© 2017 QWED Company. All rights reserved. 2017 | Home | Events | Products | Applications | Projects | About | Support | Log In

It has been proven [8] that the structures, which maintain axial symmetry of boundary conditions, belong the class of vector two-dimensional (V2D) problems. The total electromagnetic field in such structures can be decomposed into a series of orthogonal modes, of different angular field dependence of the cos(n*Phi*) or sin(n*Phi*) type, where *Phi* is angular variable of the cylindrical coordinate system and n=0,1,2... Each n-mode is analysed separately in QW-V2D. Under such assumptions the numerical analysis can be conducted in two space dimensions, over one half of the long-section of the structure, with n predefined as a parameter. Let us note that the n-mode defined above should not be confused with one mode of a circular waveguide. For example, one QW-V2D analysis with n=1 takes into account a composition of all circular waveguide modes TE_{1k} and TM_{1m} where k and m are arbitrary natural numbers.

•

calculations of radiation patterns, gain, radiation efficiency, and return loss of axisymmetrical antennas of various types (horn, rod, biconical), rigorously taking into account irregular geometry, complicated corrugations, and inhomogeneous filling

•

calculations of radiation patterns and radiation resistance of small dipole or loop radiators, located at the axis of the cylindrical coordinate system

•

accurate S-parameter calculations of circular waveguide discontinuities, also in cases involving strong dispersion and multimodal propagation

•

determination of eigenfrequencies, Q-factors, and pure modal field patterns for shielded and open inhomogeneous axisymmetrical resonators, also in cases involving closely-spaced modes or whispering gallery modes

•

calculation of heating patterns and specific absorption rate in axisymmetrical bodies

QW-V2D has been implemented on the basis of QW-3D, a three-dimensional simulation package by QWED, and a winner of the European Information Technology Prize in 1998. Thus, QW-V2D takes full advantage of the graphical user interface and modern programming techniques employed and validated within QW-3D. Moreover, the user experienced with either QW-V2D or QW-3D will find the operation of the other package straightforward.

QW-V2D can handle a variety of practical problems including:

Although *QW-Editor* automatically generates the FDTD mesh, the user is equipped with many means of controlling the meshing process, including the enforcement of global and local maximum cell size, mesh snapping planes, and mesh refinement in regions of expected rapid field variation.

•

accurate and stable representation of curved metal boundaries, without time-step reduction

•

higher-order modelling of media interfaces

•

wide-band modelling of skin effect in lossy metals

•

guaranteed spurious-free behaviour of the algorithm, also in the presence of strong spatial irregularities

•

matched modal excitation based on the field and impedance template

•

a new system of S-parameter extraction incorporating differential decomposition of fields into incident and reflected waves, template filtering for desired mode extraction, and compensation for imperfect absorbing boundaries

•

a novel variable source impedance technique for emulation of pure eigenmodes in inhomogeneous resonators

•

anisotropic boundary conditions (wire grids)

•

a specialised procedure, which transforms the near fields simulated in cylindrical coordinates to the far fields in spherical coordinates

•

hill-top and thermal display of instantaneous field values in the *xr* -, *rPhi*- planes

•

hill-top and thermal display of two-dimensional field envelopes in the *xr* -, *rPhi*- planes

•

hilltop and thermal display of instantaneous, maximum, and average SAR and dissipative power in the *xr* -, *rPhi*- planes

•

field envelopes along any line parallel to the *x- *or *r* - axes

•

field variation along any contour

•

field variation in time at any point

•

S-parameters versus frequency in linear, quadratic or decibel scale, on Smith chart and in polar coordinates

•

radiation patterns versus angle, radiated power, and antenna efficiency for a set of frequencies

Unique on the market and ultra fast Vector 2D (QW-V2D) electromagnetic solver is applicable to the analysis of axisymmetrical devices (which are also called **Bodies Of Revolution**) as large as 2000 wavelengths, including antennas (horns, rods, biconical), circular waveguide discontinuities, resonators and coaxial structures. It is based on the Maxwell equations re-expressed in cylindrical coordinates. Definition of a 2D long-section of the structure allows for hundreds times faster simulation than brute force 3D analysis.

axisymmetrical corrugated horn antenna:

envelope of E field

envelope of E field

coaxial structure used as an output

of a travelling wave tube (TWT)

of a travelling wave tube (TWT)

used in telescopes as well as communication antennas.