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Specifics of use of the Prony's method to determine the natural frequencies from the frequency response of the object in comparison with direct fractional-rational approximation has been examined.
The time delay and widening of chirped Gaussian pulses (CGP) reflected from non-periodic Bragg layered structures have been investigated. The specific structures such as Bragg mirrors, resonators, and structures with chirp variation of thickness of the "period" have been considered. The calculation has been carried out under the conditions that carrier frequency is in the vicinity of the...
The time delay, space shift and widening of wave packet transmitted and reflected by structures with Bragg mirrors have been investigated. The specific structures such as Bragg mirrors, resonators, and structures with chirp variation of thickness of the “period” have been considered. The calculation has been carried out under the conditions that carrier frequency and incidence angle is in the vicinity...
The influence of various types of apodization on the eigen parameters of the distributed Bragg reflector, layered Bragg reflectors and resonators has been analyzed. The conditions of reduction of the quality factor of unwanted side Bragg oscillations in quasiperiodic apodized resonators have been determined. It has been proposed the construction of periodic and quasiperiodic structures and apodized...
Experimental results of reflectivity measurements for metal sphere with diameter of 35.5 mm and cylinder with the base diameter of 38 mm and the height of 76 mm in the range of 38–52 GHz at the grid of 256 frequencies are presented. Application of reference discontinuity in the form of iris positioned in the throat of the horn allowed implementing Fourier-holography principle and obtaining complex...
The transformation of the shape of pulses reflected by Bragg resonators with step-up and step-down perturbation types of period contrast under conditions than carrier frequency is in the vicinity of the resonance Bragg frequency have been considered. Integral and differential estimates of the delay time have been compared. The coefficients of skewness and kurtosis for the reflected pulses versus carrier...
Through-the-wall radars development is very actual problem [1]. For instance, the equipment of such sort can be used for testing the state of valve situated behind a wall. Using wideband microwave signals of millimeter range allow us to detect objects positioned behind barrier non-transparent in optical range and to obtain their radio images [2]. This equipment operates in the frequency band of 38...
Synthetic aperture and inverse synthetic aperture approach is rather powerful tool of improving resolution along transversal axis [1, 2]. The scalar reflectometer operating in frequency range of 38–52 GHz at the grid of frequencies allowed us to save information about complex reflectivity of objects due to application of Fourier-holography principle [3]. The experimental data at the grid of frequencies...
A number of examinations of the influence of the rectangular window geometrical sizes on the resonant properties of the insert was made. The expressions for the transmission and reflection coefficients were calculated. The graphs of the resonant frequency dependences versus the insert length and width of the rectangular window were shown. The frequency dependence of the reflection coefficient with...
The transformation of the shape of pulse reflected and transmitted by Bragg mirrors, resonators, and structures with chirp variation of thickness of the “period” under conditions than carrier frequency is in the vicinity of the resonance Bragg frequency is considered. Integral and differential estimates of the delay time have been compared. The coefficients of skewness and kurtosis for the reflected...
A new approach to permittivity profile reconstruction based on Newton-Kantorovich iterative scheme is considered. The novelty of the investigation is concerned with a new treatment with the problem of reflecting interfaces localization. The problem is ruled by a technique composing parametrical spectral analysis and approximate reconstruction by the scheme using exponential basis for the purpose of...
The possibility of consumption of the biconical cavity-based sensors for characterization of dielectric materials is calculated. Oriented the reckoning, a biconical cavity is made, and experimental investigations of its characteristics under interaction with dielectric materials are conducted.
To obtain accurate displacement data for the objects with non-flat surface by UHF interference method using 3 probes the neural network technologies were used. The real experiments were made. To provide quadratic characteristic of the detectors the calibration using the developed mathematical model of neural network was performed. Combining UHF interference method with neural network technologies...
The life and activities of outstanding scientist Fedor Isaakovich Kolomoytsev is presented. His 100 anniversary has been celebrated this year. Kolomoytsevpsilas contribution in the development of materials for microwave engineering, microwave measurements, antenna technique and microwave devices production is brilliant. He was a founder and the first head of the department of microwave physics in...
The results of microwave measurements for some objects combining multifrequency measurements and transversal scanning is presented. Longitudinal distance dependencies of reflectivity have been obtained by synthesis from multifrequency data. The multifrequency measurements and synthesis have been done in real-time. The measurements in free space were carried out by the apparatus using measuring modules...
Series of real experiments for obtaining of reliable data of displacement parameters of a plane object under testing by the microwave interference method using neural network technologies have been carried out. Two mathematical models of neural networks were generated. The first model was created for obtaining the quadratic law of a detector characteristic; the second one was for updating estimations...
A plant physiology development model is proposed taking into account interference of biological fields of different morphological structures for all growth periods. A principal possibility to optimize different development periods for phyto-systems by means of electromagnetic radiation of different frequency bands is shown.
The problem of single dielectric slab parameters estimation on the basis of reflectometry data taken in microwave band is considered using objective function minimization approach. The ldquoquasidurationldquo-based objective function formed from frequency reflection coefficient samples is shown to be more appropriate in comparison with standard robust objective function. The method of estimation was...
A breadboard model of the coaxial microwave resonator for displacement parameter and vibration measurement has been developed. The device has been realized in a form of a probe and can operate under various environmental conditions. Possibilities of the given device were investigated experimentally.
A new approach to permittivity profile reconstruction based on impulse reflection response processing is considered. The impulse response data is examined to be obtained with use of microwave reflection coefficient data extrapolation technique completed with discrete Fourier transform. The extrapolation is carried through special functional minimization procedure providing minimum of quasiduration...
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