The ornamental design for a multi-band antenna, as shown and described.
The FIGURE is a front elevational view of a multi-band antenna showing our new design.
The design for a double-band antenna is so thin that it is barely discernable in top, bottom, and side views. All elements of the design are flat and coplanar with each other.
The broken line portion of the figure is included to show unclaimed subject matter only and forms no part of the claimed design. The three shaded areas are the only areas that are claimed.