Scalar Network Research Articles

Analytical Study of a Rectangular Microstrip Patch Antenna

This work presents the analytical study of a rectangular microstrip patch antenna design which is developed on FR4 type substrate material. The resonant frequency of this rectangular microstrip patch antenna is first estimated using Transmission Line Model (TLM) and Cavity Model (CM) based Computer Aided Design (CAD) procedure. The dielectric constant of the FR4 type substrate is assumed to be 4.4 for these calculations. The estimated value of resonant frequency is 2472 MHz. The Return Loss (RL) and Voltage Standing Wave Ratio (VSWR) of the antenna are then measured around the estimated Resonant Frequency of antenna, using a Scalar Network Analyzer setup. The actual resonant frequency of the antenna is found to be 2380 MHz from Return Loss measurements of the antenna. The dielectric constant of substrate is then estimated from the geometry and Resonant Frequency of the antenna. The estimated value of the dielectric constant of substrate comes out to be 4.7545. The probe feed location is also calculated. The radiation pattern of the antenna is measured at the Resonant Frequency 2380 MHz.

In-Line Wood Defect Detection Using Simple Scalar Network Analyzer

Timber is widely used in new structures. The leading causes of structural failure are sited at bolt connections, cavities, and knots. This paper introduces a simple method to detect bolts in wood using a UHF Scalar Network Analyzer (SNA). The electronics placed inside an aluminum box with a slot aperture transmit a microwave signal through the slot, and the near-field signal determines the reflection coefficient (S11). Major changes from baseline are an accurate method to detect cavities and bolts inside the wood. Experiments were conducted on pinewood beams with cross-section dimensions of (70 mm × 70 mm). The scalar network analyzer circuit can detect bolts and cavities within a 30 mm range from the wood surface. The technique can be used for timber beam preparation in an automated sawmill at speed.

Investigation of the Structure and Magnetic and Microwave Absorption Properties of Nanocomposite PVA/Graphite/CoFe1.97Ce0.03O4

Composites PVA/Graphite/CoFe1.97Ce0.03O4 and PVA/CoFe1.97Ce0.03O4 were synthesized and studied. The morphology and structure of the starting materials and composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS) and infrared spectroscopy (IR). The magnetic parameters were measured using a vibrating magnetometer. The absorptive capacity of the obtained materials was evaluated based on the results of measuring the transmission and reflection coefficients using a scalar network analyzer in the range of 8–12 GHz. The results show that the absorption characteristics of the PVA/Graphite/CoFe1.97Ce0.03O4 composite are significantly higher than those of the PVA/CoFe1.97Ce0.03O4 composites. Effective absorption is observed for the PVA/Graphite/CoFe1.97Ce0.03O4 composite in the frequency range of 8–12 GHz and corresponds to −25.08 dB mm−1, which indicates excellent absorption characteristics of electromagnetic radiation in this frequency range.

Thermalization of Isolated Harmonic Networks Under Conservative Noise

We study a scalar harmonic network with pair interactions and a binary collision rule, exchanging the momenta of a randomly-chosen couple of sites. We consider the case of the isolated network where the total energy is conserved. In the first part, we recast the dynamics as a stochastic map in normal modes (or action-angle) coordinates and provide a geometric interpretation of it. We formulate the problem for generic networks but, for completeness, also reconsider the translation-invariant lattices. In the second part, we examine the kinetic limit and its range of validity. A general form of the linear collision operator in terms of eigenstates of the network is given. This defines an action network, whose connectivity gives information on the out-of-equilibrium dynamics. We present a few examples (ordered and disordered chains and elastic networks) where the topology of connections in action spaces can be determined in a neat way. As an application, we consider the classic problem of relaxation to equipartition from the point of view of the dynamics of linear actions. We compare the results based on the spectrum of the collision operator with numerical simulation, performed with a novel scheme based on direct solution of the equations of motion in normal modes coordinates.

