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Characteristics of semiconductor diodes as power indicators are studied. Rigorous electromagnetic model of direct problem of average detection is derived. Approximate models of the inverse problem for detector characteristic are proposed. Maximum errors of approximation for different orders of approximating polynomial and source resistance are calculated.
The parameters of pulses reflected from non-periodic Bragg layered structures have been investigated. The specific structures such as asymmetric resonators with periodic Bragg reflectors and structures with chirp variation of the thickness of the “period” have been examined. The numerical investigations have been made both in Bragg band and outside it. The frequency characteristics of the structures...
The behavior of quasi-periodic and aperiodic (chirp) Bragg structures with thin lossy layers was examined. In order to determine the frequency dependence of the reflection coefficient transmission matrix method was used. A deep minimum of the reflection coefficient for any frequency is implemented by proper choice of the thickness of the last thin film and its optical distance to the substrate. The...
A new approach to determining the amplitude levels of piecewise constant signal has been proposed that is based on using its multiplicative model and solving the problem of polynomial approximation. In case of the absence of noise, the statement of polynomial approximation problem is based on the requirement of exact match of the current signal value with the amplitude value of one of its levels....
The time delays of pulses reflected from periodic and non-periodic Bragg layered structures have been investigated. The specific structures such as Bragg reflectors 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 Bragg resonance values. The parameters of...
The influence of various types of distortion of periodicity on the eigen parameters of the layered Bragg 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 Bragg resonators with thin contrast...
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...
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane dividers is studied. A rigorous electromagnetic model of direct and inverse problems of five- and six-port measurements of complex reflection coefficient is derived. Frequency dependencies of model parameters are calculated. Properties of E-plane junctions are investigated. Approximations...
The robust estimation of far-field radiation pattern from the near-field measurement data, which are distorted by additive noise and random impulses, is suggested. The proposed technique is based on the two-stage algorithm. The first stage is to determine the radiation sources from the data of near-field measurements by the “dual method of minimum spatial extent.” The second stage is to calculate...
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane dividers is studied. Rigorous electromagnetic model of direct and inverse problems of five- and six-port measurements of complex reflection coefficient is derived. Frequency dependencies of model parameters are calculated. Properties of E-plane junctions are investigated.
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane dividers is studied. Rigorous electromagnetic model of direct and inverse problems of five-port measurements of complex reflection coefficient is derived. Frequency dependencies of model parameters are calculated. Properties of T-junctions are investigated.
Inverse problem of radiation-sources restoration from near-field measurement data is considered. Case of data distortion by additive noise and spikes is investigated. New approach based on a concept of “spatial extent” is suggested. It states that the weighted sum of spatial extent of solution discrepancy and spatial extent of solution should be a minimum. Thus, the concept of spatial extent is used...
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane dividers is studied. Rigorous electromagnetic model of direct and inverse problems of five-port measurements of complex reflection coefficient is derived. Frequency dependencies of model parameters are calculated. Properties of oblique X- and T-junctions are investigated.
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...
Localization of plane wave decomposition with use of parametric spectral analysis has been considered. Modification of Prony's method, which can be used for representation of fragment of the antenna radiation field by the local spectrum of plane waves, is offered.
The problem of creating meter of complex reflection coefficient based on the electromagnetic approach using E-plane cross-shaped divider is studied. System of the integral equation describing scattering waves by the E-cross is solved. Rigorous electromagnetic model of direct and inverse problems of five-port measurements of complex reflection coefficient is derived. Frequency dependencies of model...
Approach to robust estimation of radiation sources in an array of electric dipoles when measurement data are distorted by additive noise as well as by random impulses is suggested. It is based on a non-linear optimization technique where objective function is built by the idea of minimization of “spatial extent.” The model of radiation sources is described by a set of ideal Hertzian dipoles. The case,...
Automated analyzers, based on six-port reflectometers (SPR), are widely used for measuring the parameters of the microwave devices [1]-[3]. In the measurement transducer of SPR the matched multiport passive microwave connection is used for the complex composition of the reference wave generator and the wave reflected from the object [2]. In this case the parameters of the measurement system are found...
The consideration of electromagnetic wave propagation in open irregular waveguiding structures usually assumes either smooth varying of medium parameters [1], [2] or their rigorously periodical perturbation [3]–[6]. Combination of smooth and oscillated parameter perturbations leads to additional peculiarities of Bragg scattering [7], [8]. Anisotropy of parameters causes coupling of waves with different...
Rectangular waveguides with nonperiodical corrugation of wall are considered. The Krylov-Bogoliubov-Mitropolsky asymptotic method is used for solving boundary-value problem describing electromagnetic wave propagation in the close waveguiding structure. Mutual transformations of a wave modes propagating in such waveguides are investigated. Analytical solutions for some coupling coefficients are obtained.
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