines a characterized radar signature for the object responsible for the radar signature and based on the state telemetry and the signal representation, substantially removes the radar signature from radar data.

The invention provides a composite laminate comprising an outer, an intermediate and an inner section comprising, respectively, first layers of composite material and one or more functional layers having a printed circuit for absorbing the electromagnetic radiation incident on the composite laminate; second layers of composite material; a conducting layer contiguous to the intermediate section and third layers of composite material. The values of the resistivity of the functional layer and the thickness of the intermediate section are comprised in predefined ranges for the attenuation of the reflection of electromagnetic radiation of the composite laminate in the S or X bands up to a peak of 20 dB. The invention also refers to manufacturing methods of the composite laminate (11) and to wind turbine blades including the composite laminate.

The invention provides a wind turbine blade having a Radar Absorbing Material (RAM) and a lightning protection system arranged for guaranteeing the performance of the lightning protection system and the integrity of the RAM. The lightning protection system has lightning receptors located at a tip region and one or two down-conductors disposed inside of the wind turbine blade for driving lightning current to ground. The RAM covers the entire wind turbine blade except the tip region and has at least a functional layer and a reflector layer connected to the one or two down conductors by means of auxiliary cables.

A method begins by one or more processing modules of one or more computing devices of a radar system determining whether a radar signature varies cyclically with time, and when the radar signature varies cyclically with time the method continues with the one or more processing modules collecting state telemetry information for the radar signature, along with a signal representation for the radar system. The state telemetry information includes rotation angle, yaw angle and rotation rate for the object responsible for the observed radar signature and the signal representation for the radar system includes data sufficient to determine an I/Q signal for the radar system. The method then determines a characterized radar signature for the object responsible for the radar signature and based on the state telemetry and the signal representation, substantially removes the radar signature from radar data.

A combined omnidirectional flow turbine system includes rotors that are disposed in a vertical position and enclosed in a motionless structure that receives air flows from any external direction which are manipulated by an airfoil to cause the rotors to rotate. The motionless structure is a hollow body and it is formed by a support structure and cover, being said interior space adapted to store electronic components, which can be directly supplied by the energy, produced. On its outer surface, air particles and pollutants filters can be installed, taking advantage of the aerodynamic shape of the motionless structure, which promotes air flow adhesion along its surface, making possible to capture particles along their preferred path.

A blade mounted radar system comprises a wind turbine having a hub and blades extending therefrom; a radar antenna configured to transmit and/or receive a radio frequency (RF) signal; and a processor in electrical communication with the radar antenna and configured to generate the RF signal for transmission and/or to process the received RF signal. The radar antenna is affixed to one of the blades of the wind turbine such that relative motion is defined between the radar antenna and a target within a line of sight of the radar antenna. The radar antenna detects impending weather events. A turbine controller generates a signal which alters at least one aspect of the wind turbine to secure and protect the wind turbine from the impending weather event.

A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication device located towards the tip end of the blade and internally within the blade body. Radio absorbing material is arranged internally in the blade body in the wireless communication path between the root-and tip devices.

A wind turbine with reduced electromagnetic scattering includes a wind turbine support structure having a cylindrical shape, a wind turbine blade supported by the wind support structure, and a plurality of multi-layer absorbers to limit the electromagnetic scattering, the absorber including at least cobalt ferrite alloy nano-particles, cobalt ferrite alloy nano-flakes, and air. The wind turbine blade includes a blade root, a blade tip opposite the blade root, and a blade middle part extending between the blade root and the blade tip. The plurality of multi-layer absorbers further includes a planar absorber that covers the wind turbine support structure, and a curved absorber that covers the middle part.

A combined omnidirectional flow turbine system includes rotors that are disposed in a vertical position and enclosed in a motionless structure that receives air flows from any external direction which are manipulated by an airfoil to cause the rotors to rotate. The rotors can be connected to a transformation element, which transforms mechanical energy generated by the rotation of the rotors into electrical energy. The motionless structure is a hollow body and it is formed by a support structure and cover, being said interior space adapted to store electronic components, which can be directly supplied by the energy, produced.