BI-QUAD DUAL REFLECTOR ANTENNA FOR WLAN TASKS

2021 ◽  
pp. 47-50
Author(s):  
С.М. Фёдоров ◽  
Е.А. Ищенко ◽  
И.А. Баранников ◽  
К.А. Бердников ◽  
В.В. Кузнецова
Keyword(s):  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Copper Wire ◽  
Reflector Antenna ◽  
Free Flow ◽  
Frequency Range ◽  
Operating Frequency Range ◽  
Antenna Directivity ◽  
Dual Reflector Antenna ◽  
Open Position

Рассматривается двухрефлекторная Bi-Quad антенна, способная работать в диапазоне частот, соответствующих WLAN Wi-Fi 2,4 ГГц. Благодаря возможности управления положением рефлекторов удается добиться изменения направления излучения, что повышает эффективность использования антенны, коэффициент направленного действия. При управлении происходит поворот ячеек, из которых сформированы отражательные структуры, что позволяет пропускать электромагнитное излучение, которое формирует излучатель из медного провода в форме цифры «восемь». Предложенная конструкция позволяет обеспечить три стабильных режима работы антенны: двустороннее излучение, когда оба рефлектора в открытом положении, при таком режиме у антенны наблюдается одинаковое излучение в обоих направлениях с равным КНД; излучение вверх, в данном режиме верхний рефлектор открыт, что приводит к свободному протеканию электромагнитных волн, а от закрытого нижнего происходят отражения, в результате этого происходит увеличение КНД антенны по сравнению с ситуацией двустороннего излучения; аналогичная ситуация происходит при излучении вниз, когда открыт нижний рефлектор, так электромагнитные волны отражаются от закрытого верхнего рефлектора вниз, что приводит к увеличению КНД антенны. Предложенная конструкция обладает высокой эффективностью в диапазоне рабочих частот The article discusses a two-reflector Bi-Quad antenna capable of operating in the frequency range corresponding to WLAN Wi-Fi 2.4 GHz. Thanks to the ability to control the position of the reflectors, it is possible to achieve a change in the direction of radiation, which increases the efficiency of using the antenna, and increases the directivity. During control, the cells are rotated, from which the reflective structures are formed, which allows the transmission of electromagnetic radiation, which is formed by the emitter, formed from a copper wire in the shape of the number "eight". The proposed design makes it possible to provide three stable modes of antenna operation: double-sided radiation, when both reflectors are in the open position, in this mode the antenna has the same radiation in both directions with equal directivity; radiation upward, in this mode, the upper reflector is open, which leads to free flow of electromagnetic waves, and reflections occur from the closed lower reflector, as a result of this, the antenna directivity increases in comparison with the situation of two-sided radiation. A similar situation occurs when radiating downward, when the lower reflector is open, so electromagnetic waves are reflected from the closed upper reflector downward, which leads to an increase in the antenna directivity. The proposed design is highly efficient in the operating frequency range

FORMATION OF A SCANNING ANTENNA BASED ON A HALF-WAVE DIPOLE

2021 ◽  
pp. 20-24
Author(s):  
С.М. Фёдоров ◽  
Е.А. Ищенко ◽  
И.А. Баранников ◽  
К.А. Бердников ◽  
В.В. Кузнецова
Keyword(s):  
Short Distance ◽  
Electromagnetic Waves ◽  
High Stability ◽  
Frequency Range ◽  
Current Position ◽  
Form Complex ◽  
Operating Frequency Range ◽  
Half Wave ◽  
Focus Radiation ◽  
Antenna Systems

Рассматривается полуволновый диполь с установленным рефлектором, который позволяет производить сканирование пространства с использованием вращения рефлектора вокруг диполя. Для полученной конструкции производилось моделирование основных параметров, которые показали высокую стабильность при различных положениях рефлектора, постоянное значение коэффициента направленного действия, ширины главного лепестка. Изменение направления излучения совпадает с текущим положением рефлектора. По сравнению с ситуацией, когда у антенны отсутствовал рефлектор, КНД антенны увеличился, так как произошла фокусировка электромагнитных волн. Коэффициент полезного действия и передне-заднее отношение сохраняют высокие значения во всем диапазоне рабочих частот. Применение предложенной конструкции позволяет упростить конструкцию сканирующих антенн, так как для ее реализации требуются лишь полуволновой диполь и плоский рефлектор, установленный на малом расстоянии от источника излучения. В процессе управления характеристиками требуется вращать рефлектор вокруг диполя, при этом диполь остается неподвижным, что позволяет повысить эффективность предложенной конструкции, так как не требуется формировать сложных антенных систем или устанавливать комбинацию из нескольких антенн для фокусировки излучения в одном направлении от источника The article discusses a half-wave dipole with an installed reflector, which allows scanning space using the rotation of the reflector around the dipole. For the resulting structure, we simulated the main parameters, which showed high stability at various positions of the reflector, a constant value of the directivity factor, and the width of the main lobe. The change in the direction of radiation coincides with the current position of the reflector. Compared to the situation when the antenna did not have a reflector, the directivity of the antenna increased since the focusing of electromagnetic waves took place. The efficiency and the front-to-back ratio remain high throughout the entire operating frequency range. The use of the proposed design makes it possible to simplify the design of scanning antennas since the implementation of the proposed design requires only a half-wave dipole and a flat reflector installed at a short distance from the radiation source. In the process of controlling the characteristics, it is required to rotate the reflector around the dipole, while the dipole remains stationary, which makes it possible to increase the efficiency of the proposed design, since it is not required to form complex antenna systems or install a combination of several antennas to focus radiation in one direction from the source

