Matching Elements Research Articles

Arbitrary coupling arbitrary phase couplers with improved bandwidth

In this study, an arbitrary coupling and arbitrary phase coupler with improve bandwidth is proposed. The proposed couplers use a series stub of electrical length θ at all ports which acts as matching element and thereby improves the effective bandwidth of the coupler. A lossless transmission line model is used to obtain design equations and design graphs. Return loss, isolation, amplitude and phase imbalances all four conditions are considered for bandwidth calculation. Two 3 dB couplers with phase difference of 30° and 45° and the third coupler with 4.77 dB coupling and phase difference of 60° are fabricated and measured to validate the proposed topology. Bandwidth improvement is obtained in all the cases. In some cases, the effective bandwidth is more than 100%.

65-nm CMOS element of matching for content-addressable memory resilient to impact of single nuclear particles

65-nm CMOS element of matching for content-addressable memory resilient to impact of single nuclear particles is proposed. Element includes upset-hardened STG DICE memory cell and XOR logical gate based on two tristate inverters. Transistors of the element are separated into two identical joint groups spaced on the chip by distance of more than 4 μm, which practically excludes the possibility of cell upset under impact of single nuclear particles. Designed element of matching is implemented in resilient to single event effects translation lookaside buffer of microprocessor.

A Novel Method for Osteometric Reassociation Using Hamiltonian Markov Chain Monte Carlo (MCMC) Simulation

Traditional osteometric reassociation uses an error-mitigation approach, which seeks to eliminate possible matches, rather than a predictive approach, where possible matches are directly compared. This study examines the utility of a Bayesian approach for resolving commingling by using a probabilistic framework to predict correct matches. Comparisons were grouped into three types: paired elements, articulating elements, and other elements. Ten individuals were randomly removed from the total sample ( N = 833), acting as a small-scale, closed-population commingled assemblage. One element was chosen as the independent variable, with the ten possible matching elements representing the dependent variable. A Bayesian regression model was constructed using the remaining total sample, resulting in a distribution of possible values that were smoothed into a probability density, and probabilities were calculated. The element with the highest posterior probability was considered the best match. This process was repeated 500 times for each comparison. The correct match was identified 51.60% of the time. Paired elements performed the best, at 80.76%, followed by 42.10% for articulating and 33.63% for other comparisons. These results suggest that metric analysis of commingled assemblages is complex and that both elimination-based and prediction-based approaches have a role in resolving commingling. In this regard, the strength of a Bayesian approach is versatility, allowing for prediction of the correct match and elimination of possible matches, as well as integration of independent lines of evidence within one cohesive model.

A Coaxial RF Applicator for Ultra-High Field Human MRI.

To develop a novel radio-frequency (RF) concept for ultra-high field (UHF) human magnetic resonance imaging (MRI) based on a coaxial resonant cavity. A two-channel slotted coaxial cavity RF applicator was designed for human head MRI at 9.4T. Physical dimensions made the proposed conducting structure resonant at the required frequency without tuning lumped elements. Numerical electromagnetic modeling was used to optimize the design. RF safety was assessed with two representative human body models. MR experiments on a 9.4T scanner included gradient echo images and mapping of a circularly polarized RF magnetic field in the human head phantom. The simulations and the phantom MR experiments agreed both qualitatively and quantitatively. The design was relatively simple, robust and required only a few additional reactive elements for the applicator's input impedance matching. The transmit efficiency and homogeneity of the excitation field were only 20% and 4% lower compared to a conventional 8-channel head array. The coaxial RF applicator was feasible for human MRI at UHF and required no lumped elements for its tuning. Imaging performance of the RF applicator was only moderately lower compared to the conventional transmit array, but would be sufficient to provide an anatomical reference for the heteronuclei MRI. An alternative approach with the minimal involvement of lumped elements becomes feasible to design volume-type RF coils for UHF human MRI.

Ultra-Light Reduced Graphene Oxide Based Aerogel/Foam Absorber of Microwave Radiation.

We present the polarization-dependent highly absorptive in Ka-band composition of conventional polyurethane foam filled with in situ synthesized aerogel coated by reduced graphene oxide (rGO). The rGO-based aerogel was in situ prepared into the open-cell polyurethane foam (PUF) skeleton through a bidirectional freeze-drying process. The aerogel is composed of the flat lamellas stacks, possessing the anisotropic structure and unique electromagnetic properties. Further improvement of the electromagnetic shielding ability was possible by the rGO coating introduction as a coupling layer between PUF and rGO-based aerogel. This enhances the overall conductivity of the resulting composites: 1.41 + 3.33i S/m vs. 0.9 + 2.45i S/m for PUF loaded with in situ synthesized aerogel without rGO coating.With this mechanically robust plane easy to process coating one could achieve −20 dB by power with the record light structure (0.0462 g/cm2). That could compete in view of the weight per cm2 even with graphene-based absorbers comprising either dielectric matching elements or back metal reflectors, or both.

