Volume 63, Nº 2 (2018)

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.

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.

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.

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.

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 N_R (N_R = 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 N_R= 2 and 4.

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.

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.

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.

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.