الفهرس 
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Abstract
This thesis addresses Synthetic Aperture Radar (SAR) for high resolution
microwave land imaging. The SAR is radar used to create an image of object by
using use of relative motion, between an antenna and the target region to obtain finer
spatial resolution than is possible with conventional beam-scanning means.
SARs image has two spatial dimensions, one dimension in the image is called range
(or cross track) and is distance from the radar to the target. SAR range resolution is
determined by the transmitted pulse width, i.e. narrow pulses yield fine range
resolution. The other dimension is called azimuth (or along track) and is perpendicular
to range. To obtain fine azimuth resolution, a physically large antenna is needed to
focus the transmitted and received energy into a sharp beam. The sharpness of the
beam defines the azimuth resolution.
The present thesis is concerned with enhancing the SAR imaging resolution in
both range and azimuth directions. It proposes a new scheme for SAR pulse
compression to get high resolution images in the range direction. The principle of a
chirped pulse with quadratic frequency modulation (QFM) is introduced as a way for
achieving fine SAR imaging resolution and good signal to noise ratio. Side lobe level
reduction of the matched filter response due to the received compressed pulse is
achieved using a single stage of a second order time-dependence of the frequency. The
parameters of time-dependence of the frequency are shown to have a great effect on
the lowest side lobe level of the time waveform of the signal at the output of the
matched filter and on the received pulse width as well. Simulation results of the
proposed QFM compressed signal are presented, where suppressed side lobe level is
achieved.
High-resolution wide-swath imaging using SAR system requires a radiation beam
which is narrow in the azimuth direction and relatively wide in the range direction.
Moreover. along the range direction. the signal strength should be uniform over the
beam spot area on the ground surface. Such a beam is very difficult to implement
unless an array with large number of elements and an optimized distribution