Early demonstration of a passive millimeter-wave imaging system using substrate integrated waveguide technology

Majority of the reported millimeter-wave (MMW) imaging systems are constructed on the basis of conventional waveguide technology as this technology is known to provide the best performance over higher frequency ranges. This paper proposes and presents an alternative platform of technology based on the substrate integrated waveguide (SIW) technology. Early results in the development of an SIW passive millimeter-wave imaging system are reported and discussed in this work. This technology presents many advantages over the conventional waveguide technology such as lower cost, smaller size, integrability with printed circuit board (PCB) technologies, compactness, as well as low interference susceptibility. An SIW passive imaging system operating at 35 GHz intended for concealed weapon detection is demonstrated at its early stage. It consists of a mechanically scanning reflector antenna, an SIW direct receiver and a computer running data acquisition software. The direct receiver presents a 1.5 GHz bandwidth centered at 35 GHz, 2.7 dB noise figure, and 48 dB gain. It was built upon interconnecting SIW sub-circuits in a LEGO manner which is appropriate for system prototyping. Resulting images for different scenarios are presented and the system operability is demonstrated.