Multifrequency microwave measurements in the intermediate zone of radiation with inverse aperture synthesis for radio image forming

Abstract

Experimental results of reflectivity measurements for metal sphere with diameter of 35.5 mm and cylinder with the base diameter of 38 mm and the height of 76 mm in the range of 38-52 GHz at the grid of 256 frequencies are presented. Application of reference discontinuity in the form of iris positioned in the throat of the horn allowed implementing Fourier-holography principle and obtaining complex time-domain signal of reflection from the object by Fourier transform of data in frequency domain. The magnitude of reflection directly from the sphere is proportional to its diameter. The method of inverse aperture synthesis on the basis of the method generalized spatial inverse filtration is proposed. The peculiarity of inverse aperture synthesis implementation is application this approach to the time-domain signal. For the experimental data the spatial resolution was improved in 2 times by inverse aperture synthesis. The suggested data processing method provided possibility to form radio image of the objects.