Showing papers in "IEEE Antennas and Propagation Magazine in 2014"

An overview of three-dimensional frequency-selective structures

Abstract: Three-dimensional (3-D) frequency-selective structures are a recent development that exhibit superior filtering responses compared to conventional two-dimensional (2-D) frequency-selective surfaces. A three-dimensional frequency-selective structure typically comprises a two-dimensional periodic array of multimode cavities the modes of which and the coupling of which with air can be controlled to obtain a desired frequency response. Based on their distinct configuration, we seek to classify them as a separate class of high-performance frequency-selective structures, and to highlight their unique features in this paper. We also present a review of recent advances in three-dimensional frequency-selective structures, and suggest a number of related research topics for future exploration.

Antenna applications corner: Miniature implantable and wearable on-body antennas: Towards the new era of wireless body-centric systems

Abstract: Wireless body-centric sensing systems have an important role in the fields of biomedicine, personal healthcare, safety, and security. Body-centric radio-frequency identification (RFID) technology provides a wireless and maintenance-free communication link between the human body and the surroundings through wearable and implanted antennas. This enables real-time monitoring of human vital signs everywhere. Seamlessly integrated wearable and implanted miniaturized antennas thus have the potential to revolutionize the everyday life of people, and to contribute to independent living. Low-cost and low-power system solutions will make widespread use of such technology become reality. The primary target applications for this research are body-centric sensing systems and the relatively new interdisciplinary field of wireless brain-machine interface (BMI) systems. Providing a direct wireless pathway between the brain and an external device, a wireless brain-machine interface holds an enormous potential for helping people suffering from severely disabling neurological conditions to communicate and manage their everyday life more independently. In this paper, we discuss RFID-inspired wireless brain-machine interface systems. We demonstrate that mm-size loop implanted antennas are capable of efficiently coupling to an external transmitting loop antenna through an inductive link. In addition, we focus on wearable antennas based on electrically conductive textiles and threads, and present design guidelines for their use as wearable-antenna conductive elements. Overall, our results constitute an important milestone in the development of wireless brain-machine interface systems, and a new era of wireless body-centric systems.

Advances in antenna designs for UHF RFID tags mountable on conductive items

Abstract: The design of antennas for metal-mountable radio-frequency identification tags is driven by a unique set of challenges: cheap, small, low-profile, and conformal structures need to provide reliable operation when tags are mounted on conductive platforms of various shapes and sizes. During the past decade, a tremendous amount of research has been dedicated to meeting these stringent requirements. Currently, the tag-reading ranges of several meters are achieved with flexible-label types of tags. Moreover, a whole spectrum of tag-size performance ratios has been demonstrated through a variety of innovative antenna-design approaches. This article reviews and summarizes the progress made in antennas for metal-mountable tags, and presents future prospects.

Electromagnetic Design and Performance Analysis of Airborne Radomes: Trends and Perspectives [Antenna Applications Corner]

Abstract: The spectacular advancements in antenna technologies for control, guidance, surveillance, and communication applications for airborne platforms have resulted in the realization of novel conformal antenna arrays, embedded antenna systems on the body of the fuselage, and structurally integrated radiating systems. Such antenna systems/ radiating structures facilitate superior functional capabilities with reduced payloads, desirable for airborne applications. They demand novel airborne radome structures with superior electromagnetic (EM) performance characteristics. Furthermore, rapid progress in the fields of frequency-selective surfaces (FSS) and metamaterials has had significant impact on the development of radome technology. Since conventional EM design techniques, based on transmission-line models, may not be sufficient for such applications, new techniques, based on numerical methods, have been developed. In order to circumvent the limitations of conventional low-frequency/high-frequency methods in analyzing antenna-radome interaction phenomena, hybrid methods, in conjunction with novel algorithms, are currently used. Considering the significant growth in EM technologies for airborne radome applications, the objective of this paper is to provide a glimpse of the techniques/methods for the EM design and analysis of airborne radomes. Some of the challenging EM issues/problems pertaining to airborne radome development are also discussed, which may be of interest to the radome community in the aerospace sectors.

