The Triple Feed Patch antenna is a directional circularly polarized antenna that I created in collaboration with Robin Theunis, one of my co-workers. The main design goals were:
- Good radiation efficiency. Most FR4-based patches have terrible efficiency because FR4 is very lossy at 5.8 GHz.
- Good axial ratio, not just directly perpendicular to the patch but also off-center.
- Cheap and easy to manufacture with high accuracy, even for a hobbyist.
(strictly according to Maarten Baer design requirements, learn more, please click: http://www.maartenbaert.be/quadcopters/antennas/triple-feed-patch-antenna/)