scholarly journals Influence of water content of expanded clay on the reflection coefficient of electromagnetic shild

2021 ◽  
Vol 66 (1) ◽  
pp. 93-100
Author(s):  
T. V. Borbot’ko ◽  
S. E. Savanovich
Keyword(s):  
Reflection Coefficient ◽  
Moisture Content ◽  
Electromagnetic Radiation ◽  
Pore Size ◽  
Operating Frequency ◽  
Reflection Coefficients ◽  
Frequency Range ◽  
Operating Frequency Range ◽  
Influence Of Water ◽  
The Relationship

The regularities of the influence of the moisture content of expanded clay on the values of the reflection coefficient of electromagnetic radiation (EMR) of this material in the frequency range of 1–17 GHz have been established. The relationship between the size of fractions (pore size) of expanded clay and the operating frequency range of the EMR screen samples has been determined. It is shown that a twofold increase in the moisture content of expanded clay with fractions of 1…4 and 10…20 mm provides an extension of the operating frequency range of the EMR shield samples made on the basis of this material, with a decrease in the reflection coefficient of the test samples by 1.7 and 3 times, respectively. It was found that an increase in the moisture content of expanded clay from 19 to 40 % with a decrease in the size of its fractions from 10…20 to 1…4 mm and a pore size from 0.1…0.2 to 0.01…0.06 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 7.7–17.0 GHz, and an increase in the size of expanded clay fractions from 1…4 to 10…20 mm with an increase in the size of its pores from 0.01…0.06 to 0.1…0.2 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 1.0–7.7 GHz. It is shown that the practical use of these regularities makes it possible to form EMR screen samples with reflection coefficients from –2.8 to –22.0 dB in the frequency range 1–17 GHz, which makes it possible to recommend them for use when creating shielded rooms.

scholarly journals DOES ENHANCED ELECTROMAGNETIC RADIATION DISTURB HONEYBEES’ BEHAVIOUR? OBSERVATIONS DURING NEW YEAR’S EVE 2019

2020 ◽  
Vol 8 (11) ◽  
pp. 7-14
Author(s):  
Daniel Favre ◽  
Olle Johansson
Keyword(s):  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Wide Frequency Range ◽  
Global Network ◽  
Limited Attention ◽  
Frequency Range ◽  
Acoustic Behaviour ◽  
Major Threat ◽  
New Year’S Eve

Insects, and especially honeybees, are under major threat everywhere around the globe. Current studies lack in the consideration of potential effects which may directly affect other organisms or ecosystems, because of the very limited attention which is usually received by the potential adverse ecological effects of radiofrequency electromagnetic fields. Here, it is hypothesized that planetary enhancement of electromagnetic radiation produces a disturbing pollution for honeybees. In order to test this hypothesis, a bi-directional wide frequency range microphone was placed during the New Year’s Eve night 2019 in a honeybee hive, in order to detect and analyze potential changes in the acoustic behaviour of the bees due to increased phone induced RF- EM radiation. It was observed that the honeybees produced strong worker piping signals. Such signals are typically produced shortly before takeoff of a swarm, or as the sign of a disturbed colony. It is therefore hypothesized that planetary enhancement of electromagnetic radiation produces a disturbing pollution for honeybees, such as during the New Year’s Eve night. Evidence of proof of such electromagnetic waves taking place at New Year's Eve should be investigated worldwide during forthcoming similar events based on a global network of long term EM measurements.

scholarly journals The prospects for the application of the electromagnetic waves in the terahertz frequency range for the purpose of physiotherapy (a retrospective review)

2016 ◽  
Vol 15 (4) ◽  
pp. 209-215
Author(s):  
Vera Vasil’evna Kir’yanova ◽  
E. N Zharova ◽  
N. T Bagraev ◽  
A. S Reukov ◽  
S. V Loginova
Keyword(s):  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Biological Effects ◽  
Physical Factor ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Vital Activity ◽  
Terahertz Frequency Range ◽  
High Biological Activity ◽  
Neurological Conditions

