10 February 1981 Experimental Investigation In Microwave Range Of Diffraction By Classical And Crossed Gratings
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Abstract
The behaviour of classical gratings (echelette, lamellar and sinusoidal) is correctly described by present electromagnetic theories by means of which new interesting profiles and more elaborate Fourier gratings can be obtained. Confrontation of theory and experiment is critical in the optical field because the groove spacing is less than one micrometer and the profile is not always regular. On the other hand, it is possible to work in the microwave range (26.5 to 40 GHz) with isomorphic-gratings having periods of several millimeter and perfectly ruled profiles. Our experimental equipment consists of a tridimensional 3 m radius goniometer, placed in an anechoic chamber. The antennae for emission and reception are parabolic D = 60 A diameter mirrors. The measurements are obtained using a phase-amplitude receiver, a ratiometer and a chart-recorder made by "Scientific-Atlanta". The system of data acquisition and analysis is obtained with a "Hewlett-Packard 9825" minicomputer. The relative accuracy of the grating efficiency measurement is better than 3%. We have already studied echelette, lamellar and Fourier gratings and, recently, we have studied crossed-gratings (round-holed grids and planar distributions of pyramids or half prolate spheroids both intended for solar captation). Agreement between theory and experiment is excellent and this apparatus is very powerful for diffraction or diffusion effect measurements - this is very important when the grating models are not treated theoretically.
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Patrick Bliek, Roger Deleuil, "Experimental Investigation In Microwave Range Of Diffraction By Classical And Crossed Gratings", Proc. SPIE 0240, Periodic Structures, Gratings, Moire Patterns, and Diffraction Phenomena I, (10 February 1981); doi: 10.1117/12.965665; https://doi.org/10.1117/12.965665
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