Circular Wireless offers you the best in quality and performance with this 5.8Ghz Skew Planer antenna.

The circularly polarized omnidirectional antenna ideal for use in the video transmitter. Combined with other Skew Planar Wheel at the receiver offers coverage in all directions, with moderate range. Combined with a helical in the receiver provides more range than you might need. All antennas are Right Hand Circular Polarized, and are supplied with SMA male connector. They are made of MIG wire coated with three layers of metal-free paint, and the weld is reinforced with epoxy. 

More info on the antenna design available here.