A New Approach to the Link Budget Concept for an OAM Communication Link

Following on from the increasing interest for electromagnetic waves carrying Orbital Angular Momentum (OAM), different configurations of antenna systems able to generate such beams have been proposed. However, in our opinion, a traditional radiation pattern approach does not provide the right picture of an OAM-based communication link. For this reason we propose a new general concept, the "OAM-link pattern", which takes into account the peculiar phase structure characterizing these waves. Focusing on OAM transmissions between antenna arrays, we introduce a formula for the link budget evaluation which describes the whole communication link and directly leads to a "classically shaped" main lobe pattern for a proper rephased reception in the case of uniform circular arrays.Comment: 4 pages, 3 figure

OAM multiple transmission using uniform circular arrays: numerical modeling and experimental verification with two digital television signals

In this work we present the outcomes of a radio-frequency OAM transmission between two antenna arrays performed in a real-world context. The analysis is supplemented by deep simulative investigations able to provide both a preliminary overview of the experimental scenario and a posteriori validation of the achieved results. As a first step, the far-field OAM communication link is tested at various frequencies and the corresponding link budget is studied by means of an angular scan generated by the rotation of the receiving system. Then, on the same site, two digital television signals encoded as OAM modes ($\ell$=1 and $\ell$=-1) are simultaneously transmitted at a common frequency of 198.5 MHz with good mode insulation.Comment: 16 pages, 14 figure

Characterization of an Open GTEM Cell with the COMSOL Multiphysics® Software

The Gigahertz Transverse Electromagnetic (GTEM) cell is a device used for generating known, homogeneous fields for calibration purposes and for studies on Electromagnetic Compatibility (EMC) on a wide frequency range. With the aid of the COMSOL Multiphysics® simulation software, we have analyzed the electromagnetic behavior of an existing open GTEM cell at different operating frequencies. This study allowed us to identify the region internal to the cell where the field is most purely TEM. Moreover, experimental values obtained using the real GTEM have been compared to the simulated results, providing a good agreement with them

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Full Simulative Approach to Orbital Angular Momentum (OAM) Transmissions between Antenna Arrays

The possibility of exploiting the Orbital Angular Momentum (OAM) of light as a means to simultaneously transmit radio signals at the same frequency led us to the experimental implementation of an OAM-based multiplexing scheme between antenna arrays. Within this framework, the realization of a full-wave simulation of the communication link with COMSOL Multiphysics® proved essential both as a guide to the experimental setting and as a numerical validation of the achieved results

Modeling Orbital Angular Momentum (OAM) Transmission in Waveguides with the COMSOL Multiphysics® Software

The recent years have witnessed a growing interest in the possibility of enhancing the information transfer per unit bandwidth by exploiting the Orbital Angular Momentum (OAM) of light in both free-space and guided scenarios. In the proposed paper, the propagation of suitable OAM superpositions of waveguide eigenmodes in guiding structures with a circular symmetry is analyzed both theoretically and with the aid of the software COMSOL Multiphysics®, leading to the estimation of the power attenuation constants due to the finite conductivity of the metallic guide walls

Long term perspectives of TV convergence towards 5G: Mobile and fixed applications

The third generation partnership project (3GPP) has defined in Release 14 the new evolved version of Multimedia Broadcast Multicast Service system, whose characteristics are well aligned to the technical requirements coming from the broadcast sector for TV services. This paves the way to allow broadcasters and content aggregators to deliver mobile TV content over cooperative broadcast high power high tower and mobile low power low tower network infrastructures, using a converging broadcast 3GPP technology. In a longer term perspective, in the 2020 decade, might this full-IP convergent technology become a candidate successor of DVB-T2 (ATSC or ISDB-T) also for digital terrestrial television home services? Is there a technical and business case for converging fixed and mobile TV on the same networks and technologies? The study investigates the performance of 3GPP Release 14 in theoretical, regular networks and in a real area around Turin (Italy), trying to give a technical background to answer the above strategic questions