Design for planar antenna that radiates in the plane of the antenna
At 2.44GHz, a patch antenna could suit your needs.

See for example this one:
http://esatjournals.net/ijret/2014v03/i05/IJRET20140305001.pdf

Or if the omnidirectionality spec. is not that strict, an inverted-F antenna is commonly used:
http://www.ti.com/lit/an/swra117d/swra117d.pdf

Edit: In case I misread, and you don't mean normal to the pcb plane:
Just run a dipole antenna along the edge of the PCB without any metal next to it ;)