Frequency-scalable imaging radar

A method of imaging one or both of a scanned surface and an object at least partially concealed by the scanned surface, comprising:

• using an imaging device including
• an antenna configured to transmit millimeter waves,
• a connector adapted to connect a radio frequency (RF) signal source with the imaging device,
• a signal path connected between the connector and the antenna,
• a nonlinear transmission line (NLTL)-based frequency multiplier arranged along the signal path to receive an RF signal from the RF signal source and increase a frequency of the RF signal to the extremely high frequency (EHF) band to produce a millimeter wave,
• a NLTL-based variable delay line arranged along the signal path between the NLTL-based frequency multiplier and the antenna,
• wherein a time delay of an NLTL of the NLTL-base variable delay line is variable to steer a beam of the millimeter wave in at least one dimension as the millimeter wave is transmitted by the antenna, and
• a receiver adapted to process a return signal received in response to the millimeter wave;
• arranging an aperture of the antenna a predetermined distance from a surface to be scanned;
• scanning the surface by transmitting a beam comprising a millimeter wave from the antenna of the imaging device to the surface;
• steering the beam along the at least one dimension;
• and
• imaging, while steering the beam, one or both of the scanned surface and an object at least partially concealed by the scanned surface based on a return signal received in response to the transmitted millimeter wave.

A system for imaging one or both of a scanned surface and an object at least partially concealed by the scanned surface, comprising:

• a vector network analyzer (VNA) including a radio frequency (RF) signal source;
• an imaging device including
• an antenna configured to transmit millimeter waves,
• wherein the imaging device is adapted to receive RF signals from the RF signal source of the VNA,
• a signal path connected with the antenna,
• wherein the RF signals propagate along the signal path,
• a nonlinear transmission line (NLTL)-based frequency multiplier arranged along the signal path to receive an RF signal from the RF signal source and increase a frequency of the RF signal to the extremely high frequency (EHF) band to produce a millimeter wave;
• a NLTL-based variable delay line arranged along the signal path between the NLTL-based frequency multiplier and the antenna,
• wherein a time delay of an NLTL of the NLTL-base variable delay line is variable to steer a beam of the millimeter wave in at least one dimension as the millimeter wave is transmitted by the antenna;
• and
• a receiver adapted to process a return signal received in response to the millimeter wave.