I was looking through the MIB files, trying to find the OID to return the width of the channel the AP was currently using (10MHz, 20MHz, 30MHz, 40MHz), and I could not seem to find it in the MIB.
I did track down the correct OID for this property, and I'm sharing it here just in case someone else was looking for it:
.1.3.6.1.4.1.161.19.3.3.2.83.0Returns a string with the value of the current AP Channel Bandwidth, formatted like “20.0”