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A five-slot hexagonal shape chipless RFID tag is designed, simulated, and manufactured on FR4 substrate. The designed tag's copper geometry was replicated on a wide range of dielectric substrate to quantify the impact on resonance quality factor (RQF) and resonating frequencies. The tag's performance was assessed in three configurations. First, a hexagonal shape tag's radar cross section (RCS) was studied over different dielectric substrates. The various dielectric substrate effects were investigated over the maximum read range, resonant frequencies and RQF. In the second evaluation, the physical geometry of the tag was adjusted to achieve the spectral signatures in 2–7 GHz frequency band with high RQF. In step three, the optimized tag geometry was manufactured on FR4, Roger Duroid 5880, and polyethylene naphthalate (PEN) substrates. Denford milling machine for PCB engraving and inkjet printing for silver nanoparticles deposition were used for tags manufacturing. During tag manufacturing, copper and silver were used as conducting materials for RCS backscattering. The tag RCS response was measured by vector network analyzer with bi-static antenna setup. The analysis of different dielectric substrate provides a pathway of designing a novel substrate by using various nanomaterials.

This paper demonstrates that using conventional frequency scanning methods for the evaluation of conducted electromagnetic interference generated by DC/DC converters can give misleading results when pseudo-random modulation is used as part of the converter control scheme. The paper therefore proposes that the resolution bandwidth of the super heterodyne EMI test receiver used for measurements and the dwell time should be adjusted to match the control parameters of the random modulation scheme. The use of different values for resolution bandwidth and dwell time is demonstrated and measurements for random and fixed modulation schemes are compared.

The design of a low-cost, flexible, miniaturized and a high code density chipless RFID tag is presented as a solution for tracking the transportation of biomass fuel pellets. The performance of the tag is presented and demonstrates the applicability of the design for different material systems, whilst maintaining a compact size of 5.06cm 2. The tag consists of nested concentric hexagonal elements and a central spiral resonator suitable for ID encoding. The tag presented demonstrates code density of 3.6-bits/cm 2 , possesses angular stability up to 60º and high radar cross-section. The tag performance was also observed for tracking 5kg of fly ash biomass. Additionally, as the tag mass mostly consist of FR4, PET or Taconic TLX-0 with a minute mass of either copper, gold or silver, the tag can be easily combusted and disposed of during biomass combustion. The novel features of this tag are the combination of hexagonal and spiral shape slots for maximum space utilization thereby achieving high RCS signatures along with high code density. All these properties of the proposed chipless RFID tag provides a pioneering pathway for a real-time biomass tracking application. Keywords: Authors should not add keywords, as these will be chosen during the submission process (see http://journals.cambridge.org/data/relatedlink/MRF_topics.pdf for the full list)

In this study, the authors present the latest developments on the measurements for the shielding effectiveness (SE) of gaskets and materials in reverberation chambers (RCs). A variant method, where the insertion loss of the fixture is achieved from the SE of the fixture with no sample in the aperture is found; it is appropriate for gaskets and for any flat material having a sufficiently high reflectivity at least on one side. A simple and usable condition under which the simplest method for the SE measurements of gaskets and materials in RCs can be used is also given, as well as particular cases where it can be directly applied are shown. This method, whose applicability is enhanced in this study, can be used for gaskets and any flat sample. Such developments simplify measurement setup and associated procedures. Comparisons of results support the methods for the SE measurements of gaskets and material in RCs shown in this study.

The fifth generating (5G) of wireless networks will be more adaptive and heterogeneous. Reconfigurable intelligent surface technology enables the 5G to work on multistrand waveforms. However, in such a dynamic network, the identification of specific modulation types is of paramount importance. We present a RIS-assisted digital classification method based on artificial intelligence. We train a convolutional neural network to classify digital modulations. The proposed method operates and learns features directly on the received signal without feature extraction. The features learned by the convolutional neural network are presented and analyzed. Furthermore, the robust features of the received signals at a specific SNR range are studied. The accuracy of the proposed classification method is found to be remarkable, particularly for low levels of SNR.

This paper explores the effect of using a Spread Spectrum modulation technique with a Buck Converter on a communication cable coupled at the input voltage. The EMI created by the switching of the power converter generates damped oscillations on the data cable that can have great impact on the quality of the communication channel. Frequency domain analysis shows lower EMI levels in the power cable when compared to the standard deterministic modulation. However, there is no real improvement to the actual communications as there in an increase in the measured Bit Error Rate when evaluated experimentally.

