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A G Demekhov - One of the best experts on this subject based on the ideXlab platform.
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impact of the space charge distribution in the model source of quasi electrostatic whistler mode waves on the effective length of a short Receiving Antenna
Radiophysics and Quantum Electronics, 2019Co-Authors: Evgenii A Shirokov, A G DemekhovAbstract:In our previous paper [1] it was shown, using the theory of Antennas in plasmas, that the effective length leff of a Receiving dipole Antenna can be much larger than its geometric length in case quasielectrostatic chorus emissions propagating close to the resonance cone are received. In order to simplify calculations of leff, it was proposed to use a model (“effective”) source of such emissions because taking into account all of the real source properties (that are determined by the nonlinear processes of interaction between waves and charged particles in a wide region of space) would lead to unreasonably cumbersome calculations. The present paper analyzes how the effective length of the spacecraft-borne Receiving Antenna depends on the parameters of the space charge distribution in the model source of quasi-electrostatic chorus emissions. It is found that the length leff decreases as a power function (with exponent −1/2) with increasing distance (along the group velocity resonance cone) between the model source and the Receiving Antenna. This relationship is correct up to the distance at which the effective length becomes of the order of the geometric length. At longer distances, the radiation field loses its resonance nature because of the excitation of an electromagnetic (quasi-longitudinal) wave. It is shown that under conditions of the Earth’s magnetosphere, the approximation we used can remain valid up to distances of the order of the geomagnetic field line length, which confirms the importance of the discussed effect for correct interpretation of the electric wave measurement data in the whistler-mode frequency range. It is also shown that the length leff changes by less than 10% when the characteristic scale of spectrum of the charge distribution along the model source varies as Δ ∼ (0.1–1.0) kobs, where the wave number kobs corresponds to the observed spectral maximum of radiation at a given frequency.
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dependence of the effective length of a Receiving Antenna on the space charge distribution in a model source of quasi electrostatic chorus emissions
2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018Co-Authors: Evgenii A Shirokov, A G DemekhovAbstract:Recently it was shown on the basis of general theory of Antennas in plasmas that the effective length of a Receiving dipole Antenna can be much greater than its geometric length in the case of reception of quasi-electrostatic chorus emissions propagating close to the resonance cone. For such calculations one needs to specify a model wave source, since the actual source—receiver geometry is not well known in the case of chorus emissions generated in a distributed region by a complicated nonlinear process. In this paper, we analyze how the effective length of a spacecraft-borne Receiving Antenna depends on the parameters of a model source of quasi-electrostatic chorus emissions. In particular, we study the dependence of the effective length on characteristic scales of the space charge distribution in the source and the distance between the source and the Receiving Antenna.
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effective length of a Receiving Antenna in case of spacecraft observations of quasi electrostatic chorus emissions
URSI General Assembly and Scientific Symposium, 2017Co-Authors: Evgenii A Shirokov, A G Demekhov, Yuri V Chugunov, Alexey V LarchenkoAbstract:We propose a method of calculating the effective length of Receiving Antenna for the case of spacecraft observations of quasi-electrostatic chorus emissions. Using the obtained analytical expression, we calculate this length for some measurements of chorus wave quasi-electrostatic fields onboard THEMIS spacecraft. The calculation results show that the effective length can be up to an order of magnitude greater than the geometric length of Receiving Antenna. Therefore, the actual electric field value can be much less as compared to the one calculated using the geometric length which is a conventionally used technique in the satellite data analysis. In particular, this result can be important for the estimates of electron energization by quasi-electrostatic chorus waves.
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effective length of a Receiving Antenna in case of quasi electrostatic whistler mode waves application to spacecraft observations of chorus emissions
Radio Science, 2017Co-Authors: Evgenii A Shirokov, Yu V Chugunov, A G Demekhov, Alexey V LarchenkoAbstract:We propose a method for calculating the Receiving Antenna effective length in the case of reception of quasi-electrostatic whistler mode waves in plasmas and apply it to the spacecraft observations of oblique VLF chorus waves. The method is based on the reciprocity theorem and requires an appropriate choice of the radiation source. Such a choice is possible on the basis of the measured emission parameters if a quasi-monochromatic (i.e., having narrow instant width of the dynamic spectrum) wave packet with wave normal angles near the resonance cone is detected. We analyze several typical chorus events detected by THEMIS spacecraft and show that the effective length of Receiving Antenna can be more than an order of magnitude greater than the geometric length.
