Ricerc@Sapienza

We propose a simple phased-array design based on a Fabry-Perot cavity antenna for the generation of a highly-directive pencil beam steerable along two directions in 3-D space. Each array element generates an element pattern in the far-field obtained through the excitation of a dominant cylindrical TM leaky wave inside the cavity. Hence, the resulting conical pattern is combined with the array factor of a N × N square or circular arrangement of ideal vertical electric dipoles.

The generation of higher-order cylindrical leaky waves (HOCLWs) by means of canonical electric or magnetic ring sources was discussed in Part I, where radiation formulas for such waves were also presented. In the second part of this sequence, the practical excitation of HOCLWs in a Fabry–Perot cavity antenna is discussed considering the use of ring sources in a discrete form, i.e., circular phased arrays of vertical electric or horizontal magnetic dipoles.

Radiation from cylindrical leaky waves (CLWs) supported by layered dielectric media is of interest in a variety of current applications. A comprehensive two-part study has been undertaken to investigate the generation and the radiation properties of CLWs with an arbitrary integer azimuthal order n. The first of this two-part sequence deals with the identification of continuous rings of canonical sources of electric and magnetic types, capable of exciting higher-order CLWs (HOCLWs) in planar open radial waveguides.

In this work, the spatially dispersive behavior of three different metasurface geometries has been investigated. A patch-like, a strip-like, and a fishnet-like unit cell have been compared in terms of their surface impedance for different angle of incidence at terahertz frequencies. The fishnet-like metasurface shows a TE-TM polarization independent behavior and a remarkable non-dispersive behavior, opening to very interesting possibilities in the design of Fabry-Perot cavity leaky-wave antennas with a reconfigurable pointing angle and equalized patterns at terahertz frequencies.

In this paper, a systematic design of Fabry-Perot cavity antennas based on leaky waves is proposed in the THz range. The use of different topologies for the synthesis of homogenized metasurfaces shows that a specific fishnetlike unit cell is particularly suitable for the design of efficient THz radiating devices. Accurate full-wave simulations highlight the advantages and disadvantages of the proposed geometries, thoroughly considering the bounds dictated by technological constraints and the homogenization limit as well.