Metal-only Fresnel zone plate antenna for millimetre-wave frequency bands

A metal-only Fresnel zone plate antenna (FZPA) to operate at millimetre wave frequency bands is presented in this work. The proposed antenna is a very attractive alternative to parabolic reflectors and reflectarrays because of its several advantages such as low profile, low cost, easy to manufacture and lossless. A centre-fed Fresnel zone plate whose diameter is 300 mm has been designed and analysed at 75 GHz providing a gain of 44.29 dBi, an aperture efficiency of 48.42% and a cross-polarised level lower than -40 dB for the diagonal plane (φ = 45°). A second prototype has been designed and analysed from 54 to 68 GHz to evaluate the performance of the proposed antenna compared with an already published FZPA.