Wideband harmonic rejection filtenna for wireless power transfer

Abstract: Two novel, compact, simple 2nd and 3rd harmonic rejection coplanar waveguide (CPW) feeding mechanisms for a 5.8 GHz rectenna are proposed. Both of them make use of the CPW compact microstrip resonant cell (CMRC). In the first topology, the blockage is realized by a CMRC in combination with a U-slot. In the second topology a pair of strongly coupled CMRCs is optimized. Both these new feeding mechanisms are realized in prototypes and experimentally validated, first in two back-to-back configurations, and then in combination with two CPW fed wideband monopole antennas. The measured antenna return loss at the 2nd and 3rd harmonic is in the order of 0.5 dB and 1.5 dB, respectively, which corresponds to a return loss suppression of about 4 -5 dB compared to a reference monopole antenna. Both antennas reach an 18% 10 dB return loss bandwidth, which is the highest working bandwidth reported in literature for harmonic rejection antennas. Bandwidth could become an issue when wireless power transfer systems would be implemented with a reconfigurable working frequency in order to minimize interference with local telecom equipment.

Revisiting the generation of cross-polarization in rectangular patch antennas: A near-field approach

Abstract: In this work, the cross-polarized radiation from a rectangular patch antenna was studied as a consequence of the asymmetries (or disturbances) in the near field of the antenna. It was shown that the asymmetry of the probe location results in asymmetry in the near fields in the vicinity of the antenna, causing high cross-polarized radiation in the H plane of the antenna. These near-field disturbances show a varying trend with the variation of the frequency or dimensional parameters of the antenna, which ultimately affects the far-field cross-polarized radiation. Having developed the near-field model of the cross-polarized radiation, this approach is then applied to two important known configurations with low cross-polarized radiation, namely, differential feeding (for a single patch antenna) and rotational feeding (for an array antenna). The new approach presented here provides an insightful, visualization-based understanding of the cross-polarized radiation from a rectangular patch antenna.

Wireless corner: Cognitive-radio and antenna functionalities: A tutorial

Abstract: This paper discusses the fundamental principles of a cognitive-radio RF system. The key points required to achieve a true cognitive-radio device are outlined. The operation of a cognitive-radio system is mainly divided into two tasks. In the first task, a cognitive-radio device searches and identifies any part of the spectrum that is not occupied. The second task consists of achieving an optimal mode of communication by allocating the appropriate channels to be used. In this paper, the RF requirements required to operate a cognitive-radio device are detailed. Such a device can adopt one of two scenarios of a cognitive-radio system: the ?interweave? or ?underlay? mode of operation. For both scenarios, a cognitive cycle is followed. This cycle consists of the following four steps: (1) observe, (2) decide, (3) act, and (4) learn. A cognitive-radio engine is responsible for managing and integrating these four functions together into a single cognitive-radio device. In this tutorial, the realization of the four functions of a cognitive-radio cycle are detailed for both types of cognitive radio, and various RF front-end examples are presented and discussed.

D-band on-chip higher-order-mode dielectric-resonator antennas fed by half-mode cavity in CMOS technology

Abstract: In this paper, on-chip higher-order-mode dielectric-resonator antennas (DRAs), fed by a half-mode-backed cavity structure using standard CMOS technology, are presented. With the dominant cavity mode (half-TEz100), the half-mode cavity-feeding structure provided a high antenna radiation efficiency. The dielectric resonators (DRs) were designed to operate at higher-order modes (TEx?13, TEx?15) to enhance the antenna gain. At around 135 GHz, the proposed antennas demonstrated measured gains of 6.2 dBi and 7.5 dBi for the TEx?13 and TEx?15 modes, respectively, with corresponding simulated radiation efficiencies of 46% and 42%. Both antennas had a measured impedance bandwidth of 7%. The proposed antennas not only accomplished high gain without occupying a large chip area, but also maintained comparable or even improved cost performance and simplicity over other on-chip antennas.

Physical and Quantitative Analysis of Compact Rectangular Microstrip Antenna with Shorted Non-Radiating Edges for Reduced Cross-Polarized Radiation Using Modifi ed Cavity Model

Abstract: A straightforward and compact rectangular microstrip antenna with a shorted nonradiating edge was proposed and experimentally investigated for signifi cant suppression of cross-polarized (XP) radiation compared to maximum co-polarized gain, without affecting the co-polarized radiation pattern. The proposed antenna was thoroughly studied using simulation and experimental results. A modifi ed cavity model (MCM) was also demonstrated to understand the behavior of the cross-polarized radiation and the complete resonance behavior for the new structure. The proposed theory helps to germinate a real and clear view of the observed phenomena. The proposed idea was experimentally confi rmed with the present structure on three different substrate materials, with different dielectric constants. The new approach presented here provides an insightful visualization-based understanding of cross-polarized suppression with the present structure.

