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WOS: 000431278700009, Metamaterial-based energy harvesting structures operating at GSM goo and GSM 1800 frequency bands have been proposed. The basic structure is composed of four nested U-shaped elements on the front and back side of the dielectric substrate, with a 180 degrees relationship between the front and back resonators. As energy harvesting capability is directly related to the quality of absorption, with the aim being perfect absorption, there is an air gap to allow tuning of the resonance frequency, and copper plate follows the air gap to facilitate the perfect absorption of electromagnetic waves, which is verified by means of simulation and experimental tests. A set of simulations and experimental study were further carried out to demonstrate incident and polarization angle dependency, the effects of Schottky diodes, and the optimal orientation of the U-shapes. Spectrum analysis and DC voltage measurements across the HSMS 2860 Schottky diode are also presented to test the energy harvesting capability: the spectrum analyzer shows a 40 dBm difference, while 81.7 mV maximum DC voltage is observed at 900 MHz. The simulation and experimental study results, while displaying several differences, do suggest that the proposed design can be used for running low-energy consumption devices such as sensors and switches.

The relations between the asymmetry of hemispheric activity using the EEG rhythms in resting and both trait emotional intelligence (EI-IPIP) and self-assessment of emotional reactivity on IAPS stimuli were studied in university students. The obtained EEG patterns of power asymmetry in both low-frequency and high-frequency indicate different variants of the hemispheric dominance in the anterior and posterior regions of the brain, depending not only on the valence of induced emotions, but also on selfassessment of perception or expression of emotional states. Total EI was associated with relatively greater left frontal activation on low frequency delta oscillations and on higher beta2 oscillations in posterior cortex. Using EEG mapping positive relations were found between the right hemispheric delta rhythm and emotional reactivity to negative emotive stimuli and between the left hemispheric delta and positive affect. Self-rating of positive to negative emotion during both EI and IAPS stimuli-induced affect testing was more pronounced in the relationships to asymmetry of hemispheric activity than separate traits EI. Keywords: Emotional intelligence traits, self-assessment of emotional reactivity, EEG, hemispheric asymmetry, frequency bands

WOS: 000425716800005, A novel metamaterial absorber structure is designed and characterized for microwave energy harvesting. The suggested structure is composed of two circular ring resonators with different dimensions. Due to harvesting application of the proposed structure, the main operation frequency of the suggested structure lies in WIMAX and satellite communication frequency bands and surrounds our environment. The optimum dimensions of the suggested structure are obtained through parametric study by genetic algorithm in order to realize wideband absorption and harvesting response. Simulation results show that the metamaterial-harvester-based resistive loads are useful to absorb and convert microwave energy for the operation frequency. The simulated harvested power across the resistors has been found greater than 0.4 W, which corresponds to 80% efficiency between 7.8 and 14 GHz. In addition, polarization dependence and angular stability of the proposed harvester are investigated at operation frequency to support the simulation of an experimental study for S-parameter measurement. Therefore, simulation and experimental study results show that the proposed design with good absorption and harvesting characteristics can be operated in WIMAX and satellite communication frequency bands.

An effective treatment to completely alleviate chronic tinnitus symptoms has not yet been discovered. However, recent developments suggest that neurofeedback (NFB), a method already popular in the treatment of other psychological and neurological disorders, may provide a suitable alternative. NFB is a non-invasive method generally based on electrophysiological recordings and visualizing of certain aspects of brain activity as positive or negative feedback that enables patients to voluntarily control their brain activity and thus triggers them to unlearn typical neural activity patterns related to tinnitus. The purpose of this review is to summarize and discuss previous findings of neurofeedback treatment studies in the field of chronic tinnitus. In doing so, also an overview about the underlying theories of tinnitus emergence is presented and results of resting-state EEG and MEG studies summarized and critically discussed. To date, neurofeedback as well as electrophysiological tinnitus studies lack general guidelines that are crucial to produce more comparable and consistent results. Even though neurofeedback has already shown promising results for chronic tinnitus treatment, further research is needed in order to develop more sophisticated protocols that are able to tackle the individual needs of tinnitus patients more specifically.

