I am new to antenna design and this field in general. I am looking to design a WiFi antenna (less than 15 cm x 15 cm) that can effectively increase the range of a 2.4 GHz WiFi router.
It should be extremely directional as I am only trying to increase the range in one direction (this is for a project, not for any practical use).
So far from my research, the most attractive option is a Yagi-Uda antenna, as it is relatively small and not too complicated, and it also has a high directivity. However, my first build was relatively unsuccessful. I used the design from a YouTube video.
The antenna looks like this. It is a disk Yagi and the results in the video were extremely promising.
However, my application of it is slightly different, and I was also not able to build it the exact same way, as the dimensions were not clear. It called for use of copper, and I bought copper colored aluminum, which in hindsight was a mistake, but I did not know how much it would affect the performance. It seemed to make soldering more difficult, but I can't tell if it affected the actual range.
Additionally, the disks I cut were by no means perfect and had imperfections. In order to attach the antenna to my router, I cut and soldered on an SMA male cable and connected it to the RP-SMA female under the unscrewed built in antenna on the router (with a few adaptors of course).
The antenna performed sub-optimally, only really increasing the range by around 4 meters (measured using continuous recording of the RSI value). Additionally, I very quickly put together a parabolic antenna out of tinfoil molded into a cup shape, and I just touched the bare wire on the SMA Male in order to connect it, and to my surprise this performed better than the Yagi, going up to about 6 meters away.
My question is, what is the best antenna to do this, and if it is one of the ones that I chose, what modifications should I make in order to improve it?
Additionally, any resources on proper dimensioning for the Yagi antenna (boom length, director spacing, etc.) would be greatly appreciated.