Multi-functional dipole antennas based on artificial magnetic metamaterials

The authors present the design of a multi-functional dipole antenna based on the employment of artificial magnetic metamaterials. A regular dipole antenna is placed in front of a metamaterial slab, whose effective permeability is described through the Lorentz dispersion model. Since the electromagnetic behaviour of the layer changes with the frequency, the dipole antenna may work in different operation modes. Specifically, around the resonant frequency of the effective permeability, the slab acts as an artificial magnetic conductor, while, when the effective permeability is close to zero, it behaves as a spatial filter allowing, for a given polarisation, the transmission of only a few angular components around the broadside. The proposed design is shown to be robust to the variations of the main electrical and geometrical parameters of the metamaterial slab and suitable for an actual implementation through real-life magnetic inclusions. Interesting applications of such an antenna can be found in radio base stations of mobile communication systems and in multi-functional radiators mounted in complex platforms, where space occupancy and electromagnetic interference between different sources have to be minimised.

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