卷 63, 编号 2 (2018)
- 年: 2018
- 文章: 12
- URL: https://journals.rcsi.science/1064-2269/issue/view/12449
Electrodynamics and Wave Propagation
Specificities of the Microwave Reflection Coefficients of Magnetically Excited Chiral and Ring Conductive Elements for Separation of Magnetic and Electric Responses and Broadband Matching of Radio Absorbing Composites
摘要
Distinctive features of the resonance responses of the reflection of microwaves from conducting double and single split-ring resonators, making it possible to distinguish between the magnetic and electric responses and identify the magnetic response of elements of different shapes, are studied experimentally in a rectangular waveguide and numerically in free space. It is shown that the specificities of the frequency dependence of the magnetic response can be used for broadband matching of radio absorbing composites.
Equivalent Surface Impedance of an Infinite Periodic Array of Slot Impedance Loads with Dielectric Coating
摘要
The problem of plane-wave excitation of an infinite array of slot impedance loads with a dielectric layer is considered in order to determine the equivalent surface impedance. The solution of the problem is found by the method of integral equations, solved numerically by the Krylov–Bogolyubov method, which reduces the integral equation to a system of linear algebraic equations. The numerical results are presented in the form of dependences of the equivalent surface impedance on the geometric dimensions of the structure at fixed values of the period of the array, the angle of incidence, and the thickness of the dielectric layer. It is shown that the equivalent surface impedance can be controlled by varying the width of the slot and the strip conductor. The dependences obtained are compared with the characteristics of an array of slot impedance loads without a dielectric layer.
The Method for Calculation of the Coefficient of Reflection of an Electromagnetic Wave from an Inhomogeneous Layer Having a Small Phase Thickness
摘要
Analytical expressions for the coefficient of reflection of an electromagnetic wave from a planeparallel layer with an arbitrary profile of the permittivity are obtained. It is shown that the electromagnetic model of a layer with a small phase thickness can be obtained with the help of the perturbation theory method. A method is proposed for the calculation of the reflection coefficient. The method is based on the combination of formulas of the perturbation theory and the formulas describing reflection from a homogeneous layer. The obtained expressions are compared with the numerical solutions of the electromagnetic equations. It is determined that the combined formulas describe the angular dependence of the reflection coefficient better than the formulas obtained only with the help of the perturbation theory.
Vertical Distribution of a Demodulated Low-Frequency Field in the Disturbed Low-Latitude Ionosphere
摘要
Numerical simulation of propagation of a demodulated beam of low-frequency electromagnetic waves at low latitudes in the presence of latitudinal gradients of the equatorial anomaly has been performed under the condition that the signal is recorded in the vertical direction, for example, with the use of sounding rockets. It has been shown that the wave beam has small spatial dimensions and, therefore, the amplitude distribution of the electromagnetic field in this beam is nonuniform owing to the interference effects under competitive action of the plasma density gradients and plasma anisotropy in the presence of a nonuniform geomagnetic field. Under these measurement conditions, the measurements usually conducted with the use of the instruments carried by an Earth satellite may become insufficient.
Selection of Parameters of the Primary Feed of the Luneberg Lens for the Sum–Difference Operating Mode
摘要
Excitation of the Luneberg lens by an arc antenna array of open-ended rectangular waveguides forming the H10 wave is studied. Technical limitations imposed on the array of primary feeds in order to form the sum and difference operating modes of the antenna system are discussed.
Antenna and Feeder Systems
Eikonal Distribution on the Surface of an Axisymmetric Dielectric Lens and Minimization of Aberrations
摘要
On the basis of the one-parametric theory of aberrations developed in the paper, a formula is obtained that describes the eikonal distribution on the surface of an axisymmetric dielectric lens with two focuses arbitrarily located on the axis and a source displaced from the focus in an arbitrary direction. The error of the formula is of the fourth order of the source displacement. A numerical analysis of the accuracy of the obtained formula and its expansions is performed by comparing the results of the eikonal calculation and the magnitude of aberrations on the surface of an aplanatic lens with the results of the exact geometrical optics calculation. The equation of the focal curve and the condition for the minimum of astigmatism are obtained. As an example of application of the formulas found, a wide-angle aplanate-anastigmat with optimal parameters is synthesized. The scanning characteristics of a lens antenna based on the synthesized aplanat-anastigmat are analyzed in the physical optics approximation.
