Daniele Bresciani

A Multi Facets Composite Panel Reflectarray Antenna for a Space Contoured Beam Antenna in Ku Band

A 1.3m piecewise re∞ectarray demonstrator has been designed, manufactured and tested, that radiates a contoured beam coverage over North America. A very good agreement is obtained between the theoretical and measured radiation patterns. Many innovative techniques and processes were developed in order to meet the challenging speciflcations of a space telecommunication antenna.

Polarimetric Control of Reflective Metasurfaces

This letter addresses the synthesis of reflective cells approaching a given desired Floquets scattering matrix. This work is motivated by the need to obtain much finer control of reflective metasurfaces by controlling not only their copolarized reflection, but also their cross-coupling behavior. The demonstrated capability will enable more powerful design approaches-involving all field components in phase and magnitude-and consequently better performance in applications involving reflective metasurfaces. We first expose some fundamental theoretical constraints on the cell scattering parameters. Then, a successful procedure for controlling all four scattering parameters by applying parallelogram and trapezoid transformations to square patches is presented, considering both normal and oblique incidence.

A 1.3 m facetted reflectarray in Ku band

Thales Alenia Space and its partners have developed a facetted reflectarray, made of five flat panels arranged along an offset parabolic profile. Faceting the demonstrator is essential for achieving satisfactory RF performances, and especially the largest bandwidth. A 1.3m piecewise reflectarray demonstrator has been designed, manufactured and tested, with a coverage over Canada, US, Puerto Rico and Hawaii. A very good agreement is obtained between the theoretical and measured radiation patterns. Many innovative techniques and processes were developed in order to meet the challenging specifications of a space telecommunication antenna. They are detailed in this article.

Reflectarray antenna simplification through non-radiating currents synthesis

This work presents a new design methodology aimed at simplifying the layout of microstrip reflectarrays. Towards this end, the proposed methodology reduces the size/shape variations between adjacent metallic patches, by smoothening the superficial current phase distribution required to re-radiate a desired far-field pattern. The theory of non-radiating (NR) sources is exploited to modify the current on the reflectarray surface, and the synthesis problem is solved through a Particle Swarm Optimizer (PSO) algorithm. An illustrative example is shown to verify the effectiveness and the potentialities of the developed approach.

Interval-based tolerance analysis with localized surface errors in parabolic reflectors

The analysis of the effects on the power pattern radiated by reflector antennas in presence of localized defects (also called bumps) of the parabolic surface is addressed by means of an innovative analytic strategy. The bump depths are supposed unknown or estimated with a given tolerance such that their deviations from the nominal surface can be expressed as intervals of values. The upper and lower bounds of the power pattern function including all possible patterns generated by the actual parabolic reflector with bumps having depths within the considered intervals are computed by means of the Interval Analysis. In order to show the effectiveness and efficacy of the proposed analytic tool, a benchmark example is reported and discussed.

Control of the cross-polar reflection coefficients of reflectarray cells using truncated patches

A technique for controlling the magnitude and phase of the co-to-cross reflection coefficients in microstrip reflectarrays cells is presented. It is based on truncating different patch corners, and thus can be efficiently applied to patches with sizes close to the array lattice. The main application of this technique is a novel synthesis method for reflectarrays with quasi-null cross-polarization, which requires the control of the four terms of the cells scattering matrix. However similar strategies could also be of use in other surface-based antennas and optical devices.

Comparison of Synthesis Strategies for a Dual-Polarized Reflectarray

This paper presents and compares four optimization strategies for printed reflectarrays. They are applied to synthesize a dual-polarized reflectarray using two kinds of slot-loaded patches. They provide objective criteria to deal with the numerous geometrical parameters available to tune the phase. The study relies on the comparative measurements of four different prototypes for the same 22𝜆0×22𝜆0 reflectarray (with 𝜆0 the wavelength at 𝑓0=14.25 GHz).