RF Energy Scavenging With a Wide-Range Input Power Level

Energy scavenging is a promising technique for micro-devices such as wireless sensor networks (WSNs). Radio frequency (RF) is considered a sustainable source that can be utilized and harvested due to its important features. The essential goal of this study was designing and investigating a wide input power range through a theoretical and simulation work for the 900 MHz frequency band with acceptable efficiency. In this work, we investigated both the low input power and the high input power range circuits; the two circuits were combined to achieve the goal of the wide input power range. L impedance matching elements were used to perform the desired matching between the power source and the circuit to reduce the reflected power resulted in enhanced RF-DC conversion efficiency. 60 % was the peak efficiency for the proposed design at 0 dBm with the output voltage of 16.56 V, and a generated current of 1.39 mA for the load of 12KΩ.

LTE MIMO Closed Slot Antenna System for Laptops With a Metal Cover

This paper presents an LTE MIMO closed slot antenna system for laptops with a metal cover. Its main and auxiliary antennas have the same structure that measures 130 × 3 mm 2 . They are configured in a manner of reflection symmetry on the display metallic ground plane and are 5 mm away from the hinge. The distance between the two antennas is 20 mm, and the profile height of the MIMO antenna system is only 3 mm. This LTE closed slot antenna is excited by an exciter of 30 × 3 mm 2 to cover the LTE eight-band operation (LTE700/GSM850/900/1800/1900/UMTS/LTE2300/2500). The exciter is a simple planar inverted-F antenna (PIFA) structure loaded with reactive matching elements, which can enhance the impedance matching in the desired frequency bands. This LTE MIMO closed slot antenna system has good isolation of at least 16 dB without adding any additional isolation elements. The measured antenna efficiency of the MIMO antenna system is larger than 40% in the low-frequency band and 50% in the high-frequency band, meeting the practical application requirements.

The features of the use of the waveguide radiators in smart antenna systems

The features of the use of finite waveguide antenna arrays in the structure of modern smart antenna systems are considered. The paper deals with the problem of diffraction of an electromagnetic wave on a finite waveguide antenna array scanning in the E-plane. Antenna array consists of five radiating elements. The open ends of the waveguides are surrounded by a metal screen. The resonator coupling region was chosen as matching elements. The solution of the problem is carried out by the integral equation method on the basis of the selection of overlapping regions. The problem reduces to solving the Fredholm integral equation of the second kind. An array of infinitely thin plates and that of waveguides with a finite wall thickness are considered. The main regularities for choosing the optimal geometric dimensions of the antenna array are established. Studies were carried out for arrays with a number of elements from five to fifteen. The analysis of edge effects in the final antenna array is carried out. It is shown that the introduction of a resonator region into a five-element lattice makes it possible to expand the sector of the radiation angles and avoid the effect of blinding. It is shown that this statement is valid not only for five-element lattices, but also for arrays with a large number of radiating elements. The radiation patterns are calculated. The coefficients of mutual coupling in an array with five elements are investigated. General recommendations for choosing optimal sizes of the resonator coupling region of radiators are considered.

Improving IF Algorithm for Data Aggregation Techniques in Wireless Sensor Networks

In Wireless Sensor Network (WSN), fact from different sensor nodes is collected at assembling node, which is typically complete via modest procedures such as averaging as inadequate computational power and energy resources. Though such collections is identified to be extremely susceptible to node compromising attacks. These approaches are extremely prone to attacks as WSN are typically lacking interfere resilient hardware. Thus, purpose of veracity of facts and prestige of sensor nodes is critical for wireless sensor networks. Therefore, imminent gatherer nodes will be proficient of accomplishment additional cultivated data aggregation algorithms, so creating WSN little unresisting, as the performance of actual low power processors affectedly increases. Iterative filtering algorithms embrace inordinate capacity for such a resolution. The way of allocated the matching mass elements to information delivered by each source, such iterative algorithms concurrently assemble facts from several roots and deliver entrust valuation of these roots. Though suggestively extra substantial against collusion attacks beside the modest averaging techniques, are quiet vulnerable to a different cultivated attack familiarize. The existing literature is surveyed in this paper to have a study of iterative filtering techniques and a detailed comparison is provided. At the end of this paper new technique of improved iterative filtering is proposed with the help of literature survey and drawbacks found in the literature.

