<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A technique for the determination of equivalent currents distribution from a known radiated field is described. This Inverse Radiation Problem solved through an Integral Equation algorithm that allows characterization antennas complex geometry both near to far (NF-FF) transformation purposes as well diagnostic tasks. The based on representation radiating structure by means set over...

This paper presents a novel system to obtain images from the underground based on ground penetrating radar (GPR). The proposed is composed by module mounted board an unmanned aerial vehicle (UAV), which allows safe inspection of difficult-to-access areas without being in direct contact with soil. Therefore, it can be used detect dangerous buried objects, such as landmines. measurements are coherently combined using synthetic aperture (SAR) algorithm, requires cm-level accuracy positioning...

This paper presents a compact, low-cost unmanned aerial system for antenna measurement. The proposed overcomes existing limitations in terms of vehicle positioning and data geo-referring accuracy using real-time kinematic to achieve centimeter-level accuracy. Amplitude-only measurements acquired power sensor are processed by means the phaseless sources reconstruction method. is an iterative phase retrieval technique that allows recovering equivalent currents distribution, which characterizes...

Radio frequency identification (RFID) has become a key technology in the logistics and management industry, thanks to distinctive features such as low cost of RFID tags, easiness tags' deployment integration within items be tracked. In consequence, plays fundamental role so-called digital factory or 4.0 Industry, aiming increase level automatization industrial processes. addition, also been found great help improving tracking patients, medicines, medical assets hospitals, where...

A thin Artificial Magnetic Conductor (AMC) structure for Radar Cross-Section (RCS) reduction applications is presented.The manufactured prototype, which combines two unit-cell metallization sizes, presenting resonant frequencies, shows broad AMC operation bandwidth, polarization angle independency, and its angular margin when operating under oblique incidence also tested.It shown that significant RCS can be achieved with the proposed AMCs combination even if a 180 • phaseshift between...

Active millimeter-wave radar can be used for imaging concealed objects and detecting contraband at security checkpoints. Current state-of-the-art systems are based on monostatic or quasimonostatic configurations that misrepresent areas of the target when specular reflection is oriented away from incident direction. This article presents a fully multistatic architecture human-body screening. Transmitters placed off receiving aperture panel allow maximizing surface human body reconstructed. A...

This work presents an enhanced autonomous airborne Synthetic Aperture Radar (SAR) imaging system able to provide full 3D radar images from the subsurface. The proposed prototype and methodology allow safe detection of both metallic non-metallic buried targets even in difficult-to-access scenarios without interacting with ground. Thus, they are particularly suitable for detecting dangerous targets, such as landmines Improvised Explosive Devices (IEDs). is mainly composed by Ultra-Wide-Band...

An improved Ground Penetrating Radar (GPR) system on board an Unmanned Aerial Vehicle (UAV) is presented in this contribution. The has been designed for the detection and imaging of buried targets and, particular, landmines Improvised Explosive Devices (IEDs). Resting hardware architecture a previous aerial platform, proposed scanning area increased capabilities are improved. These improvements achieved by employing two receiving antennas new processing techniques that increase...

The usage of unmanned aerial vehicles (UAVs)-based ground penetrating radar (GPR) systems has gained interest over the last years thanks to advantages ground-based systems, such as contactless inspection and capability, reach difficult-to-access areas. former is paramount importance concerning detection buried threats, improvised explosive devices (IEDs) landmines. Current state-of-the-art UAV-based GPR are able provide centimeter-level resolution use GPR-synthetic aperture (SAR) processing...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The source reconstruction method (SRM) is a recent technique developed for antenna diagnostics and carrying out near-field (NF) to far-field (FF) transformation. SRM based on the application of electromagnetic Equivalence Principle, in which one establishes an equivalent current distribution that radiates same fields as actual currents induced under test (AUT). knowledge allows determination...

Fourier-based methods for monostatic and bistatic setups have been widely used high-accuracy radar imaging. However, the multistatic configuration has several characteristics that make Fourier processing more challenging: 1) a nonuniform grid in k-space, which requires multidimensional interpolation methods, 2) image distortion when incident spherical wave is approximated by plane wave. This contribution presents imaging method systems, solving aforementioned limitations: first, using...