We propose a two-level scheduler for a frequency reuse-1 multi-cell wireless network satisfying inter- and intra-cell weighted temporal fairness constraints. As opposed to hard partitioning of the entire frequency band to different cell patterns in frequency reuse- $M$ systems $(M>1) $ , we propose sharing this band opportunistically in time by these patterns. Through numerical examples, we show notable gains in overall network throughput due to improved multi-user diversity in comparison with a conventional frequency reuse-3 system.

This paper describes the laboratory implementation of two semi-active tuned vibration absorbers (TVAs): a switching \{TVA\} and a sweeping TVA. The two absorbers are designed to control the low frequency total flexural response of a cylindrical duct excited by a stationary broadband random force. The two \{TVAs\} are composed by a seismic mass mounted on a axial spring. Both \{TVAs\} are equipped with a relative displacement and relative velocity feedback control system, which is used to vary the characteristic stiffness and damping, that is the characteristic natural frequency and damping ratio, of the TVA. The switching \{TVA\} cyclically tunes its characteristic natural frequency and damping ratio to iteratively control the resonant responses due to three targeted flexural natural modes of the duct. Alternatively the sweeping \{TVA\} continuously varies its characteristic natural frequency and damping ratio within given ranges to blindly control the resonant responses due to the same three flexural natural modes of the duct. The paper presents both simulation and experimental results regarding the feedback loop used to iteratively or continuously tune the \{TVAs\} and about the reduction of vibration produced by the two semi-active TVAs. The simulation and the experimental results show that both \{TVAs\} effectively control the flexural response of the duct in the low frequency band, which is characterised by the resonances of the three targeted flexural natural modes of the duct.

It is fundamental to diagnose fetal acidemia as early as possible, allowing adequate obstetrical interventions to prevent brain damage or perinatal death. The visual analysis of cardiotocography traces has been complemented by computerized methods in order to overcome some of its limitations in the screening of fetal hypoxia/acidemia. Spectral analysis has been proposed by several studies exploring fetal heart rate recordings while referring to a great variety of frequency bands for integrating the power spectrum. In this paper, the main goal was to systematically review the spectral bands reported in intrapartum fetal heart rate studies and to evaluate their performance in detecting fetal acidemia/hypoxia. A total of 176 articles were reviewed, from MEDLINE, and 26 were included for the extraction of frequency bands and other relevant methodological information. An open-access fetal heart rate database was used, with recordings of the last half an hour of labor of 246 fetuses. Four different umbilical artery pH cutoffs were considered for fetuses' classification into acidemic or non-acidemic: 7.05, 7.10, 7.15, and 7.20. The area under the receiver operating characteristic curve (AUROC) was used to quantify the frequency bands' ability to distinguish acidemic fetuses. Bands referring to low frequencies, mainly associated with neural sympathetic activity, were the best at detecting acidemic fetuses, with the more severe definition (pH ≤ 7.05) attaining the highest values for the AUROC. This study shows that the power spectrum analysis of the fetal heart rate is a simple and powerful tool that may become an adjunctive method to CTG, helping healthcare professionals to accurately identify fetuses at risk of intrapartum hypoxia and to implement timely obstetrical interventions to reduce the incidence of related adverse perinatal outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Castro, Loureiro, Henriques and Nunes.)

In the present work, the effects of 650 nm light exposure on the electromagnetic (EM) design of two gain hybrid amplifiers has been investigated. Both amplifiers have been optimized to operate in the 7.5–8.5 GHz frequency band according to the dark parameters of two pseudomorphic high electron mobility transistors having scaled gate widths. In addition, the EM analysis of the effects of the coaxial-to-microstrip connectors, has been addressed for a better evaluation of their impact on the electrical behavior of the amplifiers. Therefore, the comparison among the performance variations due to device illumination has been performed thus showing that the circuit behavior can be adjusted by using an optical signal.

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0 fm/s^2/sqrt(Hz) across the 0.1-100 mHz frequency band that is crucial to an observatory such as LISA. Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge build up due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument., Comment: 9 Pages, 3 figures

International audience; This paper introduces the design and simulation of multiband dielectric resonator antenna (DRA) for the fifth generation (5G) of cellular networks. The radiating element is a unique rectangular shaped DRA element with a distribution feeding technique based on micro-strip feed line coupled via an elliptical slot. The feed position and configuration has been deliberately designed for optimized matching. The structure is approximately 40mm×48mm in size, conceived on Arlan dielectric substrate. The antenna has been optimized for the 10.5-17 GHz frequency bands. Simulated return loss, radiation pattern and gain over the frequencies of interest have been presented. The proposed antenna structure is a good candidate for future 5G cellular applications.