This paper explores the impact of using a Spread Spectrum modulation technique based on a Sigma-Delta modulator for a DC-DC SiC-based power converter. A simple block is proposed for the PWM to generate square pulses close to 20 kHz with a controlled ramp profile. Then, different frequencies and repetition rates are used to systematically evaluate their influence of carrier related emissions. The comparison of results is carried out by measuring the peak of the switching harmonic and the average value over CISPR band A (9–150 kHz). The measurements are taken at the input voltage of the converter.

We present an innovative method to allow real-time visualisation of temperature fields on power electronic circuits using augmented reality. A real-time time-domain simulation incorporating the Block Arnoldi model order reduction techniques is implemented in the Unity game engine. Traditional methods run too slowly whereas the developed system allows an example model with 9232 thermal nodes to be dynamically simulated in real-time at a speed fast enough to allow for a smooth augmented reality visualisation. The aim is to show the feasibility of the technology and that it could be applied to visualising electromagnetic fields in future work.

This paper deals with the effects of radiated EMI on serial communication links using software modelling with particular emphasis on the physical layer. The effect of EMI in data links is an important problem to solve in many harsh environments such as the automotive and the transport sector as well as communications, in fact the EMI effect is able to produce sampling errors in digital/binary operations. Currently binding standards prefer the analysis in frequency domain to account for EMI impact, however when dealing with data links, time domain analysis might report useful information, therefore a link between those two is needed. The cable models are developed using SACAMOS modelling software, taking into consideration the frequency parameters. The model can be used on almost any SPICE simulator to analyse the effect of EMI. The simulations performed in this research are verified on a real laboratory experiment in order to demonstrate the capabilities of SACAMOS.

We investigate energy distribution in cable networks using random coupling model (RCM). RCM is used to model the propagation of microwaves in large complicated cavities. The model is made up of two main parts where one part is deterministic and the other is purely statistical. Both parts have been modelled using Quantum Graph (QG) theory and the properties of field quantities are presented. The effects of various boundary conditions on the behaviour of microwaves is discussed. Fourier boundary conditions at graph nodes, high loss regime (α > 1), and weakly coupled graphs ensures that QG model qualifies as an analogue of standard RCM. For Neumann boundary conditions, significant deviations from RCM are found. Analytical expressions of both the deterministic and the statistical parts are presented and shown to accurately predict the distribution of the latter.

This paper presents the design for a low cost miniaturized chipless RFID tag for short-range biomass tracking and monitoring purposes. The concentric hexagonal geometry and angular stability, leading to higher data capacity are the novel aspects of the proposed design, which can encode four data bits within a compact size of 1 cm radius. The designed is capable of encoding 2n unique IDs in a 4-to-9 GHz frequency band, where n is the number of etched slots. The angular stability makes this tag readable from any angle in biomass. Moreover, this chipless RFID tag has no hazard as compared to battery-based active tags during biomass combustion processes.

This paper presents software defined radio based implementation of Minimum Shift Keying (MSK) and Gaussian Minimum Shift Keying (GMSK) digital receiver. The performance of MSK receiver and GMSK receiver is assessed under practical multipath fading scenario in mode-stirred metal enclosure. Metal enclosure when stirred with pedal creates rich isotropic multipath fading environment. The isotropic field and the severity of fading can be reduced by placing radiation-absorbent material (RAM) in the metal enclosure. The effect of addition of number of absorbers is to reduce the number of scattered waves hence reduce isotropic field distribution in the enclosure. This effect has direct implication of increased Rician K-factor. The performance of MSK and GMSK receiver is analyzed when the metal enclosure was loaded with few pieces of RAM.

There is currently a worldwide effort to develop novel materials for solar energy harvesting which are efficient, low cost and do not emit significant levels of CO 2 during manufacture. Currently when a researcher fabricates a novel device from a novel material system, it often takes many weeks of experimental effort and data analysis to understand why any given device/material combination produces an efficient or poorly optimized cell. The net result of this is that it can often take the community tens of years to transform a promising material system (e.g. perovskites/small molecule devices) to a fully optimized cell ready for production. In this work, we develop a new and rapid approach to understanding device/material performance which uses a combination of machine learning, device modeling and experiment. The method is able to provide a set of electrical device parameters (charge carrier mobilities, recombination rates etc..) in a matter of seconds, rather than days and thus offers a fast way to directly link fabrication conditions to device/material performance, pointing a way to further and more rapid optimization of light harvesting devices. We demonstrate the method by using it to understand annealing temperature and surfactant choice and in terms of charge transport and recombination constants for organic solar cells made from the P3HT:PCBM, PBTZT-stat-BDTT-8:PCBM and PTB7:PCBM material systems.

