The paper describes the design of a Fresnel zone plate suitable for use as an antenna in the centimetric or lower wavelength range. It has been shown that such antennas can be fabricated by using either metal or dielectric rings. Its properties have been analysed by employing the simple methods of electromagnetic diffraction. Experimental results are reported showing close agreement with the theory. A theory has been presented explaining the working of the dielectric ring zone plate. The investigation leads to the conclusion that both the metal and dielectric zone plates are useful as low gain antennas.
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