Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


2008 Research Summary

A Fully Integrated Low-Power Phased-Array Transceiver in CMOS

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Omar Mohammed Bakr, Ali Niknejad and Yanjie Wang

Beam-forming using antenna arrays is a widely used technique that can potentially improve the range and capacity of wireless networks in crowded spectrum bands by improving spatial reuse. Unfortunately, the high costs and power requirements of most beam-forming systems today limit their usage in consumer devices.

The goal of this research is to design a multi-purpose adaptive array system for a wide range of narrow band applications (e.g., cellular, WLAN) operating anywhere from 0-6 GHz in nanometer CMOS technology. The wide-frequency band of operation imposes more constraints on the linearity and interference suppression requirements of the overall system. This project will explore novel beam-forming architecture that meets the linearity and bandwidth requirements with minimum power and die area, and allow the system to scale to hundreds of antennas. The design of phase-shifters lies at the core of this architecture. The proposed phase-shifter employs both active and passive CMOS variable gain stages in a vector-combining architecture, achieving high linearity and bandwidth while consuming little DC power. We will also explore feedback techniques for improving the accuracy and reliability of the phase-shifters over process and temperature variations.

A complete multi-channel beam-forming transceiver will be realized in 90 nm technology.