Evgenii A Shirokov - One of the best experts on this subject based on the ideXlab platform.
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impact of the space charge distribution in the model source of quasi electrostatic whistler mode waves on the effective length of a short Receiving Antenna
Radiophysics and Quantum Electronics, 2019Co-Authors: Evgenii A Shirokov, A G DemekhovAbstract:In our previous paper [1] it was shown, using the theory of Antennas in plasmas, that the effective length leff of a Receiving dipole Antenna can be much larger than its geometric length in case quasielectrostatic chorus emissions propagating close to the resonance cone are received. In order to simplify calculations of leff, it was proposed to use a model (“effective”) source of such emissions because taking into account all of the real source properties (that are determined by the nonlinear processes of interaction between waves and charged particles in a wide region of space) would lead to unreasonably cumbersome calculations. The present paper analyzes how the effective length of the spacecraft-borne Receiving Antenna depends on the parameters of the space charge distribution in the model source of quasi-electrostatic chorus emissions. It is found that the length leff decreases as a power function (with exponent −1/2) with increasing distance (along the group velocity resonance cone) between the model source and the Receiving Antenna. This relationship is correct up to the distance at which the effective length becomes of the order of the geometric length. At longer distances, the radiation field loses its resonance nature because of the excitation of an electromagnetic (quasi-longitudinal) wave. It is shown that under conditions of the Earth’s magnetosphere, the approximation we used can remain valid up to distances of the order of the geomagnetic field line length, which confirms the importance of the discussed effect for correct interpretation of the electric wave measurement data in the whistler-mode frequency range. It is also shown that the length leff changes by less than 10% when the characteristic scale of spectrum of the charge distribution along the model source varies as Δ ∼ (0.1–1.0) kobs, where the wave number kobs corresponds to the observed spectral maximum of radiation at a given frequency.
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dependence of the effective length of a Receiving Antenna on the space charge distribution in a model source of quasi electrostatic chorus emissions
2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018Co-Authors: Evgenii A Shirokov, A G DemekhovAbstract:Recently it was shown on the basis of general theory of Antennas in plasmas that the effective length of a Receiving dipole Antenna can be much greater than its geometric length in the case of reception of quasi-electrostatic chorus emissions propagating close to the resonance cone. For such calculations one needs to specify a model wave source, since the actual source—receiver geometry is not well known in the case of chorus emissions generated in a distributed region by a complicated nonlinear process. In this paper, we analyze how the effective length of a spacecraft-borne Receiving Antenna depends on the parameters of a model source of quasi-electrostatic chorus emissions. In particular, we study the dependence of the effective length on characteristic scales of the space charge distribution in the source and the distance between the source and the Receiving Antenna.
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effective length of a Receiving Antenna in case of spacecraft observations of quasi electrostatic chorus emissions
URSI General Assembly and Scientific Symposium, 2017Co-Authors: Evgenii A Shirokov, A G Demekhov, Yuri V Chugunov, Alexey V LarchenkoAbstract:We propose a method of calculating the effective length of Receiving Antenna for the case of spacecraft observations of quasi-electrostatic chorus emissions. Using the obtained analytical expression, we calculate this length for some measurements of chorus wave quasi-electrostatic fields onboard THEMIS spacecraft. The calculation results show that the effective length can be up to an order of magnitude greater than the geometric length of Receiving Antenna. Therefore, the actual electric field value can be much less as compared to the one calculated using the geometric length which is a conventionally used technique in the satellite data analysis. In particular, this result can be important for the estimates of electron energization by quasi-electrostatic chorus waves.
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effective length of a Receiving Antenna in case of quasi electrostatic whistler mode waves application to spacecraft observations of chorus emissions
Radio Science, 2017Co-Authors: Evgenii A Shirokov, Yu V Chugunov, A G Demekhov, Alexey V LarchenkoAbstract:We propose a method for calculating the Receiving Antenna effective length in the case of reception of quasi-electrostatic whistler mode waves in plasmas and apply it to the spacecraft observations of oblique VLF chorus waves. The method is based on the reciprocity theorem and requires an appropriate choice of the radiation source. Such a choice is possible on the basis of the measured emission parameters if a quasi-monochromatic (i.e., having narrow instant width of the dynamic spectrum) wave packet with wave normal angles near the resonance cone is detected. We analyze several typical chorus events detected by THEMIS spacecraft and show that the effective length of Receiving Antenna can be more than an order of magnitude greater than the geometric length.
Monai Krairiksh - One of the best experts on this subject based on the ideXlab platform.
