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International audienceA novel dual-layer multibeam pillbox antenna with a slotted waveguide radiating part in substrate-integrated waveguide (SIW) technology is proposed. In contrast to previous works, the design goal is to have a multibeam antenna with arbitrary low sidelobes and at the same time a high crossing level between adjacent radiated beams. These two constraints cannot be satisfied simultaneously for any passive and lossless multibeam antenna systems with a single radiating aperture due to beam orthogonality. Here, this limitation is overcome using the “split aperture decoupling” method which consists in using two radiating apertures. Each aperture is associated with a pillbox quasi-optical system with several integrated feed horns in its focal plane so as to steer the main beam in the azimuthal plane. The antenna operates at 24.15 GHz and presents very good scanning performance over an angular sector of ±40°, with a good agreement between full-wave simulations and measurements. The crossover level between adjacent beams is about -3 dB with a sidelobe level lower than -24 dB for the central beam and better than -11 dB for the extreme beam positions. The isolation between feed horns in the same pillbox system is better than 20 d

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 m 3 and a 10 Hz frame rate.

A wide field of view inversely magnified dual-lens system for sub-millimeter wavelength imagers is presented in this contribution. The antenna is designed for near-field focusing, at a range of 2.1 m from the primary aperture and to work in the frequency range from 200 to 600 GHz. The half power beamwidth is 0.27 • (1 cm in the image plane) at 500 GHz, corresponding to a focused antenna directivity of approximately 55 dBi. The field of view is as large as ±25.4 • (±1 m at the nominal range), corresponding to a scan range of ±100 half power beamwidths. The shapes of the lens surfaces are optimized to minimize the phase aberration loss over the entire scanning range. Moreover, the lenses are designed to be as thin as possible to limit the dielectric absorption loss. The directivity reduction of the edge pattern with respect to broadside is approximately 1 dB with an efficiency of 56%, making this lens an excellent candidate for imaging applications. The dual-lens system can be refocused by displacing the secondary lens and shows an essentially unchanged angular half power beamwidth over a refocusing range of ±50% with respect to the nominal imaging distance. A demonstrator was fabricated and the experimental results at 500 GHz confirm the predicted performance.

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 cm 3 voxel resolution over a 1 m 3 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. I.