volume | PIER Journals

Abstract

A concentric circular array consisting of two rings is proposed to focus the radiated field at a point in the near-field zone. In the proposed two-ring array, the radius of the outer ring was chosen so that the radiated fields from all elements on the two rings add constructively at the focal point, thus no phase shifter is needed in this design. The N elements of the inner ring are uniformly excited in amplitude and phase, while the M elements on the outer ring are excited uniformly in phase, and given uniform magnitude excitations of N/M of that given to the inner. Therefore, two deep nulls are achieved on both sides of the focusto enhance the focal width. The focusing properties are investigated by exploring the array parameters, such as variation of the focused field along the normal to the array, field distribution on the focalplane, and depth of field (size of the focal spot). Computer simulations using the MATLAB environment are performed by point source radiators. For verification, the array was simulated using the CST microwave studio, and the obtained results showed good agreement. The array is useful for hyperthermia and imaging applications.

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Dr. Mohammed Z. Mohammed Fwzi

Prof. Khalil Sayidmarie