Antenna

FIG. 1 is a front perspective view of an antenna showing our new and ornamental design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is another rear perspective view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a left-side view thereof;

FIG. 7 is a right-side view thereof;

FIG. 8 is a top view thereof; and,

FIG. 9 is a bottom view thereof.

The broken lines in the drawings depict portions of the antenna that form no part of the claimed design.