Pole-Location-Based Estimates of Eigenmode Characteristics of Cylindrical Corrugated Structures

The paper presents an approach to estimate the range of location of the first natural frequencies of corrugated structures. It needs the knowledge of the solution of simple equations instead of the more complicated characteristic equation for the corrugated structure. Inverted and noninverted magnetron cavities are considered as examples. It is shown that not only the location of the frequencies but also the general properties of the eigenmode fields can be predicted based on an analysis of geometrical properties of the simplified characteristic equation of the structure which is carried out in terms of zeros and poles of the rigorous characteristic equation.     

Method of reducing gaseous emissions from the large hopper of a blast-furnace charging apparatus

West Siberian Metallurgical Combine. Translated from Metallurg, No. 9, pp. 23–24, September, 1989.     

Fast iterative, coupled-integral-equation technique for inhomogeneous profiled and periodic slabs

A fast coupled-integral-equation (CIE) technique is developed to compute the plane-TE-wave scattering by a wide class of periodic 2D inhomogeneous structures with curvilinear boundaries, which includes finite-thickness relief and rod gratings made of homogeneous material as special cases. The CIEs in the spectral domain are derived from the standard volume electric field integral equation. The kernel of the CIEs is of Picard type and offers therefore the possibility of deriving recursions, which allow the computation of the convolution integrals occurring in the CIEs with linear amounts of arithmetic complexity and memory. To utilize this advantage, the CIEs are solved iteratively. We apply the biconjugate gradient stabilized method. To make the iterative solution process faster, an efficient preconditioning operator (PO) is proposed that is based on a formal analytical inversion of the CIEs. The application of the PO also takes only linear complexity and memory. Numerical studies are carried out to demonstrate the potential and flexibility of the CIE technique proposed. Though the best efficiency and accuracy are observed at either low permittivity contrast or high conductivity, the technique can be used in a wide range of variation of material parameters of the structures including when they contain components made of both dielectrics with high permittivity and typical metals.     

TE-wave penetration into finite-thickness slotted circular cylinder with lossy and lossless inner coatings

A technique is developed to study the penetration of a TE-polarized plane wave into perfectly electric conducting cylindrical cavities with multiple apertures, taking into account wall thickness and multilayered inner filling. It is based on an integral representation of the tangential electric field on the slot apertures and the Galerkin method using weighted Gegenbauer polynomials as basis functions. Extensive parametric studies are performed to reveal the main features of the penetrated field in a wide frequency range for single- and double-layer coatings of three types. In particular, the effect of geometric and material parameters on the appearance and attenuation of the cavity resonances is studied. The strongest effect of cylinder thickness on the penetrated field is observed in the vicinity of the peaks of the frequency dependence and must be taken into account, even if the thickness is small.     

TE-case RCS analysis of finite-thickness slotted circular cylinder loaded with lossy filling

A generalized model is developed to study the TE-polarized plane wave scattering by coated and uncoated slotted circular cylinders of nonzero thickness and by a filled and not filled circular cylinders with sectorial cuttings. The mathematical treatment is based on the coupled integral equations (IEs) with respect to the tangential electric field at the slot/cutting apertures. The Galerkin method with weighted Gegenbauer polynomials as basis functions is used to convert IEs to a set of linear algebraic equations. Numerical simulations of the radar cross section (RCS) are carried out in the case of single slot/cutting in order to reveal the effect of thickness. Potentials of three approximations to the field in the slot/cutting domain are studied. Their use enables one to substantially accelerate the RCS calculations.     

The potentialities of hybrid model used for analysis of oscillatory systems for millimeter-wave magnetron

We consider the hybrid model from the viewpoint of its applicability to analyze equiresonator magnetron waveguide oscillatory systems used for millimeter band. The use of this model provides efficient analysis of the main characteristics including losses.     

Ridge coaxial non-periodic cavity with special frequency spectrum

Properties of the frequency spectrum of ridge coaxial magnetron-like non-periodic cavities have been studied to reveal potentials to improve a frequency rarefaction. The obtained results show that a spectrum which is free of a slight splitting of the frequency doublets, can be obtained for the first passband in the TE-case by a convenient choice of the cavity geometry.