scholarly journals RADIO SOURCE DIRECTION FINDING IN WIDE FREQUENCY BAND USING CIRCULAR ANTENNA ARRAY

2019 ◽  
pp. 30-40 ◽  
Author(s):  
Maya E. Shevchenko ◽  
Victor N. Malyshev ◽  
Dilara N. Fayzullina
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Elevation Angle ◽  
Field Studies ◽  
Direction Finding ◽  
Statistical Simulation ◽  
Wide Frequency Band ◽  
Direction Finder ◽  
Music Methods ◽  
Radio Systems

For the VHF broadband direction finder, coherent and incoherent direction finding algorithms for switched and non-switched connection of the antenna array (AR) to receiving device in single-signal and multi-signal direction finding modes are developed and investigated.Their synthesis is based on the methods of space-time theory of radio systems. Numerical calculation of the direction finding characteristics of the algorithms for different number of antenna array elements determines the operating range upper limiting frequency, in which this configuration provides single-value estimates of the azimuth and elevation angle. Statistical simulation modeling shows that for an odd number of antennas, the antenna array amplitudephase response is unique in a wider frequency band than for an even number of antennas. Due to this MUSIC based property applied in the space of antenna array elements, direction finding algorithm is developed for wide frequency band with several signals overlapping in frequency, with switched and non-switched AR connection to a radio receiver. It is shown that the use of ESPRIT and MUSIC methods in free-space diagram does not allow for direction finding in a wide frequency band with the antenna array fixed configuration. The results of the field studies of the developed algorithms are presented for the single-signal and multi-signal modes of operation, software and hardware implemented in the VHF radio direction finder. A comparative analysis of the developed algorithms with the known APs with fixed configuration is performed. It is shown that with the same AR configuration, it is the direction finding algorithm that determines the frequency range in which the direction finding is unique.

scholarly journals Interval and Point Direction Finding of Radio Emission Sources for Broadband Radio Monitoring

2020 ◽  
Vol 23 (6) ◽  
pp. 28-42
Author(s):  
M. E. Shevchenko ◽  
V. N. Malyshev ◽  
S. S. Sokolov ◽  
A. V. Gorovoy ◽  
S. N. Soloviev ◽  
...  
Keyword(s):  
Antenna Array ◽  
Elevation Angle ◽  
Direction Finding ◽  
Radio Monitoring ◽  
Point Estimates ◽  
Broadband Radio ◽  
Narrow Frequency Band ◽  
Signal Mode ◽  
Sample Interval ◽  
The Time Domain

Introduction. The point and interval direction finding of radio sources is used for broadband radio monitoring in the frequency domain. The initial data for broadband radio monitoring are spectral samples obtained from an M-element antenna array by multichannel reception. Point direction finding is based on a grouping of point estimates of azimuth and elevation angle formed for each frequency sample, in which signal components are detected. A single estimate of azimuth and elevation angle is made based on the grouped point estimates in the range of neighbouring frequency samples. Interval direction finding is based on the azimuth and elevation estimates formed entirely from the interval of adjacent frequency samples, in which the signal components are found, and the subsequent refinement of frequency sample interval boundaries for each radio source in multisignal mode by spatial selection methods. Point direction finding is mainly implemented in single-signal mode in modern operating broadband radio monitoring complexes, while the multi-signal mode based on MUSIC or ESPRIT is implemented in the time domain in a narrow frequency band.Aim. Development and investigation of methods for point and interval direction finding in multi-signal mode, as well as development of recommendations for their practical application in multi-signal and single-signal modes.Methods. Multi-signal mode for point and interval direction finding was implemented using MUSIC and ESPRIT. An experimental study of the developed direction finding methods in single-signal and multi-signal (on ESPRIT) modes with overlapping signal spectra was carried out by processing the recorded real signals. The records were made using a seven-channel coherent synchronous receiver connected to a seven-element 60° angle antenna array.Results. The research results are presented by frequency-azimuth panoramas and estimates of the amplitude spectra of separated signals and direction finding accuracy indicators.Conclusion. It was experimentally demonstrated that point direction finding should be used in single-signal mode provided the absence of information on the number of signals in the observed data. Interval direction finding is recom-mended in multi-signal mode for improving the accuracy and real-time feasibility of the process.

