A Wi-Fi antenna can support 2.4 GHz and/or 5 GHz. There are basically several kind of Wi-Fi antennas: directive, omnidirectional and sector antennas, all of them available as standard or MIMO.
Due to most of Wi-Fi access points support 2.4 GHz (operating by the IEEE 802.11b/g/n standard) as well as 5 GHz (operating by the IEEE 802.11a/n/ac standard), the antennas are suitable for both frequency bands and Wi-Fi standards.