I have had the Samsung Charge, the Droid X, and now the Bionic.....The Charge and Bionic are both having similar issues when connecting to or coming off my home network extender.
The only way to get my 3G coverage back is to turn on airplane mode and restart the radio.
I did not have this issue with my X, just my 4G phones.
I have the phone settings on CDMA only(we have no 4G in area yet) so I don't think it has to do with that...but am perplexed as to what may be causing this or what I can do to correct it.
The phone also will shut down the 3G when it is asleep, and I have to give it a few seconds to reconnect when I wake it up.