Complicating the shape of a resonant diaphragm as a way of its quality-factor increasing

Complication of shape of resonant diaphragms in order to change the coulping with a waveguide channel is one of the ways in increasing their quality-factor (Q-factor). Ridged diaphragm in rectangular waveguide has been chosen as a special case of the diaphragm with a complicated cross-section. In accordance with the known decomposition principle, for studying its resonant properties such a diaphragm is decomposed into two consecutive junctions: rectangular-to-ridged waveguide and ridged-to-rectangular waveguide ones. On determining by some technique the basis of eigenmodes of ridged waveguide, the problem of diffraction of waves on the step junction with rectangular waveguide is solved by a known projection technique, providing thus the scattering matrix which describes the junction completely. In its turn the full scattering matrix of the diaphragm is calculated after scattering matrices of key blocks

The full-wave model for plane junction of waveguides with piecewise linear coordinate boundaries

The algorithm of S-matrix calculation for generalized junction between complicated waveguides with arbitrary piecewise boundaries is described. The main goal is to generalize the mode-matching procedure on the wide class of objects to provide the possibility of exact electromagnetic analysis for the very complicated structures from microwave devices as itself up to multilayer integrated circuits

Iteration technique of the design of frequency-selective devices and the software on this base

Convertional methods of design of microwave frequency selective devices (FSD) can be divided into the methods, basing on preliminary circuit theory (CT) synthesis, and the methods, using direct numerical procedures of searching the geometry, that provides required frequency response. The short review of a third line of the approach to FSD design is given in this report. It may be called as an interaction one because of essential use of iteration processes for the fine-tuning final constructions of FSDs. Actually such an approach allows to take into account the influence of frequency dispersion of components, imitating lumped element of CT, as well as the dispersion of phase velocity in waveguide sections, multimode interaction of FSD components, and so on. On numerous occasions an iteration procedure turns out essentially time-saving one, comparing with direct numerical optimization even on the base of CT initial approximation

Bandpass and lowpass filters on ridged waveguide sections

Some aspects of designing lowpass and bandpass evanescent-mode filters based on single- and double-ridged waveguides are discussed. It is demonstrated that introduction the new type of transformers allows to obtain the lowpass filter configuration providing wide pass and stop bands. The improved procedure of initial synthesis of bandpass filters permits to obtain their geometry for pass bands up to 20% and extended stop band

Development of A Procedure for Determination of Damage to Seeds and Cotton Fibers in Cotton Cleaning Machines

Studies on the dynamic state of cotton raw materials when introducing working bodies of processing machines into it allow to draw the following proposition. Depending on the rate of penetration of the working body into the cotton medium and the density of the medium, in the formulas used to describe the state of the medium, the exponent у ρ can vary from 1.5 to 3. The exponent for density ρ is a measure of the compression and compaction of raw materials on the surface of the working body. The exponent of ρ is also related to the amount of damage to cotton fibers and seeds. For the first time, a cotton mass is considered as a compressible porous two-component medium consisting of a mixture of cotton fibers and air included in the composition of a porous medium, which is essential in dynamic processing processes, and it must be taken into account when planning technological modes. From experiments on the penetration of a splitter with a peripheral speed u=3.5 m/s into a cotton medium with a density of ρ=150–350 kg/m3, it can be seen that a locally located “air cushion” appears in the close vicinity of the split end. The pressure in it increases by 1.5–2 times in comparison with the pressure of statistical compression of cotton fibers alone, without taking into account the influence of the air located in the pores of the system. The forces of compression of cotton fibers from the action of the splitter and the force of volumetric action on the fibers are comparable in the area of the "air cushion". Using the general equations of the mechanics of the compressed medium, as well as experimental data, the fundamental equation of the dynamic state of the mass of raw cotton when the working body of the processing machine is introduced into it, such as the density of the medium, the speed of the working body, its external shape and the degree of surface treatment, is derived. The resulting equation can be used to describe the power stresses in a cotton environment in the technological processes of roller and saw ginning, and during cotton cleanin

Circular polarization splitters for three-band feed of radiotelescope reflector antenna