Design and Implementation of Microwave Dual-Band Pass Interdigital Filter Using an Analytical Approach

In this paper, benefiting from frequency transformation between the normalized frequency domain of low-pass prototype frequencies and the real frequency domain of the filter, a purely analytical procedure for dual-band filter design is used. The coupling matrix of the filter is analytically extracted, without the need to perform numerical optimization. The procedure also includes finding the equivalent circuit for these types of filters. The frequency transformation formula is verified through an example. The equivalent circuit and the coupling matrix are also analytically deduced through the same example. Using an electromagnetic structure simulator, an interdigital dual-band filter is designed and simulated. The simulation results fulfill the specifications of the given filter example, and the simulation results verify the possibility of achieving the required specifications of the filter frequency response. The designed and simulated filter has been implemented and measured using a Scalar Network Analyzer. The measurement results confirm the simulation results and the efficiency of the synthesis procedure.

Permute and Add Network Codes via Group Algebras

A class of network codes have been proposed in the literature where the symbols transmitted on network edges are binary vectors and the coding operation performed in network nodes consists of the application of (possibly several) permutations on each incoming vector and XOR-ing the results to obtain the outgoing vector. These network codes, which we will refer to as <i>permute-and-add</i> network codes, involve simpler operations and are known to provide lower complexity solutions than scalar linear network codes. The complexity of these codes is determined by their <i>degree</i> which is the number of permutations applied on each incoming vector to compute an outgoing vector. Constructions of permute-and-add network codes for multicast networks are known. In this paper, we provide a new framework based on group algebras to design permute-and-add network codes for arbitrary (not necessarily multicast) networks. Our framework allows the use of any finite group of permutations (including circular shifts, proposed in prior works) and admits a trade-off between coding rate and the degree of the code. Further, our technique permits elegant recovery and generalizations of the key results on permute-and-add network codes known in the literature.

Using a Solution Construction Algorithm for Cyclic Shift Network Coding under Multicast Network to the Transformation of Musical Performance Styles

This paper presents a theoretical framework of the circular shift network coding system through the study of nonmultiple clustered interval music performance style conversion and the analysis of music conversion by using circular shift topology, and a series of basic research results of circular shift network coding is obtained under this framework. It reveals the essential connection between scalar network coding based on finite domain and cyclic shift network coding, designs a solution construction algorithm for cyclic shift network coding under multicast network, and portrays the multicast capacity of cyclic shift network coding. It overcomes the problem that the piano roll-curtain representation cannot distinguish between a single long note and multiple consecutive notes of the same pitch, describes musical information more comprehensively, extracts musical implicit style from the note matrix based on autoencoder, and better eliminates the potential influence of musical content on musical performance style. A two-way recurrent neural network based on the gated recurrent unit is used to extract a sequence of note feature vectors of different styles, and a one-dimensional convolutional neural network is used to predict the intensity of the extracted note feature vector sequence for a specific style, which better learns the intensity variation of different styles of MIDI music.

Resonant properties of a multilayer strip-slot transition and its application for microwave measurements of dielectric properties of materials