An exponentially-tapered slot antenna on low-temperature co-fired ceramic (LTCC) substrate is presented. It is designed to be used over a broad frequency range in the millimetre-wave band. LTCC technology is used for its low-cost and high-tolerance performances. Experimental and simulation results reveal that the antenna has a satisfactory operating frequency band from 28 GHz to 65 GHz within which acceptable radiation patterns as well as a return loss better than 10 dB for most of the band are achieved.

In the original paper describing the first measurements performed with LISA Pathfinder, a bulge in the acceleration noise was shown in the 200 mHz - 20 mHz frequency band. This bulge noise originated from cross-coupling of spacecraft motion into the longitudinal readout and it was shown that it is possible to subtract this cross-talk noise. We discuss here the model that was used for subtraction as well as an alternative approach to suppress the cross talk by realignment of the test masses. Such a realignment was performed after preliminary analysis of a dedicated cross-talk experiment, and we show the resulting noise suppression. Since then, further experiments have been performed to investigate the cross-coupling behaviour, however analysis of these experiments is still on-going. © Published under licence by IOP Publishing Ltd. ESA/22331/09/NL/HB ESA/16238/10/NL/HB DLR/FKZ/OQ 0501 DLR/FKZ/50 OQ 1601 DFG/EXC/QUEST

International audience; This paper describes the design and analysis of a compact and efficient ultrawideband unidirectional printed antenna array for indoor applications.A12.2×6.3×1 cm antenna array is capable of covering an ultra-wide frequency band starting from LTE up to Wi-MAX with an average gain approaching 5 dBi over the entire bandwidth. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably better performance and supplementary compactness, which makes it competitive among other antenna models. Simulation results have also shown low cross polarization levels, where the sidelobe level was also minimized by introducing a special reflecting element in the designed model. Adopting the proposed antenna in indoor communication systems would surely enhance the quality of signal within the covered area as well as minimize the number of access points needed for a given network. © 2017, Allerton Press, Inc.

N-path filters exploiting switched-series-R-C networks can realize high-Q blocking-tolerant band-pass filters. Moreover, their center frequency is flexibly programmable by a digital clock. Unfortunately, the time variant nature of these circuits also results in unwanted signal folding. This paper proves analytically that folding can be reduced and band pass filtering can be improved by adding an inductance in series with the switched-R-C network. In contrast, a shunt capacitor degrades band-pass filter performance. The interaction between the reactive series impedance and the switched capacitors of an N-path filter complicates analysis due to memory effects associated with reactive components. Assuming N identical signal paths with 1/N duty cycle, we show it is possible to solve the set of differential equations, by assuming that the signals in each path only differ in delay. Analytical equations are verified versus simulations, and the benefits in filter properties and reduction in signal folding are demonstrated.

Driven by the future need of exploiting the so-called extremely and tremendously high-frequency bands for the rate enhancement of microwave cellular networks, in this paper, we consider the possibility of upgrading the already existing infrastructure of microwave base stations (BSs) by enabling them to convey information through microwave or terahertz (THz) links, depending on the distance and whether a line-of-sight (LOS) link exists between a mobile terminal (MT) and its serving BS. By using a tractable stochastic-geometry approach for the modeling of the position and number of BSs and possible blockages in the radio path, we derive analytical formulas for the achieved coverage probability and average rate, which exhibit a close match with the simulation results and validate the expected significant average-rate gains with respect to the communication only through microwave links. In addition, the results show that the expected tradeoff between the average-rate enhancement and coverage-probability reduction due to the high path-loss attenuation of the THz links can be greatly counteracted by employing highly directional antennas in the THz case, especially for very dense BS setups. © 1967-2012 IEEE.