A Review of Broadband Dual Linearly Polarized Microstrip Antenna Designs with High Isolation [Education Column]

Abstract: Dual-polarized antennas are used to achieve polarization diversity in order to increase the capacity and reliability of wireless communication links. In order to cater to increased wireless communication traffic, dual-polarized antennas are required having broad bandwidths and high isolation between two orthogonal ports. Various dual-polarized antenna designs have been explored to achieve broad bandwidth and high isolation across the entire band of interest. This paper reviews various techniques proposed in recent years for the design of dual linearly polarized antennas to achieve high isolation and broad bandwidth. A detailed analysis of these techniques in terms of their advantages and limitations is presented.

A simple introduction to compressed sensing/sparse recovery with applications in antenna measurements

Abstract: The aim of this tutorial paper is to introduce the compressed sensing/sparse recovery theory and its usefulness in practical electromagnetic problems. Examples allow an intuitive understanding of the theory at the basis of compressed sensing/sparse recovery techniques. Readers can also perform some numerical experiments in a simple way, using a MATLAB program that can be downloaded from the Web.

Microwave imaging using indirect holographic techniques

Abstract: This work describes how indirect holographic techniques, previously applied to the determination of antenna radiation patterns, can be adapted for the imaging of passive objects. It provides details of how complex scattered field values can be obtained in a simple and inexpensive manner from sampled scalar intensity measurements taken over a single scanning aperture. This work provides a brief outline of the basic theory of indirect microwave holography, and how the transformation of the holographic intensity pattern into the Fourier domain enables the isolation of the terms required for complex field reconstruction to be isolated from the remaining terms. The work is supported by a range of experimental results, illustrating the reconstructed complex fields for a number of simple test objects. Back-propagation techniques have also been included to reconstruct complex fields at the position of the scattering objects.

Three-dimensional position and orientation measurements using magneto-quasistatic fields and complex image theory [measurements corner]

Abstract: Traditional wireless position-location systems, operating using propagating waves, suffer reduced performance in non-line-of-sight (NLoS) applications. Traditional systems that use quasistatic fields have instead been limited to short ranges, progressive direction-finding applications, require RF fingerprinting, or do not provide complete immunity to dielectric obstacles (use of electric fields). These limitations impose severe restrictions in applications such as tracking an American football during game play, where position and orientation tracking may be required over long ranges, and when the line-of-sight (LoS) is blocked by groups of people. A technique using magneto-quasistatic fields and complex image theory was recently shown to circumvent these problems, and to enable accurate long-range one-dimensional and two-dimensional measurements. In this work, we present three-dimensional position and orientation measurements using the magneto-quasistatic system and complex image theory over an area of 27.43 m × 27.43 m. Inverting the theoretical expression for the voltage measured at the terminals of the receiving loops to determine three-dimensional position and orientation resulted in mean and median geometric position errors of 0.77 m and 0.71 m, respectively; inclination orientation mean and median errors of 9.67° and 8.24°, respectively; and azimuthal orientation mean and median errors of 2.84° and 2.25°, respectively.

Mutual coupling reduction in waveguide-slot-array antennas using electromagnetic bandgap (EBG) structures

Abstract: The application of an electromagnetic bandgap (EBG) structure as a tool for reduction of mutual coupling in planar waveguide-slot-array antennas (WSAA) is investigated for the first time. First, surface-wave suppression was demonstrated by placing an EBG array over the ground plane of a linear 1 × 4 waveguide-slot-array antenna. Two 1 × 4 waveguide-slot-array antennas were then put next to each other, with the EBG array over the conducting plane separating them, and up to 10 dB reduction in mutual coupling was observed. Based on these achievements, a planar 2 × 4 waveguide-slot-array antenna was designed using the EBG array to reduce mutual coupling. The EBG array compensated for the undesired frequency shift due to mutual coupling through surface-wave suppression. In addition, the radiation patterns of the EBG-loaded antenna remained almost the same as for the unloaded antenna, with a 1 dB increase in antenna gain. Finally, EBG-loaded and simple 2 × 4 waveguide-slot-array antennas were fabricated, and simulation results were compared with measurements, with good agreement. As a key feature of this approach, a planar waveguide-slot-array antenna could be constructed by designing a linear antenna and then forming an array from multiples of the antenna, without the need for any new design, by imposing the EBG structure to reduce the mutual coupling between the adjacent waveguides.

