Millimeter-wave imaging system with 360 degrees field of view

摘要

A passive millimeter-wave imaging system (10) is disclosed that provides a full 360° instantaneous azimuthal field-of-view (54) image of a scene. The imaging system (10) makes use of a spherical Luneburg lens (12) and a series of millimeter-wave direct detection receivers (24) configured in a ring (16) around the lens (12), and positioned at the focal plane of the lens (12). The series of receivers (24) are positioned on a plurality of consecutive sensor cards (14), where each card (14) includes a certain number of the receivers (24). The receivers (24) define a one-dimensional focal plane array with limited obscuration, and thus give a 360° instantaneous field-of-view (54) of a slice of the scene. Processing circuitry (32), including a multiplexing array interface for multiplexing the signals from the receivers (24), are positioned on an outer ring (34) outside of the sensor card ring (16). Mechanical actuators (42) are provided to cause the rings (16, 34) to move together in a precessional motion about the lens (12) so that the rings (16, 34) precess at a fixed angle Θ about a fixed reference direction (46), thus providing an elevational scan of +/- Θ about the plane perpendicular to the reference direction (46).