This project, as a part of the ongoing Master Thesis, describes the process of choosing the best frequency band for the high-frequency analysis. The project covers the need of this analysis in the case of isolated rabbit heart from the electrical-mechanical coupling point of view. The differences between the human ECG and isolated rabbit heart ECG analysis are discussed. The aim of this project is to determine the best frequency bands for the different sets of parameters, as a required step for the progress of the Master Thesis., El presente proyecto, como parte del trabajo de máster en curso, describe el proceso de selección de la banda de frecuencia óptima para el análisis de alta frecuencia. El proyecto cubre la necesidad de realizar este análisis en corazón aislado de conejo, desde el punto de vista del acoplamiento electro-mecánico. Se discuten además las diferencias entre el ECG humano y el ECG de corazón aislado de conejo. El objetivo del proyecto es la determinación de las bandas óptimas para los diferentes conjuntos de parámetros, un paso necesario para el progreso del trabajo de máster.

N-path filters exploiting switched-series-R-C networks can realize high-Q blocking-tolerant band-pass filters. Moreover, their center frequency is flexibly programmable by a digital clock. Unfortunately, the time variant nature of these circuits also results in unwanted signal folding. This paper proves analytically that folding can be reduced and band pass filtering can be improved by adding an inductance in series with the switched-R-C network. In contrast, a shunt capacitor degrades band-pass filter performance. The interaction between the reactive series impedance and the switched capacitors of an N-path filter complicates analysis due to memory effects associated with reactive components. Assuming N identical signal paths with 1/N duty cycle, we show it is possible to solve the set of differential equations, by assuming that the signals in each path only differ in delay. Analytical equations are verified versus simulations, and the benefits in filter properties and reduction in signal folding are demonstrated.

International audience; The design, realization, and experimental characterization of a 400-element electronically reconfigurable transmitarray operating in the Ka-band is presented. It is based on linearly polarized unit-cells with 180° phase-shifting capability. Several sequential rotation schemes have been compared numerically to generate a circularly polarized beam over a broad frequency band, and a random distribution has been selected to mitigate spurious cross-polarized side-lobes when scanning the main beam. The 2-D electronic beam-steering capabilities of ±60° have been verified experimentally. The prototype, illuminated by a horn antenna as a focal source, exhibits a broadside gain of 20.8 dBi at 29.0 GHz and a 3-dB bandwidth of 14.6% with radiation efficiency of 58%. The axial ratio remains below 2 dB within this bandwidth. Next, a planar substrate integrated waveguide focal source array was designed in order to reduce the focal distance by about 50% and thereby significantly improve the antenna compactness, and similar radiation performance is demonstrated numerically and experimentally. © 1963-2012 IEEE.

This work deals with the optimization of fluid viscous damper systems (FVDs) to reduce the resonant dynamic structural response of high-speed railway bridges by algebraic and numerical approaches. The presented method chooses the objective function based on the H ∞ norm over the frequency band of interest. This function allows taking into account structural damping properties and minimizing simultaneously the structural response associated with multiple modes. Especially, the proposed objective function may also be extended to nonlinear problems to determine optimal parameters of nonlinear fluid viscous dampers which may be an interesting solution in applications where high force levels are expected in the dampers. Finally, the proposed method is validated through numerical simulations. The simulation results show that the optimal FVD coefficients obtained by using the presented method are more exact than those by the previous method. Besides, the effectiveness of the method for solving the problems with the contribution of high modes and the consideration of nonlinear FVDs is also proved.

In this research paper, we propose a simple procedure for accurate, stable and broadband measurements of complex permittivity of low-loss dielectric samples with considerable lengths. We identify and demonstrate by numerical and analytical analyses the main ill-behaved factor that gives rise to inaccurate peaks for measurements of electrical properties of low-loss samples in the well-known Nicolson-Ross-Weir method. Without using this factor in the expressions and combining better features of the methods available in the literature, the proposed procedure allows highly accurate permittivity measurements over a broad band. We have validated the proposed method by permittivity measurements of a low-loss sample by different methods. © 2014 Taylor & Francis.