A comparison of automated object extraction methods for mound and shell-ring identification in coastal South Carolina

One persistent archaeological challenge is the generation of systematic documentation for the extant archaeological record at the scale of landscapes. Often our information for landscapes is the result of haphazard and patchy surveys that stem from opportunistic and historic efforts. Consequently, overall knowledge of some regions is the product of ad hoc survey area delineation, degree of accessibility, effective ground visibility, and the fraction of areas that have survived destruction from development. These factors subsequently contribute unknown biases to our understanding of chronology, settlements patterns, interaction, and exchange. Aerial remote sensing offers one potential solution for improving our knowledge of landscapes. With sensors that include LiDAR, remote sensing can identify archaeological features that are otherwise obscured by vegetation. Object-based image analyses (OBIA) of remote sensing data hold particular promise to facilitate regional analyses thorough the automation of archaeological feature recognition. Here, we explore four OBIA algorithms for artificial mound feature detection using LiDAR from Beaufort County, South Carolina: multiresolution segmentation, inverse depression analysis, template matching, and a newly designed algorithm that combines elements of segmentation and template matching. While no single algorithm proved to be consistently superior to the others, a combination of methods is shown to be the most effective for detecting archaeological features.

Structure-dynamic and functional relationships in a Li+-transporting sodium‑calcium exchanger mutant

The cell membrane (NCX) and mitochondrial (NCLX) Na+/Ca2+ exchangers control Ca2+ homeostasis. Eleven (out of twelve) ion-coordinating residues are highly conserved among eukaryotic and prokaryotic NCXs, whereas in NCLX, nine (out of twelve) ion-coordinating residues are different. Consequently, NCXs exhibit high selectivity for Na+ and Ca2+, whereas NCLX can exchange Ca2+ with either Na+ or Li+. However, the underlying molecular mechanisms and physiological relevance remain unresolved. Here, we analyzed the NCX_Mj-derived mutant NCLX_Mj (with nine substituted residues) imitating the ion selectivity of NCLX. Site-directed fluorescent labeling and ion flux assays revealed the nearly symmetric accessibility of ions to the extracellular and cytosolic vestibules in NCLX_Mj (Kint = 0.8–1.4), whereas the extracellular vestibule is predominantly accessible to ions (Kint = 0.1–0.2) in NCX_Mj. HDX-MS (hydrogen-deuterium exchange mass-spectrometry) identified symmetrically rigidified core helix segments in NCLX_Mj, whereas the matching structural elements are asymmetrically rigidified in NCX_Mj. The HDX-MS analyses of ion-induced conformational changes and the mutational effects on ion fluxes revealed that the “Ca2+-site” (SCa) of NCLX_Mj binds Na+, Li+, or Ca2+, whereas one or more additional Na+/Li+ sites of NCLX_Mj are incompatible with the Na+ sites (Sext and Sint) of NCX_Mj. Thus, the replacement of ion-coordinating residues in NCLX_Mj alters not only the ion selectivity of NCLX_Mj, but also the capacity and affinity for Na+/Li+ (but not for Ca2+) binding, bidirectional ion-accessibility, the response of the ion-exchange to membrane potential changes, and more. These structure-controlled functional features could be relevant for differential contributions of NCX and NCLX to Ca2+ homeostasis in distinct sub-cellular compartments.

Asymptotic theory of bimodal quarter-wave impedance matching for full mode-converting transmission

A quarter-wave impedance-matching element inserted between two dissimilar media allows full-power transmission, but this phenomenon occurs only when the mode of the incident and transmitted waves remains unaltered, either longitudinal (L) or transverse (T). Here, we report our asymptotic bimodal quarter-wave impedance-matching theory for full-power mode-converting transmission. It requires that two coupled quarter waves should be simultaneously formed inside a matching element possessing specific anisotropy for phase matching and L-to-T (T-to-L) mode conversion. Simulations using designed metamaterial matching elements show that nearly full mode-converting transmissions can be realized within a single medium or between two dissimilar media. We expect that our theory can be critically useful for medical and industrial ultrasonic applications wherever highly efficient mode conversion and high-powered transverse waves are required.

