antenna-theory.com

[hagster]

https://www.kickstarter.com/projects/1096577862/the-biquad-yagi-antenna-for-wifi-and-fpv/description

I came across this Kickstarter for the bi-quad yagi antenna and was initially quite sceptical about the performance claims. He claims 18dBi for the smaller variant and 22dBi for the larger one. That would be huge for something so small and he doesn't detail where he got those figures from.

When, I look through the guys youtube videos, I see lots of very rough and ready measurements using wifi dongles and reporting performance as percentages, which doesn't inspire confidence that the figures quoted are real.

The bi-quad isn't really an antenna that I had really looked at in detail before now, but to satisfy my curiosity I ran a simple nec2 model of the basic bi-quad and double bi-quad and got gains of about 11dBi and 13dBi respectively and with near perfect SWR on the first. So, maybe it really is somewhere near as good as he claims.

Has anyone else got an opinion on this? Is it worth backing?

[Parna]

He gives the dimensions for what he says was the first prototype for the 18dBi on his youtube channel:

https://www.youtube.com/watch?v=TanbyHBKrvU

Can you run a simulation for it? The gain does seem overstated. If a 14 element yagi has 14 dBi gain (http://www.radiolabs.com/products/antennas/2.4gig/14eleyagi.php), then just because this one outperforms that one in "signal strength percentage", doesn't make you think its gain is 18 dBi..