Objective At present, there are no well-validated biomarkers for attention-deficit/hyperactivity disorder (ADHD). The present study used an infrared motion tracking system to monitor and record the movement intensity of children and to determine its diagnostic precision for ADHD and its possible associations with ratings of ADHD symptom severity. Methods A Microsoft motion sensing camera recorded the movement of children during a modified Go/No-Go Task. Movement intensity measures extracted from these data included a composite measure of total movement intensity (TMI measure) and a movement intensity distribution (MID measure) measure across 15 frequency bands (FB measures). In phase 1 of the study, 30 children diagnosed with ADHD or at subthreshold for ADHD and 30 matched healthy controls were compared to determine if measures of movement intensity successfully distinguished children with ADHD from healthy control children. In phase 2, associations between measures of movement intensity and clinician-rated ADHD symptom severity (Clinical Global Impression Scale [CGI] and the ADHD-Rating Scale IV [ADHD-RS]) were examined in a subset of children with ADHD (n = 14) from the phase I sample. Results Both measures of movement intensity were able to distinguish children with ADHD from healthy controls. However, only the measures linked to the 15 pre-determined 1 Hz frequency bands were significantly correlated with both the CGI scores and ADHD-RS total scores. Conclusions Preliminary findings suggest that measures of movement intensity, particularly measures linked to the 10–11 and 12–13 Hz frequency bands, have the potential to become valid biomarkers for ADHD. Electronic supplementary material The online version of this article (doi:10.1186/s13034-016-0135-2) contains supplementary material, which is available to authorized users.

We investigate the spin wave spectra in a magnonic waveguide using the plane wave expansion method. The structure under the investigation has the form of thin strips of permalloy and cobalt, alternately arranged as a planar waveguide. The structure is assumed to be infinite in length and finite in thickness and width. Spin wave propagation is assumed along the length of the stripe, parallel to the external applied field, in a backward volume configuration. We derive both static and dynamic fields in the magnonic waveguide using the plane wave method, after reducing the linearized Landau-Lifshitz equation to an eigenfrequency problem. The eigenfrequencies corresponding to a wave vector are then numerically calculated and plotted, with the eigenmodes yielding the spatial variation in spin wave amplitudes. The demagnetizing fields, along the length and thickness, were derived from the magnetostatic potential and shows both bulk and edge mode characteristics. In a nonuniform demagnetizing field, low frequency spin waves concentrate their amplitude in a region of low internal magnetic field. These appear as standing wave excitations in the permalloy resulting in zero group velocity, or a flat band structure in the ?(k) dispersion diagram. Finally the dependence of the frequency band gap on the angle between spin wave vector and the applied field is also investigated. � 1965-2012 IEEE.

Distribution transformer is the key element in the electricity transmission throughout the nation. Hence, serious attention for the transformer condition monitoring is a crucial. With an occurrence of short-circuit in the power system, the transformer active parts such as core and winding will experience a mechanical movement created by the electromagnetic forces. There are various types of transformer condition monitoring measurement in market, but the monitoring of the mechanical movement in transformer is still lacking. Therefore, Sweep Frequency Response Analysis (SFRA) has been introduced to assess any mechanical movement especially of the transformer's core and winding. The frequency response of the transformer provides mechanical information of core and winding conditions. The SFRA measurement results were validated using the actual transformer untanking process.

In this article we investigate the performance of underwater acoustic communications between an AUV and a ground control station in a realistic use case for harbor protection/monitoring in the North Sea. In particular we focus on the contribution of nearby shipping noise and how it influences the maximum communication range of an underwater modem in two relevant frequency bands for high and low data rate communications. Our results suggest that acoustic communication performance is highly dependent on in situ shipping conditions and future tools for autonomous operation planning in harbor environment must take into account this effect to ensure efficiency and robustness.

International audience; In this contribution, we present the design of a 400-element electronically reconfigurable transmitarray working in Ka-band with 180° phase-shifting unit-cells. The sequential rotation technique is applied to generate a circularly-polarized beam over a broad frequency band. The proposed configuration exhibits a broadside gain of 20.3 dBi at 29.0GHz and cross polarization discrimination of 30.0 dB. Multiple focal sources are also used to reduce the overall antenna thickness. © 2016 European Association of Antennas and Propagation.

International audience; A compact wideband monopole antenna for mobile and wireless monitoring applications is presented. The proposed antenna will be implemented in a wireless system devoted to remote monitoring water and wastewater applications. The antenna is mainly designed to operate within the frequency range of 700-2700 MHz covering different mobile and wireless frequency bands with a return loss less than -6dB. Omnidirectional radiation pattern and improved radiation performances are very suitable. An optimization process based on global algorithm has been used to achieve the design goals. The design of the proposed antenna is carried out using optimization and simulation tools of full-wave electromagnetic simulation software. A prototype of the proposed antenna was manufactured and tested in order to verify the performances of the antenna including in the real environment conditions. © 2016 European Association of Antennas and Propagation.

