If you are looking for a basic WiFi scanner for macOS then the command line airport utility may fit your needs.
The utility is located at:
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport
Typing the above command path can be avoided by creating a symbolic link to the command in /user/sbin/
by copying and pasting below into a terminal window.
`sudo ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/sbin/airport`
This will allow you to simply type airport
in the terminal window to execute the command.