scholarly journals OPERATION OF THE RADIOLOCATION ANGULAR SYSTEM IN THE CONDITIONS OF THE SIGNAL CREATED BY COHERENT SOURCES OF RADIATION FROM TWO SPOTS

Doklady BGUIR ◽  
2019 ◽  
pp. 22-29
Author(s):  
A. A. Dyatko ◽  
S. M. Kostromitski ◽  
P. N. Shumski ◽  
I. N. Davydenkо
Keyword(s):  
Radiation Pattern ◽  
Radiation Source ◽  
Initial Conditions ◽  
Angular Position ◽  
Antenna System ◽  
Stationary States ◽  
Angular Coordinate ◽  
Radiation Sources ◽  
Input Signals ◽  
The Given

The purpose of the work, the results of which are presented within the framework of the article, was to analyze the operation of the radar goniometer system under the conditions of a signal generated by coherent radiation sources from two points in space (cross-eye interference). To achieve the goal in the present work, a study was made of the dependence of the settings of the goniometric system on the ratio of the parameters of the cross-eye jammer and the angular coordinate meter itself. As a goniometric system, an angular coordinate meter was used, operating by the method of amplitude instantaneous signal comparison. The studies were carried out by the method of theoretical analysis of the influence of the radiation pattern parameters of the antenna system of the meter on the result of measuring the angular position of a virtual radiation source. As a result, an equation is obtained that relates the angular position of the virtual radiation source with the radiation pattern parameters of the antenna system of the meter, the shape of which was approximated by a gaussian curve. To illustrate the functioning of the goniometric system at specific values of the parameters supplied to its input signals, the method of mathematical modeling was used. Modeling was performed for the given parameters, which determine both the position of the radiation sources in space and the algorithm of operation of the angular coordinate meter. Based on the results obtained, it is shown that the angular coordinate meter has three stationary states corresponding to the position of the virtual radiation source in space. It is shown that only two of these states are stable. The latter means that, depending on the initial conditions, the angular coordinate meter can fix one of the two possible positions of the virtual radiation source in space. The scientific novelty of this work is to establish a relationship between the position of the virtual radiation source in space and the parameters of the angular coordinate meter.

A compact omnidirectional to directional frequency reconfigurable antenna for wireless sensor network applications

2021 ◽  
pp. 1-12
Author(s):  
Melvin Chamakalayil Jose ◽  
Radha Sankararajan ◽  
Balakrishnapillai Suseela Sreeja ◽  
Mohammed Gulam Nabi Alsath ◽  
Pratap Kumar
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Radiation Pattern ◽  
Antenna System ◽  
Wireless Sensor ◽  
Dual Band ◽  
Design Parameters ◽  
Pin Diodes ◽  
Band Frequency ◽  
Directional Radiation

Abstract In the proposed research paper, a novel compact, ultra-wideband electronically switchable dual-band omnidirectional to directional radiation pattern microstrip planar printed rectangular monopole antenna (PRMA) has been presented. The proposed antenna system has an optimum size of 0.26 λ0 × 0.28 λ0. A combination of radiators, reflectors, and two symmetrical grounds does place on the same layer of the rectangular microstrip PRMA. The frequency agility and the radiation pattern from omnidirectional to directional are achieved using two SMD PIN diodes (SMP1340-04LF). The directional radiation patterns with 180° phase shifts are achieved at the C-band frequency spectrum. The parametric study of the proposed antenna system was performed for different design parameters, and the antenna characteristics were analyzed. An antenna prototype is fabricated using the printed circuit board etching method by using RMI UV laser etching and cutting tools. The measurements of the proposed antenna are conducted in an anechoic chamber to validate the simulations. There are three states of operations due to two SMD PIN diodes being used in switching circuits. In state-I, the proposed antenna radiates at 6.185 GHz (5.275–6.6 75 GHz) in the Ф = 270° direction with a gain of 2.1 dBi, whereas in state-II, it radiates at 5.715 GHz (5.05–6.8 GHz) in the Ф = 90° direction with a gain of 2.1 dBi. In state-III, the antenna exhibits the X-band frequency with center frequency at 9.93 GHz (8.845–10.49 GHz), and the omnidirectional pattern offers a gain of 4.1 dBi. The features of the proposed antenna are suitable for high-speed wireless sensor network communication in industries such as chemical reactors in oil and gas and pharmaceuticals. It is also well suited for IoT and 5G-sub-6-GHz applications.

Radiation Pattern Antenna System Measurement

2021 ◽  
Author(s):  
Michal Dzuris ◽  
Norbert Grilli ◽  
Imrich Szolik ◽  
Jozef Hallon
Keyword(s):  
Radiation Pattern ◽  
Antenna System

scholarly journals Serial femtosecond and serial synchrotron crystallography yield data of equivalent quality: a systematic comparison

2020 ◽  
Author(s):  
P. Mehrabi ◽  
R. Bücker ◽  
G. Bourenkov ◽  
H.M. Ginn ◽  
D. von Stetten ◽  
...  
Keyword(s):  
Radiation Source ◽  
Room Temperature ◽  
Delivery Device ◽  
Analysis Software ◽  
Yield Data ◽  
Time Resolved ◽  
Systematic Comparison ◽  
Figures Of Merit ◽  
Radiation Sources ◽  
Data Statistics

AbstractFor the two proteins myoglobin (MB) and fluoroacetate dehalogenase (FAcD), we present a systematic comparison of crystallographic diffraction data collected by serial femtosecond (SFX) and serial synchrotron crystallography (SSX). To maximize comparability, we used the same batch of crystals, the same sample delivery device, as well as the same data analysis software. Overall figures of merit indicate that the data of both radiation sources are of equivalent quality. For both proteins reasonable data statistics can be obtained with approximately 5000 room temperature diffraction images irrespective of the radiation source. The direct comparability of SSX and SFX data indicates that diffraction quality is rather linked to the properties of the crystals than to the radiation source. Time-resolved experiments can therefore be conducted at the source that best matches the desired time-resolution.

