Antenna Devices Research Articles

THE SIMULATION OF METAL-DIELECTRIC ANTENNA ON THE BASE OF COMBINED APPROACH

The structure of modern radio transmitting devices may include antennas formed of both metal and dielectric components-metal-dielectric antennas. They are compact enough and can be placed on various objects of equipment. The paper presents a simulation of a metal-dielectric antenna based on a combined approach. The scheme of antenna construction in different planes is given. The process of scattering of a plane electromagnetic wave on an antenna is considered. The combined algorithm including the method of the integral equation, parallel approach and genetic algorithm is developed. In this paper, the integral equation is used to determine the unknown surface electric currents on the antenna surface, it is solved on the basis of the method of moments. A parallel algorithm was used to speed up the calculations. The impedance matrix is represented as a block matrix. Each block has its own parallel stream. Taking into account the influence of a plane dielectric waveguide on the scattered field, a method associated with a generalized scattering matrix is used. To solve the problem of multi-alternative optimization associated with determining the linear dimensions of the antenna device at a given operating frequency of the antenna, a genetic algorithm is used. As a result, the dimensions of the designed antenna for the specified dimensions of its components are obtained В состав современных радиопередающих устройств могут входить антенны, сформированные как из металлических, так и диэлектрических компонентов - металлодиэлектрические антенны. Они являются достаточно компактными и могут размещаться на различных объектах техники. В работе проведено моделирование металлодиэлектрической антенны на основе комбинированного подхода. Приведена схема построения антенны в разных плоскостях. Рассмотрен процесс рассеяния плоской электромагнитной волны на антенне. Разработан комбинированный алгоритм, включающий метод интегрального уравнения, параллельный подход и генетический алгоритм. В работе интегральное уравнение применяется для того, чтобы определить неизвестные поверхностные электрические токи на поверхности антенны, оно решается на основе метода моментов. Для ускорения расчетов использовался параллельный алгоритм. Матрица импедансов представляется как блочная. Для каждого из блоков применяется свой параллельный поток. При учете влияния на рассеянное поле плоского диэлектрического волновода используется метод, связанный с обобщенной матрицей рассеяния. Для решения задачи многоальтернативной оптимизации, связанной с определением линейных размеров антенного устройства при заданной рабочей частотой антенны, используется генетический алгоритм. В результате получены размеры спроектированной антенны для заданных размеров входящих в ее состав компонентов

Tap-to-Pair

Ad-hoc wireless device pairing enables impromptu interactions in smart spaces, such as resource sharing and remote control. The pairing experience is mainly determined by the device association process, during which users express their pairing intentions between the advertising device and the scanning device. Currently, most wireless devices are associated by selecting the advertiser's name from a list displayed on the scanner's screen, which becomes less efficient and often misplaced as the number of wireless devices increases. In this paper, we propose Tap-to-Pair, a spontaneous device association mechanism that initiates pairing from advertising devices without hardware or firmware modifications. Tapping an area near the advertising device's antenna can change its signal strength. Users can then associate two devices by synchronizing taps on the advertising device with the blinking pattern displayed by the scanning device. By leveraging the wireless transceiver for sensing, Tap-to-Pair does not require additional resources from advertising devices and needs only a binary display (e.g. LED) on scanning devices. We conducted a user study to test users' synchronous tapping ability and demonstrated that Tap-to-Pair can reliably detect users' taps. We ran simulations to optimize parameters for the synchronization recognition algorithm and provide pattern design guidelines. We used a second user study to evaluate the on-chip performance of Tap-to-Pair. The results show that Tap-to-Pair can achieve an overall successful pairing rate of 93.7% with three scanning devices at different distances.

