2.4 GHz Chip antenna layout
That is a filter.  It's a stub filter.  The length of the trace is tuned a multiple of the wavelength of interest an then shorted to the ground plane.

Stub Matching



They come in all shapes and sizes



Here are some that show the non-connected nature of some styles:
http://home.sandiego.edu/~ekim/e194rfs01/filterek.pdf