Statement of the problem: One of the actual problems of applying radio materials at high and ultrahigh frequency ranges is the problem of increased requirements for the accuracy of assessing their dielectric properties. Currently, non-resonant and resonant methods are applied to assess the dielectric properties of radio materials at the frequency ranges indicated above. Non-resonant methods are expedient for application in non-destructive testing of large-area sheet materials. Their implementation requires the application of an expensive vector network analyzer. Resonant methods are applied with a limited amount of the test material or in its powder state. In the implementation of resonant methods the main investigated parameter is the displacement of the frequency of the electrical resonance. As a consequence, only the amplitude values of the transmission and reflection coefficients need to be known. This feature makes it possible to carry out microwave measurements for the resonant method applying a scalar network analyzer which has a lower cost compared to a vector network analyzer. That feature is an advantage in some cases. One of the promising directions in the development of the resonant measurement method is its implementation based on applying of a volumetric-modular technology. In particular its implementation that based on application of a multilayer strip-slot transition. The problem with this approach is the lack of researches in terms of the effectiveness of the application of the multilayer strip-slot transition as a device with a tunable frequency of electrical resonance. Aim: The aim of this article is to present a resonant method based on the application of the multilayer strip-slot transition as a basic measuring device. Such a design solution for the implementation of resonant microwave measurements has no analogues. This determined the conduction of current research. The task of which is to theoretically and experimentally substantiate the effectiveness of applying a multilayer strip-slot transition to implement the resonant method for measuring the dielectric properties of materials. Results: The results of theoretical and experimental studies of the resonance properties of the multilayer strip-slot transition are presented. Its application makes it possible to realize an original volume-modular device for the resonant method of measuring the dielectric parameters of materials in the microwave range of wavelengths. The theoretical research is based on the development of an equivalent circuit, which is presented in the form of a cascade connection of four-port networks. The results of mathematical simulation of the multilayer strip-slot transition prove the possibility of implementing on its basis the resonance method for measuring the dielectric parameters of materials in the microwave range of wavelengths. Experimental studies were carried out on a sample of a volume-modular device with the multilayer strip-slot transition. The test material was a powder representing barium hexaferrite BaFe10Ti2O19 partially substituted by titanium. The coincidence of the results of mathematical simulation and experimental studies of the frequency-selective properties of a multilayer strip-slot transition is more than 95%. The error in assessing the permittivity of the used powder material based on the results of theoretical and experimental studies does not exceed 4.5%. Practical significance: The results of the research showed the possibility of applying of the multilayer strip-slot transition as a basic element for the implementation of the resonance method for measuring the dielectric properties of materials. The advantages of the proposed design are compactness and the ability to measure the dielectric properties of powder materials using scalar network analyzers.

Capacity Limits of Full-Duplex Cellular Network

This paper aims to characterize the capacity limits of a wireless cellular network with a full-duplex (FD) base-station (BS) and half-duplex user terminals, in which three independent messages are communicated: the uplink message $m_1$ from the uplink user to the BS, the downlink message $m_2$ from the BS to the downlink user, and the device-to-device (D2D) message $m_3$ from the uplink user to the downlink user. From an information theoretical perspective, the overall network can be viewed as a generalization of the FD relay broadcast channel with a side message transmitted from the relay to the destination. We begin with a simpler case that involves the uplink and downlink transmissions of $(m_1,m_2)$ only, and propose an achievable rate region based on a novel strategy that uses the BS as a FD relay to facilitate the interference cancellation at the downlink user. We also prove a new converse, which is strictly tighter than the cut-set bound, and characterize the capacity region of the scalar Gaussian FD network without a D2D message to within a constant gap. This paper further studies a general setup wherein $(m_1,m_2,m_3)$ are communicated simultaneously. To account for the D2D message, we incorporate Marton's broadcast coding into the previous scheme to obtain a larger achievable rate region than the existing ones in the literature. We also improve the cut-set bound by means of genie and show that by using one of the two simple rate-splitting schemes, the capacity region of the scalar Gaussian FD network with a D2D message can already be reached to within a constant gap. Finally, a generalization to the vector Gaussian channel case is discussed. Simulation results demonstrate the advantage of using the BS as relay in enhancing the throughput of the FD cellular network.

The Mountain Sanctuary of Matzanni in Sardinia: Project Motivations and Preliminary Research Results

AbstractThe Matzanni Project tracks the role of the large mountain sanctuary of Matzanni-Vallermosa (southwestern Sardinia) in a scalar network from the local to, potentially, the Bronze Age global. Exploitation of metals in the mountainous setting of the sanctuary constitutes a major research focus together with understanding how metal extraction and religion may have intersected.