Design and Realization of Microstrip 4x4 Patch Circular MIMO Antenna at 2.4 GHz Frequency for WLAN 802.11n Applications

The development of wireless technology is very rapid in line with the needs of users for high-speed, efficient, reliable and quality communication systems. One of the technologies favored by telecommunication service users is Wireless Fidelity (WiFi) which is already supported byMIMO technology. Multiple Input Multiple Output (MIMO) is a system consisting of more than one terminal or antenna on the transmitter and receiver sides. With the use of more than one antenna, MIMO supports transmission media specifications that require a large capacity in the communication system. This research discusses the design and realization of the MIMO 4x4 microstrip circular patch antenna that can work on the 2.4 GHz frequency band for WiFi technology applications. The inset feed method is used to get the impedance value that matches between the patch and the line. To increase gain, a linear array method is used for each antenna. Testing the effect of the distance between antennas on the mutual coupling value. As well as testing the signal strength performance of the antenna if implemented as an antenna device at the access point. The results of the MIMO 4x4 test results Circular Microstrip Patch show the value of Return Loss = -13.3 dB; Mutual Coupling = -39.3 dB; VSWR = 1.482; Signal Strength = -25 dB.

Controlling Radiation Beams by Low-Profile Planar Antenna Arrays with Coding Elements.

Beam diversity enables antenna arrays to play important roles in radar, communications, imaging, and next-generation wireless systems. However, achieving flexible control of beams in a low-cost way is still very challenging. Here, we propose low-profile planar antenna arrays with coding elements to control and engineer radiation patterns more freely and flexibly. The proposed planar antenna array consists of binary radiating elements which are characterized by digital codes “0” and “1”. By designing spatial coding patterns of the radiating elements, multifarious functionalities can be well realized, such as beam splitting, beam scanning, and beam deflection. More importantly, coding metasurfaces can be properly arranged around the digital radiating elements to reduce the radar cross section of the antenna, while the radiation performance is well preserved. The low-profile, high-gain, lightweight digital antenna arrays are verified numerically and experimentally in the microwave band. The proposed digital coding planar antenna arrays derive a new paradigm to control the radiation patterns in low-overhead and advanced digital design fashions and offer promising applications in multitasked and intelligent antenna devices and new information systems.

Resonant metasurface with tunable asymmetric reflection

Suppression of backscattered electromagnetic waves by carefully designed structures is highly demanded in a range of applications, some of which are radar invisibility, antenna isolation, and many others. Salisbury screens, composed of a mirror with an additional layer on top, are traditionally used for these purposes. Here, we report on the design and experimental demonstration of a reciprocal screen, which demonstrates asymmetric reflection properties when illuminated from opposite directions. The structure utilizes near-field magneto-electric coupling between subwavelength split ring resonators and wires, forming a metasurface. While the reciprocal structure demonstrates perfect symmetry in transmission, strong backscattered asymmetry is shown to be controllable by carefully choosing the Ohmic losses, which are implemented with lumped resistors soldered into the resonators. Depending on the load, the meta-screen demonstrates switching properties that vary between fully symmetric and completely asymmetric reflection between the forward and backward directions of incident illumination. The frequency selective surface acts as a Huygens element when illuminated from one side and as a perfect mirror when illuminated from the other. The ability to tailor the asymmetric reflectance of electromagnetic metasurfaces by controlling Ohmic losses allows employing additional degrees of freedom in designing of radomes and other antenna devices. Furthermore, the concept could be extended to optical frequencies, where resistive losses can be controlled via direct carrier injection into semiconductor devices.

Design and Simulation of a High-Selective Plasmon-Induced Reflectance in Coupled Dielectric-Metal-Dielectric Nano-structure for Senor Devices and Slow Light Propagation

A new framework of high-selective plasmonic-induced reflectance (PIR) in a plasmonic-induced transparency (PIT) system is presented by using planar dielectric-metal-dielectric (DMD) metamaterial nano-structure. We used glass as substrate, the first dielectric, gold as metal thin film, and prism as the second dielectric. The proposed plasmonic nano-structure has been investigated based on finite difference time domain (FDTD) method. Results show that by coupling incident light with dark and bright plasmonic modes, without losing the metamaterial structure symmetry, the transparent window is created at 1550 nm and can be tuned. The transmittance (T), reflectance (R), and absorbance (A) coefficients of the presented nano-structure can be considerably varied by changing the thickness of thin films and dimension of the strips. The reflectance coefficients of dip1 (200 THz) and dip2 (265.5 THz) are almost near zero, and the transmittance coefficient of PIR (227.1 THz) is 0.93. Also, the maximum sensitivity and figure of merit are 664 and 3.77 for reflectance dip2, respectively. Similarly, the maximum quality factor (Q) is 10.74 for reflectance dip1. The presented plasmonic metamaterial nano-structure with mentioned unique features is a good candidate for several applications such as multi-channel plasmonic filters, bio and refractive index sensors, optical antenna, and slow-light devices for using in optical nano-electronic circuits and systems.

