The ornamental design for a substrate for antennadevice, as shown and described.
FIG. 1 is a front, bottom, and left side perspective view for a substrate for antenna device showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof, the bottom view being identical thereof; and,
FIG. 5 is a right side view thereof, the left side view being identical thereof.
The dashed lines depict portions of the substrate for antenna device that form no part of the claimed design. The dot-dash lines define the bounds of the claimed design and form no part thereof.