Nujira has been demonstrating how its envelope-tracking (ET) technology could make it practical to use CMOS power amplifiers (PAs) in the RF circuits of 4G smartphones.
According to Jeremy Hendy, v-p sales and marketing at Nujira, traditionally CMOS PAs suffer from low inherent linearity. This means they could be used for lower spec 2G and 3G devices with lower transmit power, but not high-end 3G and 4G phones.
Source:
http://www.electronicsweekly.com/Articles/2013/02/18/55582/nujira-makes-cmos-amplifiers-work-for-4g.htm
