You can get a good idea of the signal path to the antenna mounts with the photo provided, especially the photo visible via the underlying link to dx.com. Trace width would be set to match desired impedance (e.g. 50Ohm), generous spacing from adjacent ground plane for isolation, and big radii on corners to minimize self-capacitance. The 45deg component mounting is unusual, especially since the equivalent (?) PCB on dx.com doesn't have it. Perhaps this board was fabbed in low enough volume that optimizing pick & place to only do multiples of 90deg wasn't needed.