Università Roma Tre

Unit 1: Introduction to metamaterials.
Negative-index metamaterials. Classification and terminology. Engheta’s resonator. Pendry’s lens. Transmission-line metamaterials. Miniaturization of electromagnetic components. Miniaturized antennas. Design of inclusions for microwave metamaterials. Design of transmission-line metamaterials and design of miniaturized microwave components (elementary cells, phase shifters, rat-race, etc.). Computed-based exercises.

Unit 2: Introduction to metasurfaces.
Introduction to metasurfaces. Purely-electrical metasurfaces. Magnetoelectric sheets. Metasurfaces for anomalous reflection and refraction. Microwave metasurfaces. Optical metasurfaces based on array of nanoparticles. Electromagnetic characterization of metals at optical frequencies. Drude model. Effect of shape and size on the optical response of materials. Surface dispersion effect. Two-dimensional homogenization techniques. Applications of optical metasurfaces: electromagnetic invisibility, optical absorbers, anti-reflection coatings and transparent screens. Extension of the two-dimensional model to dielectric metasurfaces. Applications of dielectric metasurfaces. Computed-based exercises.

Unit 3: Electromagnetic invisibility.
Reduction of radar observability. Basic concepts on electromagnetic invisibility. Radar and scattering cross section. Figure of merit for EM cloaks. Basic principles of the transformation of transformation-electromagnetism. Invisibility cloaks based on transformation-electromagnetism. Other approaches to achieve electromagnetic invisibility. Basiuc principles on scattering cancellation. Scattering cancellation by volumetric metamaterials. Scattering cancellation by metasurfaces (mantle cloaking). Mie theory for spherical and cylindrical objects covered by volumetric layers and surface impedances. Implementation of invisibility devices based on the scattering cancellation at microwaves: volumetric materials and metasurfaces. Applications of electromagnetic invisibility to microwaves: invisibility of passive objects, invisibility of receiving antennas and sensors, mutual invisibility of transmitting antennas. Non-linear and waveform-selective electromagnetic invisibility devices and related applications. Computed-based exercises.

Unit 4: Space-time modulated metamaterials and metasurfaces.
Introduction to EM non-reciprocity based on natural and artificial materials. Introduction to space-time modulated metamaterials. Analysis of a resonator loaded with a space-time modulated metamaterial: coupled mode theory, resonant modes and frequency response. Applications. Free-space and slab propagation in space-time modulated materials. Time-domain propagation in a dielectric slab. Space-time modulated metasurfaces.

Unit 5: Metamaterials for structured fields.
Topological properties of structured fields. Introduction to the concept of orbital angular momentum, phase singularity and topological charge. Generation of EM fields with phase singularities at optical and microwave frequencies. Generation of composite vortices and related topological properties (robustness with respect to the interaction with opaque objects and vortex-less fields). Application examples: patch antenna with Moebius polarization, shaping of the direction pattern, sectorial and saddle radiation patterns. Full-wave and analytical simulations.

Learning materials provided by the teacher.