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•UWB S-band MIMO Array Imaging System
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•2-4 GHz UWB S-band chirp
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•Utilizing airborne SAR imaging algorithm for beamforming
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•Simultaneous transmit and receive (FMCW radar mode)
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•1 mW transmit power
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•Range gate
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•High sensitivity capable of imaging 1.25 inch tall nails
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•Imaging through lossy dielectric slabs
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•This system was developed as part of my PhD dissertation at
the Michigan State University Electromagnetics Research Group
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•The following information is provided:
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•Abstract
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•Pictures of each radar system are shown
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•Data and radar imagery
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•Publications
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•Misc. ppt slide shows
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•Engineering notes
ABSTRACT
A Low-Power Radar Imaging System
By
Gregory Louis Charvat
A near real-time radar-based imaging system is developed in this dissertation. This system uses the combination of a spatially diverse antenna array, a high sensitivity range-gated frequency-modulated continuous wave (FMCW) radar system, and an airborne synthetic aperture radar (SAR) imaging algorithm to produce near real-time high resolution imagery of what is behind a dielectric wall. This system is capable of detecting and providing accurate imagery of target scenes made up of objects as small as 6 inch tall metallic rods and cylinders behind a 4 inch thick dielectric slab. A study is conducted of through-dielectric slab imaging by the development of a 2D model of a dielectric slab and cylinder. The SAR imaging algorithm is developed and tested on this model for a variety of simulated imaging scenarios and the results are then used to develop an unusually high sensitivity range-gated FMCW radar architecture. An S-band rail SAR imaging system is developed using this architecture and used to image through two different dielectric slabs as well as free-space. All results are in agreement with the simulations. It is found that free-space target scenes could be imaged using low transmit power, as low as 5 picowatts. From this result it was decided to develop an X-band front end which mounts directly on to the S-band rail SAR so that objects as small as groups of pushpins and aircraft models in free-space could be imaged. These results are compared to previous X-band direct conversion FMCW rail SAR work. It was found that groups of pushpins and models could be imaged at transmit powers as low as 10 nanowatts. A spatially diverse S-band antenna array will be shown to be developed for use with the S-band radar; thereby providing the ability for near real-time SAR imaging of objects behind dielectric slabs with the same performance characteristics of the S-band rail SAR. The research presented in this dissertation will show that near real-time radar imaging through lossy-dielectric slabs is accomplished when using a highly sensitive radar system located at a stand-off range from the slab using a free-space SAR imaging algorithm.
Publications
Dissertation Defense Power Pointe Slides:
A Low-Power Radar IMaging System Dissertation Defense PPT Slides
Dissertation at Michigan State University Library
Engineering Notes
S-band YIG oscillator measured data (frequency, amplitude, vs. voltage). Right-click to download open-office document.
Measurement slab holding apparatus.
Current Work:
A real-time through-wall radar imaging system.