Electromagnetic Waves Attenuation due to Rain: A Prediction Model for Terrestrial or L.O.S SHF and EHF Radio Communication Links

2009 ◽  
Vol 30 (6) ◽  
pp. 622-632 ◽  
Author(s):  
Fidèle Moupfouma
Keyword(s):  
Prediction Model ◽  
Electromagnetic Waves ◽  
Radio Communication ◽  
Communication Links

scholarly journals Rain Attenuation Prediction Model for Lagos at Millimeter Wave Bands

2014 ◽  
Vol 31 (3) ◽  
pp. 639-646 ◽  
Author(s):  
Abayomi Isiaka Yussuff ◽  
Nor Hisham Haji Khamis
Keyword(s):  
Prediction Model ◽  
Millimeter Wave ◽  
Prediction Models ◽  
Percentage Error ◽  
Radio Communication ◽  
Southwestern Nigeria ◽  
Coastal Station ◽  
International Telecommunication Union ◽  
Proposed Model ◽  
X Band

Abstract Lagos, Nigeria (6.35°N, 3.2°E), is a coastal station in the rain forest area of southwestern Nigeria with an altitude of 38 m. Since most communication now takes place above the X band because of congestion of lower bands, it was necessary to look into ways of maximizing X-band usage. There are inadequate data for use in rain propagation studies at microwave frequencies, and even less so at millimeter wave bands where most of the signal depolarization and fading has been discovered to exist. The proposed model is a modification of the International Telecommunication Union–Radio Communication Sector (ITU-R) model combined with locally obtained regression coefficients for estimating specific attenuation as proposed by G. Olalere Ajayi. The Dissanayake, Allnutt, and Haidara (DAH), Simple Attenuation Model (SAM), and ITU-R attenuation prediction models were investigated along with the proposed model. The ITU-R model was observed to produce the best results at 40 GHz, with percentage error values of 0.61%, 0.55%, and 0.49% at 0.1%, 0.01%, and 0.001% of the time, respectively. In comparison, the proposed prediction model showed good performance at 20-GHz down-link frequency, with percentage error values of 3.6%, 3.3%, and 2.9% at 0.1%, 0.01%, and 0.001% of the time, respectively. The obtained results also showed good agreement with other similar works in the open literature. The results presented in this work are valuable for the design and planning of a satellite link in the tropical regions.

scholarly journals Development of Broadband Underwater Radio Communication for Application in Unmanned Underwater Vehicles

2020 ◽  
Vol 8 (5) ◽  
pp. 370
Author(s):  
Igor Smolyaninov ◽  
Quirino Balzano ◽  
Dendy Young
Keyword(s):  
Electromagnetic Waves ◽  
Impedance Matching ◽  
Underwater Vehicles ◽  
Skin Depth ◽  
Radio Communication ◽  
Propagation Length ◽  
Unmanned Underwater Vehicles ◽  
Communication Technique ◽  
Surface Electromagnetic Waves ◽  
Small Form Factor

This paper presents several novel designs of small form factor underwater radio antennas operating in the 2 MHz, 50 MHz and 2.4 GHz bands. These antennas efficiently excite surface electromagnetic waves (SEW) which propagate along the surface of seawater. The antenna operation is made possible due to implementation of an impedance matching enclosure, which is filled with de-ionized water. Enhanced coupling to surface electromagnetic waves is enabled by the enhancement of the electromagnetic field at the antenna apex. These features allow us to make antenna dimensions considerably smaller compared to typical free space designs. They also considerably improve coupling of electromagnetic energy to the surrounding seawater. Since SEW propagation length is considerably larger than the skin depth in seawater, this technique is useful for underwater broadband wireless communication. We conclude that the developed broadband underwater radio communication technique will be useful in networking of unmanned underwater vehicles.

scholarly journals Software Define Radio System for HF Noise Measurements

2017 ◽  
Vol 23 (3) ◽  
pp. 18-23
Author(s):  
Iulian Bouleanu ◽  
Vlad-Cosmin Vasile
Keyword(s):  
Time Spectrum ◽  
Radio Communication ◽  
Radio System ◽  
Different Types ◽  
Communication Links ◽  
Lightning Impulse ◽  
Noise Measurements ◽  
Radio Communication System ◽  
Technical Solutions ◽  
Reference Document

