A millimeter-wave integrated-circuit antenna based on the Fresnel zone plate

A new type of millimeter-wave integrated-circuit antenna is based on a quasi-optical design is investigated. It consists of a Fresnel zone plate on one side of a dielectric substrate and a resonant strip dipole antenna at the focus of the zone plate on the opposite side of the substrate. All of the components are made using simple integrated-circuit fabrication techniques: thin-film metal depositions on planar dielectric substrates. Another features of this design is the short focal length of the zone plate; the focal length/diameter (f /d) for the zone plates studied ranges from 0.1 to 0.5. The antennas described are for a frequency of 230 GHz (λ₀ =1.3 mm); however, the design is easily scaled to other millimeter-wave or submillimeter-wave frequencies. Measured results are reported for four different focal length zone plates. Moderate gains, above 20 dB, are obtained. A theory is developed which predicts the on-axis gain, beamwidth, and sidelobe levels. Design graphs are given to aid in the selection of the geometrical parameters to achieve a desired gain from the integrated-circuit zone-plane antenna