The buckling torque may be much less than the yield torque in very thin rectangular tubes under torsion. In this paper, simple closed-form formulae are presented for buckling analysis of long hollow rectangular tubes under torsion. By the presented formulae, one can obtain the critical torque or the critical angle of twist of the tube in terms of its geometrical parameters and material constant...

Regular boundary element method is employed for the variational formulation of Helmholtz equation that governs the waveguiding problems. Like in the Charge simulation method, in this method, the source points associated with the fundamental solutions are allocated outside the domain so that the singular integrals which occur in the standard boundary element procedure can be avoided. First, the ...

FEMLAB and MicroWaveLab, two finite element solvers, are evaluated in the context of needs of microwave power engineering. Limitations of the codes are identified by simulation of characteristics of applicators based on circular and rectangular waveguides as well as coaxial-to-ridgedand coaxial-to-double-ridged waveguide transitions. Results are verified by QuickWave-3D.

In this paper, the wave propagation and the cutoff frequencies of a rectangular metallic waveguide, partially filled the metamaterial multilayer slabs have been studied. The equations of the TMM method are not complex and the numerical examples show that we can easily obtain the characteristics of the metamaterial multilayer’s rectangular waveguide satisfyingly. The cutoff frequencies of the me...

Abstract: The propagation of guided and nonconfined optical waves at fixed frequency through dielectric structures with piecewise constant, rectangular permittivity is considered in two spatial dimensions. Bidirectional versions of eigenmodes, computed for sequences of multilayer slab waveguides, constitute the expansion basis for the optical electromagnetic field. Dirichlet boundary conditions...

A novel dual-band filter based on substrate integrated waveguide (SIW) is presented in this paper. The proposed filter is composed of two filters with different center frequencies and bandwidths, where they share input and output ports with source-load coupling using rectangular SIW cavity structure. Multi-transmission zeros have been obtained through electrical coupling between the source and ...

The digital waveguide mesh is an extension of the onedimensional (1-D) digital waveguide technique. The mesh can be used for simulation of twoand three-dimensional (3-D) wave propagation in musical instruments and acoustic spaces. The original rectangular digital waveguide mesh algorithm suffers from direction-dependent dispersion. Alternative geometries, such as the triangular mesh, have been ...

Analysis of dielectric resonator probe (DRP) arrays operating in an oversized hard waveguide with sectoral hard horn excitation is presented. A single DRP excited by a coaxial probe is first investigated inside a hollow rectangular waveguide and a waveguide loaded with hard walls, respectively. Simulation results are compared with measurement results and show a good agreement. Then, a one-dimen...