  New experiments at Fermilab require higher beam intensities at Booster,
resulting in higher influence of magnet steel on the beam. In order to
carefully take these effects into account it is necessary to know geometric and
material properties of magnets. This work is dedicated to the measurement of
magnetic permeability of steel laminations of Booster gradient magnets as a
complex function of frequency in the frequency range from several megahertz up
to 1 GHz. The magnetic permeability is estimated by analyzing S-parameters of
microstrip lines made up from laminated steel.