Magnetic and dielectric spectroscopic studies in Zn substituted Y-type barium hexaferrite

Zinc substituted samples of Y-type barium hexaferrite with chemical formula Ba2(Co1-xZnx)2Fe12O22 (0 ≤x≤ 1) were synthesized by solid state reaction method to tune their magnetic properties and to understand their dielectric relaxation. The samples are found to be in single phase form with rhombohedral structure as per the analysis of X-ray diffraction patterns using Rietveld refinement technique. Magnetization measurements show that these samples exhibit ferrimagnetic and spin-reorientation transitions. The ferrimagnetic transition temperature (Tc) is found to decrease from 600 K for x = 0 to 380 K for x = 1.0 and the spin reorientation transition temperature (Ts) decreases from 225 K for x = 0 to around 60 K for x = 0.75. They are explained in terms of weakening of super-exchange interaction and the reduction of the planar magnetic anisotropy with increase in Zn concentration. The saturation magnetization value (Ms) measured at room temperature is found to increase from 5.85 μB/f.u. for x = 0 to 8.43 μB/f.u. for x = 0.5 and is explained in terms of preferential occupation of Zn2+ ions at spin down tetrahedral sites, 6Civ and 6Civ*. The complex permeability measurements in the frequency range of 100 MHz to 1 GHz suggest that Y-type barium hexaferrite is suitable for applications in radio frequency (RF) and antenna devices in the high frequency band. The relaxation dynamics of charge carriers is studied by measuring the frequency (100 Hz–1 MHz) dependence of dielectric constant and electrical conductivity at different temperatures.

A SET OF THE SPECIALIZED SOFTWARE FOR ANALYSIS AND SYNTHESIS OF AESA

The issue of expediency of application of in-house specialized software in resolving problems of design of antenna devices is reviewed. The functional capabilities of existing software models of antenna arrays have been analyzed. The application of the developed software in designing a whole set of tasks for the adoption of basic design and engineering solutions at the stage of design of active phased antenna arrays as well as at the state of their upgrade is substantiated. The developed software has an intuitive user-friendly interface adapted to a specific set of tasks. As an example, a description is given of a set of developed software models for the study of equidistant linear and two-dimensional antenna arrays, as well as non-equidistant arrays. The developed set of programs differs from the multi-purpose software of electrodynamic modeling by high speed of preparatory and calculation operations, and the convenience of use.

Secure Transmission Via TAS in MIMO Wiretap Channels

In the multiple-input multiple-output (MIMO) system, the transmit antenna is selected by transmitting antenna selection (TAS) at the transmitter and Maximal Ratio Combining (MRC) at the eavesdropper. Consider the actual transmission situation: the transmitter cannot get the channel information of the eavesdropper’s channel. The main channel between the transmitter and the receiver is selected, and an antenna with the largest instantaneous signal- to-noise ratio (SNR) is selected for transmission. Receiver is a single antenna device. The main channel and the eavesdropper’s channel is independent and distributed Rayleigh channel. In this paper, we derive closed-form expressions of probability and safety outage probability for TAS. Various numerical results are presented that corroborate the analysis.

Magnetoelectric heterostructure and device application

The magnetoelectric (ME) heterostructure is composed of ferromagnetic and ferroelectric materials. The heterostructural ME effect originates from piezoelectric effect in the ferroelectric component and magnetostrictive effect in the ferromagnetic component. The magnetoelectric heterostructure has higher magnetoelectric coupling coefficient and lower dielectric loss than the particulate composites, and thus leading to several promising applications such as in the magnetic field sensors, the energy harvesters, antenna and memory devices. In this paper, we review the recent research progress in ME heterostructure for device applications, and present a development course of ME heterostructure. Finally, we also summarize the challenges of developing the ME heterostructure and point out its perspectives.

