Propagation of electromagnetic waves in a rectangular waveguide with periodic lattices

The problem of propagation of electromagnetic waves in a waveguide with one or two periodic lattices of simple or special form is solved in strict formulation. The formulas obtained are studied by computer, and the numerical results obtained analyzed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 21, No. 12, pp. 1834–1839, December, 1978.The author considers it her pleasant duty to thank V. P. Shestopalov and L. I. Belousov for their constant interest and assistance in the study.     

Propagation of electromagnetic surface waves in a radially inhomogeneous optical waveguide

The propagation of electromagnetic surface waves along a radially inhomogeneous dielectric waveguide is investigated. The problem is formulated in terms of differential equations to be satisfied by the radially dependent parts of the electromagnetic field vectors. The dielectric waveguide is assumed to consist of a homogeneous cladding of infinite extent and a radially inhomogeneous core of higher permittivity. Numerical solutions of the differential equations in the core are obtained by two different methods, viz. by direct numerical integration and by substitution of an appropriate power series expansion. In the cladding the field is expressed in terms of modified Bessel functions. Imposing the boundary conditions at the interface of core and cladding, an equation for the unknown propagation coefficient is obtained. From this equation the propagation coefficients for the lower order modes are computed numerically. Numerical results are presented for some permittivity profiles of practical interest in single-mode transmission along optical fibres.Nomenclature a radius of the core - a _q vector coefficient in the power series expansion off() - A _i constants - A square matrix - b _q coefficient in the power series expansion of _r() - B square matrix - C square matrix - c _n unknown constant - d _n unknown constant - D() fundamental matrix - E,E _r,,z electric field vector and components - E,e _r,,z radially dependent parts ofe _r,,z - f solution vector - G _q square matrix - H,H _r,,z magnetic field vector and components - h _r,,z radially dependent parts ofE _r,,z - h reduced wavenumber - i radial mode number - j imaginary unit - k _0,m wave number - K _n modified Bessel function of the second kind and order n - n azimuthal mode number - t time - U normalized propagation constant - Z _m plane wave impedance of the cladding - r, , z cylindrical co-ordinates - p, q, s integers - propagation coefficient - increment - _0,m,r permittivity - normalized radiusr - ₀ wavelength in free space - ₀ permeability - angular frequency - d _r, differentiation with respect tor, Engineering and Professor H. J. Frankena of the Physics Department for their valuable discussions.     

Propagation of electromagnetic waves in a waveguide with a radially symmetric height irregularity of the upper wall

We study the influence of a gradual (in the wavelength scale), radially symmetric height perturbation of a planar waveguide on the field of a vertical electrical dipole placed in the waveguide. We found an analytical expression for the Hertz potential for the dipole and observation point located on the uncurved wall. Radiophysical Research Institute, Nizhny Novgorod, Russia Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 43, No. 6, pp. 530–535, June, 2000.     

Propagation of electromagnetic waves in the earth-ionosphere waveguide with a gradual periodic inhomogeneity of the ionospheric upper-boundary impedance

We study the influence of a gradually inhomogeneous periodic disturbance of the upper-wall impedance of a plane Earth-Ionosphere waveguide on the radiation of a vertical electric dipole immersed in the waveguide channel. We consider the case where the disturbance amplitude is commensurable with the undisturbed value of the impedance. An expression is obtained for the Hertz potential when the source and the observation point are located at the lower wall of the waveguide. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 3, pp. 374–383, March, 1998.     

有损金属圆波导中电磁波传输特性的研究

基于电磁模式的色散方程，研究了有损金属圆波导中电磁模式的传输问题.在考虑了损耗层厚度影响的情况下，得到了各模式传输常数的近似解析表达式，此式适用于截止频率附近.通过解析表达式和波导模式色散方程，对衰减常数和相位常数进行了大量数值计算，得到了它们随损耗层厚度、频率以及损耗层电导率的变化规律，两种方法所获得的结果有较好的一致性.研究表明，损耗强度和损耗层厚度的变化会改变波导中电磁模式的色散和简并特性，对于改善高功率回旋行波放大器中注波互作用带宽和模式竞争非常有益. 关键词： 有损圆波导 相位常数 衰减常数 色散方程     

Characteristic electromagnetic waves in a circular waveguide filled with a biisotropic medium

A numerical solution is given for the problem of characteristic electromagnetic waves in a circular waveguide with a biisotropic rod. The dependences of the propagation constants of the different wave modes on the chirality parameter, nonreciprocity, and permittivity of the rod are obtained. The results presented can be useful when developing devices and measuring the parameters of biisotropic materials. State University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 48–52, February, 1997.     

Propagation of electromagnetic waves in a medium with nonlinear magnetic susceptibility

The interaction of electromagnetic waves in a medium with nonlinear magnetic susceptibility is investigated. On the basis of Tinkham's measurements an antiferromagnet showing a resonance in the submillimeter region is considered as a nonlinear medium. The solution of both the Landau-Lifshitz and Maxwell equations leads to the RHS wave equation. Its solution with boundary conditions shows that the amplitude of the reflected wave from the nonlinear medium on a combined frequency can be non-zero.     

Propagation of electromagnetic waves in a conducting magnetic medium

We study helicon-spin waves (hybrid polaritons) in a ferromagnetic conducting medium in a strong static magnetic field and determine their existence domains. It is shown that the spatial dispersion of the conductivity tensor gives rise to collisionless damping of these waves when they propagate obliquely to the magnetic field. In the absence of collisionless damping (for wave propagation along the magnetic field), the conditions of amplification of hybrid polaritons in a static electric field are determined. Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Kharkov, Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol.43, No. 1, pp. 38–44, January 2000.     

Propagation of electromagnetic waves over a foamed sea surface

We study the propagation of electromagnetic waves over a smooth sea surface with impedance fluctuations due to copious foaming. This problem is solved analytically with allowance for multiple scattering at small grazing angles. An analytical expression for the effective impedance of the mean field is found in the case of large variance in the perturbation of the dielectric properties of the interface. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 5, pp. 438–451, May 1999.