Comprehensive Analysis and Measurement of Frequency-Tuned and Impedance-Tuned Wireless Non-Radiative Power-Transfer Systems

Abstract: This paper theoretically and experimentally investigates frequency-tuned and impedance-tuned wireless non-radiative power-transfer (WNPT) systems. Closed-form expressions for the efficiencies of both types of systems are presented as functions of frequency and system (circuit) parameters. In the frequency-tuned system, the operating frequency is adjusted to compensate for changes in mutual inductance that occur for variations of transmitter and receiver loop positions. Frequency-tuning is employed for a range of distances over which the loops are strongly coupled. In contrast, the impedance-tuned system employs varactor-based matching networks to compensate for changes in mutual inductance, and to achieve a simultaneous conjugate impedance match over a range of distances. The frequency-tuned system is simpler to implement, while the impedance-tuned system is more complex, but can achieve higher efficiencies. Both of the experimental wireless non-radiative power-transfer systems studied employ resonant shielded loops as transmitting and receiving devices.

Numerical Solutions to Poisson Equations Using the Finite-Difference Method [Education Column]

Abstract: The Poisson equation is an elliptic partial differential equation that frequently emerges when modeling electromagnetic systems. However, like many other partial differential equations, exact solutions are difficult to obtain for complex geometries. This motivates the use of numerical methods in order to provide accurate results for real-world systems. One very simple algorithm is the Finite-Difference Method (FDM), which works by replacing the continuous derivative operators with approximate finite differences. Although the Finite-Difference Method is one of the oldest methods ever devised, comprehensive information is difficult to find compiled in a single reference. This paper therefore provides a tutorial-level derivation of the Finite-Difference Method from the Poisson equation, with special attention given to practical applications such as multiple dielectrics, conductive materials, and magnetostatics.

Handbook of reflector antennas and feed systems. volume 3: applications of reflectors [reviews and abstracts]

Abstract: The implementation of electromagnetic bandgap (EBG) structures in all areas of high-frequency design is gaining widespread use. The applications for antennas include low-profile antennas, on-chip antennas, phased arrays, waveguides, and microwave filters. This book is an excellent resource on this subject. The book appeals to a wide array of readers that includes students, researchers, and practitioners. The book is a reference that presents the state of the art in antenna-specific EBG technologies. The book could also serve as a textbook for a class on the subject, as there are suggested projects at the end of each chapter that can be implemented to check for understanding. I especially like how each chapter builds upon the understanding of the previous chapters.

Multimode beamforming networks for space applications

Abstract: Increased demand for narrow multi-linguistic beams, and a reduction in the number of antennas for multi-spot systems, are revitalizing the need for lossless multimode networks at various frequencies. This paper reviews basic concepts, techniques, and technologies of multimode beamforming networks for satellite multiple beams and reconfigurable antennas.

Radio Propagation Channel Measurements for Multi-Antenna Satellite Communication Systems: A Survey

Abstract: For the terrestrial infrastructure, the multiple-input multiple-output (MIMO) architecture is a key technology that has brought the wireless gigabit vision closer to reality. Satellite communication systems have not been immune from this wave of innovation, and theoretical and experimental efforts have recently been devoted to the investigation of the applicability of multiple-antenna techniques to these systems. This paper intends to highlight and critically present the most important results from measurement campaigns conducted to characterize the radio channel of multi-antenna satellite systems. Emphasis is given on the viability of MIMO technology over satellite, and the potential enhancements in terms of channel capacity and link reliability that can be achieved through spatial and/or polarization diversity. The configurations under investigation range from very simple single-input multiple-output (SIMO) systems, with multiple antennas only at the terrestrial receiver, to quite complex and challenging systems, such as dual-satellite multiple-input single-output (MISO) systems, and single-satellite dual-polarized MIMO systems. The spotlight is on land mobile satellite (LMS) systems in outdoor radio propagation environments. However, satellite-to-indoor reception is also included.

Wave-propagation management in indoor environments using micro-radio-repeater systems

Abstract: This paper investigates the ability of micro-radio repeaters for managing wave propagation by enhancing signal coverage for the nodes of a mobile ad-hoc network in a complex environment. Such radio repeaters can be considered to be scatterers with a large radar cross section (RCS). Strategically positioning them enables a chain of line-of-sight (LoS) propagation between the transmitter and receiver when the straight signal path is blocked by obstacles such as walls. To specify repeater parameters, wave propagation in various hallway junctions were analyzed using a ray-tracing method that accounted for reflection, penetration, and diffraction. By adding the repeater model to such propagation models, the ability of micro-radio-repeater systems to enhance wave propagation in indoor environments was demonstrated. The results were verified with various measurement examples using a bench-top repeater system at 2.4 GHz. To allow multiple access through a single repeater, a simple repeater structure, composed of two omnidirectional antennas and one amplifier with sufficient gain, was considered. Measurement results indicated that in the chosen various indoor scenarios, a repeater system with an active gain of more than 35 dB with omnidirectional antennas could present scattering larger than typical building diffraction, and thus could enhance signal connectivity at 2.4 GHz.

