A DSP based retrodirective array for duplex digital communications

Retrodirective arrays are unique phased array systems that are capable of providing power gain in the direction of a received source with no prior knowledge of the source's location. When compared to fully adaptive arrays that adapt their beam patterns to the signal environment based on the received spatial signature, retrodirective arrays do not require the computational burden for antenna pattern adaptation. Traditionally, retrodirective arrays have been designed around analog methods such as doubled local oscillator phase conjugation and heterodyning for use in line of sight non-fading channels. This thesis describes a novel implementation of a retrodirective array for duplex digital communications and explains how retrodirective arrays can be used in flat fading channels to increase system performance. Measurements of the antenna pattern for a two element retrodirective array using flexible uplink and downlink modulation schemes are presented and show that the designed system is capable of tracking a signal source accurately under duplex communications conditions.