The ornamental design for an antenna for repeater, as shown and described.
FIG. 1 is a front perspective view of an antenna for repeater showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is another perspective view of the antenna for repeater in which other repeaters are shown in broken lines to illustrate an example environment; and,
FIG. 9 is another perspective view of the antenna for repeater in which the antenna is shown in a bent position and other repeaters are shown in broken lines to illustrate an example environment.
The broken lines illustrating portions of the antenna for repeater are for environmental purposes only and form no part of the claimed design.