The Gamma-Gamma Signal Fading Model: A Survey [Wireless Corner]

Abstract: In a wireless communication medium, the received signal envelope fluctuates randomly due to the scattering nature of these channels. This paper is intended to present a comprehensive literature review on the gamma-gamma signal fading model and its use in the performance analysis of different communication systems, with more elaboration on wireless radio-frequency (RF) communication networks, including cellular and relay networks, and wireless optical networks. First, the different communication channels where the gamma-gamma distribution is used to model the signal-fading phenomena are described. Second, the reported results on the statistics for the gamma-gamma distribution, including the product, the quotient, the sum, and the order statistics are presented. Finally, the performance analyses carried out in the open literature for wireless RF systems, relay networks, and wireless optical systems are summarized, and some possible directions for future research are highlighted.

Design Approach for Robust UHF RFID Tag Antennas Mounted on a Plurality of Dielectric Surfaces [Antenna Designer's Notebook]

Abstract: A design approach is presented for passive UHF RFID tag antennas to function efficiently when mounted on a wide variety of dielectric materials of arbitrary thickness. It is well understood that the presence of materials can detune an antenna by shifting its operational band. It is therefore important to design tags that can accommodate such a shift in frequency due to material effects. In this paper, we propose a way to modify existing classical tag designs to enable them to operate over a wide range of materials (3 <; e r <; 13 ) and arbitrary thickness. Experimental results showed that when compared to commercially available tags, the modified tags achieved better performance when mounted on a wide range of materials.

Electromagnetic fields in cavities: Deterministic and statistical theories [Advertisement]

Abstract: Advertisement for the book, "Electromagnetic fields in cavities: Deterministic and statistical theories."

ZigBee Radio Channel Analysis in a Complex Vehicular Environment [Wireless Corner]

Abstract: In this paper, the influence of the topology and morphology of a particularly complex scenario on the deployment of ZigBee wireless sensor networks is analyzed. This complex scenario is a car. The existence of loss mechanisms, such as material absorption (seats, dashboard, etc.), and strong multipath components due to the great number of obstacles and the metallic environment (bodywork), as well as the growing demand for wireless systems within a vehicle, emphasize the importance of the configuration of heterogeneous intra-car wireless systems. Measurement results, as well as simulation results by means of an in-house three-dimensional ray-launching algorithm, illustrate the strong influence of this complex scenario on the overall performance of the intra-car wireless sensor network. Results also show that ZigBee is a viable technology for successfully deploying intra-car wireless sensor networks.

Matlab-based fem ¿ parabolic-equation tool for path-loss calculations along multi-mixed-terrain paths [wireless corner]

Abstract: A novel Finite-Element Method - Parabolic-Equation (FEMPE) based MATLAB tool is developed. This calculates the electromagnetic field strength and path loss for one-way, forward propagation over multi-mixed irregular terrain paths through an inhomogeneous atmosphere, recommended by the ITU. The well-known smooth-Earth Millington curve-fitting model, based on analytic ray and mode approaches, is also included.

GPU accelerated finite-element computation for electromagnetic analysis

Abstract: General-purpose computing on graphics processing units (GPGPU), with programming models such as the Compute Unified Device Architecture (CUDA) by NVIDIA, offers the capability for accelerating the solution process of computational electromagnetics analysis. However, due to the communication-intensive nature of the finite-element algorithm, both the assembly and the solution phases cannot be implemented via fine-grained many-core GPU processors in a straightforward manner. In this paper, we identify the bottlenecks in the GPU parallelization of the Finite-Element Method for electromagnetic analysis, and propose potential solutions to alleviate the bottlenecks. We first discuss efficient parallelization strategies for the finite-element matrix assembly on a single GPU and on multiple GPUs. We then explore parallelization strategies for the finite-element matrix solution, in conjunction with parallelizable preconditioners to reduce the total solution time. We show that with a proper parallelization and implementation, GPUs are able to achieve significant speedups over OpenMP-enabled multi-core CPUs.

