Design and analysis of 1-to-4 Wilkinson power divider for antenna array feeding network

In this paper, A Novel 1 to 4 modified Wilkinson power divider operating over the frequency range of (3 GHz to 8 GHz) is proposed. The design perception of the proposed divider based on two different stages and printed on FR4 (Epoxy laminate material) with the thickness of 1.57mm and ϵr =4.3 respectively. The modified design of this power divider including curved corners instead of the sharp edges and some modification in the length of matching stubs. In addition, this paper contain the power divider with equal power split at all ports, reasonable insertion loss, acceptable return loss below -10 dB, good impedance matching at all ports and satisfactory isolation performance has been obtained over the mentioned frequency range. The design concept and optimization development is practicable through CST simulation software

Design an ultra-wideband modified wilkinson power divider fed-by balanced antipodal vivaldi antenna array for imaging applications

In this paper, design of compact and modified geometrical structure of 1-to-4 way ultra-wideband Wilkinson power divider used as a feeding network for 4-element of balanced antipodal Vivaldi antenna (BAVA) array has introduced. The proposed Wilkinson power divider has been designed and printed on low-cost Epoxy laminate substrate FR4 along with the thickness of 1.6mm and relative permittivity of ɛr =4.3 respectively. The transformation of power divider network which are based on bent corners as a replacement of sharp corners or edges used for the decrement in unintended radiation and employing a single radial stub on each branch to encounter the antenna-specifications. Further some adjustments in the dimension of stubs matching in order to increase the reflection of the power divider network. The design presents the model of a power divider and maintains an equal power splitting at different ports with practical insertion loss and conventional return loss below -10dB. The reasonable impedance matching has achieved at every single port with acceptable isolation performance values over the (3-to-10 GHz) frequency range. The divider as well as antenna elements design and its optimization are practicable via computer simulation technology (CST) simulation software. The experimental results are revealed to encounter the array-specifications under ultra-wideband frequency range

Design and parametric evaluation of UWB antenna for array arrangement

This paper has introduced the concept of UWB antenna in array arrangements. The four elements of Balance Antipodal Vivaldi Antenna (BAVA) has been used for planar and H-plane array configuration in this research. Each single element of BAVA Antenna is printed on the glass-reinforced epoxy laminate material (FR4) along an overall thickness of 1.57mm and εr=4.3 respectively. The optimized measurement of each particular element is 60.75mm x 66mm approximatel. Further the parametric evaluation of four BAVA elements in different planes has been observed in this paper. The placement of array elements has almost coverd entire UWB frequency range and appropriate reflection coefficient which is better than -10dB has been established in both combinations. According to simulation results, the array elements in planar arrangement presenting a suitable reflection and works well at 3.2GHz frequency while the arrangement in H-plane the array elements works well at 7GHz of frequency. In planar arrangement, the operating frequency of antenna elements is shifting as results of the distance among inter elements which increase in wavelength. In H-plane arrangement an antenna elements generate additional gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The CSTMWS simulation software has been used for antenna structural design and parametric verification

Comparative analysis of UWB balance Antipodal Vivaldi Antenna for array configuration

In this paper, an Ultra-wideband Balance Antipodal Vivaldi Antenna in planar and h-plane array configuration is presented. The comparison of four elements of BAVA array in both planes has been observed. Each element of an antenna printed on the glass-reinforced epoxy laminate material (FR4) with a thickness of 1.5mm and relative permittivity of 4.3. The dimension of every single element is 60.75mm x 66mm approximately. The array elements of both planes almost cover the whole UWB frequency range with the reflection coefficient of -10dB. Based on the simulation results, the array elements in planar configuration showing good reflection and works well at 3.2GHz frequency while the configuration in h-plane the array elements works well at 7GHz of frequency. In planar configuration, the operating frequency of antenna elements is shifting as a result of the distance between inter elements which intensification in wavelength. The array elements in h-plane produce more gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The antenna design and optimization development are verified using CST simulation software

UWB antenna based time-domain approach for through the walls gap estimation

This paper has introduced a novel experimental system adopted a time domain approach for estimating through wall distance and recognizes buried objects behind the wall. The designed and fabricated balanced antipodal Vivaldi antenna (BAVA) has been used for the development of UWB system. The working mechanism of an intended detection system based on time domain reflectometry (TDR) and ground-penetrating radar (GPR). A miniature pulse in the UWB range is generated by the vector network analyzer (VNA) to irradiate a barrier made of two walls separated by airgap between them. The signal radiations reflect partially from the front wall while remaining goes through for getting reflected from the rear wall. The VNA is used for measuring the time interval passed between the instant when an incident signal irradiates the first wall and the instant when the incident signal gets reflected from the rear wall. The investigational process of a system is carried out by UWB antenna probe. The detected information is attained using the values of reflection coefficient (S 11 ) represented in time domain measurements. Experimental results have been proved the ability to detect wall gap as well as the width estimation between two walls with high accuracy. The maximum percentage error has been found to not exceeding 4.5% in the worst condition