In vitro artifact assessment of an MR-compatible, microwave antenna device for percutaneous tumor ablation with fluoroscopic MRI-sequences

Objective: To evaluate artifact configuration and diameters of a magnetic resonance (MR) compatible microwave (MW) applicator using near-realtime MR-fluoroscopic sequences for percutaneous tumor ablation procedures.Material and methods: Two MW applicators (14 G and 16 G) were tested in an ex-vivo phantom at 1.5 T with two 3 D fluoroscopic sequences: T1-weighted spoiled Gradient Echo (GRE) and T1/T2-weighted Steady State Free Precession (SSFP) sequence. Applicator orientation to main magnetic field (B0), slice orientation and phase encoding direction (PED) were systematically varied. The influence of these variables was assessed with ANOVA and post-hoc testing.Results: The artifact was homogenous along the whole length of both antennas with all tested parameters. The tip artifact diameter of the 16 G antenna measured 6.9 ± 1.0 mm, the shaft artifact diameter 8.6 ± 1.2 mm and the Tip Location Error (TLE) was 1.5 ± 1.2 mm.The tip artifact diameter of the 14 G antenna measured 7.7 ± 1.2 mm, the shaft artifact diameter 9.6 ± 1.5 mm and TLE was 1.6 ± 1.2 mm. Orientation to B0 had no statistically significant influence on tip artifact diameters (16 G: p = .55; 14 G: p = .07) or TLE (16 G: p = .93; 14 G: p = .26). GRE sequences slightly overestimated the antenna length with TLE(16 G) = 2.6 ± 0.5 mm and TLE(14 G) = 2.7 ± 0.7 mm.Conclusions: The MR-compatible MW applicator’s artifact seems adequate with an acceptable TLE for safe applicator positioning during near-realtime fluoroscopic MR-guidance.

Efficient radar backscatter suppression

Researchers at Queen's University Belfast's Centre for Wireless Innovation (CWI) have combined expertise in on-body wireless sensors and frequency selective surfaces to solve a problem limiting the RF performance of medical sensors. Conventional frequency selective surfaces (FSSs) reflect or transmit microwave energy at particular resonant frequencies. However, there is a newer class of periodic structures, thin resistively loaded FSS absorbers, which absorb most of the incident power. This class of microwave absorber has the potential to significantly enhance the RF performance of all existing and future physical layer communication systems used in environments, hostile to propagation. Thin resistivity loaded FSS absorbers have planar, thin and lightweight metal-backed patterned screens, making them particularly suitable for suppressing wave refl ections from metal objects such as wind turbines as well as land, air or space-based vehicles. Normally, FSS arrays are simulated and measured in the ‘far field’ of the excitation antenna. This means that the separation distance is sufficiently large for the periodic absorber surface to be excited by plane waves. For all conventional RF applications this is a reasonable assumption, for example a radar system is generally positioned remotely and far from the structure that it interrogates. However, for healthcare monitoring applications, near field solutions are required as there is close contact between the absorber surface and excitation antenna. In this issue of Electronics Letters, Dr Gareth Conway and colleagues have evaluated the performance of this new class of FSS absorber when in close proximity to an excitation antenna. The thin resistivity loaded FSS consists of a 3 mm thick metal-backed patterned substrate with each unit cell composed of four hexagonal-shaped elements that are similar in size to the antenna. “So, effectively the excitation waves impinge on just one of the nested loops,” explains Conway. “Moreover, in the near field the amplitude and phase of the waves vary spatially across the unit cell. This is totally different to the conventional far field operation of these absorbers, where the wave ‘sees’ an infinite array of unit cells, and the amplitude and phase is the same across each cell.” The results reported show that no detuning is observed at the operating frequency of the antenna when the thin resistivity loaded FSS absorber is placed in very close proximity (λ/30 and λ/5), whereas at such distances a tissue phantom or metal sheet significantly reduces the radiation efficiency of the antenna.. This shows that the FSS structure greatly suppresses radar backscatter and is suitable for use in near field systems, such as wearable systems. Members of the team in the anechoic chamber at the university's Institute of Electronics, Communications and Information Technology. From the left: Dmitry Zelenchuk, Robert Cahill, Gareth Conway and Niamh McGuigan, who is wearing a test device incorporating the FSS. A close-up of a wearable medical monitoring device with the FSS absorber positioned between the device's antenna and the body-side of the device. The human body presents a notoriously difficult propagation environment that is very specific to the individual person. Thin resistivity loaded FSS surfaces decouple the environment surrounding the antenna, such that a tailored electromagnetic barrier is formed. This opens up a large number of new applications in near field environments that were previously “unimaginable”; making wireless performance predictable and reliable regardless of the platform on which the antenna is placed. This is in stark contrast to existing solutions, which cannot deliver this behaviour. In addition to enhancing the performance of on-body wireless sensors, this technology could meet the need to suppress RF energy scattering from satellite platforms, which host large antenna farms. By selective placement of thin resistivity loaded FSS structures on the surface of the space vehicle, radiation pattern degradation and antenna coupling will be reduced, both of which currently require costly solutions. The results obtained from the reported preliminary measurement campaign in this Letter, suggest that this approach has excellent potential for isolating mobile platforms such as the human body. “However, this is only the ‘tip of the iceberg’, researchers have been tackling the problem of electromagnetic scattering from platforms for years, and still continue to do so”, says Conway. “The step change in performance capability of field deployable antennas embedded into electromagnetic control surfaces will allow greater communication link margins, hence facilitating significantly higher quality of service for medical data transfer than is currently envisioned. However, at present, the processes necessary to optimise the design and manufacture of such FSS structures are not well understood. To develop this technology to an acceptable engineering standard, the research must explore the combined spaces between state-of-the-art artificial engineered electromagnetic surface design and new multifunctional additive manufacturing technology. We would be zealous to see the synthesis and demonstration of the operation of a new innovative surface which radically accelerates the application of wireless enabled mobile communication and healthcare sensor technology.”

