One method to transition controlled impedance lines from layer to layer is
to form a coaxial line where the center via is your transmission line
which is then surrounded by a ring of ground vias. Ground via diameter is dictated
by the dielectric constant of your substrate material.
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\_ Mike McNulty \_
\_ Lockheed Martin GES \_
\_ Moorestown NJ \_
\_ Phone:(609)722-7323 \_
\_ Fax:(609)722-2207 \_
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does anyone have any data concerning 50 ohm transmission lines
starting on the first layer and using vias to transport it to an inner layer.
I have looked at the IPC specs concerning microstrip etc. good info.
unfortunately it just doesn't mention anything about how to get a
impedance controlled line from one layer to the next. I know that
someone out there has done the numbers or knows where to go to
get them. Please let me know
thanks in advance.