An antenna assembly includes a tool mandrel having a tool axis, and a coil including a plurality of windings wrapped about the tool mandrel at a winding angle offset from the tool axis. A soft magnetic band radially interposes the coil and the tool mandrel and extends about a circumference of the tool mandrel at a band angle parallel to the winding angle. The soft magnetic band includes a plurality of stacked inserts extending perpendicular to the coil about the circumference of the tool mandrel and each stacked insert includes a plurality of rods positioned end-to-end.