Several studies have reported working memory deficits in patients with mild cognitive impairment (MCI). However, previous studies investigating the neural mechanisms of MCI have primarily focused on brain activity alterations during working memory tasks. No study to date has compared brain network alterations in the working memory state between MCI patients and normal control (NC) subjects. Therefore, using the index of regional homogeneity (ReHo), we explored brain network impairments in MCI patients during a working memory task relative to the resting state, and identified frequency-dependent effects in separate frequency bands.Our results indicate that, in MCI patients, ReHo is altered in the posterior cingulate cortex (PCC) in the slow-3 band (0.073-0.198 Hz), and in the bottom of the right occipital lobe and part of the right cerebellum, the right thalamus, a diffusing region in the bilateral prefrontal cortex (PFC), the left and right parietal-occipital regions, and the right angular gyrus in the slow-5 band (0.01-0.027 Hz). Furthermore, in NCs, the value of ReHo in clusters belonging to the default mode network (DMN) decreased, while the value of ReHo in clusters belonging to the attentional network increased during the task state. However, this pattern was reversed in MCI patients, and was associated with decreased working memory performance. In addition, we identified altered functional connectivity of the abovementioned regions with other parts of the brain in MCI patients. This is the first study to compare frequency-dependent alterations of ReHo in MCI patients between resting and working memory states. The results provide a new perspective regarding the neural mechanisms of working memory deficits in MCI patients, and extend our knowledge of altered brain patterns in resting and task-evoked states.

A multivariate sample entropy metric of signal complexity is applied to EEG data recorded when subjects were viewing 4 prior-labeled emotion-inducing video clips from a publically available, validated database. Besides emotion category labels, the video clips also came with arousal scores. Our subjects were also asked to provide their own emotion labels. In total 30 subjects with age range 19–70 years participated in our study. Rather than relying on predefined frequency bands, we estimate multivariate sample entropy over multiple data-driven scales using the multivariate empirical mode decomposition technique (MEMD) and show that in this way we can discriminate between 5 self-reported emotions (p < 0.05). These results could not be obtained by analyzing the relation between arousal scores and video clips, signal complexity and arousal scores, and self-reported emotions and traditional power spectral densities and their hemispheric asymmetries in the theta, alpha, beta, and gamma frequency bands. This shows that multivariate, multiscale sample entropy is a promising technique to discriminate multiple emotional states from EEG recordings. ispartof: International Journal of Neural Systems vol:26 issue:2 ispartof: location:Singapore status: published

International audience; This study presents a new Phoenix unit cell with reduced size (λ0/3 at centre frequency). Three different techniques are investigated to preserve a complete 360° phase range, with quasi-linear and parallel phase responses over a reasonable frequency band, in spite of this small size. The phase cycle successively uses two different printed elements with complementary capacitive and inductive responses. The studied techniques aim at increasing the insufficient inductive effect. As a demonstration, a 1877-element reflectarray is fabricated with the technique compatible with a single-substrate fabrication process. Measured results show a 1 dB gain bandwidth of 11.3%. © The Institution of Engineering and Technology 2016.

WOS: 000380832000009, We demonstrate numerically and experimentally a dynamical chiral metamaterial that uniaxially creates giant optical activity and circular dichroism. In addition, the structure gives a high negative refractive index due to the large chirality. The proposed chiral metamaterial includes four L attached cross (FLAC) wire strips and offers a simple geometry, flexibility and more efficient results for chiral metamaterial applications such as polarization rotator, EM filter and so on. The experimental results are in a good agreement with the numerical simulation. It can be seen that FLAC wire strips based chiral metamaterial can also be used to achieve natural-small chirality with a constant value in a wide frequency range between 3.5-4.5 GHz. This is also another crucial feature of the structure. Therefore, the proposed chiral metamaterial with constant chirality value can be used to design novel EM devices such as polarization converter, anti-reflection filters for a certain frequency range., TUBITAK [113E290]; Turkish Academy of Sciences, This work is supported by the TUBITAK under Projects No: 113E290. One of the authors M. K. also acknowledges partial support from the Turkish Academy of Sciences.