This review of the literature publications is focused on the articles in domestic and foreign editions devoted to the research on biological effects of electromagnetic radiation in the terahertz (THz) frequency range. It makes use of the Scopus, Web of Science, MedLine, RSCI, and other databases containing the relevant references for the period from 1970 up to the present days. This physical factor has found application in the Russian physiotherapeutic practice not very long ago. The main areas of its application include cardiovascular disease and neurological conditions. At the same time. the influence of electromagnetic radiation in the terahertz frequency range on human health and vital activity remains virtually unexplored. The available publications give evidence of the high biological activity of the terahertz electromagnetic waves which suggests the necessity of their further investigation.

The working standard of the unit of power of electromagnetic waves in the frequency range from 37,5 to 220 GHz

2020 ◽  
pp. 53-58
Author(s):  
A. V. Koudelny ◽  
I. M. Malay ◽  
V. A. Perepelkin ◽  
I. P. Chirkov
Keyword(s):  
Microwave Power ◽  
Electromagnetic Waves ◽  
Primary Standard ◽  
The State ◽  
Frequency Range ◽  
Working Standard ◽  
Extended Frequency Range ◽  
Effective Efficiency ◽  
Extended Frequency ◽  
Good Agreement

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.

Gradient structures of Ni – Zn ferrites for electromagnetic radiation protection devices

2021 ◽  
Vol 5 ◽  
pp. 39-46
Author(s):  
V. V. Karanskij ◽  
◽  
S. V. Smirnov ◽  
A. S. Klimov ◽  
E. V. Savruk ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electromagnetic Radiation ◽  
Radiation Protection ◽  
Electromagnetic Compatibility ◽  
Protective Coatings ◽  
Frequency Range ◽  
Near Surface ◽  
Zn Ferrite ◽  
Absorbing Materials ◽  
Plasma Electronic

Increasing the reliability requirements for electromagnetic compatibility of electronic equipment requires the creation of protective coatings that absorb electromagnetic radiation or the development of new radio-absorbing materials. In the frequency range up to 1 GHz, radio-absorbing materials based on Ni – Zn ferrites are of the greatest interest. The absorption of electromagnetic radiation by ferrites occurs due to resonant phenomena at the level of domains and atoms. Improving the performance of ferrites is possible by modifying their surface properties. In this paper, gradient structures for electromagnetic radiation protection products are obtained by treating the surface of Ni – Zn ferrite samples with a low-energy electron beam. To generate the electron beam, a unique development was used — a forevacuum plasma electronic source that allows forming and transporting a beam with a power density of up to 105 W/cm2 under conditions of high pressure and high gas release. As a result of processing, gradient structures were found on the surface of ferrites. A theoretical analysis and experimental study of the obtained structures “non – magnetic conductor – ferrite”, characterized by an increased attenuation coefficient and a reduced reflection coefficient of electromagnetic radiation in the frequency range from 0.5 to 2.5 GHz. The possibility of obtaining near-surface layers depleted in zinc with increased electrical conductivity and reduced magnetic permeability is shown.

scholarly journals Design of Broadband Compact Canonical Triple-Sleeve Antenna Operating in UHF Band

2021 ◽  
Vol 21 (4) ◽  
pp. 291-298
Author(s):  
Chandana SaiRam ◽  
Damera Vakula ◽  
Mada Chakravarthy
Keyword(s):  
Wireless Communication ◽  
Instantaneous Frequency ◽  
Dipole Antenna ◽  
Frequency Range ◽  
Broadband Antenna ◽  
Operating Frequency Range ◽  
Half Wave ◽  
Measurement Results ◽  
Antenna Configuration ◽  
Good Agreement

In this paper, a novel compact broadband antenna at UHF frequencies is presented with canonical shapes. Hemispherical, conical and cylindrical shapes have all been considered for antenna configuration. The designed antenna provides an instantaneous frequency range from 370 to 5,000 MHz with omnidirectional characteristics. The antenna was simulated in CST Microwave Studio, fabricated and evaluated; the results are presented. The simulated and measurement results are in good agreement. The antenna has voltage standing wave ratio (VSWR) ≤ 1.9:1 in 400–570 MHz, 2,530–3,740 MHz and 4,180–4,620 MHz; it has VSWR ≤ 3:1 over the operating frequency range 370–5,000 MHz and the measured gain varies from -0.6 to 4.5 dBi over the frequency band. The concept of canonical-shaped antenna elements and the incorporation of triple sleeves resulted in a reduction of the length of the antenna by 62% compared to the length of a half-wave dipole antenna designed at the lowest frequency. The antenna can be used for trans-receiving applications in wireless communication.

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