At 12:25 PM 8/20/98 -0400, fabrizio zanella wrote:
>Gentlemen, formulae for calculating impedances of stripline/microstrip
>traces are only somewhat accurate for certain geometries. The formulae
>were developed many years ago, when line widths were .010"+, dielectric
>thicknesses differed from today's designs, and most designs used 50 ohm
>transmission lines. For high impedance tlines, (80+ ohms), the accuracy of
>the formulae gets terrible.
>If you want to match your TDR measured impedances to calculations, you need
>to use a field solver tool. There are many good tools available that use
>boundary element or finite element analysis. Try Apsim's 'RLGC' tool, or
>Ansoft's Maxwell EZ2D.
Air Force Research Lab
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Kirtland AFB NM 87117-5776
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