Assessing the effectiveness of high-dose influenza vaccine in preventing hospitalization among seniors, and observations on the limitations of effectiveness study design

BackgroundThe availability of high-dose (HD) influenza vaccine for seniors should decrease influenza-related hospitalization. Studies to date show a range of mostly moderate increased HD vaccine effectiveness (VE). While a ‘healthy vaccinee’ phenomenon can inflate VE, for influenza and particularly an HD vaccine targeted at frailer adults, an ‘at-risk vaccinee’ bias may deflate VE estimates. We assessed senior HD vaccine effectiveness against influenza-related hospitalization by linking immunization registry records to hospitalizations. We also examined whether adding strata typically ignored in case-control matching schemas, such as residence areas, exact age, and provider biases, would increase VE. MethodsFor the 2016–17 influenza season in the Portland metropolitan area, the differential VE for the HD vaccine in preventing PCR-confirmed influenza hospitalization was assessed by a nested series of models across matching strata. For an exact match for high-dose and standard-dose seniors, matching elements included exact age, gender, residence type, race-ethnicity, provider bias, and residence area (zipcode). ResultsAs a first step, a simple aggregate comparison of influenza-related hospitalization risk showed no added HD effectiveness. For the nested models, adding strata increased VE. In the final model, among 23,712 matched pairs of HD to SD vaccinated seniors, the HD vaccine was 30.7% (95%CI: 8–48%) more effective in preventing influenza-related hospitalization. ConclusionFor this study, the high-dose influenza vaccine provided superior protection for seniors against influenza hospitalization. Including matching elements as exact year of age and residence zipcode all added to the calculation of VE. As a warning, non-matched or overly simple matched VE study designs may substantially under-estimate VE.

A Wideband Circularly Polarized Patch Antenna With Enhanced Axial Ratio Bandwidth via Co-Design of Feeding Network

A wideband circularly polarized (CP) patch antenna with enhanced axial ratio (AR) bandwidth via co-design of feeding network is proposed in this paper. One $\pmb \lambda/4 $ resonator and one $\pmb \lambda/2 $ resonator are introduced and coupled in proximity to two orthogonal points of a square patch radiator to excite two orthogonal modes. These two resonators not only function as impedance matching elements to achieve equal magnitude of two orthogonal modes in a wide frequency band but also provide the required 90° phase difference. In this way, two minima in the AR response appear, resulting in extended AR bandwidth. The wideband design of the antenna is carried out based on the equivalent circuit model, where the patch radiator is treated as a conductance, inductance, and capacitance parallel resonator. In particular, the feeding network and the patch are jointly considered as a three-port network for synthesis design. By mapping the radiated far field to the magnitude and phase on the radiation conductance in the circuit model, the AR response of the antenna becomes predictable in a straightforward manner. Measured results experimentally demonstrate that the 3-dB AR bandwidth of our proposed CP patch antenna is 2.7 times that of the traditional one fed with two 90° offset lines.

Insertion Loss Characterization of Impedance Matching Networks for Low-Power Rectennas

An impedance matching network inserted between an antenna and a rectifier is essential for rectennas, but few studies have characterized the insertion loss of the matching network if nonideal matching elements are considered. In general, the matching elements, including lumped capacitors, lumped inductors, and transmission lines, are approximated as lossless; if the overall conversion efficiency decreases, the underlying reason seldom attributes to the loss of the matching network. In this paper, we derive the insertion loss of the matching network comprising actual lumped elements and transmission lines. The loss is quantified using the operating power gain of a two-port network, which varies with different levels of input power. When the input power ranges between −30 and 0 dBm, more than 95%, 90%, and 75% of power dissipates at 900 MHz, 1.8 GHz, and 2.4 GHz, respectively, due to the use of actual matching elements. The numerical results are verified by experimental data, and all the analyses demonstrate that the loss of the matching network becomes very serious as the input power is low. These observations are explained using the contour plot of operating power gain. Accordingly, this study provides a theoretical development for rectenna designers.

Damaging nature of decelerations: Do we adequately prepare players?

Frequent and intense accelerations and decelerations are crucial elements of match play.1–4 Both accelerations and decelerations expose players to high levels of mechanical stress, are recognised as key contributors to...

