A complete UMTS transmitter using BAW filters and duplexer: A 90‐nm CMOS digital RF signal generator and a 0.25‐μm BiCMOS power amplifier

A complete UMTS transmitter is proposed. It is composed of a radiofrequency (RF) signal generator, a power stage, and a bulk acoustic wave (BAW) duplexer. The 90‐nm CMOS digital RF signal generator is based on a third‐order delta‐sigma modulator using innovative design techniques to increase work frequency and a BAW filter to get rid of out‐of‐band quantization noise. The filter exhibits very high rejection, 3 dB of insertion losses at 1.95 GHz for a 3% fractional bandwidth. The 0.25‐μm BiCMOS power stage feeds a BAW duplexer that allows to share a common between W‐CDMA emission and reception. This 4 × 4 mm² duplexer, built with flip‐chipped BAW on glass substrate, ensures good isolation. The full transmitter measurements show the compliance with respect to spurious emissions in the different frequency bands and an EVM measurement at the state of the art (<5%). © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.