Gaussian to flat-top beam shaping in an off-axis reflective scenario by a millimeter-wave metasurface.

In this paper, we present a metallic reflectarray for shaping the emitted Gaussian beam of a 100 GHz horn antenna in reflective and off-axis mode. The proposed reflectarray is a compact planar surface consisting of a 2D array of unit cells with a thin Rogers 5880 substrate. This reflectarray offers advantages over other beam shapers in millimeter-wave (MMW) imaging, as it generates a flat-top beam in off-axis reflective mode and is straightforward to fabricate.

Improving the quality of active millimeter wave standoff imaging by incorporating the cross-polarized scattering wave.

In this paper, we study the feasibility of incorporating the cross-polarized scattered wave in active standoff millimeter-wave imaging in order to improve the edge detection and background suppression for metallic objects. By analyzing the scattering from a perfectly conducting (PEC) patch of a simple geometrical shape we show that the edge diffraction is the major source of cross-polarized scattering. A similar scattering behavior is also observed for a PEC patch placed on a dielectric medium.

Generating uniform irradiance in the Fresnel region by quasi-optical beam shaping of a millimeter-wave source.

In this paper, we report on the design, simulation and measurement of a flat-top beam shaper (FBS) lens for a millimeter-wave (mm-wave) antenna coupled source. The beam shaper is designed to transform the pseudo-Gaussian beam of the mm-wave source into a flat-top beam of sharp roll-off at a specific distance in the Fresnel region. Firstly, relying on the geometrical optics principles, we propose an analytical formulation for the design of lens profiles.

Achieving subwavelength field confinement in sub-terahertz regime by periodic metallo-dielectric waveguides.

In this paper, we report on a periodic metallo-dielectric structure that supports geometry-induced surface plasmons in the sub-terahertz regime. The proposed structure is made up of a dielectric-coated metallic grating sandwiched by parallel metal plates. Based on the modal analysis of 2D and 3D structures, the impact of a metal cladding and a customized dielectric coating on the dispersion relation and field distribution of the guided surface wave is investigated.

Design of a hybrid spoof plasmonic sub-terahertz waveguide with low bending loss in a broad frequency band.

The effect of dielectric cladding on the waveguiding characteristics of an array of metallic pillars on a metal plane in the sub-terahertz band is explored. Firstly, a 2D structure made up of a metallic grating of infinite lateral width with various dielectric overlays is analytically studied to get more insight into the problem. Then the ideas inferred from the 2D structure are applied to the realistic 3D structure that has a finite lateral width.