Planning the efficiency of forming and using the production potential of industrial enterprise

The article researches the peculiarities of planning of efficient formation and use of the industrial enterprise’s production potential. The author specifies the enterprise’s production potential essence and proves the actuality of planning of its efficient use for reaching strategical goals of economic entity’s activity. It is determined that the enterprise’s production potential is a component part of organization’s general potential. The directions of its use for reaching the development goals are ascertained at the level of strategical planning, and the enterprise’s current activity is aimed at providing the sufficient level of production resources, which bring regular functioning. It is substantiated that the main task of planning the enterprise’s production and sales activities is the optimal use of producer’s resources to manufacture products and satisfy consumers’ demand. The paper determines the structure and the offer of the enterprise’s production resources according to the goals of their use, which allow to speed up the rates of economic activity efficiency. The results of the study shows that to perform the planning process of production potential efficient formation and use is reasonable in the following succession: to set the enterprise’s objective and goals; to analyze the current conditions; to develop enterprise’s general strategy; to estimate production potential taking into consideration the prospects of the organization development; to form the functional strategy of the production potential development; to implement and control the fulfilment of the plan of enterprise’s production potential efficient formation and use. The critical analysis of the professional literature allows to draw a conclusion that the production potential is the mutually matching element within the processes of strategical and current planning for the enterprise’s activity. The goals reflecting the direction of the economic entity development taking into account its potential, are implemented in the real economic activity foreseen by the results of the current planning of the production and sales.

A novel JSON based regular expression language for pattern matching in the internet of things

The Internet of Things work by constantly sensing the physical properties in the vicinity of the user such as ambient light, sounds, motion and temperature. These sensors produce huge volumes of data that has to be efficiently sifted for relevant events required triggering certain actions. In addition, filtering has to be performed to ensure that privacy-sensitive confidential data is not leaked. Efficient and expressive pattern matching is thus a key enabling technology for the full realization of ambient and humanized computing. The bulk of research in this area has focused on the use of specialized hardware and reducing of the memory footprint. Unfortunately, there has been limited work if any on optimizing the core elements of pattern matching- the regular expression language and the compilation process that is responsible for converting patterns into internal data structures. The importance of writing good REs so that on compilation they do not lead to unrealizable data structures is relatively less understood. In the proposed research, we empirically compare different RE processing engines and practically demonstrate that the compilation phase is highly memory intensive and time-consuming as compared to the matching phase -and hence is worth exploring for new techniques and optimizations. As a second important contribution, we propose a novel technique for defining regular expressions by utilizing JavaScript Object Notation. Our evaluation with carefully created patterns shows that the performance of the proposed technique is at par with competing approaches. It is also less ambiguous, extensible, more expressive and much appropriate for defining large and complex patterns.

A Broadband Impedance-Matching Method for Microstrip Patch Antennas Based on the Bode-Fano Theory

Abstract Considering the narrow bandwidth of microstrip antennas, but also their applicability in upcoming technologies, this paper addresses the problem of wide-band matching, the theoretical bounds on the matching bandwidth and low-cost and low-complexity matching strategies. In this context the Bode-Fano bounds of single mode, linearly polarized aperture-coupled microstrip antennas is evaluated, optimized and compared to the theoretical bounds on matching bandwidth of other common feeding technologies. A detailed study of the input impedance of aperture-coupled patch antennas shows how to widen the Fano bounds. Based on this, a straight-forward and effective method to optimize the Fano bound is given. After optimization of the antennas input impedance, basic matching techniques can be applied, to exploit the enlarged bandwidth potential. As an example a $\lambda/4$-transformer as matching element is proposed. Design equations and simulation and measurement results of X-band prototypes are given as verification.

Modified coaxial wire method for measurement of transfer impedance of beam position monitors

The transfer impedance is a very important parameter of a beam position monitor (BPM) which relates its output signal with the beam current. The coaxial wire method is a standard technique to measure transfer impedance of the BPM. The conventional coaxial wire method requires impedance matching between coaxial wire and external circuits (vector network analyzer and associated cables). This paper presents a modified coaxial wire method for bench measurement of the transfer impedance of capacitive pickups like button electrodes and shoe box BPMs. Unlike the conventional coaxial wire method, in the modified coaxial wire method no impedance matching elements have been used between the device under test and the external circuit. The effect of impedance mismatch has been solved mathematically and a new expression of transfer impedance has been derived. The proposed method is verified through simulation of a button electrode BPM using cst studio suite. The new method is also applied to measure transfer impedance of a button electrode BPM developed for insertion devices of Indus-2 and the results are also compared with its simulations. Close agreement between measured and simulation results suggests that the modified coaxial wire setup can be exploited for the measurement of transfer impedance of capacitive BPMs like button electrodes and shoe box BPM.