%0 Thesis
%9 Doctoral
%A Antonik, P.
%B Department of Electronic and Electrical Engineering
%D 2009
%F discovery:18746
%I UCL (University College London)
%P 238
%T An investigation of a frequency diverse array
%U https://discovery.ucl.ac.uk/id/eprint/18746/
%X This thesis presents a novel concept for focusing an antenna beam pattern as a function  of range, time, and angle. In conventional phased arrays, beam steering is achieved by  applying a linear phase progression across the aperture. This thesis shows that by  applying an additional linear frequency shift across the elements, a new term is  generated which results in a scan angle that varies with range in the far-field.  Moreover, the antenna pattern is shown to scan in range and angle as a function of time.  These properties result in more flexible beam scan options for phased array antennas  than traditional phase shifter implementations. The thesis subsequently goes on to  investigate this phenomenon via full scale experimentation, and explores a number of  aspects of applying frequency diversity spatially across array antennas. This new form  of frequency diverse array may have applications to multipath mitigation, where a radio  signal takes two or more routes between the transmitter and receiver due to scattering  from natural and man-made objects. Since the interfering signals arrive from more than  one direction, the range-dependent and auto-scanning properties of the frequency  diverse array beam may be useful to isolate and suppress the interference. The  frequency diverse array may also have applications to wideband array steering, in lieu  of true time delay solutions which are often used to compensate for linear phase  progression with frequency across an array, and to sonar, where the speed of  propagation results in large percentage bandwidth, creating similar wideband array  effects. The frequency diverse array is also a stepping stone to more sophisticated joint  antenna and waveform design for the creation of new radar modes, such as simultaneous  multi-mode operation, for example, enabling joint synthetic aperture radar and ground  moving target indication.
%Z Copyright restricted material has been removed from the e-thesis.