In this work we present low cost time-domain wireless channel sounding using software defined radio (SDR). We performed SDR based time-domain wireless indoor channel sounding using random sequences. We used three random sequences for channel measurements because of their excellent auto-correlation and cross-correlation properties. More specifically PN code sequence, Gold code sequence, and Zadoff-Chu sequences are used. The channel measurements are performed in indoor laboratory environment at two locations at RF frequency of 5.2 GHz and 5.8 GHz respectively. Channel measurements are performed by transmitting sequences with software defined radio in indoor laboratory environment.

© 2018 Wiley Periodicals, Inc. The planar Gunn diode offers the potential of microwave, milli-metric and THz-based oscillators, which can be fabricated as part of a microwave monolithic integrated circuit (mmic). The paper develops an electrical representation of an aluminum gallium arsenide (AlGaAs) based planar Gunn diode with an active channel length of approximately 4 μm and width of 120 μm, embedded in an oscillator circuit. The work indicates a maximum simulated RF output power of +5 dBm compared with published experimental results of −19 dBm for similar diodes.

One of the most significant coupling paths for electromagnetic interference into systems is via cables [1], This may be cable to cable coupling within a bundle of conductors or coupling from an illuminating electromagnetic field [2]–[4], These coupling effects may be enhanced by non-ideal cable terminations such as pigtail connections of shields or by crosstalk within connectors [5], In addition, imperfect cable shields allow coupling via transfer impedance and transfer admittance [6][7].

We report a new planar antenna design in the shape of a diamond. The performance of the antenna design is initially obtained through simulation, then fabricated, and its performance evaluated through experiment. Experimental characterization of the diamond-shaped monopole antenna shows good agreement with simulation. In comparison with a simple monopole antenna, our diamond-shaped monopole antenna features smaller geometric footprint and displays a higher bandwidth at millimeteric wave frequencies.

Inkjet printing of multiple materials is usually processed in multiple steps due to various jetting and curing/sintering conditions. In this paper we report on the development of all inkjet-printed UV-curable electromagnetic responsive inks in a single process, and the electromagnetic characterization of the developed structure. The ink consists of iron oxide (Fe3O4) nanoparticles (nominal particle size 50–100nm) suspended within a UV curable matrix resin. The viscosity and surface tension of the inks were tuned to sit within the inkjet printability range.Multiple layers of the electromagnetic active ink were printed alongside passive UV-curable ink in a single manufacturing process to form a multi-material waffle shape. The real permittivity of the cured passive ink, active ink and waffle structure at a frequency of 8–12GHz were 2.25, 2.73 and 2.65F/m, respectively. This shows the potential of additive manufacturing (AM) to form multi-material structures with tunable electromagnetic properties.

We propose an analogue of the random coupling model (RCM) which is used to study the properties of irregular electromagnetic cavities connected to multiple channels. The proposed model is based on a quantum graph (QG) formalism which has been validated through experiment by measuring the reflection coefficient, $S_{11}$ , of a polygonal graph. The theoretical prediction compares favourably with the experimental results. Because of its simplicity in modelling arbitrary graphs with complicated topologies, the model provides a flexible tool which could be used to study interference effects which is significant in electromagnetic compatibility studies. Also, the model provides us with a more tractable alternative in understanding information transfer rates within multichannel communication systems.

We present a model of scattering parameters of electromagnetic waves propagating through networks of cables based on the quantum graph formalism. We compare directly the model with experimental measurements, using real, lossy cables. In contrast to previous studies which have focused on the statistical distribution of reflection coefficients, we compare the theoretical model predictions of scattering matrix elements with experiments. The laboratory measurements compares favourably to the theoretical predictions of the derived quantum graph model for various scenarios of graph topologies. The graph model is easily extendable to include graphs with multiple leads (ports) as well as more complicated topologies in the study of electromagnetic interference (EMI) within wired systems.

This paper reports results on the shielding effectiveness parameter of laminated epoxy composites with carbon fibre reinforcements. Measurements of shielding effectiveness were carried out with a coaxial transmission line testing chamber according to ASTM 4935 standard and epoxy-matrix composites with continuous carbon-fibres were proven to be an excellent electromagnetic interference shielding material, where a composite slab made of 4 layers of prepregs provided more than 99.9% of electromagnetic attenuation. It was found that the reflection mechanism of the shielding material was mainly influenced by the fibre volume ratio, and that an increase in the number of layers of the composite resulted in higher shielding effectiveness due to a greater absorption mechanism. Calculations of the shielding effectiveness parameter of the material used were made by means of commercial electromagnetic simulation tools, having determined experimentally the overall resistivity of the composite. The findings presented in this work suggest that in presence of a greater number of interfaces at different impedance the separate modelling of matrix and fibres at mesoscopic scale must be taken into account.

