S-Band MIMO FMCW Imaging Radar and MIMO Array Calibration Algorithm

Through dielectric radar sensing has a significant part in the detection of buried objects. The radar used in these applications should meet two criterions, first, it should operate at low frequencies to be able to penetrate the medium the object is buried in and second, it should have a high spatial resolution to be able to discriminate between the object of interest and clutter reflections caused by the medium. The presented radar is based on an FMCW architecture and operates in the S-band, 2 to 4 GHz, to meet the first criterion. Spatial resolution in the cross-range dimension is accomplished by using a MIMO antenna array made of overall six broadband Vivaldi antennas, two transmit and four receive antennas. A calibration process to calibrate the phase and amplitude response of the MIMO array is presented, requiring only one measurement of a reference target at a known position.