Single layer Multimodal OAM Reflectarray

In this work, the procedure for the design of innovative reflectarray (RA) antennas able to radiate multiple Orbital Angular Momentum (OAM) modes is introduced. Extending the concepts at the base of multifocal lenses, the RA is designed in such a way that, depending on the direction of arrival of the incident field, it radiates a broadside beam carrying an OAM with different index. As a proof of concept, a circular RA with diameter D = 20λ at the the frequency f0 = 30 GHz, able to radiate OAMs with l = 2 and l = 4 has been designed. The results obtained through its full-wave simulation, confirm the effectiveness of the proposed solution

Single-Layer, Multi-Mode OAM Reflectarray Antennas

In this letter, an innovative ReflectArray (RA) antenna able to radiate in the same direction multiple Orbital Angular Momentum (OAM) modes, is presented: depending on the direction of arrival of the impinging field, the RA radiates a broadside beam carrying on an OAM mode with different index. Two circular RAs with diameter D = 19.8λ at the the frequency f0 = 30 GHz, able to radiate two or four OAMs, have been designed and simulated, while a prototype of the dual-mode configuration has also been manufactured and experimentally characterised. The obtained results prove that vortex beams are successfully generated in the range of frequencies from 28 to 32 GHz, confirming the effectiveness of the proposed design

High-efficiency Reflectarray Using Dielectric Resonator Elements

In this paper, a dielectric resonator-based unit-cell is used to design a reflectarray antenna with improved efficiency. The unit-cell is a dielectric structure composed of a cylindrical element placed on a squared base having a ground plane at the bottom. The diameter of the cylinder is the parameter chosen for controlling the phase of the reflection coefficient. To verify its effectiveness, the proposed cell is employed to design a Ka-band offset reflectarray consisting in 52 × 52 elements. Simulated results show that the antenna is able to achieve a maximum gain of 32.3 dBi at 30 GHz, corresponding to an aperture efficiency of 55%

Multifocal Approach for Reflectarray Antenna for DTH Applications

In this paper, numerical and experimental results on the design of a multifocal, planar Reflectarray with scanning capabilities in both elevation and azimuth, are presented. The antenna is a possible alternative to the conventional parabolic reflectors in Direct-To-Home (DTH) receiving systems, with the planar reflector fixed to a building wall and the pointing obtained mechanically moving the feed to steer the main beam of the reflectarray