Typical brain networks consist of many peripheral regions and a few highly central ones, i.e., hubs, playing key functional roles in cerebral inter-regional interactions. Studies have shown that networks, obtained from the analysis of specific frequency components of brain activity, present peculiar architectures with unique profiles of region centrality. However, the identification of hubs in networks built from different frequency bands simultaneously is still a challenging problem, remaining largely unexplored. Here we identify each frequency component with one layer of a multiplex network and face this challenge by exploiting the recent advances in the analysis of multiplex topologies. First, we show that each frequency band carries unique topological information, fundamental to accurately model brain functional networks. We then demonstrate that hubs in the multiplex network, in general different from those ones obtained after discarding or aggregating the measured signals as usual, provide a more accurate map of brain's most important functional regions, allowing to distinguish between healthy and schizophrenic populations better than conventional network approaches.

Sound mapping over large areas can be computationally expensive because of the large number of sources and large source-receiver separations involved. In order to facilitate computation, a simplifying assumption sometimes made is to neglect the sound speed gradient in shallow water. The accuracy of this assumption is investigated for ship generated sound in the Dutch North Sea, for realistic ship and wind distributions. Sound maps are generated for zero, negative and positive gradients for selected frequency bands (56 Hz to 3.6 kHz). The effect of sound speed profile for the decidecade centred at 125 Hz is less than 1.7 dB. © 2016 Acoustical Society of America.

Sound mapping over large areas can be computationally expensive because of the large number of sources and large source-receiver separations involved. In order to facilitate computation, a simplifying assumption sometimes made is to neglect the sound speed gradient in shallow water. The accuracy of this assumption is investigated for ship generated sound in the Dutch North Sea, for realistic ship and wind distributions. Sound maps are generated for zero, negative and positive gradients for selected frequency bands (56 Hz to 3.6 kHz). The effect of sound speed profile for the decidecade centred at 125 Hz is less than 1.7 dB. © 2016 Acoustical Society of America.

In this paper, a triple-band 1 × 2 and 1 × 4 microstrip patch antenna array for next-generation wireless and satellite-based applications are presented. The targeted frequency bands are 3.6, 5.2 and 6.7 GHz, respectively. Simple design procedures and optimization techniques are discussed to achieve better antenna performance. The antenna is designed and simulated using Agilent ADS Momentum using FR4 substrate (r = 4.2 and h = 1.66 mm). The main patch of the antenna is designed for 3.6 GHz operation. A hybrid feed technique is used for antenna arrays with quarter-wave transformer-based network to match the impedance from the feed-point to the antenna to 50. The antenna is optimized to resonate at triple-bands by using two symmetrical slits. The single-element triple-band antenna is fabricated and characterized, and a comparison between the simulated and measured antenna is presented. The achieved simulated impedance bandwidths/gains for the 1 × 2 array are 1.67%/7.75, 1.06%/7.7, and 1.65%/9.4 dBi and for 1 × 4 array are 1.67%/10.2, 1.45%/8.2, and 1.05%/10 dBi for 3.6, 5.2, and 6.7 GHz bands, respectively, which are very practical. These antenna arrays can also be used for advanced antenna beam-steering systems. Copyright © Cambridge University Press and the European Microwave Association 2014.

Conference name: Proceedings of the conference - Wave Propagation: From Electrons to Photonic Crystals and Metamaterials in honor of Prof. C. M. Soukoulis’ 60th birthday Date of Conference: 8-11 June 2011 A dual-frequency division de-multiplexing mechanism is demonstrated using cascaded photonic crystal waveguides with unequal waveguide widths. The de-multiplexing mechanism is based on the frequency shift of the waveguide bands for the unequal widths of the photonic crystal waveguides. The modulation in the waveguide bands is used for providing frequency selectivity to the system. The slow light regime of the waveguide bands is utilized for extracting the desired frequency bands from a wider photonic crystal waveguide that has a relatively larger group velocity than the main waveguide for the de-multiplexed frequencies. In other words, the wider spatial distribution of the electric fields in the transverse direction of the waveguide for slow light modes is utilized in order to achieve the dropping of the modes to the output channels. The spectral and spatial de-multiplexing features are numerically verified. It can be stated that the presented mechanism can be used to de-multiplex more than two frequency intervals by cascading new photonic crystal waveguides with properly selected widths.