Modeling and Calibration of Multi-Port Based Receiver Systems Mitigating System Imperfections and Hardware Impairments

Abstract

Six-port based homodyne receiver architecture is a low power and low cost alternative to the conventional homodyne receiver using diode based mixers. The problems of dc-offset, I/Q cross-talk, high conversion loss and nonlinearities due to diode mixers are some of the issues that make the conventional homodyne receiver architecture not very useful for practical low power communication systems employing envelope varying modulation scheme signals. The radio frequency (RF) front-end in a typical six-port based receiver (SPR) consists of a linear and passive six-port junction circuit that can be easily designed to cover a very large bandwidth. This makes the SPR concept an attractive candidate for software defined radio (SDR) receiver applications. The six-port based RF front-end provides low loss and doesn’t pose any nonlinearity issues. Sources of errors due to circuit and system components impairments can be easily calibrated and compensated in a SPR system as shown in this thesis.