AbstractAccurate noise estimation in the HF band is a defining aspect in the evaluation of SNR for communication links. The reference document that specifies how different types of electromagnetic noise can be taken into account by radio communication system planners is the ITU-R Recommendation P.372.Meanwhile a series of studies have demonstrated that Gaussian noise in the HF band is not always valid because this band noise is strongly affected by atmospheric emission sources such as lightning impulse. This leads to the idea that a distribution suited to express the noise variance is the Bi-Kappa distribution. In addition, over the past decade, SDR devices and real-time spectrum analysers, which can be used to evaluate this noise, have registered explosive growth. This article indicates technical solutions and procedures used to estimate the noise level in the HF subband which can be used for Near Vertical Incidence Skywave (NVIS) communications and proposes a measurement system based on a SDR solution which meets these requirements.

scholarly journals Issues with Modeling a Tunnel Communication Channel through a Plasma Sheath

Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 398
Author(s):  
Anna V. Bogatskaya ◽  
Andrey E. Schegolev ◽  
Nikolay V. Klenov ◽  
Evgeniy M. Lobov ◽  
Maxim V. Tereshonok ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Communication Channel ◽  
Plasma Layer ◽  
Solid Angle ◽  
Protective Layer ◽  
Antenna System ◽  
Plasma Sheath ◽  
Channel Noise ◽  
Radio Communication ◽  
Ionized Gas

We consider two of the most relevant problems that arise when modeling the properties of a tunnel radio communication channel through a plasma layer. First, we studied the case of the oblique incidence of electromagnetic waves on a layer of ionized gas for two wave polarizations. The resonator parameters that provide signal reception at a wide solid angle were found. We also took into account the unavoidable presence of a protective layer between the plasma and the resonator, as well as the conducting elements of the antenna system in the dielectric itself. This provides the first complete simulation for a tunnel communication channel. Noise immunity and communication range studies were conducted for a prospective spacecraft radio line.

APPLICATION OF PLASMA ANTENNA TECHNOLOGY TO IMPROVE RADIO COMMUNICATION STEALTH IN VHF BAND

2022 ◽  
pp. 76-80
Author(s):  
И.А. Баранников ◽  
Е.А. Ищенко ◽  
С.М. Фёдоров
Keyword(s):  
Electromagnetic Waves ◽  
Dipole Antenna ◽  
Plasma Cloud ◽  
Radio Communication ◽  
Dipole Antennas ◽  
High Radiation ◽  
Plasma Antenna ◽  
Equivalent Dipole ◽  
Conductive Surface ◽  
Electrodynamic Modeling

Рассматривается плазменная вибраторная антенна, которая предназначена для работы в VHF диапазоне на частоте 140 МГц. Вибраторные плазменные антенны отличаются от обычных вибраторных антенн тем, что металлический проводник заменяется плазмой в газоразрядной трубке. Плазменный вибратор, создаваемый разрядом в трубке, способен включаться и выключаться за время порядка микросекунд. Применение плазменной антенны позволяет обеспечить два режима работы: активный, когда плазма индуцирует проводящую поверхность, и скрытый, когда антенна становится практически невидимой для электромагнитных волн, а плазменное облако отсутствует. Для определения характеристик антенны использовалось электродинамическое моделирование. Полученные результаты показывают, что характеристики плазменной вибраторной антенны близки к характеристикам эквивалентного ей металлического диполя, при этом длина плазменной антенны меньше. Для определения эффективности скрытного режима антенны производилось сравнение характеристик эффективной площади рассеяния плазменной антенны с выключенным плазменным облаком и эквивалентного металлического диполя. Полученные результаты показывают, что плазменная антенна обладает высокой эффективностью излучения, диаграммами направленности, схожими с эквивалентной дипольной антенной, и значительно меньшими значениями эффективной площади рассеяния (ЭПР) в выключенном режиме The article discusses a plasma dipole antenna, which is designed to operate in the VHF band at a frequency of 140 MHz. Plasma dipole antennas differ from conventional dipole antennas in that the metal conductor is replaced by plasma in the discharge tube. The plasma dipole created by the discharge in the tube is capable of turning on and off in times of the order of microseconds. The use of a plasma antenna makes it possible to provide two modes of operation: active, when the plasma induces a conductive surface, and hidden, when the antenna becomes practically invisible to electromagnetic waves, and the plasma cloud is absent. We used electrodynamic modeling to determine the characteristics of the antenna. The results show that the characteristics of the plasma dipole antenna are close to those of the equivalent metal dipole, while the length of the plasma antenna is shorter. To determine the efficiency of the hidden mode of the antenna, we compared the characteristics of radar cross-section of the plasma antenna with the plasma cloud turned off and the equivalent metal dipole. The results obtained show that the plasma antenna has a high radiation efficiency, directional patterns similar to an equivalent dipole antenna, and significantly lower RCS values in the off mode

scholarly journals Characterization and Investigation of Nonlinear Behaviour of Radio Refractivity during the Rainy and Dry Seasons in the Coastal Region of Nigeria

