Abstract: A method and a system of determining a surface location defining an interface between an object to image and an antenna is provided. The method uses geometric principles and the fact that an impedance mismatch at the interface results in significant reflection. A propagation time from the surface to each antenna of a plurality of antennas is estimated. The propagation time locates the surface on a circle centered at each antenna and having a radius calculated using the propagation time. A tangent line connects the intersection of adjacent circles with the surface. The surface is estimated to be located at the tangent point where the circle and the shared tangent line between adjacent antennas intersect. Multiple tangent points may be averaged for each interior antenna. A curve is fit to the set of tangent points to provide an estimate of the surface location.

Abstract: Microwave imaging via space-time beamforming is carried out by transmitting microwave signals from multiple antenna locations into an individual to be examined and receiving the backscattered microwave signals at multiple antenna locations to provide received signals from the antennas. The received signals are processed in a computer to remove the skin interface reflection component of the signal at each antenna to provide corrected signal data. The corrected signal data is provided to a beamformer process that time shifts the received signals to align the returns from a scatterer at a candidate location, and then passes the time aligned signals through a bank of filters, the outputs of which are summed, time-gated and the power therein calculated to produce the beamformer output signal at a candidate location. The beamformer is then scanned to a plurality of different locations in the individual by changing the time shifts, filter weights and time-gating of the beamformer process.

Abstract: Microwave imaging via space-time beamforming is carried out by transmitting microwave signals from multiple antenna locations into an individual to be examined and receiving the backscattered microwave signals at multiple antenna locations to provide received signals from the antennas. The received signals are processed in a computer to remove the skin interface reflection component of the signal at each antenna to provide corrected signal data. The corrected signal data is provided to a beamformer process that time shifts the received signals to align the returns from a scatterer at a candidate location, and then passes the time aligned signals through a bank of filters, the outputs of which are summed, time-gated and the power therein calculated to produce the beamformer output signal at a candidate location. The beamformer is then scanned to a plurality of different locations in the individual by changing the time shifts, filter weights and time-gating of the beamformer process.