A MISO Frequency Diverse Array Implementation

Abstract

The separation of RF signals from different angles of arrival is a key objective for a radarreceiver. A common approach to spatial separation relies on the measurement of a linear phaseprogression across multiple receive antenna elements, where the rate of progression relates directlyto a spatial angle of arrival.With a single antenna receiver, spatial separation can still be achieved using spatially diverseemission structures. One such emission structure is the Frequency Diverse Array (FDA), whichtransmits a frequency shifted version of a common waveform out of each element. Due to thefrequency shifts, the peak of the mainbeam sweeps across time and space.With a careful choice of waveform and frequency shift, the waveforms transmitted from eachelement can be identified and separated in delay, and only a single receiver antenna element isneeded to measure a phase progression across the waveform responses or "virtual array" in delay.In this thesis, a Multiple Input Single Output (MISO) radar system capable of performingrange, Doppler, and spatial estimation will be presented and experimentally validated. The systemleverages key features of the LFMCW-FDA emission structure to achieve a single channel receiverarchitecture which can realize the aforementioned performance and simultaneously remain computationally inexpensive. When compared to other spatially diverse emissions, the system is shownto retain the unambiguous range and Doppler spaces. The potential for this type of emission structure to be used in a search radar context is also explored. Additionally, an adaptive processingalgorithm will be introduced along with simulated results showing an improved ability to separateclosely spaced scatterers in range and space.