1. UWB X-band rail SAR imaging System

  2. 7.5-12.5 GHz UWB linear FM chirp

  3. Simultaneous transmit and receive (FMCW radar mode)

  4. 10 mW transmit power

  5. Range gate

  6. High sensitivity capable of imaging pushpins and model aircraft

  7. Nano-watt radar operation

  8. This system was developed as part of my PhD dissertation at the

    Michigan State University Electromagnetics Research Group

  1. The following information is provided:

  2. Abstract

  3. Pictures of of this X-band rail SAR

  4. Data and imagery

  5. Publications

  6. Misc. ppt slide shows

  7. Engineering notes


A Low-Power Radar Imaging System


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.


G. L. Charvat, L. C. Kempel, C. Coleman, “A Low-Power High-Sensitivity X-Band Rail SAR Imaging System,” IEEE Antennas and Propagation Magazine, Vol. 50, No 3, June 2008, pp. 108-115.

    (draft of this article)

G. L. Charvat, ``A Low-Power Radar Imaging System," Ph.D. dissertation, Dept. of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, 2007.

    Dissertation Defense Power Pointe Slides:

    A Low-Power Radar IMaging System Dissertation Defense PPT         Slides

Misc. PPT Slide Shows

G. L. Charvat, “A low-power radar imaging system,” The Boston Chapter of the IEEE APS Society, December 11, 2007

Engineering Notes

X-band YIG oscillator measured data (frequency, amplitude, vs. voltage).  Right-click to download open-office file.


Low-Power X-Band Rail SAR

Photo Albums:

X-Band Rail SAR Hardware

June 2007

X-Band Rail SAR data, acquired at MSU

June 2007