Stefano Vellucci

Mantle cloaking for co-site radio-frequency antennas

We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

Scattering by Conducting Cylinders Below a Dielectric Layer With a Fast Noniterative Approach

A spectral-domain technique to solve the scattering by perfectly conducting cylinders placed below a dielectric layer is presented. Propagation fields are expressed in an analytic form, in the frame of the cylindrical wave approach. The fields scattered by the buried objects are decomposed into cylindrical waves, which are, in turn, represented by plane-wave spectra. Due to the interaction with a layered layout, the scattered fields experience multiple infinite reflections at the boundaries of the layer. Using suitable reflection and transmission coefficients inside the plane-wave spectra, the interaction with such a layered geometry can be solved with a single-reflection approach. Multiple reflections are collected by a set of two scattered fields, i.e., an upward-propagating field, excited by the scatterers and transmitted up to the top medium, and a down-propagating one, which from the top medium reaches the scatterers after transmission through the layer. Therefore, the analytical theory is developed in a very compact way and can be solved through a fast and efficient numerical implementation. Numerical results are evaluated in an accurate way and validated by comparisons with results obtained with a multiple-reflection approach. The scattered field can be evaluated in any point of the domain, in the far-field as well as the near-field region. Two-dimensional maps displaying the magnitude of the total scattered field are reported, showing examples of applications of the technique.

Satellite Applications of Electromagnetic Cloaking

We discuss the possibility to exploit electromagnetic cloaking for enhancing the performances of communication antennas installed on nanosatellite platforms. As a case study, we consider a CubeSTAR system and show that properly designed metasurfaces can be effectively used to minimize the impact of its deployable payload sensors on both radiation and electrical characteristics of the antennas. The results discussed here pave the way to new strategies for the design of extremely compact nanosatellite platforms equipped with multifunctional antennas and sensors.

Use of Mantle Cloaks to Increase Reliability of Satellite-to-Ground Communication Link

In this paper, we show how mantle cloaking can be effectively used in satellite scenarios to reduce the deteriorating effects of the deployable equipment on the link budget between a miniaturized satellite and its ground station. The proposed idea is applied to a nanosatellite scenario and is validated through a simple analytical analysis of its communication link with the ground. The effectiveness of the designed cloaking metasurfaces is evaluated through a proper combination of numerical strategies taking into account the electrically large domain of the problem and the electrically small features of the metasurfaces. This innovative solution can be used to enhance the performances of existing satellite communication systems or to design new extremely compact nanosatellite platforms equipped with multifunctional antennas and sensors.

Metamaterials meeting industrial products: A successful example in Italy

In this contribution, we present the main results of the recent and ongoing research activities on metamaterials developed as a joint collaboration between Roma Tre University and Finmeccanica. The main goal of the applied research is focused on the development of miniaturized microwave components for radar and communication systems. The exploitation of innovative metamaterial concepts has led to the development of innovative industrial products for passive beam-forming networks of polarimetric antennas and compact radiating systems. This research has been awarded with the Finmeccanica Innovation Award in 2014 and the Finmeccanica Innovation Award for young researchers in 2015, respectively. The research activities leading to these two prestigious industrial awards are briefly summarized in this paper.