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The technique of simultaneously determination of thickness and electrical conductivity of structures based on semiconductor layers, which play a role of the irregularity in one-dimensional waveguide photonic crystals has been developed. The experimental results and the inverse problem solving are presented.
The peculiarities of practical realization of the method, that provides measurement of the current-voltage and capacitance-voltage characteristics by ultra-short pulses, are considered.
Presented in this paper is the research of basic scattering mechanisms in semiconductor heterostructures, as well as basic characteristics of transfer processes at space charge mode using statistical modeling technique. Outstanding feature of this method is statistic modeling and self-consistent solution of hydrodynamic model equation, that allowed us to define the basic physical mechanisms, that...
We propose an engineering model for determination of minimum detectable microwave power (MDMP) of a spin-torque microwave detector (STMD) connected to a standard 50-Ohm load. We obtain that the MDMP of a STMD can reach 10 nW at room temperature. The developed formalism can be used for the optimization of the practical parameters of various systems based on a STMD.
This paper presents a model for calculating the optical absorption spectrum of quantum dots for cases of strong and weak spatial constraints. This model agrees well with experimental data and can be used in mathematical models describing the operation of photovoltaic cells based on quantum dots.
The theoretical analysis of influence of temperature on the resonant sensitivity and signal-to-noise ratio of a resonance-type spin-torque microwave detector (STMD) has been carried out. We reveal that the resonant sensitivity does not always improve with the decrease of temperature. The developed formalism can be used for the optimization of the practical parameters of a STMD in a wide range of temperatures.
The low-signal impedance of a microwave diode on AlGaAs/GaAs nanostructure with electron tunnel injection through AlGaAs potential barrier and transit in GaAs drift layer is investigated. Frequency dependences of the impedance at width and height of a barrier layer of 2.5 nm and 0.3 eV is studied at different diode diameter and transit angle values. Maximal negative conductance of 192 mS is reached...
It is revealed that for the asymmetrical three-barrier resonant and tunnel structures with thin high barriers the system of non-stationary self-consistent Schrödinger and Poisson equations with open edge conditions on all channels of the dispersion, describing resonant transitions between three quantum levels in the strong high-frequency electrical field in case of the same edge conditions can have...
Cutoff frequency of resonant tunneling diodes (RTD's) designed for operation in millimeter wave subharmonic mixers is analyzed and investigated. The delay of electrons in the RTD quantum well and localized electron states at heterointerfaces of RTD active layers are observed experimentally.
The features of uniform nickel electrochemical deposition into the pores of thin ordered porous anodic alumina (PA) are considered. The influence of deposition conditions on ordering and topological parameters of nickel nanopillars are investigated. The impact of the barrier layer thinning process at the PA pores bottom on the origination and growth of the ordered metal nanopillars is discussed.
Simulation of the excitation of mechanical vibrations in carbon nanotube arrays by ponderomotive forces is presented in continual approximation on the basis of electrodynamics of moving bodies, elasticity theory and van der Waals interactions' theory.
The problem of electromagnetic wave transition through a plane layer with chiral properties of a composite material, made of resistive fibers in the form of few-coil helices, is solved. The influence of different parameters that characterize the composite on angular and frequency dependencies of amplitude and polarization characteristics of the passing and reflected electromagnetic waves is investigated.
The features of density estimation of obstacle nonlinear scatterers (NS), based on «metal-oxide-metal» structures with the system of preliminary nonlinear sounding (SPNS), are considered. The expediency of usage for SPNS as a probing signal of the additive combination of the component of phase-modulated (FM) signal and «white» Gaussian noise is shown. We also show that the presence of features of...
The function circuit and performance characteristics of dual band radioelectronic facilities (DBRF) “Burevisnyk-3”, which is a new-generation complex integrated radio electronics system operating in the X-band and Ka-band wavelength with a unitary control system, are described. The above radar system is intended for technical surveillance and monitoring of open water area situation. It is located...
The RT22 CrAO radio telescope antenna has been observed with a C-band Synthetic Aperture Radar (SAR) for the purpose of deriving scattering properties and pointing information. Space-based radars benefit from accurate calibration targets and for the lower frequency bands such targets can be rather large in physical sense in order to derive level information. Active transponders are used. A large reflector...
The problem of determination of combined response signal (RS) from the obstacle nonlinear scatterers (NS) by a special system of preliminary nonlinear sounding (SPNS) in nonlinear radar is examined. The investigation of interaction of the components of combined RS from the obstacle NS, which arbitrarily spread in space and have different scattering capability is done. It is shown that for the definition...
Method of scanning tomography and holography of subsurface dielectric objects based on inverse scattering problem solution for the pseudopulse synthesized by multifrequency measurements of scattered field is studied.
An algorithm for the construction of the air flying objects routes was created with using the robust method. Mathematical tools of the method were presented there, practical results based on a study of the real signal of the radio source (IRI) were also shown. A comparison of existing methods for the determination of the objectives' range was made; their advantages and disadvantages were noticed....
An algorithm for optimizing microstrip hairpin bandpass filter, based on quasi-static analysis of the cross-section of coupled-line sections and genetic algorithm to find solutions was developed. Optimization of microstrip hairpin bandpass filter with slots in the ground plane to reduce the insertion losses in the HFSS has been proposed.
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