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path loss model and measurements of 5 8 ghz wireless network in durian garden
International Symposium on Communications and Information Technologies, 2008Co-Authors: Rattapong Suwalak, Kittisak Phaebua, Chuwong Phongcharoenpanich, Monai KrairikshAbstract:This paper presents the path loss model and measurement of wireless network in durian garden at 5.8 GHz. This study is important in wireless communication system for predication and design the communication system of durian garden such as communication range, power transfer, position of transmitting and Receiving Antenna. From the results, it is obvious that the path loss at the distance of 128 m from the transmitter is less than -50 dB.
Takehiro Imura - One of the best experts on this subject based on the ideXlab platform.
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equivalent circuit for repeater Antenna for wireless power transfer via magnetic resonant coupling considering signed coupling
Conference on Industrial Electronics and Applications, 2011Co-Authors: Takehiro ImuraAbstract:Wireless power transfer technology has received much attention recently. Although the technology has been existed for a long time, never before has it has received the current level of attention. This can be primarily attributed to social demand related to the increased use of mobile devices, which need frequent recharging, and plugging the device into an outlet is not convenient. It is also due to changes in available technology. The emergence of electromagnetic resonant coupling, which works over a large air gap with high efficiency has until recently not been possible with typical technologies. However, there are limitations to using only a transmitting and a Receiving Antenna. Repeater Antennas have been proposed to extend the length of the air gap. Long distance power transfer is achieved by simply installing a repeater between the transmitting and Receiving stations. And by installing repeaters inside walls, below desks, and under the floor, it will be possible to realize a fully wireless house in which it is possible to charge devices anywhere inside its confines. Previous studies have demonstrated that a repeater Antenna can extend the distance of the power transfer with the installation of a repeater Antenna between a transmitting Antenna and a Receiving Antenna. Detailed studies of mutual inductance, the position of repeater Antennas and theoretical studies about equivalent circuits cannot be found in the literature. This paper proposes that theoretical study of equivalent circuits of repeater Antennas it includes the problem of sign of mutual inductance which is occurred when the repeater Antennas are used.
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wireless power transfer during displacement using electromagnetic coupling in resonance
Ieej Transactions on Industry Applications, 2010Co-Authors: Takehiro Imura, Hiroyuki Okabe, Toshiyuki Uchida, Yoichi HoriAbstract:This paper proposes a novel way for achieving wireless power transfer from a transmitting Antenna to a Receiving Antenna. This technique is suitable for charging electric vehicles (EVs) because the proposed Antennas can transfer power wirelessly with high efficiencies when the Antennas are displaced and have large air gaps. This technique utilizes near-field Antennas at resonance; however, this technique is still being perfected. This paper describes this techniques' analysis, its results, as well as the possible Antennas that are suitable for EVs.
B Woestenburg - One of the best experts on this subject based on the ideXlab platform.
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unified definitions of efficiencies and system noise temperature for Receiving Antenna arrays
IEEE Transactions on Antennas and Propagation, 2010Co-Authors: Karl F Warnick, M V Ivashina, Rob Maaskant, B WoestenburgAbstract:Two methods for defining the efficiencies and system noise temperature of a Receiving Antenna array have recently been developed, one based on the isotropic noise response of the array and the other on an equivalent system representation. This letter demonstrates the equivalence of the two formulations and proposes a new set of standard definitions of Antenna figures of merit for beamforming arrays that accounts for the effect of interactions between Antenna element mutual coupling and receiver noise on system performance.
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equivalent system representation to model the beam sensitivity of Receiving Antenna arrays
IEEE Antennas and Wireless Propagation Letters, 2008Co-Authors: M V Ivashina, Rob Maaskant, B WoestenburgAbstract:In this letter, it is demonstrated that the beam sensitivity of an Antenna array Receiving system can be analyzed by using an equivalent single-channel receiver model. In this model, the Antenna array is represented by an equivalent single-port Antenna and the multiport active beamforming network is replaced by an equivalent two-port amplifier. Herein, the beam sensitivity is defined at the input of the Receiving system and is a function of the equivalent Antenna model parameters. Such a simplified representation helps us to identify the predominant factors that affect the receiver sensitivity of complex Antenna array systems, without having to consider the entire system in full detail. The receiver noise is computed with the proposed model and compared to the one computed by a direct numerical method to validate its consistency. For this purpose, we consider a four-element actively beamformed dipole array with strongly coupled Antenna elements causing significant noise coupling effects.