The results of the design and testing of circular polarization splitters (polarizers) of the Ka-, X-, and S-bands, intended for operation as constituent parts of a three-band feed of a radio telescope reflector antenna, are presented. In addition, the results of developing a set of polarizers intended for connecting to waveguide outputs of band-measuring horn antennas are presented. These polarizers are developed to measure the antenna feed patterns on the co- and cross circular polarizations

Construction of A Method for Detecting Arbitrary Hazard Pollutants in the Atmospheric Air Based on the Structural Function of the Current Pollutant Concentrations

This paper reports the construction of a method for calculating the structural function within a moving window of the fixed size, based on measuring the vector of current concentrations of arbitrary air pollutants. The use of a moving window makes it possible to reveal the current moments of the emergence of inhomogeneities in the polluted atmosphere. In this case, the time shift of the structural function reveals the corresponding time scale of this heterogeneity. It has been shown that, in contrast to the known method, the proposed method makes it possible to reveal the dynamics of the levels and scales of local inhomogeneities of the polluted air using only the current measurements of concentration for an arbitrary number of pollutants. It is noted that the method does not use information about the current meteorological conditions of the atmosphere and the features of urban infrastructure near a pollution control point. Therefore, the method is universal; it could be applied to arbitrary control points of atmospheric pollution across various territories of states. The efficiency of the proposed method was tested using the example of actual measurements of the concentrations of urban air pollutants involving formaldehyde, ammonia, and nitrogen dioxide. The reported results generally indicate the applicability of the proposed method. It has been experimentally established that the method makes it possible to identify, in real time, the areas of local inhomogeneities characteristic of hazardous air pollution associated with the absence of dispersion and accumulation of pollutants in the air. In addition, the method makes it possible to detect in real time both the levels and the scale of inhomogeneities in the polluted atmosphere. It has been experimentally established that before the occurrence of the tested reliable emergency in a polluted atmosphere, the level of local heterogeneity was 0.015 units at its time scale corresponding to 8 counts. Next, by the time of the emergency, the level of heterogeneity decreased to 0.0025 units at the time scale corresponding to 2 counts. It has been experimentally established that for this case the forecast time of the occurrence of an emergency was 4 counts or 24 hour

Construction of A Method for Detecting Arbitrary Hazard Pollutants in the Atmospheric Air Based on the Structural Function of the Current Pollutant Concentrations

This paper reports the construction of a method for calculating the structural function within a moving window of the fixed size, based on measuring the vector of current concentrations of arbitrary air pollutants. The use of a moving window makes it possible to reveal the current moments of the emergence of inhomogeneities in the polluted atmosphere. In this case, the time shift of the structural function reveals the corresponding time scale of this heterogeneity. It has been shown that, in contrast to the known method, the proposed method makes it possible to reveal the dynamics of the levels and scales of local inhomogeneities of the polluted air using only the current measurements of concentration for an arbitrary number of pollutants. It is noted that the method does not use information about the current meteorological conditions of the atmosphere and the features of urban infrastructure near a pollution control point. Therefore, the method is universal; it could be applied to arbitrary control points of atmospheric pollution across various territories of states. The efficiency of the proposed method was tested using the example of actual measurements of the concentrations of urban air pollutants involving formaldehyde, ammonia, and nitrogen dioxide. The reported results generally indicate the applicability of the proposed method. It has been experimentally established that the method makes it possible to identify, in real time, the areas of local inhomogeneities characteristic of hazardous air pollution associated with the absence of dispersion and accumulation of pollutants in the air. In addition, the method makes it possible to detect in real time both the levels and the scale of inhomogeneities in the polluted atmosphere. It has been experimentally established that before the occurrence of the tested reliable emergency in a polluted atmosphere, the level of local heterogeneity was 0.015 units at its time scale corresponding to 8 counts. Next, by the time of the emergency, the level of heterogeneity decreased to 0.0025 units at the time scale corresponding to 2 counts. It has been experimentally established that for this case the forecast time of the occurrence of an emergency was 4 counts or 24 hour