2021 ◽  
Vol 25 (7) ◽  
pp. 1155-1161
Author(s):  
A.E. Adeniji ◽  
E.M. Ajeigbe ◽  
K.S. Ojo
Keyword(s):  
Meteorological Parameters ◽  
Coastal Region ◽  
Nonlinear Effects ◽  
Nonlinear Behaviour ◽  
Radio Communication ◽  
National Space ◽  
Communication Links ◽  
Radio Signals ◽  
Quantification Analysis ◽  
Dry Seasons

The transmission and receiving of good quality of signals globally has been impaired due to the internal activities of the troposphere linked to the nonlinear behaviour of the meteorological parameters. This paper focusses on characterizing and investigating the nonlinear behaviour of radio refractivity during the rainy and dry seasons in the coastal region of Nigeria using temperature, pressure and relative humidity data collected over a period of two years by the Centre for Atmospheric Research, National Space Research and Development Agency (NASRDA) from Lagos state. Data obtained were analyzed by False Nearest Neighbour (FNN) and Recurrence Quantification Analysis (RQA). The results show that recurrence techniques are able to identify the periods where there are high predictability and low predictability. The investigation of nonlinear effects of meteorological parameters and the hydrometeors on the troposphere help to avoid fading of radio signals along with the radio communication links.

scholarly journals Эксперимент по созданию канала радиосвязи в морской среде

2021 ◽  
Vol 47 (11) ◽  
pp. 48
Author(s):  
А.К. Томилин ◽  
А.Ф. Лукин ◽  
А.Н. Гульков
Keyword(s):  
Marine Environment ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Communication Channel ◽  
Radio Signal ◽  
Short Wave ◽  
Full Scale ◽  
Radio Communication ◽  
Full Scale Experiment ◽  
Scale Experiment

A full-scale experiment on the transmission of a short-wave modulated radio signal in a marine environment using spherical antennas at a distance of 470 m is described. The special transceiver equipment is designed in accordance with the results of the generalised electrodynamics theory. An assumption is made about the possibility of creating a high-frequency radio communication channel in the marine environment by means of longitudinal electromagnetic waves.

scholarly journals Effects of Rainfall Attenuation on Frequencies 1 and 3 GHZ in Nigeria

2016 ◽  
Vol 15 (5) ◽  
pp. 6711-6723
Author(s):  
Ogherohwo, E. P ◽  
Bukar, B ◽  
Baba, D. D.
Keyword(s):  
Frequency Dependence ◽  
Everyday Life ◽  
Frequency Spectrum ◽  
Spectral Range ◽  
Mobile Communications ◽  
Electromagnetic Waves ◽  
Rain Rate ◽  
Rainfall Data ◽  
Radio Communication ◽  
Rainfall Attenuation

Mobile communications are part of our everyday life. The non-ideal environment which is filled with many attenuation factors affects the electromagnetic waves, which radio communication depends. This study considers the spectral range of 1 and 3GHz. At these frequencies, interesting phenomena due to rain are supposed to happen. The study of this frequency spectrum has been undertaken in an attempt to evaluate the frequency dependence of rain effects on electromagnetic waves. The study of rain effects on communication presented in this study relied solely on rainfall data collected from Nigeria Metrological Agency (NiMet) station in Lagos, Nigeria. The months for January to December for 1981-2011 were summed together and the averages were determined. The average is then used to calculate the rain rate and rainfall attenuation using the extracted results for all the locations (Bauchi, Ikeja, Jos, Kebbi, Maiduguri and Warri). The results show that Warri has the highest rainfall rate followed by Lagos. Kebbi and Maiduguri has the least while Jos and Bauchi demonstrated moderate rainfall rates. This also deduced that attenuation has less impact on lower frequencies but increase with higher frequencies. The study reveals that at higher frequencies, the rainfall attenuation is observed to be greater.

Sign in / Sign up

Export Citation Format

Share Document