Efficient Eigenmode Analysis for Planar Transmission Lines

A unified analysis for planar transmission fines is performed rising the mode-matching technique. Exploiting the fact that the thickness of the metal coating (fins or strips) is normally very small in comparison to all other dimensions, the characteristic equations are formulated in a way which preserves the physical meaning of their individual terms. Thus, simplifications of far-reaching consequences can be introduced for all eigenmodes showing a cutoff frequency. It is shown in particular that the higher order modes can be derived approximately from the fundamental mode. Moreover, the dispersion relation of fin-lines can be given by a simple expression because the equivalent dielectric constant linearly depends on frequency. Both steps reduce the computer time by about two orders of magnitude in comparison to the spectral-domain method.

[1]  W.J.R. Hoefer.  Empirical Analytical Expressions for Fin Line Design , 1981, 1981 IEEE MTT-S International Microwave Symposium Digest.

[2]  I. Wolff,et al.  A Solution of the Earthed Fin Line with Finite Metallization Thickness , 1980, 1980 IEEE MTT-S International Microwave symposium Digest.

[3]  T. Itoh,et al.  Generalized Spectral Domain Method for Multi-Conductor Printed Lines and its Application to Tunable Suspended Microstrips , 1978, 1978 IEEE-MTT-S International Microwave Symposium Digest.

[4]  Lorenz-Peter Schmidt,et al.  Spectral Domain Analysis of Dominant and Higher Order Modes in Fin-Lines , 1979 .

[5]  Tatsuo Itoh,et al.  Characteristics of Unilateral Fin-Line Structures with Arbitrarily Located Slots , 1980 .

[6]  S. Hopfer,et al.  The Design of Ridged Waveguides , 1955 .

[7]  P. J. Meier,et al.  Integrated Fin-Line Millimeter Components , 1974 .

[8]  Raj Mittra,et al.  A Technique for Computing Dispersion Characteristics of Shielded Microstrip Lines (Short Papers) , 1974 .

[9]  K. Schunemann,et al.  Closed-form approximations for fin-line eigenmodes , 1982 .

[10]  A.-M.A. El-Sherbiny.  Exact Analysis of Shielded Microstrip Lines and Bilateral Fin Lines, Jul. 1981 , 1981 .

[11]  Tatsuo Itoh,et al.  Spectral Domain Immittance Approach for Dispersion Characteristics of Shielded Microstrips with Tuning Septums , 1979, 1979 9th European Microwave Conference.

[12]  Raj Mittra,et al.  Analytical and Numerical Studies of the Relative Convergence Phenomenon Arising in the Solution of an Integral Equation by the Moment Method , 1972 .