  We report measurements of the complex resistivity in $YBCO$ and $MgB_2$ thin
films over a continuous frequency spectrum in the microwave range, making use
of a Corbino disk geometry. The paper mainly focuses on the extraction of the
resistivity from raw data, displaying data analisys procedure and its limits of
validity. We obtain and show resistivity curves as a function of frequency and
temperature denoting a frequency dependent widening of the superconductive
transition.
