scholarly journals Infinite linear waveguide antenna array with metal-dielectric structures in the "floquet channel"

2020 ◽  
Vol 28 (1) ◽  
pp. 91-96
Author(s):  
V. M. Morozov ◽  
V. I. Magro ◽  
E. Yu. Trakhtman
Keyword(s):  
Antenna Array ◽  
Dielectric Coating ◽  
Reflection Coefficients ◽  
System Of Equations ◽  
Dielectric Structure ◽  
Near Zone ◽  
Incident Waves ◽  
Dielectric Structures ◽  
Infinite Linear

An electrodynamics calculation is performed for an infinite waveguide antenna array in the form of open ends of waveguides, in the near zone of which a metal-dielectric structure is located. This metal-dielectric structure is located in the "Floquet channels" and is a combination of a dielectric coating over the antenna array and horns. In this case, the horns are not a continuation of the waveguides, but are located at some distance from them. The space between the waveguides and the horns is filled with a dielectric. A system of equations that allows calculating the reflection coefficients of incident waves in waveguides is obtained.

scholarly journals AN ANTENNA BASED ON A HYBRID METAL–DIELECTRIC STRUCTURE

2021 ◽  
Vol 26 (3) ◽  
pp. 270-277
Author(s):  
D. V. Mayboroda ◽  
◽  
S. O. Pogarsky ◽  
Keyword(s):  
Standing Wave ◽  
Dielectric Waveguide ◽  
Periodic Sequence ◽  
Voltage Standing Wave Ratio ◽  
Dielectric Waveguides ◽  
Dielectric Structure ◽  
Frequency Range ◽  
Dielectric Plate ◽  
Frequency Selection ◽  
Near Zone

Purpose: Nowadays, in the millimeter frequency range, the dielectric waveguides of various modifications have certain advantages over the standard metal waveguides, primarily due to the possibility of creating functional units based on them. This is due to the relative simplicity and low cost of manufacturing the dielectric waveguides and functional units using them, the high degree of their integration with active elements, the use in their manufacture of different dielectrics and polymers with a wide range of material constants and a variety of mechanical properties (in particular, some materials have a significant flexibility). After making a series of physical experiments we have found the possibility of implementing the frequency selection and radiation into free space of electromagnetic waves by a hybrid metal-dielectric structure. Design/methodology/approach: The studied electrodynamic structure belongs to the class of hybrid metal-dielectric structures. It includes a modified inverted dielectric waveguide with a periodic sequence on the dielectric plate of fifteen dielectric rods with metallized coating on one of the faces placed outwards. The structure efficiency was estimated by the voltage standing-wave ratio (VSWR) values and power attenuation in the duct. The measurements were made with the reflectometer method. To estimate the degree of electromagnetic field concentration near the rod inhomogeneities in the near zone, the mobile probe method was used. The field structures were visualized with the method of isolines. Findings: The results of a series of experimental investigations showed the possibility of matching the structure with the external waveguides in the frequency range of 26.5-32.5 GHz with the voltage standing-wave ratio (VSWR) less than 1.8. The frequency dependence of attenuation is oscillatory with clearly expressed frequency ranges with small and large attenuation values. Moreover, the dependence is almost periodic, which is typical of periodic structures. The frequency response slope in the transition zones can be quite high and reach values of 41.26 dB/GHz. The degree of concentration of the electric field near the waveguide dielectric rod and the degree of excitation of the dielectric inhomogeneities was found by directly measured electric field strength in the near zone. Measurements of energy characteristics made under the short-circuit conditions for the main guide and in the mode of matched load of the main guide showed both the ability to control the polarization characteristics and the ability to change the appearance of the pattern and its orientation in space. Conclusions: It has been experimentally proven that a hybrid metal-dielectric structure, being a modified inverted dielectric waveguide with a periodic sequence on the dielectric plate of fifteen dielectric rods with metalized coating on one of the faces placed outwards, can be effectively integrated into a standard transmission line. It is found that this structure can be matched with the external circuits in a fairly wide frequency range. It is also found that in different frequency ranges this hybrid metal-dielectric structure shows the possibility of both efficient frequency selection and radiation in free space. Antenna measurements have shown the beam pattern shape controllability. Key words: inverted dielectric waveguide, periodic sequence, voltage standing-wave ratio (VSWR), attenuation, reflectometer method, mobile probe method, directivity pattern

scholarly journals ACCELERATING OF THE ELECTRONS OF ELECTRON BUNCHES IN A WAVEGUIDE LOADED DIELECTRIC STRUCTURE

2021 ◽  
pp. 67-71
Author(s):  
A.F. Linnik ◽  
I.N. Onishchenko ◽  
O.L. Omelayenko ◽  
V.I. Pristupa ◽  
G.V. Sotnikov ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Bunch Length ◽  
Dielectric Structure ◽  
Steady State Mode ◽  
Electron Bunches ◽  
Simple Physical Model ◽  
Wake Wave ◽  
The Difference ◽  
Wake Fields ◽  
Dielectric Structures

