is there a way to diagnose the wireless antenna in my MacBook Air?

Recently my MacBook Air has struggled with wifi speed. Running a speed test results in 1 -2 Mbps, while running one on my iPhone right next to the MacBook results in 260 Mbps. I have done all the typical things - restart the computer, clear the caches, ensure latest version of all software is installed, run a virus scan, etc. - to no effect. I get 1 bar on the wireless connection. I am wondering if there is a hardware issue with the antenna, or something else. Does anyone have any suggestions?