Measurement apparatus and method
AssigneeQinetiq Limited
InventorsShahid Hussain, Greg Peter Wade Fixter, Stefan Szwarnowski
Life of this patent
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Abstract
A method of measuring the reflectivity of a region of an article to electromagnetic radiation, in particular for the characterisation of the radio-frequency (RF) properties of wind turbine blades. The article is arranged in the near-field of a transceiver antenna, which performs both illumination and measurement of reflected radiation from the region of the article undergoing measurement. The method is beneficial in that it can be used with an antenna in close proximity (or in contact) to the article to be measured, for example for use in on site measurement of specific regions of a turbine blade.
Claims23
A method of measuring the reflectivity of a region of an article to electromagnetic radiation comprising the steps of:
- a) arranging the article in the near-field of a transceiver antenna,
- b) aligning the antenna along a direction substantially orthogonal to a surface of the region to be measured and at a predetermined distance from said surface,
- c) illuminating the region of the article with electromagnetic radiation transmitted from the antenna over a desired frequency range,
- d) receiving electromagnetic radiation reflected from the region of the article in the near-field of the antenna using said antenna,
- e) measuring the reflected radiation and determining there-from the reflectivity of said article in said region;
- wherein at least one substantially rigid spacing member is provided in mechanical communication with the article and the antenna so as to align the antenna, and
- the spacing member comprises an optical element comprising a polymer foam disposed between the antenna and the article and wherein the illuminating and measuring steps are performed through said optical element.
A reflectometer comprising a transceiver antenna having a spacing member depending there-from, the spacer member defining a measurement region within the near-field of the antenna within which to admit articles to measured, wherein the spacing member comprises an optical element arranged in optical and mechanical communication with the antenna, the optical element having a substantially planar surface within the measurement region, said planar surface being arranged substantially orthogonal to a transceiving axis of the antenna.
Dependencies are inferred from the claim text.