A single-pixel imaging remote sensor operating at 330 GHz is described. It is based on a frequency modulated continuous wave (FMCW) and aimed at detection of concealed objects for ranges up to 40 m. The system consists of 2 horn-lens antennas integrated with a homodyne transceiver. The synthesized linear FMCW signal at X-band is multiplied by a factor of 32 to generate the transmitted signal. An intermediate frequency (IF) signal obtained in the output port of the 2-nd harmonic mixer is employed for image processing. Distance measurements were made by performing data acquisition unit based on LabView interface and resulting in a range resolution about 1 cm. Examples of 2D and 3D images reconstructed with this sensor are presented.

Sub-millimeter and Terahertz waves maintain reasonable penetration depth in certain common materials, such as cloth, plastic, wood, sand and soil. Therefore, THz radiation can detect concealed weapons since many non-metallic, non-polar materials are transparent to this type of radiation (and are not transparent to visible radiation). Target compounds such as explosives and illicit drugs have characteristic THz spectra that can be used to identify these compounds. Investigation, design and development of a sub-millimeter wave remote sensing RADAR system for homeland security applications are presented. The RADAR, operating at 330GHz is based on transmission of a frequency modulated continuous wave (FMCW) and aimed at detection of concealed objects for ranges up to 20m. The system consists of 2 horn-lens antennas integrated with a homodyne transceiver. The synthesized linear FM signal with a frequency span of 200MHz at X-band is multiplied by a factor of 32 to generate the transmitted Tera-Hertz wave. Using a splitter, the signal is fed to an antenna and to a local oscillator port of a second harmonic balanced mixer. As a result, an intermediate frequency signal is obtained, containing the information on the target. Distance measurements were made by performing data acquisition and signal processing commercial programs, resulting in a range resolution better than 1cm. Preliminary Tera-Hertz imaging was also carried out to perform a three-dimensional image of the object.Index Terms -Millimeter, sub-millimeter and Tera-Hertz radar.

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A sub-mm system prototype is presented for imaging objects hidden under human body clothes. The system is primarily intended for in-door and out-doors homeland security applications. Its hardware is based on Rx-Tx modules operating with FMCW signal at the range 325 -335 GHz. In order to improve spatial resolution the standard horn antennas have been integrated with focusing Teflon lenses. Computer design of such antenna system has been performed using CST Microwave Studio I-Solver. As a result the beam spot diameter about 1cm at the distance up to 2m was formed. The target imaging algorithms based on averaged-weighted procedure has been suggested for reconstructing the shape of a tested object. Examples of 2D and 3D image reconstructions are reported.