Wow ! It’s a surprise for me to see that helical antennas are working so good on 5ghz to 6ghz band. Here is a company that selling them http://www.q-par.com/products/helical-antennas/5-6-ghz-helical-antenna
GAIN ~10 to 11.5 dBic by specification -who knows
So if You like to try 5ghz wireless links, You may try helical antennas . I’ll be waiting for results if someone try to build and test this.
Here is the picture of one of this - nothing unusual really: