A high frame rate, 340 GHz 3D imaging radar for security

Funding: European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312745.The need for improved security at airports with high detection performance, high throughput rates and an improved passenger experience is motivating research into new sensing technologies. The European Union funded CONSORTIS project is addressing these aims by demonstrating a system which combines a submillimeter wave radar, a dual-band passive submillimeter wave camera and automatic anomaly detection software for reliable detection while ensuring passenger privacy. In this paper we describe the 340 GHz 16-channel FMCW radar which produces 3D maps of the subject with ∼1 cm3 voxel resolution over a 1 m3 sense volume at multi-hertz frame rates. The radar combines advanced transceiver electronics with high speed mechanical beam steering and parallelized processing to achieve this level of performance.Postprin

High resolution, wide field of view, real time 340GHz 3D imaging radar for security screening

Funding: Part of the research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312745.The EU FP7 project CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) is developing a demonstrator system for next generation airport security screening which will combine passive and active submillimeter wave imaging sensors. We report on the development of the 340 GHz 3D imaging radar which achieves high volumetric resolution over a wide field of view with high dynamic range and a high frame rate. A sparse array of 16 radar transceivers is coupled with high speed mechanical beam scanning to achieve a field of view of ~ 1 x 1 x 1 m3 and a 10 Hz frame rate.Publisher PD

The CONSORTIS 16-channel 340-GHz security imaging radar

We have completed a 16-channel 340 GHz 3D imaging radar for next-generation airport security screening under the European Union funded CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) project. The radar maps a 1 x 1 x 1 m3 sense volume with ∼1 cm3 voxel resolution at multi-hertz frame rates. The radar has been installed in the CONSORTIS system enclosure and integrated with a passenger control system and command module. The full system will ultimately also incorporate a dual-band passive submillimeter wave imager and automatic anomaly detection software for reliable, ethical detection of concealed objects. A large data collection trial on targets of interest has been conducted to support the development of automatic anomaly detection software. Initial threat detection analysis indicates promising results against aviation-relevant objects including simulant dielectric threat materials.Publisher PD

Broadband and polarization independent waveguide-fiber coupling

Waveguide-to-fiber coupling is one of the key challenges in silicon photonics. Many approaches have already been experimentally demonstrated, such as grating couplers, inverse tapers, sub-wavelength structures, lensed fibers, photonic wire bonds, small-core fibers and separate waveguide interposers. However, it is difficult to find a concept that simultaneously offers broadband operation, polarization independency, low optical loss, simple fabrication and easy assembly. In this paper, the pros and cons of different concepts are reviewed. Then two alternative concepts are introduced for coupling light between 3 µm thick SOI waveguides and standard single-mode fibers with ultra-broadband (&gt;500 nm bandwidth) and polarization independent operation. Experimental results with 1-2 dB loss per waveguide-fiber interface are reported for 1) separate 12 µm SOI interposers and 2) polymer lenses directly written to the end facets of the 3 µm SOI waveguides. The insertion loss of the interposer concept includes both the waveguide-interposer and interposer-fiber interfaces, as well as the loss of the interposer itself. The loss of the polymer lens concept includes the losses of the waveguide-to-lens, lens-to-air and air-to-fiber interfaces, as well as the loss of the directly written lens. Polymer lenses were also integrated on top of up-reflecting mirrors to demonstrate vertical fiber coupling. The scalability of the two concepts for low-cost silicon photonics packaging is also analyzed, taking into account the ability to align fibers passively into V-grooves or others such structures on the SOI chips.</p