1 GHz Programmable Analog Phase Shifter for Adaptive Antennas

Abstract

Adaptive antennas are currently being considered as a means to improve spectral efficiency of wireless networks. They can be used to spatially separate different mobile user, by forming radiation pattern nulls at the interfering signals. However, the relatively high cost of adaptive antenna systems compared to non-adaptive antennas has hampered their commercial application. The purpose of this thesis is to investigate the feasibility of realizing an integrated circuit that will implement a one GHz programmable analog phase shifter, an important building block of adaptive antenna systems. This could lower the system's cost of adaptive antennas. The programmable analog phase shifter is comprised of a 900 phase shifter, a variable gain amplifier, a summer and a digital-to-analog converter. The resulting chip area is small enough to allow 16 complete phase shifter circuits to be included in a single package, thereby allowing control of an array of 16 antenna elements.