Simulation of electromagnetic field distribution in the measuring cell for determining the dielectric permittivity of materials at microwave frequencies

To determine the dielectric permittivity of materials in a wide frequency range with the automation of measurements and the necessary accuracy, measuring cells have been created to ensure the simplicity of the design of the waveguide path. In order to obtain information about the suitability of measuring cells based on irregular SHF waveguides for estimation of dielectric parameters of materials, we simulated the structure of electromagnetic field in the system consisting of two irregular waveguides and waveguide chamber placed between them using a three-dimensional electrodynamic simulation in Ansoft HFSS package environment. The distribution of the electric field was simulated when an empty polyethylene tube, a rod of fluoroplastic and a rod of textolite are placed in the measuring cell. It was demonstrated that high order modes fade out in irregular waveguide and do not affect the precision of obtained results, and significant edge effects were not detected. It allows one to utilize measuring cells based on irregular waveguides together with a scalar or vector network analyzer and using the partial filling of the waveguide method or the modified Nicholson – Ross – Weir method for measurements of dielectric permittivity  of materials. The results of modeling the dependence of the amplitude and phase of the reflection coefficient of the textolite and fluoroplastic on the frequency in Ansoft HFSS environment are given. The simulation results are compared with the results obtained experimentally. The frequency dependencies of  were obtained experimentally for test materials – textolite and fluoroplastic – in the frequency range of 25,95–37,50 GHz. The experimental data are in satisfactory agreement with the results of theoretical calculations and do not go beyond the boundaries specified by the measurement uncertainty.

Examining Keyboard Bitonality in the Middle-Period Music of Karol Szymanowski

Abstract A characteristic technique of Karol Szymanowski’s middle-period style (1914–18) is “keyboard bitonality”: the juxtaposition of the black-key pentatonic and white-key diatonic scales. To explore Szymanowski’s treatment of keyboard bitonality, I introduce the scalar alignment network, a biscalar landscape of all possible pairings of black- and white-key pitch classes that highlights the effects of a particular alignment, such as the resultant pitch-class pairings and intervallic patterns. To accomplish this, I employ a variety of transformational tools, including diatonic transpositions, Julian Hook’s (2007) interscalar transformations, and what I call SHIFT transformations. Analyzed works include: Masks (1916), Métopes (1915), Myths (1915), Twelve Etudes (Op. 33, 1916), and Violin Concerto No. 1 (1916).

A Method for Determining Vector Reflection Coefficient Based on Scalar Amplitude

Short-circuited reflection method is usually used to characterize the dielectric property of materials. When using the method, the extraction of the vector reflection coefficient (VRC) of the metal-backed sample is the key to determine the complex permittivity of the sample. Traditionally, the VRC is measured by a vector network analyzer associated with the transmission line or the antenna. In this letter, a method for determining the VRC using a scalar network analyzer is presented, which requires only one perturbation-two-port network composed of a standard sample layer. Based on the amplitude of the VRC, the phase of the VRC can be determined by the proposed rigorous analytical algorithm. The proposed method has been confirmed theoretically and experimentally, and the applicability of the method is analyzed.

Estimation of Cholesterol in the Presence of Urea and Other Constituents in Blood Tissue

The determination of cholesterol in pathological laboratories is more painful and may lead to infections if no proper precautions are taken into consideration. The manuscript presented here describes a non-invasive method to estimate blood cholesterol using Radio Frequency (RF) probe signal in the range of 10MHz – 500MHz. The method uses Scalar Network Analyzer and injects RF signal less than -30dbm, which is quite safe for human tissue and the frequency range falls in non-ionizing radiation wavelengths. Due to the absorption of RF signal by various body tissues including cholesterol, the received signal by the spectrum analyzer bears the signatures of percentage of the cholesterol present in the blood. These signatures are then analyzed using multivariate approach to estimate the Cholesterol. The Signal Processing Unit consists of Partial Least Square Regression (PLSR) tool based on the SIMPLS Algorithm. The results show that there is a good agreement between the predicted percentages of Cholesterol as compared to the actual. Though the study here uses only 5 components, the technique can also be used to include other blood components for the estimation of Cholesterol.