Ultra-wideband antipodal vivaldi antenna for radar and microwave imaging application

In this an ultra-wideband antipodal Vivaldi antenna among end fire radiation patterns function at UWB (3.1 GHz to 10.6 GHz) frequency range for radar and microwave imaging application is proposed. This article presents the designing of two different types of antipodal Vivaldi antennas. First is conventional and second is modified antipodal Vivaldi antenna. This paper presents a parametric analysis of each antenna. While designing the proposed antennas, originally a conventional antipodal Vivaldi antenna is presented for wide impedance bandwidth performance assessment. Further, the Vivaldi antenna is modified by incorporating corrugations on the edges which results in gain significantly along with increased directivity in the low frequency band. In addition, the antenna offers high gain and flat gain in the operating UWB band. The design and optimization process is carried out using the CST simulation software for performance assessment of parameters of return loss, radiation pattern, directivity and input impedance. Prototypes of two different proposed antennas are fabricated and tested for its return loss and directional pattern

Computer Vision for Substrate Detection in High‐Throughput Biomaterial Screens Using Bright‐Field Microscopy

High-throughput screening (HTS) can be used when ab initio information is unavailable for rational design of new materials, generating data on properties such as chemistry and topography that control cell behavior. Biomaterial screens are typically fabricated as microarrays or “chips,” seeded with the cell type of interest, then phenotyped using immunocytochemistry and high-content imaging, generating vast quantities of image data. Typically, analysis is only performed on fluorescent cell images as it is relatively simple to automate through intensity thresholding of cellular features. Automated analysis of bright-field images is rarely performed as it presents an automation challenge as segmentation thresholds that work in all images cannot be defined. This limits the biological insight as cell response cannot be correlated to specifics of the biomaterial feature (e.g., shape, size) as these features are not visible on fluorescence images. Computer Vision aims to digitize tasks humans do by sight, such as identify objects by their shape. Herein, two case studies demonstrate how open-source approaches, (region-based convolutional neural network and algorithmic [OpenCV]), can be integrated into cell-biomaterial HTS analysis to automate bright-field segmentation across thousands of images, allowing rapid, spatial definition of biomaterial features during cell analysis for the first time

An interdisciplinary framework for Islamic cognitive theories

The Islamic psychology (IP) community in Europe has recently witnessed a heated debate about the credentials required to participate in the theoretical substantiation of IP and Islamically integrated psychotherapy and counseling. This debate has provided convenient circumstances for Muslim psychologists and Islamic scholars alike to rethink their roles within the flourishing movement. Specifically, the discussions hint toward the importance of adopting a collaborative research methodology for IP, in particular for basic research. The methodology of choice will need to define the necessary qualifications and responsibilities of scholars and psychologists in a collaborative research process (personal collaboration) and evince its capability to appropriately marry knowledge and data, diverging research methods, and perspectives, concepts, and theories from Islamic studies and contemporary psychology (content-related collaboration). Here, we devise and offer a case illustration of an Islamic Psychology Basic Research Framework (coined the SALAAM Framework). This framework uses the Institute for Interdisciplinary Studies (IIS) Model of Interdisciplinary Research, developed by the IIS at the University of Amsterdam. Our first aim is to appropriate the IIS model for the IP literature by applying the model's research process phases and technique for the integration of disparate bodies of knowledge—that is, the identification of common ground—to methodological approaches in the contemporary IP literature. Our second aim is to exemplify the devised SALAAM Framework using the relatively unexplored area of Islamic cognitive theories (ICTs), which remain underdeveloped in contemporary psychological literature, primarily because of a lack of commensurability with the nomenclature of contemporary psychology. We thus provide a primer on the potential scope of ICTs. Toward the end of this article, we discuss the potential of the project of interdisciplinary construction of Islamic psychological theory, and the ability of the SALAAM Framework to establish a research program in IP that centers on cognition. We finally offer our reflections on the distinctiveness of Islamic psychologies in comparison to mainstream and Christian psychology.Q4WOS:0004589189000062-s2.0-8506156876

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially