Том 64, № 4 (2019)
- Жылы: 2019
- Мақалалар: 13
- URL: https://journals.rcsi.science/1064-2269/issue/view/12500
Electrodynamics and Wave Propagation
The Method of Integral Equations for Calculation of Smoothly Irregular Out-of-Line Waveguide Transitions
Аннотация
Features of Radio Wave Resonant Scattering on the Sea Surface in the Presence of Long Waves
Аннотация
The effects caused by changes in the local angle of incidence when propagation of resonant waves over a curved surface formed via long waves were analyzed. The models, which describe the dependence of the geometric scattering coefficient for the incidence angle when sounding a sea surface in millimeter, centimeter, and decimeter wavelength bands, were constructed. An approach to bring closer the model estimations of the polarization ratio and estimations via measurement data of spacecraft is developed. The curvilinearity of the surface approximately improves one and half times the correspondence of model calculations with direct measurements data.
Antenna Characteristics of a Hemispherical Luneburg Lens in the Scan Mode
Аннотация
The antenna characteristics of a hemispherical Luneburg lens with a flat screen on the lens side opposite to the position of the feed are studied. The hemispherical geometry of the lens allows the lens to be effectively used in the scan mode. In the scan mode of the antenna, it is possible to choose the shape and parameters of the radiation pattern depending on the position of the feed.
Representation of a Pulsed Wave Field as a Set of Metaparticles
Аннотация
The paper considers the properties of a directionally radiated axisymmetric pulse of a wave field represented as a set of axisymmetric metaparticles of pulsed wave fields. The value of the energy transferred by the considered pulse and obtained as the sum of the energies of the constituent metaparticles is found.
Antenna and Feeder Systems
Specific Features of Multibeam Directional Patterns in Analog-Digitial Active Phased Antenna Arrays
Аннотация
Formation of multibeam directional patterns in active phased antenna arrays (APAAs) with the known analog-digital signal control at the emitters is considered. Numerical simulation is used to study dynamics of interference of partial directional patterns (DPs) that leads to distortions and angular shift of the maxima and effects related to amplitude modulation of the emitter signals. A method to decrease the level of the DP side lobes using a system that forms intersecting subapertures in which a step of the digital-level subarray is less than the step of the analog-level subarray is proposed. Effect of peak correction of signal amplitudes at the emitters on the partial DPs of the multibeam APAA is studied.
Statistical Radiophysics
Analysis of Loss Factor of Supercooled Pore Water at Frequencies of 60–140 GHz
Аннотация
Loss factor of supercooled pore water is studied at frequencies of 60–140 GHz at temperatures of down to –70°C using silica gel. It is shown that, with disregard of the effect of monomolecular nonfreezing layer of bound water, the loss factor of pore water in the silicate material is determined by the Debye relaxation of water corresponding to the properties of bulk water, additional loss in a temperature interval centered at ‒45°C owing to the effect of the second critical point of water, and the surface conduction at the interface due to the formation of ferroelectric ice 0 provided that the freezing point of water in pores is lower than ‒23°C. The experimental results can be used in the problems of radiation transfer in aerosols and porous wetted finely dispersed media.
The Experimental Study of Electromagnetic Waves Scattering of Underlying Terrain in Centimeter and Millimeter Ranges
Аннотация
Theory and Methods of Signal Processing
Quadratic Method of the Angular Resolution of Two Closely Spaced Targets
Аннотация
A method for the formation of measurements of the angular coordinates of two closely spaced point targets by four independent receivers located at the same distance from each other is proposed. It is shown that the target angles are determined by the fixed points of some linear fractional transformation and can be found by solving a quadratic equation with complex coefficients. A method for calculating the accuracy of measuring the angular coordinates and a criterion for target resolution are substantiated. Results of numerical analysis on a model example are given. The method is designed for measuring the angular coordinates of two closely spaced targets and the elevation angle of a low-flying target against the background of the underlying surface (marine or terrestrial), as well as for measuring the coordinates of the target under the conditions of active interference.
Impulse Noise Rejection Method in LFM Radars
Аннотация
Radio Phenomena in Solids and Plasma
Waveguide Bandstop Filters Based on Microwave Photonic Crystals with Parameters Controlled by n–i–p–i–n Diodes
Аннотация
A feasible design of a system with an allowed band with near-unity frequency-independent transmission utilizing the reflective properties of photonic crystals with dielectric filling and resonant irises in a setup with a Y-circulator is demonstrated. The existence of impurity modes of oscillation damping in the allowed band of this photonic crystal with disturbed periodicity is confirmed. Bandstop filters with parameters controlled by n–i–p–i–n diodes are constructed based on photonic crystals with resonant irises. These filters have a rejection level of >43.0 dB in the stop band and losses below 0.8 dB outside of it.
Applications of Radiotechnology and Electronics in Biology and Medicine
Remote Control of the Surface Movement of an Object Using a Two-Channel SHF Autodyne Generator
Аннотация
In this paper, we describe a method for restoring reflector motion using a radio-wave signal from a super high frequency (SHF) autodyne generator based on a Gunn diode. The proposed method consists in sequential emission and reception of an electromagnetic SHF signal reflected from an object using two channels that differ in electrical length providing the π/2-phase shift of interference signals. With this method, there is no ambiguity in determining the amplitude of reflector movement and no need to determine the initial phase of the detected signal.
Electron and Ion Optics
On the Possibility of Nonpulsed Electron Beam Transport in a NonBrillouin Magnetic Field
Аннотация
Novel Radio Systems and Elements
Microstrip Spurious-Coupling Band-Pass Filters with Quarter-Wavelength and Π-Shaped Resonators
Аннотация
Microstrip band-pass filters (BPFs) containing quarter-wavelength resonators and a Π-shaped half-wavelength resonator placed next to each other along the same line have been analyzed. These filters have more various frequency characteristics from the use of a Π-shaped half-wavelength resonator and spurious magnetic cross-talk coupling. The possibility of describing these filters using a coupling matrix is considered. The results of the simulation and measurement of the frequency characteristics of three microstrip BPFs with a central frequency of 2 GHz have been presented.