T-SIMn: A trace collection and simulation framework for 802.11n networks

In this paper, we describe the design, implementation and evaluation of a new framework for the trace-based evaluation of 802.11n networks, which we call T-SIMn. In order to accurately estimate the fate of frames that could have been sent at any rate, traces collected for use in trace-based simulators, like T-SIMn, require a sufficiently large number of samples to be collected using each different rate in a relatively short period of time. In this paper, we devise two novel techniques for collecting and processing traces for 802.11n networks that incorporate Frame Aggregation (FA). The first technique, called direct measurement, samples all rates while aggregating the maximum number of possible frames for each sample. This approach is attractive because frame error rates (FERs) may vary with the position of the frame within the aggregated frame and this techniques directly captures the fate of each subframe. However, the length of the aggregated frames limits this approach to smaller numbers of rates, making it unusable for devices with 3 antennas (e.g., 96 rates). As a result, we also devise second technique that collects traces with frame aggregation turned off, permitting a larger number of rates to be sampled within the same period of time. This approach, called inferred measurement, infers the FER of each subframe using models derived from calibration traces combined with a new measure of changing channel conditions we call the channel dynamic indicator (CDI). Using the direct measurement methodology, we evaluate the T-SIMn framework by collecting traces using an iPhone, which is representative of a wide variety of one antenna devices. We show that our framework can be used to accurately simulate several scenarios and demonstrate the fidelity of SIMn by uncovering problems with our initial evaluation methodology. We then demonstrate that our inferred measurement technique permits us to collect traces that sample all 96 rates in a 3x3:3 802.11n MIMO systems. These traces are then used to accurately simulate transmissions in environments with highly variable channel conditions that include mobility and multiple sources of interference.We expect that the T-SIMn framework will be suitable for easily and fairly comparing algorithms that must be optimized for different and varying 802.11n channel conditions, which are challenging to evaluate experimentally. These include rate adaptation, frame aggregation and channel bandwidth adaptation algorithms.

SRR loaded periwinkle flower shaped fractal antenna for multiband applications

AbstractThe split ring resonator (SRR) loaded periwinkle flower (PWF) shaped fractal antenna for multiband applications are presented. The CPW‐Fed antenna consists of SRR, which is fixed on the back side of the FR4 and periwinkle petals which are etched on top of the FR4 i.e., on the circular patch. The periwinkle flower‐shaped irregular fractal patch is erected on the substrate whose dimensions are Ws × Ls × h mm3 and the ground is also modified (MG) to achieve multiple frequency bands covering 3.476 GHz at S‐band, 4.844 GHz at C‐band, 8.3 GHz also 10.28 GHz at X‐band, 17.76 GHz and at Ku‐band. Parametric analysis and measured antenna device results are also presented.