Potential health effects of radiofrequency (RF) radiation from mobile phones arouse widespread public concern. RF fields from handheld devices near the brain might trigger or aggravate brain tumors or neurodegenerative diseases such as Parkinson's disease (PD). Aggregation of neural α-synuclein (S) is central to PD pathophysiology, and invertebrate models expressing human S have helped elucidate factors affecting the aggregation process. We have recently developed a transgenic strain of Caenorhabditis elegans carrying two S constructs: SC tagged with cyan (C) blue fluorescent protein (CFP), and SV with the Venus (V) variant of yellow fluorescent protein (YFP). During S aggregation in these SC+SV worms, CFP, and YFP tags are brought close enough to allow Foerster Resonance Energy Transfer (FRET). As a positive control, S aggregation was promoted at low Hg2+ concentrations, whereas higher concentrations activated stress-response genes. Using two different exposure systems described previously, we tested whether RF fields (1.0 GHz CW, 0.002-0.02 W kg−1; 1.8 GHz CW or GSM, 1.8 W kg−1) could influence S aggregation in SC+SV worms. YFP fluorescence in similar SV-only worms provided internal controls, which should show opposite changes due to FRET quenching during S aggregation. No statistically significant changes were observed over several independent runs at 2.5, 24, or 96 h. Although our worm model is sensitive to chemical promoters of aggregation, no similar effects were attributable to RF exposures. Bioelectromagnetics. 37:116–129, 2016. © 2016 Wiley Periodicals, Inc.

This paper aims to experimentally investigate the susceptibility of several wired network protocols (Low Voltage UART, RS232 and CAN) to time-domain interference (TDI). Further results are used to begin to determine which precise components of the initial TDI waveform lead to the disruption of the network.

In this paper statistical channel modelling of fifth-generation (5G) millimeter-wave cellular communication is simulated. This study is based on statistical channel modelling software developed by NYUWireless known as NYUSIM. NYUSIM is built upon statistical channel model for broadband 5G cellular communication. The simulator can handle wideband of carrier frequencies from 500 MHz to 100 GHz and for different environment types which include urban microcell, urban macrocell and rural macrocell. It also supports RF bandwidth from 0 Hz to 800 MHz which makes it suitable software for statistical channel modelling of 5G mmWave based cellular communication. Here, we have considered operating carrier frequency of 28 GHz and the performance of urban microcell in LOS has been studied considering the directional, omnidirectional and small scale power delay profiles (PDPs).

This paper describes the development and application of sophisticated multi-conductor cable bundle models for Spice simulation. The cable models developed include frequency dependent parameters, transfer impedance coupling and incident plane wave excitation. The models may be used in frequency domain or transient simulations and are intended for EMC/ EMI studies. Simulations of realistic scenarios are presented to demonstrate typical applications.

Realization of a non-interfering and equally strong multi-channel MIMO communication in the near-field regime is presented. This is achieved by introducing decoupling and matching networks that optimize the transmitted power. A demonstration of such communication is given for by a simple 2×2 MIMO configuration whose transfer matrix is obtained from full-wave electromagnetic simulations.

Railway signaling systems have the function of controlling the movement of rolling stock on the railway network without compromising security. Nowadays, signaling systems in operation in the U.K., rely on a physical interconnection grid for power supplying and data transferring, causing a high cost of implementation and maintenance related to infrastructure. In a previous paper [1], a ZigBee-based network was proposed as a modular low power wireless alternative for railway signaling systems, and studied in a synthetic environment created in a reverberation chamber (RC) in presence of realistic sources of EM interference. The performance of the ZigBee modules used, shown a persistent communication even in presence of high sources of interference, allowing the transference of information. Based on the previous, a complete multi-node signaling system was designed and implemented. In this paper, the performance of a low power communication system is studied and measured in a realistic environment where multiple elements such as rolling stock, power lines, and sources of interference are present. Additionally, the utilization of radio-frequency identification (RFID) technology has been included as part of train detection system, essential to control the movements of rolling stock, restricted by the Limit of Movement Authorities (LMA), which are a set of rules to keep coordination among the railway network and avoid collisions. Whilst a fuller knowledge of train location may allow train operators to allocate a greater number of rolling stock on the same railway network the adoption of the RFID tagging of items of rolling stock may be used in the wider context of asset management.

