Giorgio Giordanengo

Fast Antenna Testing With Reduced Near Field Sampling

This paper proposes an innovative functional testing methodology suitable for RF end-to-end antenna testing. Any measurement point requires mechanical movement and signal integration time to produce a sample; thus, the most radical way to reduce testing time is to reduce the number of required measured samples to a minimum. The presented approach exploits existing measurement capabilities, and allows a radical under-sampling via insertion of a-priori information by way of suitable use of advanced numerical modeling tools. The methodology can be used also with non-canonical grids, and when only a limited number of measured points is available. Experimental results are provided to show the potentials of the method.

Reconfigurable antenna system for wireless applications

Nowadays wireless applications are widespread, and the demand for smart antenna technology grows exponentially. Although there are a large variety of effective algorithms to control antennas, they lack in the requirements of the next generation smart devices for industrial and societal applications which demand integration in compact, low cost and low power architectures. In this work we present a Wi-Fi device coupled with an antenna, where the receiver is able to adapt to a changing signal environment by providing a constant and reliable connectivity. Design criterion follows a strong low power approach, single front-end USB powered connected to an embedded low energy consumption platform. In addition, we come up in a low cost solution that does not require any external hardware. Decoding and antenna control algorithm are software-defined, while antenna beam steering is obtained by means of varactor diodes, voltage biased, used in a suitable way through hybrid couplers in phase shift configuration.

Software-defined reconfigurable antenna for energy efficient wireless links

The ability to reconfigure an antenna can also allow energy saving in autonomous system as, e.g. the nodes of a deployable wireless sensor network. This option appears not yet fully exploited. Software-defined radio (SDR) plays an important role in this scenario. This paper shows how a simple antenna with reconfigurable beam can reduce the energy consumption of wireless links (WI-FI), while preserving channel capacity and reducing interferers.

The Green Computing Continuum: the OPERA Perspective

Cloud computing is an emerging paradigm in which users’ access to a shared pool of computing resources is dynamically allocated (i.e. ubiquitous computing service), depending on their specific needs. Such paradigm exploits the infrastructural capabilities of modern data centers to provide computational power and storage space required to satisfy modern application demands. The seamless integration of Cyber-Physical Systems (CPS) and Cloud infrastructures allows the effective processing of the huge amount of data collected by smart embedded systems, towards the creation of new services for the end users. However, trying to continuously increase data center capabilities comes at the cost of an increased energy consumption. The OPERA project aims at bringing innovative solutions to increase the energy efficiency of Cloud infrastructures, by leveraging on modular, high-density, heterogeneous and low-power computing systems, spanning data center servers and remote CPS. The effectiveness of the proposed solutions is demonstrated with key scenarios: a road traffic monitoring application, the deployment of a virtual desktop infrastructure, and the deployment of a compact data center on a truck.

Energy Efficient System for Environment Observation

Environment observations provide a unique source of consistent information about the natural environment and they provide resource managers the information to assess the current state of the environment, weight the requirements of different uses by multiple stakeholders, and manage the natural resources and ecosystems in a sustainable manner. Most of the observations are based on satellites, but remote-sensing technologies alone cannot guarantee observations at the spatio-temporal resolution and with the accuracy requested for monitoring and modeling applications targeting, like weather and climate extremes and the complex feedback processes between the natural environment and human activities. Dense networks of standard and in-situ weather related sensors are present in EU and US, but it may happen that their data are not always available in real-time or updated with the required scale for various weather and climate applications. Then, high-resolution, (near) real-time on field monitoring systems are needed to satisfy the demand to sample environmental data, both in dense populated regions and in less developed and getting more populated regions, where essential in-situ observational capabilities can be lacking or deteriorating. The paper would demonstrate the possibility to have energy efficient computing and communication systems that can be employed for environment observation and that can enrich traditional in-situ and remote sensing environmental data, to enable a significant step forward in the environment monitoring of a wide range of weather and climate data. The paper will present an approach going in this direction (computing/communication everywhere with low-power constrains), tested in a harsh environment, by exploiting low-power boards to perform data pre-processing and reconfigurable antennas to send data in a more energetically convenient way applied to a real case as it may be the monitoring of ionospheric scintillation in Antarctica.

Low Power Computing and Communication System for Critical Environments

The necessity of managing acquisition instruments installed in remote areas (e.g., polar regions), far away from the main buildings of the permanent observatories, provides the perfect test-case for exploiting the use of low power computing and communication systems. Such systems are powered by renewable energy sources and coupled with reconfigurable antennas that allow radio-communication capabilities with low energy requirements. The antenna reconfiguration is performed via Software Defined Radio (SDR) functionalities by implementing a phase controller for the array antenna in a flexible low power General Purpose Platform (GPP), with a single Front-End (FE). The high software flexibility approach of the system represents a promising technique for the newer communication standards and could be also applied to Wireless Sensor Networks (WSNs). This paper presents the prototype that is devoted to ionospheric analysis and that will be tested in Antarctica, in the Italian base called Mario Zucchelli Station, during summer campaigns. The system, developed to guarantee its functionality in critical environmental conditions, is composed of three main blocks: Communication, Computing and Power supply. Furthermore, the computing and communication system has been designed to take into account the harsh environmental conditions of the deployment site.

Parametric interpolation using physics-based basis functions

An interpolation procedure to approximate the electromagnetic responses of structures for different values of some parameters describing the structures geometry is presented. Basis functions are obtained from known families (e.g. polynomials or trigonometric polynomials) and from a post-process of some actual responses of the system. The fitting, in the least squares sense, can be handled efficiently leveraging on the Kronecker form of the resulting linear system.

Frequency interpolation in the method of moments using the Discrete Empirical Interpolation Method

We present some preliminary results on the construction of a Reduced Order Model to simulate the electromagnetic response of a structure at different frequencies with Surface Integral Equations. The Discrete Empirical Interpolation Method, introduced for the simulation of nonlinear differential equations, is used in this context to accelerate the construction of the Reduced Order Model.

Empirical study of a Reduced Order Model for electromagnetic scattering problems

Some numerical results about the use of a Reduced Order Model to map currents to their radiated field in the presence of a scatterer are shown for antenna design and placement.

Time efficient NF test technique for AIT/AIV with stationary satellite

Nowadays, the final RF functional verification has to be performed on the integrated satellite due to the increasing complexity and stringent performance in RF instruments and payloads. To reduce the global time and cost of future Antenna Integration and Test Verification (AIV/AIT) it needs to develop advanced test methodologies. This paper shows the results of a functional testing solution for RF end-to-end antenna testing. The approach proposed is based on structured use of existing measurement capabilities and advanced numerical modeling tools. The scope of this activity is to show the possibility to achieve accurate and fast measurement results using a radical measurement under sampling with respect to the conventional Nyquist criteria.