  We consider an inverse scattering problem for time-harmonic acoustic or
electromagnetic waves. The goal is to localize several small penetrable objects
embedded inside an otherwise homogeneous background medium from observations of
far field patterns of scattered fields corresponding to plane wave incident
fields with one fixed incident direction but several different frequencies.
Taking advantage of the smallness of the scatterers with respect to wave length
we utilize an asymptotic representation formula for the far field pattern to
design and analyze a MUSIC-type reconstruction method for this setup. We
establish lower bounds on the number of frequencies and receiver directions
required to recover the number and the positions of the scatterers for a given
configuration by the reconstruction algorithm. Furthermore we apply the method
to the practically interesting case of multifrequency backscattering data.
Numerical examples are presented to document the potentials and limitations of
this approach.