Benchmarking a Commercial (Sub-)THz Focal Plane Array Against a Custom-Built Millimeter-Wave Single-Pixel Camera

For the first time, the characteristics of an evolving commercial camera technology that can operate at millimeter-wave frequencies has been independently investigated. In this work, we benchmark the TeraSense camera against a custom-built single-pixel camera at W-band, for image quality and aperture reflectance. It is found that the Tera-1024 TeraSense camera exhibits limited image resolution and fidelity, with significant levels of systematic spatial noise. In a poor signal-to-noise ratio scenario, the addition of random noise exacerbates these problems. Possible causes of both beam and image distortion have been identified in quasi-optical applications, which gives important insight into the best use of (sub-)THz cameras and interpretation of their images. Inherent standing waves caused by the significant power reflectance of the camera aperture is investigated in detail. A simple W-band one-port quasi-optical scalar network analyzer is developed, to determine the levels of reflectance for both cameras, with its bespoke calibration routine derived from first principles - providing a low-cost solution for many non-destructive testing applications. It is found that the TeraSense camera (with additional RAM) and single-pixel camera (having default RAM) have measured reflectance values of 27% and 3%, respectively, over a corresponding aperture area ratio of approximately 714:1. While our single-pixel camera provides excellent image resolution and fidelity, it inherently suffers from very slow raster-scanning speeds and operational bandwidth limitations. For this reason, the TeraSense camera technology is excellent for performing qualitative measurements in real time, with the caveats outlined in this paper.

Soil Urea Estimation using Embedded Systems

With the advancements in technology constant efforts are being made towards making agriculture sustainable. Green Revolution made extensive use of chemical fertilizers to increase the crop yield, which gave the desired outputs, but high usage of fertilizers led to soil degradability, ground water contamination etc. Precision farming techniques are currently being used to make agriculture sustainable and profitable. Lot of automation is involved in the techniques used for irrigation, harvesting, soil testing etc. Soil testing is an important aspect in agriculture as it decides the crops that can be grown in a particular type of soil and also todecide how much external inputs can be applied to give a good crop yield. Precision farming involves techniques which are real time based. The paper discusses the design and development of a novel soft core embedded platform on Altera FPGA for estimation of urea in soil. RF spectra of five different constituents found in soil are recorded using a scalar network analyzer consisting of Signal Hound tracking generator TG44A and Signal Hound spectrum analyzerUSB-SA124B and a dielectric cell. The samples for recording the RF spectra are prepared in the laboratory by mixing five different constituents namely urea, potash, phoshate, salt and lime taken in the study in distilled water in different proportions. The spectra obtained are then passed through a multivariate system ported on FPGA for the estimation of an unknown concentration of urea in a sample. The multivariate analysis is done using Partial Least Square Regression (PLSR) technique and is implemented using SIMPLS algorithm developed in C. The results obtained show that the estimated values of urea have percentage error of around 5% which is acceptable. Even if the sample concentrations lie outside the confidence interval i.e CI, the estimated results are still satisfactory.

Grassmannian Codes With New Distance Measures for Network Coding

Grassmannian codes are known to be useful in error correction for random network coding. Recently, they were used to prove that vector network codes outperform scalar linear network codes, on multicast networks, with respect to the alphabet size. The multicast networks which were used for this purpose are generalized combination networks. In both the scalar and the vector network coding solutions, the subspace distance is used as the distance measure for the codes which solve the network coding problem in the generalized combination networks. In this paper, we show that the subspace distance can be replaced with two other possible distance measures which generalize the subspace distance. These two distance measures are shown to be equivalent under an orthogonal transformation. It is proved that the Grassmannian codes with the new distance measures generalize the Grassmannian codes with the subspace distance and the subspace designs with the strength of the design. Furthermore, optimal Grassmannian codes with the new distance measures have minimal requirements for the network coding solutions of some generalized combination networks. The coding problems related to these two distance measures, especially with respect to network coding, are discussed. Finally, by using these new concepts, it is proved that the codes in the Hamming scheme form a subfamily of the Grassmannian codes.

