  We report results on deep Jansky Very Large Array A-configuration
observations at 22 GHz of the hotspots of the radio galaxies 3C227 and 3C445.
Synchrotron emission in the optical on scales up to a few kpc was reported for
the four hotspots. Our VLA observations point out the presence of unresolved
regions with upper limit to their linear size of about 100 pc. This is the
first time that such compact components in hotspots have been detected in a
mini-sample, indicating that they are not a peculiar characteristic of a few
individual hotspots. The polarization may reach values up to 70 per cent in
compact (about 0.1 kpc scale) regions within the hotspot, indicating a highly
ordered magnetic field with size up to a hundred parsecs. On larger scales, the
average polarization of the hotspot component is about 30-45 per cent,
suggesting the presence of a significant random field component, rather than an
ordered magnetic field. This is further supported by the displacement between
the peaks in polarized intensity and in total intensity images that is observed
in all the four hotspots. The electric vector position angle is not constant,
but changes arbitrarily in the central part of the hotspot regions, whereas it
is usually perpendicular to the total intensity contours of the outermost edge
of the hotspot structure, likely marking the large-scale shock front. The
misalignment between X-ray and radio-to-optical emission suggests that the
former is tracing the current particle acceleration, whereas the latter marks
older shock fronts.
