The treatment of geometrically small structures in FDTD by the modification of assigned material parameters

A number of different improvements to the analysis by finite-difference time-domain (FDTD) of small structures, such as wires, strips and slots have been proposed in the literature. One of these methods takes account of the fringing fields associated with metal edges and wires by empirically modifying the assigned material parameters in neighboring cells. In this contribution it is shown that, in many cases, it is possible to derive these modified assigned material parameters (MAMPs) analytically. In this form, the approach provides an alternative, and novel, way of incorporating Static Field Solutions into the FDTD method which has advantages of simplicity and robustness over existing techniques. Results are presented for a number of structures including wire transmission lines and a microstrip patch antenna.

[1]  C. Balanis.  Advanced Engineering Electromagnetics , 1989 .

[2]  D. Zutter,et al.  Modeling of discontinuities in general coaxial waveguide structures by the FDTD-method , 1992 .

[3]  M. Mrozowski,et al.  A conductive wedge in Yee's mesh , 1998, IEEE Microwave and Guided Wave Letters.

[4]  Ian J Craddock,et al.  A new technique for the stable incorporation of static field solutions in the FDTD method for the analysis of thin wires and narrow strips , 1998 .

[5]  T. Weiland.  Time Domain Electromagnetic Field Computation with Finite Difference Methods , 1996 .

[6]  K. Esselle,et al.  The theory of a singularity-enhanced FDTD method for diagonal metal edges , 2003 .

[7]  The treatment of thin wires in the FDTD method using a weighted residuals approach , 2004, IEEE Transactions on Antennas and Propagation.

[8]  M. Celuch-Marcysiak.  Local stereoscopic field singularity models for FDTD analysis of guided wave problems , 2003, IEEE MTT-S International Microwave Symposium Digest, 2003.

[9]  W. Heinrich,et al.  FDTD accuracy improvement by incorporation of 3D edge singularities , 1999, 1999 IEEE MTT-S International Microwave Symposium Digest (Cat. No.99CH36282).

[10]  FDTD analysis of microwave circuits using edge condition , 2002 .

[11]  G. Mur.  The Modeling of Singularities in the Finite-Difference Approximation of the Time-Domain Electromagnetic-Field Equations , 1981 .

[12]  C. Railton,et al.  Wire above ground plane transmission line formulation in FDTD algorithm , 2004 .

[13]  Dominique L. Paul,et al.  Analysis of Circular Waveguide Filter Using Enhanced FDTD , 2002 .

[14]  M. Kivikoski,et al.  An improved thin-wire model for FDTD , 2002 .

[15]  T. Weiland.  A discretization model for the solution of Maxwell's equations for six-component fields , 1977 .

[16]  A. Taflove,et al.  Calculation and experimental validation of induced currents on coupled wires in an arbitrary shaped cavity , 1987 .

[17]  Chris J Railton.  The Choice of Cell Size and the use of Pre-Calculated Correction Factors in the Analysis of Planar Circuits using FDTD and TLM , 2001, 2001 31st European Microwave Conference.

[18]  Chris J. Railton.  The inclusion of fringing capacitance and inductance in FDTD for the robust accurate treatment of material discontinuities , 2000, IMS 2000.

[19]  W. Heinrich,et al.  Treatment of field singularities in the finite-difference approximation , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.