Programmable Deployment of Tensegrity Structures by Stimulus-Responsive Polymers

Tensegrity structures with detached struts are naturally suitable for deployable applications, both in terrestrial and outer-space structures, as well as morphing devices. Composed of discontinuous struts and continuous cables, such systems are only structurally stable when self-stress is induced; otherwise, they lose the original geometrical configuration (while keeping the topology) and thus can be tightly packed. We exploit this feature by using stimulus responsive polymers to introduce a paradigm for creating actively deployable 3D structures with complex shapes. The shape-change of 3D printed smart materials adds an active dimension to the configurational space of some structural components. Then we achieve dramatic global volume expansion by amplifying component-wise deformations to global configurational change via the inherent deployability of tensegrity. Through modular design, we can generate active tensegrities that are relatively stiff yet resilient with various complexities. Such unique properties enable structural systems that can achieve gigantic shape change, making them ideal as a platform for super light-weight structures, shape-changing soft robots, morphing antenna and RF devices, and biomedical devices.

Ultrawide Thermo-optic Tuning of PbTe Meta-Atoms.

Subwavelength Mie resonators have enabled new classes of optical antenna and nanophotonic devices and can act as the basic meta-atom constituents of low-loss dielectric metasurfaces. In any application, tunable Mie resonances are key to achieving a dynamic and reconfigurable operation. However, the active tuning of these nanoantennas is still limited and usually results in sub-linewidth resonance tuning. Here, we demonstrate the ultrawide dynamic tuning of PbTe Mie resonators fabricated via both laser ablation and a novel solution-processing approach. Taking advantage of the extremely large thermo-optic (TO) coefficient and a high refractive index of PbTe, we demonstrate high-quality factor Mie resonances that are tuned by several linewidths with temperature modulations as small as ΔT ∼ 10 K. We reveal that the origin for this exceptional tunability is due to an increased TO coefficient of PbTe at low temperatures. When combined into metasurface arrays, these effects can be exploited in ultranarrow active notch filers and metasurface phase shifters that require only a few kelvin modulation. These findings demonstrate the enabling potential of PbTe as a versatile, solution-processable, and highly tunable nanophotonic material that suggests new possibilities for meta-atom paints, coatings, and 3D metamaterials fabrication.

Highly integrated VO2-based tunable antenna for millimeter-wave applications

We report the concept of a frequency tunable antenna device operating in the millimeter wave frequency domain. The ability of the antenna to switch between two frequency states is achieved by the monolithic integration of a metal-insulator transition material (vanadium dioxide, VO2). The VO2 material is an insulator at room temperature but can be driven in a high conductivity metallic state when it is electrically activated using a continuous (DC) voltage. The antenna design is based on a slot antenna excited by a microstrip line having a length that can be conveniently varied using a VO2-based switch. Following the high-frequency VO2 material characterization, we present its monolithic integration in the device prototype along with the comparison between the measured and the simulated performances of the agile antenna. Thus, depending on the VO2 material state, the antenna device can be conveniently switched between 33 and 37 GHz operating frequency bands presenting stable radiation patterns with 5.28 dBi and 5.41 dBi maximum gains, respectively.