Further Validation of an Electromagnetic Macro Model for Analysis of Propagation Path Loss in Cellular Networks Using Measured Driving-Test Data

Abstract: Received signal level measurements are frequently used to check the performance and the quality of service (QOS) inside the coverage area in cellular networks These expensive, time-consuming measurements are carried out using actual driving tests to assess the coverage area of a base station for a given cell, and to thus evaluate the quality of service In a driving-test measurement system, a receiving antenna is placed on top of a vehicle The vehicle is then driven along radial and circular lines around the base station, to measure the received power and thus assess the quality of service These driving-test measurements are also used to tune the empirical models in the radio-planning tools that have to be employed for various types of environments This model tuning is a lengthy procedure In this paper, it is shown that an electromagnetic macro modeling of the environment can provide simulation results comparable to the data one would obtain in an actual driving-test measurement for a cellular environment The input parameters for the electromagnetic macro model can be generated using only the physical parameters of the environment, such as the height of the transmitting and receiving antennas over the ground, their tilts towards the ground, and the electrical parameters of the ground Such analysis can provide realistic plots for the received power as functions of the separation distance between the receiving and the transmitting base-station antennas The novelty of the electromagnetic-analysis technique proposed in this paper lies in its ability to match the macro-model-based simulation results and the driving-test measurements without any statistical or empirical curve fitting or an ad hoc choice of a reference distance In addition, a new concept, called the proper route, is introduced to enhance the analysis of the measured data A Method-of-Moments-based integral-equation-solver code has been used to simulate the effects of the macro parameters of the environment on the propagation-path loss of the signals emanating from a base-station antenna The perfect match between the simulation results and the driving-test data was illustrated by monitoring the signal levels from some cellular base stations in western India and Sri Lanka, and then comparing the observed results with the simulated results The goal here is to illustrate that these numerical simulation tools can accurately predict the propagation path loss in a cellular environment without tweaking some non-physical models based on statistical modeling or heuristic assumptions

Measurements corner: Three-dimensional position and orientation measurements using magneto-quasistatic fields and complex image theory

Abstract: Traditional wireless position-location systems, operating using propagating waves, suffer reduced performance in non-line-of-sight (NLoS) applications. Traditional systems that use quasistatic fields have instead been limited to short ranges, progressive direction-finding applications, require RF fingerprinting, or do not provide complete immunity to dielectric obstacles (use of electric fields). These limitations impose severe restrictions in applications such as tracking an American football during game play, where position and orientation tracking may be required over long ranges, and when the line-of-sight (LoS) is blocked by groups of people. A technique using magneto-quasistatic fields and complex image theory was recently shown to circumvent these problems, and to enable accurate long-range one-dimensional and two-dimensional measurements. In this work, we present three-dimensional position and orientation measurements using the magneto-quasistatic system and complex image theory over an area of 27.43 m × 27.43 m. Inverting the theoretical expression for the voltage measured at the terminals of the receiving loops to determine three-dimensional position and orientation resulted in mean and median geometric position errors of 0.77 m and 0.71 m, respectively; inclination orientation mean and median errors of 9.67° and 8.24°, respectively; and azimuthal orientation mean and median errors of 2.84° and 2.25°, respectively.

State-of-the-Art in Antenna Software Benchmarking - "Are we there yet?"

Abstract: Last year, within the yearly benchmarking cycle of the EurAAP Working Group on Software, a follow-up study was performed of the \"World GSM Antenna\", a very challenging topology for antenna software tools. The results were considerably better than in 2009, when the first study on this antenna was published, but still not fully satisfying. This year, in an effort \"to boldly go where no one has gone before,\" two structures were benchmarked. The \"World GSM Antenna\" was analyzed for the third time, focusing again on the S parameters. A new structure, a wideband diamond antenna mounted on a large dihedral metal platform, was benchmarked, focusing on the radiation patterns. As far as the Software WG can see, antenna software benchmarking has never been brought to such a level. The results were presented at the special session of the EurAAP Software Working Group at EuCAP 2014, and are summarized in this article.

Rfid-based traceability along the food-production chain [Wireless Corner]

Abstract: This contribution explains and analyzes the use of RFID (radio-frequency identification) for defining a complete traceability system applied to the food-production chain. The paper contains a summary of the actual work developed to test the ability of radio technologies to perform traceability at different food companies in a variety of sectors: wine, fish, and meat. Each pilot experience is explained, with special emphasis on the radio segment implemented by RFID technologies and sensors, whether connected by wired or as elements of a wireless sensor network. The application of the new RFID-based system at the three investigated sectors, and the return on investment that the companies could obtain by its usage, are the core of the paper.