Synthetic ultra-wideband millimeter-wave imaging for tissue diagnostics

Abstract

The present disclosure relates to an apparatus and method for synthetically making an ultra-wide imaging bandwidth in millimeter-wave frequencies, resulting in improved image resolutions to values previously unattained. The synthetic approach sums up a number of available sub-bands (channels) to build an unavailable ultra-wideband system. Each channel contains an antenna unit which is optimized for operation within that specific sub-band. The number and position of the channels can be adjusted to cover any frequency range as required for the specific application.

1 . (canceled) 
     
     
         2 . A method comprising the steps of:
 transmitting, from each of a plurality of sub-band imaging elements to a target, output signals operating in a corresponding one of a plurality of predetermined sub-bands of a range of millimeter-wave frequencies;   wherein each sub-band imaging element of the plurality of sub-band imaging elements is configured to operate only in its corresponding sub-band which is different from the sub-band of each remaining one of the plurality of sub-band imaging elements;   receiving return signals reflected from the target in response to the performance of the transmitting step for each of the plurality of sub-band imaging elements;   combining, at a processor, the return signals received from the performance of the transmitting and receiving steps to form an integrated signal covering the range of millimeter-wave frequencies; and   using the integrated signal to generate an image of the target.   
     
     
         3 . The method of  claim 2 , wherein the receiving step is performed at one or more of the plurality of sub-band imaging elements. 
     
     
         4 . The method of  claim 2 , wherein the transmitting and receiving steps are performed sequentially as a cycle for each sub-band imaging element of the plurality of sub-band imaging elements at each of a plurality of scanning locations. 
     
     
         5 . The method of  claim 4 , wherein each sub-band imaging element of the plurality of sub-band imaging elements is sequentially positioned at a distinct position in each of the plurality of scanning locations for the performance of the transmitting and receiving steps. 
     
     
         6 . The method of  claim 5 , wherein the distinct position of each of the plurality of sub-band imaging elements relative to the target is adjustable. 
     
     
         7 . The method of  claim 4 , wherein each successive pair of the plurality of scanning locations are spaced from each other by a distance which is less than half of the smallest operating wavelength in which the sub-band imaging elements of the plurality of sub-band imaging elements operate. 
     
     
         8 . The method of  claim 2 , wherein the step of using the integrated signal to generate an image of the target includes calculating pulse responses from incident pulses in frequency domain by using the integrated signal. 
     
     
         9 . The method of  claim 8 , wherein the step of using the integrated signal to generate an image of the target includes converting the pulse responses to time domain by using an Inverse Fourier Transform operation. 
     
     
         10 . The method of  claim 9 , wherein the step of using the integrated signal to generate an image of the target includes applying a reconstruction algorithm to the pulse responses to generate the image of the target. 
     
     
         11 . The method of  claim 2 , wherein each of the plurality of sub-band imaging elements includes a corresponding one of a plurality of antennas. 
     
     
         12 . The method of  claim 11 , wherein each antenna of the plurality of antennas has a size; and wherein the size of each antenna of the plurality of antennas is different from the sizes of the other antennas of the plurality of antennas. 
     
     
         13 . A device for imaging, comprising:
 an imaging element configured to transmit, from each of a plurality of sub-band imaging elements to a target, output signals operating in a corresponding one of a plurality of predetermined sub-bands of a range of millimeter-wave frequencies;   wherein each sub-band imaging element of the plurality of sub-band imaging elements is configured to operate only in its corresponding sub-band which is different from the sub-band of the other sub-band imaging elements of the plurality of sub-band imaging elements;   wherein at least one sub-band imaging element of the plurality of sub-band imaging elements is configured to receive return signals reflected from the target in response to the transmission of the output signals, for each of the plurality of sub-band imaging elements; and   a processor, configured to combine the return signals to form an integrated signal covering the range of millimeter-wave frequencies and use the integrated signal to generate an image of the target.   
     
     
         14 . The device of  claim 13 , wherein said at least one sub-band imaging element is configured to transmit and receive sequentially as a cycle for each sub-band imaging element of the plurality of sub-band imaging elements at each of a plurality of scanning locations. 
     
     
         15 . The device of  claim 14 , wherein each sub-band imaging element of the plurality of sub-band imaging elements is adapted to be sequentially positioned at a distinct position in each of the plurality of scanning locations to perform transmitting and receiving. 
     
     
         16 . The device of  claim 15 , wherein the distinct position of each of the plurality of sub-band imaging elements relative to the target is adjustable. 
     
     
         17 . The device of  claim 13 , wherein said image of the target is generated by calculating pulse responses from incident pulses in frequency domain by using the integrated signal. 
     
     
         18 . The device of  claim 17 , wherein said image of the target is generated by converting the pulse responses to time domain by using an Inverse Fourier Transform operation. 
     
     
         19 . The device of  claim 18 , wherein a reconstruction algorithm is applied to the pulse responses to generate said image of the target. 
     
     
         20 . The device of  claim 13 , wherein each of the plurality of sub-band imaging elements includes an antenna. 
     
     
         21 . The device of  claim 20 , wherein each antenna of the plurality of antennas has a size; and wherein the size of each antenna of the plurality of antennas is different from the sizes of the other antennas of the plurality of antennas.