In this work various techniques are proposed to reduce the energy consumption in Cognitive Radio Wireless Sensor Networks (CRWSNs) and hence enhance the network life-time of CRWSNs. We propose CRWSNs network life-time can be improved by using concept of correlated signal-to-noise ratio (SNR) and on-demand spectrum sensing with double threshold based energy-detector. It is analytical and intuitively explained that energy in densely deployed CRWSNs can be conserved by using double threshold energy-detector and limiting sensing activity to few sensors which participate in spectrum sensing and pass the decision to neighboring sensors with little compromise in performance degradation. The sensing decision of current sensing node can be used because of the correlated SNR values hence little difference in probability of detection and probability of false alarm values.

In this work we have studied the performance analysis of OSTBC-encoded 16-QAM by transmitting digital image over fading channels.The performance of 2×2 MIMO fading channels is compared with SISO fading channel with no OSTBC encoding at signal-to-noise ratio (SNR) of 20 dB. Multipath MIMO channels under-discussion are time-selective in nature and have flat channel response in frequency. Hence, we specify only Doppler shift which in our case is modelled by Jakes Doppler spectrum. The performance of 2×2 communication system over MIMO time-selective fading channels has been studied. The key performance indicative parameters of OSTBC-encoded 16-QAM over 1×1 single-input single-output (SISO), 2×1 multiple-input single-output (MISO) and 2×2 MIMO wireless communication have been recorded appropriately.

The positioning of electromagnetic (EM) sources on the complex plane, though a mathematical construct, is often applied in solving EM problems with directive confined (collimated) propagation characteristics. Equivalent dipole modeling, which finds its application in characterizing various current sources can be computationally expensive for large structures. Here, the complex localization of equivalent source points combined with the particle swarm optimization is used to improve the performance of the equivalent dipole modeling.

This paper discusses how the measurements of the near-field emissions in the time domain can be used to characterize the broadband emissions from complex sources such as multifunctional Printed Circuit Boards (PCBs). The near-fields, transverse to the measurement surface, are sufficient to characterise the radiator provided the surface contains all the significant fields. For time domain measurements, the field probe is calibrated over a broad bandwidth for both amplitude and phase to provide the probe impulse response. A suitable digital filter applied with the same probe impulse response to extract the time domain magnetic field data from the probe output voltage. Results show that good agreement in the can be obtained. The measured near fields can then be used to create an equivalent model of the PCB which can be used to predict the emissions in the far field or in any environment. In this work the objective is to create an equivalent time dependent dipole array model of the DUT.

In this paper a high frequency model of the Electrical Nacelle Anti-Ice (ENAI) system is described for a typical aircraft application. The ENAI system, usually modelled only at the normal operating frequency, is modified in order to include a detailed high frequency description, which is of interest for conducted emission studies. Using this enhanced model it is possible to predict the conducted emissions resulting in a useful tool for Electromagnetic Interference (EMI) filter design. In this paper two different SCR switching modes are considered, Burst and Phase mode respectively. Experimental testing validates the proposed model, showing good agreement between predicted and measured conducted emissions.

Railway signaling systems are used to efficiently control railway traffic to maximize the throughput of rolling stock on the railway network without compromising security and safety, allowing railway transportation operators to allocate a greater number of trains on the same track. Current U.K. signaling systems rely on a physical interconnection grid for power supplying and data transferring. Hence, a very high cost is related to infrastructure. Therefore, there is a need for a low cost, low power modular wireless system, able to be easily deployed and incorporated within existing signaling networks. In this paper, the study of a low cost, low power communication system is addressed. Sequentially, an alternative modular wireless solution is presented, based on ZigBee-Protocol, followed by a performance analysis tests, evaluated in terms of coverage, network throughput and data capacity, conducted in two different scenarios: an outdoor environment and in an synthetic environment created within a reverberation chamber in presence of realistic sources of electromagnetic interference. The results of these tests are used as guidelines to produce a wireless signaling system able to be placed on trackside, allowing node-to-node and node-to-train communication.

Matrix converters have been recently proposed as an alternative solution to the standard back-to-back converter in aerospace applications. However, Electromagnetic Interference (EMI), in particular, conducted emissions represent a critical aspect for this converter family. Direct Matrix Converter (DMC) are usually modelled only at the normal operating frequency, but for the research presented in this paper, the model is modified in order to include a detailed high frequency description, which is of interest for conducted emission studies. This paper analyzes the performance of DMC, when different control and modulation techniques are used. Experimental results are shown to validate the simulation models.

This paper describes the progress of work towards an Open Source software toolset suitable for developing Spice based multi-conductor cable models. The issues related to creating a transmission line model for implementation in Spice which include the frequency dependent properties of real cables are presented and the viability of spice cable models is demonstrated through application to a three conductor crosstalk model. Development of the techniques to include models of shielded cables and incident field excitation has been demonstrated.