Digital Beam-Forming for Passive Millimetre Wave Security Imaging

This paper reviews digital beam-forming as an alternative technology for the development of passive millimetre wave (PMMW) imagers. Considering recent technology developments and end-user requirements, digital beam- forming is an attractive prospect for a new architecture of PMMW security imager. The radiometric sensitivity in PMMW electronic beam-forming is investigated using beam- former simulations and comparisons made with a mechanical scanning PMMW imager. The objectives, design considerations and progress to date on a demonstrator programme for a PMMW digital beam-forming imager directed at the commercial security screening market are discussed. The benefits of digital beam-forming for security scanners are reviewed together with the calibration technique and the programme future.