Dipole vs Patch Antenna for indoor wifi

Hello. I am working on a project to improve wifi strength of an android tv box in a classroom. It comes with a 50 ohm dipole antenna. In the classroom, the router or repeater is situated in the rear of the classroom. I proposed replacing the antenna with a transmission line fed patch antenna. Simulation indicates 7.14dBi directional gain compare to under 3dBi in the dipole. I was quite positive with my proposal.


I installed the "Wifi Analyzer" app to measure the signal strength of both dipole and the patch. I designed the patch using FR4 substrate and measured the return loss on VNA. When I plugged the dipole antenna, the app measured signal strength of -50dB, while the patch antenna measured lower at -58dB. I was disappointed that it didn't work to my expectation.

I have come to a conclusion that the wall in the classroom scatter the EM waves which meant that the omnidirectional antenna has an advantage over the more directional patch antenna. Would you agree?

I am planning to try a PIFA antenna or a circularly polarised patch antenna to see if this improves the signal strength. Does anyone have a suggestion?

That one may not be a dipole antenna and may be a collinear antenna, which gives more dB's of gain than a simple patch antenna.
Are very few chances that the radio waves from the omni-directional antenna to arrive at the destination (after many reflections) with the right phase and adding constructively.

There are few options of building simple high gain antennas for WiFi:

Coffee Can Antenna:
**broken link removed**

Helical antenna:
**broken link removed**

Yagi antenna:
https://www.instructables.com/id/Easy-to-Build-WIFI-24GHz-Yagi-Antenna/