The paper presents some results of experimental studies of the excitation of wake fields and the acceleration of electrons in waveguide-dielectric structures (DS) upon injection of a sequence of electron bunches into them. Exper-iments have shown an increase in the amplitude of the wake wave and the acceleration of a small fraction of elec-trons when the wavelength of the excited field is equal to the doubled bunch length. A simple physical model of the observed phenomenon is given. Also, the paper proposes a method for accelerating a part of each electron bunch in the steady-state mode of the resonator dielectric structure. Some of the electrons are “cut out” by the collimator and enter the accelerating phase of the previously excited wake wave. The wave is displaced due to the difference in the distances traveled by the wave and the accelerated part of the electrons.

scholarly journals Virtual Antenna Array for Minimization of DOA Estimation Systematic Error Caused by Scattering of Incident Waves on Antenna Carrier Body

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 308
Author(s):  
Yuri G. Pasternak ◽  
Aleksander V. Ashikhmin ◽  
Yuri A. Rembovsky ◽  
Sergey M. Fedorov ◽  
Dmitry V. Zhuravlev
Keyword(s):  
Systematic Error ◽  
Antenna Array ◽  
A Priori ◽  
Doa Estimation ◽  
Antenna System ◽  
Resonant Frequencies ◽  
Quasistatic Approximation ◽  
Analytical Functions ◽  
Priori Information ◽  
Incident Waves

The Direction of Arrival (DOA) estimations of systematic errors are caused by diffraction distortions of the measured spatial structure of a electromagnetic field. These distortions result from scattering of incident waves on the antenna system and nearby scatterers (mobile carrier body, antenna mast, underlying surface, etc.) in wide frequency band, including the resonant frequencies of nearby objects. This article proposes a method for minimizing the DOA estimation systematic error by forming an additional virtual receiving channel—a Virtual Antenna Array (VAA). The VAAs were formed by use of classical apparatus of electrodynamics—the Huygens-Kirchhoff principle, the method of equivalent fields and sources, and the quasistatic approximation of the field based on the theory of analytical functions of the complex variable (Cauchy integral, Laurent series). The proposed method does not require calibration of the antenna system or a priori information about the geometry and material properties of the scatterers (dry or wet soil, opened or closed vehicle doors, etc.). Therefore, it gives good results in cases of mobile and stationary arrays, or changing carrier body geometry.

scholarly journals Calibration of Siberian Radioheliograph antenna gains using redundancy

2021 ◽  
Vol 7 (4) ◽  
pp. 104-110
Author(s):  
Mariia Globa ◽  
Sergey Lesovoi
Keyword(s):  
Antenna Array ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Dynamic Range ◽  
Special Care ◽  
System Of Equations ◽  
Signal To Noise ◽  
Double Step ◽  
Phase Calibration ◽  
High Dynamic

The paper describes application of standard gain calibration using redundancy for a 48-antenna prototype of Siberian Radioheliograph. Traditionally, for calibration, the visibilities were measured only between adjacent antennas since they have the highest signal-to-noise ratio and are sufficient for phase calibration. We have shown that this limited set of visibilities did not allow using the antenna array redundancy potential and obtaining images with a high dynamic range on a permanent basis. Images without amplitude calibration contain many artifacts and require special care when analyzed. The inclusion of visibility measurement between antennas with a double step made it possible to significantly increase the accuracy of solving the system of equations for amplitudes. Images constructed using both phase and amplitude calibrations do not have visible artifacts and are more reliable.

scholarly journals DIAGNOSTICS OF HEADLIGHTS FROM NEAR AREA ON PLACE OF BASING

2020 ◽  
Vol 3 (61) ◽  
pp. 124-127
Author(s):  
O. Besova ◽  
V. Karlov ◽  
O. Lukashuk ◽  
I. Petryshenko
Keyword(s):  
Antenna Array ◽  
Phased Array ◽  
Phase Distribution ◽  
Near Field ◽  
Operating Time ◽  
Array Antenna ◽  
Phased Array Antenna ◽  
Phased Antenna Array ◽  
Near Zone ◽  
Microwave Diagnostics

Methods of microwave diagnostics of a phased array allow reconstructing the amplitude-phase distribution in the antenna and implement on this basis methods for adapting the lattice control to those found in the amplitude-phase distribution to defects. The methods of microwave diagnostics from the near zone described in the well-known literature are realizable only in anechoic chambers or on specially equipped training grounds. To solve the problems of adapting a phased antenna array to a technical state and increasing its operating time under extreme conditions, it is necessary to have methods of integrated microwave diagnostics of a phased antenna array at its location. The aim of the article is to develop a method for microwave diagnostics of a phased array antenna, implemented from the near zone of the antenna at its location, and eliminating the influence of echo signals (ES) on the diagnostic results. The article proposes a method for microwave diagnostics of a phased array antenna from the near field, which allows to exclude the influence on the accuracy of diagnostics of the echo signal present at the measuring site and errors in the positioning of the measuring probe. The proposed method will make it possible to implement microwave diagnostics of the antenna from the near field at its location. The results of microwave diagnostics are supposed to be used to implement various methods of adapting a phased array to a technical condition, significantly increasing its life

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