Theory and Methods of Signal Processing
Correlation Functions of Navigational GBOC Signals
摘要
The structure of generalized binary offset carrier (GBOC) signals of satellite radio navigation systems, such as global positioning system (GPS) (USA), global navigation satellite system (GLONASS) (Russia), Galileo (European Union), and BeiDou/Compass (China), is examined. Analytical expressions for the correlation functions (CFs) characterizing the single components of the GBOC-signal modulation function (MF) are derived at the typical pulse multiplicity coefficients NR (NR = 2 and 4) and different duty cycles. The CFs properties of the components of GBOC-signal MFs are discussed and their graphs are constructed at ρ = 0 (or ρ = 1) corresponding to binary phase-shift keying signals, ρ = 0.1 (or ρ = 0.9), ρ = 0.25 (or ρ = 0.75), ρ = 0.3 (or ρ = 0.7), ρ = 0.45 (or ρ = 0.55), and ρ = 0.5 corresponding to binary offset carrier signals. The energy spectra (power spectral densities) of the single components of GBOC-signal MFs are calculated via the Fourier transform of CFs at the pulse multiplicity coefficients NR= 2 and 4.
Radio Phenomena in Solids and Plasma
Potential of Image Forces in a Dielectric Film
摘要
The potential of image forces for the charge in a three-layer medium (a dielectric film between two dielectrics) is considered in terms of electric fields (by definition) rather than potentials. It is demonstrated that the result differs from the usual result by a constant. Related issues are discussed.
Applications of Radiotechnology and Electronics in Biology and Medicine
Effect of Gold Nanorods on the Remote Decapsulation of Liposomal Capsules Using Ultrashort Electric Pulses
摘要
Decapsulation of nanocomposite liposomal capsules due to the effect of ultrashort electric pulses is obtained when the liposomal sheaths of the capsules are bound to significantly anisotropic gold nanoparticles (nanorods). Destruction of the liposomal sheath is interpreted using the rotational displacement of gold nanorods in the presence of the pulsed electric field. Such an interpretation is used to derive an expression for the critical electric field that determines the threshold level of the effect. The calculated critical field is in agreement with the experimental results. It is shown that the decapsulation is related to the presence of the gold nanorods in the sheath of liposomal capsules and is not obtained in the absence of the nanorods.
Electromagnetic Safety of Workstations Equipped with Active Systems for Data Protection
摘要
Methods for active protection of computer-processed data using low-energy electromagnetic noise are considered. Information and ecology–ergonomic safety of workstations equipped with active protection systems is analyzed. An intermodulation repeater for active protection of workstations is proposed and experimentally tested.
Nanoelectronics
Regularization of One-Electron Quasi-Steady States in Ideal Quantum Dots in the Electric Field
摘要
One-electron states localized on ideal quantum dots, i.e., zero-dimensional heterostructures capable of keeping only one electron, in the external electric field are discussed. A technique for regularization of the Gamow wave function of such states in which the electric field strength is supplemented by an infinitely small imaginary addition is proposed. It is found that, starting with a certain threshold, physically important calculated data become independent of this addition; in this case, integrals in a weak field converge to the saddle-point estimates. Using this technqiue, the binding energy and the probability of ejection of an electron localized on an ideal quantum dot by the electric field have been calculated. It is demosntrated that the main difference between the obtained results and the well-studied delta-potential approximation is that the contribution to the integrals is made by two saddle points rather than one.
Physical Processes in Electron Devices
Autodyne Effect of the System Involving Two Mutually Synchronized Oscillators under Strong Coupling
摘要
The results of research into the autodyne effect of a self-oscillating system subjected to reflected self-radiation and composed of two mutually synchronized partial oscillators with delayed interconnection are presented. The behavioral peculiarities of autodyne changes in the oscillation amplitude of partial oscillators, frequency, phase difference, and the response in the power supply circuit of active components are discussed at different oscillator parameters and various conditions of their mutual coupling. Experimental data are obtained for the flange-type double-diode oscillator built around 8-mm-band Gunn diodes.