Alterations in White Matter Microstructure and Connectivity in Young Adults with Alcohol Use Disorder.

Magnetic resonance imaging (MRI) studies have shown differences in volume and structure in the brains of individuals with alcohol use disorder (AUD). Most research has focused on neuropathological effects of alcohol that appear after years of chronic alcohol misuse. However, few studies have investigated white matter (WM) microstructure and diffusion MRI-based (DWI) connectivity during early stages of AUD. Therefore, the goal of this work was to investigate WM integrity and structural connectivity in emerging adulthood AUD subjects using both conventional DWI metrics and a novel connectomics approach. Twenty-two AUD and 18 controls (CON) underwent anatomic and diffusion MRI. Outcome measures were scalar diffusion metrics and structural network connectomes. Tract-Based Spatial Statistics was used to investigate group differences in diffusion measures. Structural connectomes were used as input into a community structure procedure to obtain a coclassification index matrix (an indicator of community association strength) for each subject. Differences in coclassification and structural connectivity (indexed by streamline density) were assessed via the Network Based Statistics Toolbox. AUD had higher fractional anisotropy (FA) values throughout the major WM tracts, but also had lower FA values in WM tracts in the cerebellum and right insula (pTFCE <0.05). Mean diffusivity was generally lower in the AUD group (pTFCE <0.05). AUD had lower coclassification of nodes between ventral attention and default mode networks and higher coclassification between nodes of visual, default mode, and somatomotor networks. Additionally, AUD had higher fiber density between an adjacent pair of nodes within the default mode network. Our results indicate that emerging adulthood AUD subjects may have differential patterns of FA and distinct differences in structural connectomes compared with CON. These data suggest that such alterations in microstructure and structural connectivity may uniquely characterize early stages of AUD and/or a predisposition for development of AUD.

Unsteady aerodynamic modeling based on fuzzy scalar radial basis function neural networks

In this paper, a fuzzy scalar radial basis function neural network is proposed, in order to overcome the limitation of traditional aerodynamic reduced-order models having difficulty in adapting to input variables with different orders of magnitude. This network is a combination of fuzzy rules and standard radial basis function neural network, and all the basis functions are defined as scalar basis functions. The use of scalar basis function will increase the flexibility of the model, thus enhancing the generalization capability on complex dynamic behaviors. Particle swarm optimization algorithm is used to find the optimal width of the scalar basis function. The constructed reduced-order models are used to model the unsteady aerodynamics of an airfoil in transonic flow. Results indicate that the proposed reduced-order models can capture the dynamic characteristics of lift coefficients at different reduced frequencies and amplitudes very accurately. Compared with the conventional reduced-order model based on recursive radial basis function neural network, the fuzzy scalar radial basis function neural network shows better generalization capability for different test cases with multiple normalization methods.

Better than Rician: modelling millimetre wave channels as two-wave with diffuse power

This contribution provides experimental evidence for the two-wave with diffuse power (TWDP) fading model. We have conducted two indoor millimetre wave measurement campaigns with directive horn antennas at both link ends. One horn antenna is mounted in a corner of our laboratory, while the other is steerable and scans azimuth and elevation. Our first measurement campaign is based on scalar network analysis with 7 GHz of bandwidth. Our second measurement campaign obtains magnitude and phase information; it is additionally sampled directionally at several positions in space. We apply Akaike’s information criterion to decide whether Rician fading sufficiently explains the data or the generalised TWDP fading model is necessary. Our results indicate that the TWDP fading hypothesis is favoured over Rician fading in situations where the steerable antenna is pointing towards reflecting objects or is slightly misaligned at line-of-sight. We demonstrate TWDP fading in several different domains, namely, frequency, space, and time.