Mario Orefice

In this paper, a new concept to obtain an azimuthal shaping of an omnidirectional antenna pattern for mm-waves will be presented. Previous papers have shown that a dual reflector antenna with parabolic subreflector, conical main reflector and a suitable feed pattern and excitation exhibits a linearly polarized omnidirectional pattern; here the conical main reflector is modified in its azimuthal profile in order to produce a non uniform power distribution in azimuth.

In this paper the results of the design and the experimental characterization of a Convex Conformai Reflectarray Antenna are presented. The considered configuration, designed to operate in the Ka band, consists of 43×43 square elements printed on a substrate with a radius of curvature of 20 λ and offset fed. In order to validate the design procedure, a prototype has been manufactured and characterized experimentally. The obtained radiation patterns are in good agreement with those computed through a full-wave approach.

This paper overviews the emerging antenna and EM field measurement strategies based on the modern Unmanned Aerial Vehicle (UAV) technology. UAVs are currently being exploited as source/probe antenna positioners in various applications from HF to microwaves. Several contributions from all-over the world will be discussed in terms of measurement approach, RF setup and positioning strategies. A measurement example at 350 MHz highlights the importance of position and orientation accuracy in the post-processing chain.

In this work some results about the design and the analysis of Conformai Reflectarray Antennas (CRAs) mounted on curved surfaces are presented. In particular, a comparison among three different Reflectarray configurations i.e. a planar, a convex cylindrical and a convex spherical RA, all working in the Ka-band, is carried out. In order to highlight the effect of the single or double curvature on the radiation characteristics of the designed antennas, the three reflectors have the same size, are printed on the same substrate and are off-set fed.

The design, the numerical analysis and the experimental characterisation of a convex conformal reflectarray (CRA) has been carried out, with the aim of investigating the feasibility of reflectarrays bent on convex curved surfaces. A medium‐size offset CRA in Ka‐band has been designed, and a demonstrator has been manufactured and measured. The results prove the correctness of the design procedure and the feasibility of this type of antenna, pointing out the differences, also in terms of radiation performances, with respect to a planar reflectarray.

A quad-band compact, frequency-reconfigurable patch-type antenna is presented, designed to operate fully integrated on a full real-life printed circuit board (PCB), taking also into account the effect of a number of electronic components distributed on the board. Reconfigurability is obtained through a set of shorting pins switchable to the ground plane; the switches employ p-i-n diodes. The antenna is designed via an optimization process that jointly accounts for both patch shape and frequency. Reconfigurability in four subbands from 824 to 1990 MHz is achieved with two switches only, with an antenna space occupation of less than λ/10 × λ/10 × λ/30 at the lowest frequency. A full prototype of the assembly (antenna, board, and components) has been built, and its performances have been tested with respect to those obtained by the numerical approach, showing a satisfactory agreement between design and measurements.

In this paper, some results about the design and the full-wave analysis of Printed Conformal Reflectarray Antennas, able to work in the Ka band, using non-conventional re-radiating elements are presented. They introduce an improvement of the radiation characteristics, and in particular an enhancement of the bandwidth.

In antenna measurements, test procedures and best practices, validated by comparative measurements, constitute widely adopted tools to determine the uncertainty and thus the achieved accuracy of a given antenna measurement. For numerical simulations, there are no equivalent standards or tools to determine the accuracy of the numerical modelling of the same antenna. A highly stable reference antenna of which the mechanical deviations from the intended design has been minimized through careful manufacturing, has been identified as part of a EurAAP facility comparison campaign. The antenna has been measured in different facilities and simulated by different software vendors using different numerical methods. A comparison of simulations and measurements of this antenna at 10.7GHz and 18GHz has been reported in [1-2]. In this paper, we report our findings on the correlation between measurement and simulation at 30GHz and 38GHz. The investigation comprises additional measurements ranges and software vendors.

A numerical approach based on the Volume Electric Field Integral Equation is presented for investigating the permittivity profile of dielectric scatterers able to synthesize a determined near-field distribution. Starting from the cloaking design approaches available in the literature, in this paper, the main concept is to mathematically postulate the field in certain regions (i.e., cloaked and coating areas) and imposing unperturbed field lines for all the external observers positioned in the near-field zone. The general mathematical framework is presented with a Contrast-Field (CF) formulation and some numerical examples are given.