A series of transverse electromagnetic transmission cells (TEM cells) developed at the National Bureau of Standards (NBS) is three-dimensional analyzed using a mixed discretization based on both of constant and linear elements in a boundary element method (mixed BEM). Mixed BEM presented here is generalized in order to be usable in two and three dimensions. Conductor surface of TEM cell models is discretized using non-uniform elements so that the flux distribution can be approximated more accurately in the less number of elements. The distributed characteristic impedance, which is important to design the cell, in the main line section is evaluated through the flux induced in the center conductor. The calculated results are in good agreement with those in two dimensions in spite of the small number of elements. As a result, it is proved that three-dimensional cell models are effectively and accurately solved by using mixed BEM and non-uniform elements together. The present work plays a preliminary part in an analysis of more realistic NBS cell models taken into account a tapered section. In future, therefore, we will be able perform a reliable analysis of TEM cells using mixed BEM and non-uniform elements.

A particle trajectory estimation method from far electromagnetic fields are discussed in this paper. Authors have already presented a trajectory estimation method for single particle system and good agreements between a source particle trajectory and an estimated one have been obtained. For this, this paper discusses twin particles system as an examples of multi-particles systems for simplicity. First of all, it is pointed out that far electromagnetic fields from the twin particles system show quite different aspect from the single particle system using an example, radiation patterns produced by two particles which carry out circular motion. This result tells us that any trajectory estimations for general multi-particles system are almost impossible. However, it is shown that when the distance between the particles is small, the estimation method for the single particle system can be applied to the twin particles system, and that twin particles effects appear as disturbance of estimated trajectory.

A new boundary integral formulation is presented in order to solve a general Laplace-Poisson's equation, which is one of the basic equations of semiconductor devices. As this formulation is based on Green's second identity or Gauss' divergence theorem, no conventional volume integral is needed, regardless of arbitrary distributions of space charge. The potentials and electric field intensities at interface nodes put between a Laplace and a Poisson domain are analytically calculated, because interface nodes are treated as same as internal points. It is effective and powerful to device analysis of such a junction-gate field effect transistor with interfaces movable according to operation bias conditions. On the basis of simple numerical experiments, the present method is applied to a simplified device models. It is shown that device analysis can be easily obtained for a more small discretized model. In consequence, numerical results also demonstrate the effectiveness of this approach.

We extend the position angle in the two-conductor transmission line to the position angle matrix in the multiconductor lines. The position angle matrix is applied to analysis of cascaded transmission lines, so that the relationship of the voltage vectors (or the current vectors, or the impedance matrices) between two different points on the line can be expressed in the compact form by using the position angle matrices.

Transverse electromagnetic transmission cells are analyzed with high accuracy using a mixed discretization based on both of constant and linear elements in a boundary element method, in which we can take account into discontinuous values of a normal derivative of the potential at corners in the cells.

Open strip lines with unbounded regions are analyzed using the boundary element method (BEM) with pseudo-infinite boundary elements which are considered as the semi-infinite boundary of unbounded regions. Numerical results with accuracy show that use of the pseudo-infinite elements used in BEM is available in analyzing the unbounded regions.

In order to effectively solve a three-dimensional unsteady convective diffusion equation, kernel approximation is introduced into the boundary integral procedure in the boundary-element method. It is shown that the present method gives a good approximate solution of the convective diffusion equation in case of not a dominant convection. Also, we find that very fast numerical integration can be carried out on supercomputers.

We have presented a formulation of convective diffusion equations based on the method of sub-regions and the boundary element method, especially in three dimensions, in order to analyze very long and narrow convection-diffusion fields which we frequently encounter. In this formulation, we have introduced mixed-type boundary elements, which have more advantages in boundary element computation, and the weighted conservation law of mass in each sub-boundary model so as to be conservative in itself. In addition we have proposed a coupling technique at interface boundaries in order to equalize the number of equations to that of interface unknowns. As a result, it is found that the present method will give more accurate and stable solutions and also have more merits even on the basis of the method of sub-regions, and so is suitable and applicable particularly to a three-dimensional problem. The present formulation for mixed elements is also usable not only to convective diffusion problems, but also to Laplace and Helmholtz-type equations in steady and unsteady state.

This paper describes a finite element method to obtain an accurate solution of the scalar Helmholtz equation with field singularities. It is known that the spatial derivatives of the eigenfunction of the scalar Helmholtz equation become infinite under certain conditions. These field singularities under mine the accuracy of the numerical solutions obtained by conventional finite element methods based on piecewise polynomials. In this paper, a regularized eigenfunction is introduced by subtracting the field singularities from the original eigenfunction. The finite element method formulated in terms of the regularized eigenfunction is expected to improve the accuracy and convergence of the numerical solutions. The finite element matrices for the present method can be easily evaluated since they do not involve any singular integrands. Moreover, the Dirichlet-type boundary conditions are explicitly imposed on the variables using a transform matrix while the Neumann-type boundary conditions are implicitly imposed in the functional. The numerical results for three test problems show that the present method clearly improves the accuracy of the numerical solutions.

Boundary-element solutions of an unsteady-state convective diffusion equation are investigated using a mixed boundary-element method with both constant and linear elements. Transient numerical solutions at each discrete time are compared with exact solutions so that the dependence of their relative errors on time and space are demonstrated. It is shown that the present method is applicable to an electromagnetic field analysis governed by the partial differential equation of convective-diffusion type as in a steady state problem.

Numerical characteristics of mixed element solutions are studied in comparison with constant and linear elements'. It is shown that mixed elements give accurate solutions as similar to the previous investigations and also the system of equations is better-conditioned than other elements'.

A steady-state convective diffusion problem is analyzed using a mixed boundary element method with both of constant and linear elements in three dimensions. The usefulness of the present method is shown as compared with a boundary element method with only constant elements.

Axisymmetric modes of axisymmetric resonant cavities are studied by using the hybrid boundary element method (H-BEM). We can see that H-BEM solutions have high accuracies from comparison of numerical solutions with exact solutions. It is shown that H-SEM is useful to study axisymmetric modes of axisymmetric cavities.