On a Certain Class of Expanding Systems

2010 ◽  
Vol 17 (2) ◽  
pp. 299-306
Author(s):  
Adam Żuchowski
Keyword(s):  
Transfer Function ◽  
Input Signal ◽  
Initial Conditions ◽  
System Optimization ◽  
Gain Coefficient ◽  
Time Intervals ◽  
System Parameters ◽  
Linear Dynamic ◽  
Subsequent Time ◽  
Input Signals

On a Certain Class of Expanding Systems The interesting properties of a class of expanding systems are discussed. The operation of the considered systems can be described as follows: the input signal is processed by a linear dynamic converter in subsequent time intervals, each of them is equal to Ti. Processing starts at the moments n · Ti, always after zeroing of converter initial conditions. For smooth input signals and a given transfer function of the converter one can suitably choose Ti and the gain coefficient in order to realize the postulated linear operations on input signals, which is quite different comparing it to the operation realized by the converter. The errors of postulated operations are mainly caused by non-smooth components of the input signal. The principles for choice of system parameters and rules for system optimization are presented in the paper. The referring examples are attached too.

scholarly journals A Mathematical Model for Nipah Virus Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Assefa Denekew Zewdie ◽  
Sunita Gakkhar
Keyword(s):  
Virus Infection ◽  
Reproduction Number ◽  
Initial Conditions ◽  
Nipah Virus ◽  
Virus Transmission ◽  
Globally Asymptotically Stable ◽  
Dead Bodies ◽  
Manifold Theory ◽  
The Impact ◽  
The Given

It has been reported that unprotected contact with the dead bodies of infected individuals is a plausible way of Nipah virus transmission. An SIRD model is proposed in this paper to investigate the impact of unprotected contact with dead bodies of infected individuals before burial or cremation and their disposal rate on the dynamics of Nipah virus infection. The model is analyzed, and the reproduction number is computed. It is established that the disease-free state is globally asymptotically stable when the reproduction number is less than unity and unstable if it is greater than unity. By using the central manifold theory, we observe that the endemic equilibrium is locally stable near to unity. It is concluded that minimizing unsafe contact with the infected dead body and/or burial or cremation as fast as possible contributes positively. Further, the numerical simulations for the given choice of data and initial conditions illustrate that the endemic state is stable and the disease persists in the community when the reproduction number is greater than one.

scholarly journals A New Approach for Solving the Undamped Helmholtz Oscillator for the Given Arbitrary Initial Conditions and Its Physical Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Alvaro H. Salas S ◽  
Jairo E. Castillo H ◽  
Darin J. Mosquera P
Keyword(s):  
Differential Equation ◽  
Approximate Solution ◽  
Analytical Solution ◽  
Initial Conditions ◽  
Negative Ions ◽  
Nonlinear Problems ◽  
New Approach ◽  
Weierstrass Elliptic Function ◽  
Electronegative Plasma ◽  
The Given

In this paper, a new analytical solution to the undamped Helmholtz oscillator equation in terms of the Weierstrass elliptic function is reported. The solution is given for any arbitrary initial conditions. A comparison between our new solution and the numerical approximate solution using the Range Kutta approach is performed. We think that the methodology employed here may be useful in the study of several nonlinear problems described by a differential equation of the form z ″ = F z in the sense that z = z t . In this context, our solutions are applied to some physical applications such as the signal that can propagate in the LC series circuits. Also, these solutions were used to describe and investigate some oscillations in plasma physics such as oscillations in electronegative plasma with Maxwellian electrons and negative ions.

scholarly journals Ultralow Profile, Low Passive Intermodulation, and Super-Wideband Ceiling Mount Antennas for Cellular and Public Safety Distributed Antenna Systems

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2456
Author(s):  
Kok Jiunn Ng ◽  
Mohammad Tariqul Islam ◽  
Adam M. Alevy ◽  
Mohd. Fais Mansor
Keyword(s):  
Radiation Pattern ◽  
Public Safety ◽  
Ground Plane ◽  
Antenna System ◽  
Band Ratio ◽  
Antenna Performance ◽  
Distributed Antenna ◽  
Small Disc ◽  
Passive Intermodulation ◽  
Better Than

This paper presents an ultralow profile, low passive intermodulation (PIM), and super-wideband in-building ceiling mount antenna that covers both the cellular and public safety ultra high frequency (UHF) band for distributed antenna system (DAS) applications. The proposed antenna design utilizes a modified 2-D planar discone design concept that is miniaturized to fit into a small disc-shaped radome. The 2-D planar discone has an elliptical-shaped disc monopole and a bell-shaped ground plane, a stub at the shorting path, with asymmetrical structure and an additional proximity coupling patch to maximize the available electrical path to support the 350 MHz band range. The proposed design maximizes the radome area with a reduction of about 62% compared to similar concept type antennas. Besides, the proposed design exhibits an improved radiation pattern with null reduction compared to a typical dipole/monopole when lies at the horizontal plane. A prototype was manufactured to demonstrate the antenna performance. The VSWR and radiation pattern results agreed with the simulated results. The proposed antenna achieves a band ratio of 28.57:1 while covering a frequency range of 350–10000 MHz. The measured passive intermodulation levels are better than −150 dBc (2 × 20 Watts) for 350, 700 and 1920 MHz bands.

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