Antenna configuration has more to do with the bands supported than the technology used. It does require a different chipset to support CDMA.
There are CDMA/GSM phones available by implementing both technologies (and Qualcomm does provide hybrid chips). The Droid 2 Global is the best example right now. It supports CDMA 850/1900; GSM 850/900/1800/1900; UMTS 850, 1900, 2100.
There are CDMA/GSM phones available by implementing both technologies (and Qualcomm does provide hybrid chips). The Droid 2 Global is the best example right now. It supports CDMA 850/1900; GSM 850/900/1800/1900; UMTS 850, 1900, 2100.