EDITOR’S FOREWORD

Dr. Philippe Jean Pierre, President of the Regional Committee for Innovation of Reunion Island, officially opened the fourth edition of the Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2016) that was held at Hotel Le Récif, Saint-Gilles Les Bains, Reunion Island from 10th to 13th October 2016. The conference was organized by the Radio Society (Mauritius) and it was jointly sponsored by the IEEE Antennas and Propagation Society (APS) and Université de La Réunion. In addition, IEEE RADIO 2016 was technically co-sponsored by Union Radio Scientifique Internationale (URSI), IEEE Region 8 and IEEE France Section. The local organizing committee consisted of researchers from CentraleSupélec, France, Université de La Réunion and University of Mauritius.IEEE RADIO 2016 is the fourth of a series of conferences, covering the fields of antennas and propagation, organized in the Indian Ocean region. The idea behind the organization of the RADIO international conference originated at the start of this decade following discussions with engineers and researchers from countries of the Indian Ocean region as well as from other parts of the world. It was unanimously acknowledged that there was an urgent need to initiate a platform that would provide engineers and researchers of the Indian Ocean region opportunities to share knowledge in the field of radio frequency engineering with their international peers. IEEE RADIO 2016 gathered participants from over twenty countries coming from different regions of the world including Africa, Asia, Australia, Europe, Middle-East and North America, and we can confidently say that we have succeeded in our goal.The conference featured fourteen oral sessions on state-of-the-art research themes including antenna design, bio-electromagnetics, computational electromagnetics, devices and circuits, metamaterials and applications, radio astronomy, remote sensing and wireless sensor networks. Invited talks were delivered by Prof. Tapan Sarkar from Syracuse University, USA, Prof. Qing Liu from Duke University, USA and Prof. Monaï Kraikriksh from King Mongkut’s Institute of Technology, Ladkrabang, Thailand. A special session, organized by Dr. Eric Mokole, Vice-Chair of IEEE APS Special Interest Group on Humanitarian Technology (SIGHT), was dedicated to humanitarian activities and projects in the Indian Ocean.All accepted papers that were effectively presented during the conference were submitted to the IEEE Xplore Digital Library. And, in line with the previous editions, a call to extended contributions for publication as a volume in the IoP Conference Series: Materials Science and Engineering (MSE) was made. All of the twenty full papers that were submitted were then peer-reviewed, revised according to the reviewers’ comments and ultimately fourteen papers were accepted for publication in this volume.This fourth edition of the IoP Conference Series: MSE dedicated to selected papers presented at IEEE RADIO 2016 is representative of the scientific content and quality of the RADIO international series of conferences.EditorVikass Monebhurrun

Structured Non-Uniformly Spaced Rectangular Antenna Array Design for FD-MIMO Systems

Full-dimensional multiple-input multiple-output (FD-MIMO) systems, whereby each base station is equipped with a uniformly spaced rectangular antenna array (URA), provides a practical means of realizing massive MIMO systems. However, the spectral efficiency of URA is considerably lower than that of its uniformly spaced linear array counterpart having the same number of antenna elements. In this paper, we first introduce a discrete angular resolution metric for quantifying the low resolution of URA in the antenna-elevation domain. This motivates us to propose a novel antenna device design, referred to as the structured non-uniformly spaced rectangular array (NURA), in which the antenna elements are non-uniformly distributed in the elevation-angle domain. Specifically, we conceive a structured NURA device for which the nonuniform distribution of the elevation-domain antenna elements is controlled by a single parameter. The design of the optimally structured NURA for the given nonlinear antenna-element-positioning function then becomes a single-parameter optimization, namely, that of maximizing the spectral efficiency of the FD-MIMO system, which can be solved efficiently. Our simulation results demonstrate that our structured NURA design significantly outperforms the standard URA in terms of achievable spectral efficiency. Our proposed structured NURA design therefore offers an effective practical framework for enhancing the achievable performance of FD-MIMO systems.

Role of stilbene-triazine sulfonic acid sodium salts in tuning electro-conductivity of polypyrrole-paper composites

Electro-conductive paper-based products can suit the needs of various end-use applications, e.g., antenna and energy-storage devices. Here, the concept of using stilbene-triazine sulfonic acid sodium salts (STAS) as dopants for enhancing the conductivity of polypyrrole-paper composites and mitigating the decay of conductivity was demonstrated. Noticeably, the combined use of hexa-sulfonic STAS and 9,10-anthraquinone-2-sulfonic acid sodium salt (AQSAS) as dopants delivered significant enhancement of conductivity. Meanwhile, the decay of conductivity during storage was substantially mitigated. Moreover, the effectiveness of hexa-sulfonic STAS was much more pronounced than the other two types of STAS, i.e., di-sulfonic STAS and tetra-sulfonic STAS.