The optimization and use of a sparse array configuration for an active three dimensional (3D) millimeter wave imaging system personnel security screening is presented in this work. combination the procedure with Compressed Sensing techniques allows drastic reduction number sensors, thereby simplifying design fabrication reducing its cost. Representative simulation results showing good performance proposed are provided supported by sample measurements.

In this paper, we propose a ball grid array (BGA) module with an integrated 3-D-printed plastic lens antenna for application in dedicated 130 GHz OOK transceiver that targets the area of 5G backhaul/fronthaul systems. The main design goal was full integration small footprint energy-efficient transceiver. system must be compact and cost effective while delivering approximately 30 dBi gain working band, defined as 120 to 140 GHz. Accordingly, 2 × aperture-coupled patch antennas designed 7...

In recent years there has been an increasing research interest in the development of airborne-based Ground Penetrating Radar (GPR) systems for safe and fast detection buried threats such as landmines Improvised Explosive Devices (IEDs). Compared to other sensors metal detectors or magnetometers, GPR is able detect either metallic non-metallic targets. Besides, use Ultra Wide Band (UWB) radiofrequency hardware allows retrieving high resolution images subsoil, thus improving capabilities....

A source reconstruction technique from the measured near fields is proposed to obtain a set of equivalent currents that will characterize forward and backward radiation patterns an antenna. Once sources are determined, electromagnetic field at any aspect angle distance antenna can be calculated. In this paper, method applied evaluation commercial antennas observation point. The electric DCS base station 1800 MHz horn 2500 have been calculated plotted several distances This used in...

An extension of the sources reconstruction method (SRM) for antenna diagnostics using amplitude-only field measurements is presented. While previous works limit application to canonical domain cases, combination SRM capabilities handling with arbitrary-geometry domains jointly phase retrieval techniques, allows complex geometry and acquisition domains. The consideration radiation inverse problem a general integral equation formulation currents domains, phaseless information, supposes...

The aim of the millimeter-wave imaging system presented in this work is to produce accurate geometry reconstruction human body torso and objects concealed under clothing detection. To effect, two techniques will be combined. First, an inverse source-based fast multipole method which provides a first approach true profile considered. Second, retrieved refined with Iterative Field Matrix technique, based on parameterization retrieved. Assuming smooth variations profile, objects' detection...

This paper presents a broadband and phaseless synthetic aperture radar (SAR) with efficient sampling. The design relies on novel monostatic element comprising transmitter receiver. element, together computationally inexpensive algorithm, can retrieve the phase of scattered field at all working band except for two small safety margins lower upper frequencies. Furthermore, retrieval works independently transmitter/receiver position. Consequently, conventional approaches to reduce number...

Practical asset and people tracking in indoor scenarios using Received Signal Strength (RSS) ZigBee-based sensor network is presented. The Indoor Location System (ILS) based on a novel algorithm that uses relative field levels gathered by set of transmitter nodes. These are introduced into cost function which minimum gives the location estimation. use levels-based avoids need system calibration due to signal strength fluctuation. method tested two real scenarios: first example devoted...

This paper presents a novel interrogation system that combines multiple millimeter wave transmitters and receivers to create real-time high-resolution radar images for personnel security screening. The main novelty of the presented is can be created as person being screened continuously moves across corridor where receivers, working in fully coherent architecture, are distributed. As moves, sequentially activated collect data from different angles inspect whole body. Multiple images, similar...

This paper introduces three methodologies to improve synthetic aperture radar (SAR)-based techniques used in ground-penetrating (GPR) systems. They consist of: 1) equalization of the frequency response transmitting (Tx) and receiving (Rx) antennas; 2) processing SAR images using partially overlapped subbands; 3) imaging domain clustering. The goal is combine ground penetration capabilities lower bands with resolution achieved when increasing overall band, resulting enhanced detection...

The design of a novel SHF-band uniplanar artificial magnetic conductor (AMC) is presented. A prototype manufactured and characterized based on reflection coefficient phase. designed shows broad AMC operation bandwidth polarization angle independency. Its angular margin when operating under oblique incidence also tested. results are supported by finite element method (FEM) simulations measurements in an anechoic chamber.