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The quest for increasing the scanning range of a phased array is a challenging task for antenna engineers, and its solution could lead to significant advances in different applicative scenarios, ranging from 5G and beyond 5G communications to radar and satellite systems. For this purpose, the use of a deflecting meta-dome is one of the most promising solutions recently proposed that, however, still presents some inherent limitations, such as the significant reduction of the broadside gain of the array, due to the diverging effect of the dome, as well as the complexity of the implementation due to the need of a continuous phase profile. In this framework, the paper aims at proposing some technical solutions for maximizing the meta-dome performance and relaxing the implementation complexity. In particular, by properly discretizing and engineering the phase profile along the dome and by taking into account the different angles of incidence onto the meta-cells, we show how it is possible designing realistic meta-domes with reduced insertion loss at broadside, improved steering capabilities, and a reduced profile. In addition, a complete design workflow for a realistic meta-dome based on cascaded metasurfaces is presented., (in press)

Wireless communications and sensing have notably advanced thanks to the recent developments in both software and hardware. Although various modulation schemes have been proposed to efficiently use the limited frequency resources by exploiting several degrees of freedom, antenna performance is essentially governed by frequency only. Here, we present a new antenna design concept based on metasurfaces to manipulate antenna performances in response to the time width of electromagnetic pulses. We numerically and experimentally show that by using a proper set of spatially arranged metasurfaces loaded with lumped circuits, ordinary omnidirectional antennas can be reconfigured by the incident pulse width to exhibit directional characteristics varying over hundreds of milliseconds or billions of cycles, far beyond conventional performance. We demonstrate that the proposed concept can be applied for sensing, selective reception under simultaneous incidence and mutual communications as the first step to expand existing frequency resources based on pulse width., 61 pages, 6 figures, 26 supplementary figures

Next-generation of wireless communications and beyond-5G systems will require extreme performance in terms of low latency, data rates, reliability, just to name a few, and the possibility to tailor the communication channel on demand would be a key enabling technology for the so-called smart environment systems. Therefore, conventional antennas with fixed functionalities cannot be considered an efficient solution, and a new paradigm change in antenna design is thus required. In this frame, here, we show some of the most interesting possibilities enabled by functionalized conformal metasurfaces coating wired antennas for enabling unprecedented electromagnetic behaviours. In particular, we report the design of metasurface coats loaded with electronic elements allowing scattering, frequency, and radiation pattern tunability, in view of the designs of intelligent antennas whose properties can be tailored on demand.

The use of fifth-generation (5G) new radio (NR) spectrum around 26 GHz is currently raising the quest on its compatibility with the well-established Earth exploration-satellite service, which may be blinded by the spurious radiation emitted above the horizon (AtH) by base station (BS) antennas. Indeed, AtH grating lobes are often present during cell scanning due to the large interelement spacing in BS array antennas for achieving higher gains with a reduced number of RF chains. In this letter, we propose an approach based on an electrically thin metasurface-based dome for the reduction of AtH grating lobes in 5G-NR BS antennas. The proposed scanning range shifting approach exploits the natural lower amplitude of the grating lobes when the antenna array scans in an angular region closer to the broadside direction. The grating lobe reduction is here demonstrated considering a 1x4 phased linear antenna array operating under dual-liner +/- 45 degrees-slant polarization. A simple design procedure for designing the metasurface dome is reported, together with the antenna performances, evaluated through a proper set of numerical experiments. It is shown that the grating lobe radiation toward the satellite region is significantly reduced, whereas the overall insertion loss is moderate.

In this contribution, we look at some recent applications of metasurfaces and we highlight their potential in the scenario of next-generation wireless systems. We show how metasurfaces allow overcoming some limiting effects of the environment on wireless systems, and we discuss their fundamental role in the practical development of smart electromagnetic environments.

Psychopathy is a condition characterized by atypical emotions and socially maladaptive behavioral patterns. Among incarcerated people, psychopathy has been associated with higher rates of crimes, recidivism, and resistance to treatment. Many studies have indicated significant heritability of psychopathic traits, but little is known about the specific contribution of genes and their interaction with adverse experiences in life. Considering the primary role that serotonin plays in cognition and emotion, we investigated TPH2-rs4570625, 5-HTTLPR, MAOA-uVNTR, HTR1B-rs13212041 and HTR2A-rs6314 as risk factors for psychopathy in the largest sample of institutionalized individuals studied so far, consisting of 793 US White male incarcerated adults, and in a replication sample of 168 US White male incarcerated adolescents. In a subgroup of the adult sample, the interaction between genetics and parenting style, assessed by the Measure of Parental Style (MOPS) questionnaire, was also evaluated. The HTR1B-rs13212041-T/T genotype, as compared to HTR1B-rs13212041-C allele, predicted higher psychopathy scores in both the adult and the adolescent samples. The interaction between HTR1B-rs13212041-T/T genotype and paternal MOPS scores, investigated in a subgroup of the adult sample, was an even stronger predictor of higher levels of psychopathy than either the genetics or the environment taken individually. Overall, these data, obtained in two independent samples, shed new light on neurobiological correlates of psychopathy with promising implications both at a clinical and forensic level.

In this contribution, we propose a quadratic-gradient metasurface dome operating in the near-field region of a dual-polarized phased array able enhancing its grating-lobe-free scanning range without affecting its other characteristics. The dome consists of an array of Huygens unit-cells exhibiting an extremely low insertion loss and a proper phase shift in transmission. The main characteristic of the proposed dome is the quadratic-gradient phase profile, which minimizes the beam divergence in broadside direction, whereas linearly increases the scanning region in off-broadside pointing angles. A proper set of numerical simulations have been performed showing the capability of the proposed dome to enhance the grating lobe free scanning region from -58° to -83°.

In this contribution, we report a new approach for the design of frequency reconfigurable antennas equipped with cognitive capabilities. Specifically, we show how the complex-valued input impedance of a wire antenna can be tuned by using an appropriate conformal metasurface. We prove that, by properly engineering the metasurface response, it is possible to modify the operative frequency of the antenna without compromising its radiation pattern and impedance matching with the source. As a relevant example, the case of a reconfigurable dipole antenna coated by a multi-layered metasurface loaded with varactor diodes is discussed. By tuning the junction capacitance of the varactors, the antenna operative frequency can be continuously shifted within a quite broad range of frequencies (2/3 octave bandwidth), enabling wideband reconfigurability capabilities.

Antenna arrays with large interelement spacing are marginally used in practical applications despite their highly directive main lobe. Their disuse is primarily attributed to the onset of grating lobes even for low scanning angles. In this contribution, we propose the design of a gradient metasurface dome able to reduce the grating lobe amplitude of a dual-polarized phased array. The dome consists of an array of Huygens unit-cells exhibiting an extremely low insertion loss and a properly designed phase of the transmission coefficient. The proposed solution is based on the scanning range shifting approach, which exploits the lower grating lobe levels exhibited by the array when radiating towards directions close to the broadside. A proper set of numerical simulations have been performed considering a 1×4 phased linear antenna array covered by a properly designed metasurface dome, showing its capability to significantly reduce the grating lobe amplitude without significantly reducing the performances in the pointing direction.