scholarly journals A New Design of a Wideband Miniature Antenna Array

2017 ◽  
Vol 7 (4) ◽  
pp. 1850
Author(s):  
Oulhaj Otman ◽  
Naima A. Touhami ◽  
Mohamed Aghoutane ◽  
Abdelmounaim Belbachir Kchairi
Keyword(s):  
Reflection Coefficient ◽  
Circular Polarization ◽  
Antenna Array ◽  
Frequency Band ◽  
Microstrip Antenna ◽  
Antenna Element ◽  
Wide Frequency Band ◽  
Microstrip Antenna Array ◽  
Miniature Antenna

In this work, we present a new configuration of a new miniature microstrip antenna array having a wide frequency band and with a circular polarization. The bandwidth is about 2GHz for a reflection coefficient under -10dB and centered on the ISM ‘Industrial Scientific Medical’ band at 5.8 GHz. To design such array, we have started the design by validating one antenna element at 10 GHz and after that by using the technique of defected ground, we have validated the antenna array in the frequency band [4 GHz -6 GHz] which will permit to miniature the dimensions. The final fabricated antenna array is mounted on an FR4 substrate, the whole area is 102.48 X 31.39 mm<sup>2</sup>  with a gain of 5dBi at 4GHz.

scholarly journals BUTLER MATRIX IN MICROSTRIP-SLOT TECHNOLOGY

2017 ◽  
Vol 5 (4) ◽  
pp. 268-273
Author(s):  
D. Rajeswari ◽  
T. Jayanthy
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Common Ground ◽  
Ground Plane ◽  
Butler Matrix ◽  
Wide Frequency Band ◽  
Electromagnetic Simulations ◽  
Full Wave ◽  
Dielectric Layers ◽  
The Matrix

The design of a 4 x 4 Butler Matrix for use in a multi-beam antenna array operating over wide frequency band is presented. In order to achieve wideband characteristics, the matrix uses microstrip-slot technology that employs two microstrip dielectric layers with a common ground plane and a coupling slot. The designed Butler matrix is compact in size and does not use crossovers. Its prototype is manufactured. The performance of the designed device is assessed via full-wave electromagnetic simulations and measurements.

scholarly journals Physical Principles of a Piezo Accelerometer Sensitive to a Nearly Constant Signal

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3258 ◽  
Author(s):  
Valery Gupalov ◽  
Alexander Kukaev ◽  
Sergey Shevchenko ◽  
Egor Shalymov ◽  
Vladimir Venediktov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Band ◽  
Linear Acceleration ◽  
High Sensitivity ◽  
Element Model ◽  
Wide Frequency Band ◽  
Piezoelectric Accelerometer ◽  
The Finite Element Model ◽  
Physical Principles

The paper considers the construction of a piezoelectric accelerometer capable of measuring constant linear acceleration. A number of designs are proposed that make it possible to achieve high sensitivity with small dimensions and a wide frequency band (from 10−5 Hz). The finite element model of the proposed design was investigated, and its output characteristic and scale factor (36 mV/g) were obtained.

scholarly journals Flexible ultrathin metamaterial absorber for wide frequency band, based on conductive fibers

2018 ◽  
Vol 19 (1) ◽  
pp. 711-717 ◽  
Author(s):  
Young Ju Kim ◽  
Ji Sub Hwang ◽  
Bui Xuan Khuyen ◽  
Bui Son Tung ◽  
Ki Won Kim ◽  
...  
Keyword(s):  
Frequency Band ◽  
Metamaterial Absorber ◽  
Wide Frequency Band ◽  
Conductive Fibers
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