1. UWB S-band MIMO Array Imaging System

  2. 2-4 GHz UWB S-band chirp

  3. Utilizing airborne SAR imaging algorithm for beamforming

  4. Simultaneous transmit and receive (FMCW radar mode)

  5. 1 mW transmit power

  6. Range gate

  7. High sensitivity capable of imaging 1.25 inch tall nails

  8. Imaging through lossy dielectric slabs

  9. 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 each radar system are shown

  4. Data and radar 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, E. J. Rothwell, C. Coleman, and E. L. Mokole, ``A through-dielectric ultrawideband (UWB) switched-antenna-array radar imaging system" IEEE Transactions on Antennas and Propagation, Vol. 60, No. 11, November 2012, pp. 5495-5500.

G. L. Charvat, L. C. Kempel, E. J. Rothwell, C. Coleman, E. J. Mokole. "An ultrawideband (UWB) switched-antenna-array radar imaging system"  Waltham, MA:  IEEE International Symposium on Phased Array Systems & Technology, October  2010.

    (slides from this conference)

G. L Charvat, L. C. Kempel, E. J. Rothwell, C. Coleman, “A Low-Power, Real-Time, S-Band Radar Imaging System.” Boston Massachusetts: Antenna Measurement and Techniques Association Conference, November 2008.

    (slides from this conference)

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

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

    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.


UWB S-band MIMO Phased Array Radar System for Looking Through Dielectric Slabs

Photo Albums:

MIMO array real-time imager

July 2007

MIMO array real-time data, acquired at MSU

July 2007