Planar asymmetric dual diode for millimetre wave detection and power measurement

Waveguide-to-planar circuit transition for millimetre-wave detectors

We present a novel design of a waveguide to microstrip or coplanar waveguide transition using a unilateral finline taper. The transition from the unilateral finline mode to the TEM microstrip mode is done directly, avoiding the antipodal finline tapers that have commonly been employed. This results in significant simplification of the design and fabrication, and shortening of the chip length, t...

Microwave and millimetre wave sensors for crack detection

Millimetre-Wave Personnel Scanners for Automated Weapon Detection

The ATRIUM project aims to the automatic detection of threats hidden under clothes using millimetre-wave imaging. We describe a simulator of realistic millimetre-wave images and a system for detecting metallic weapons automatically. The latter employs two stages, detection and tracking. We present a detector for metallic objects based on mixture models, and a target tracker based on particle fi...

Asymmetric wave propagation in planar chiral fibers.

We demonstrate the realization of a two-dimensional chiral optical waveguide with an infinite translational symmetry that exhibits asymmetric wave propagation. The low-symmetry geometry of the cross-section that lacks any rotational and mirror symmetries shows in-principal directional asymmetric polarization rotation. We use general symmetry arguments to provide qualitative analysis of the wave...

Using of Broadened Asymmetric Waveguide Structure for 980nm Diode Laser

Laser diode beam divergence is the main parameter for beam shaping and fiber optic coupling. Increasing the waveguide layer thickness is the conventional method to decrease the beam divergence. In this paper, the broadened asymmetric waveguide is introduced to decrease the divergence without increasing the optical power. The asymmetric waveguide was used to shift the vertical optical field to n...