Millimeter-Wave and Sub-THz Modulated Metasurface Antennas

Abstract

Modulated metasurfaces (MTSs) have sprung up in the last decade as an attractive solution for wave guidance and radiation. More precisely, modulated MTS antennas stand out for providing an unprecedented control of the aperture fields with low-profile and lightweight structures. In this class of antennas, a surface-wave (SW) is gradually radiated, owing to its interaction with a modulated impedance boundary condition (IBC). This IBC is typically implemented in the microwave regime by several thousands of sub-wavelength patches printed on a grounded slab. However, dielectric losses may hinder the use of standard printed circuit board (PCB) technology at higher frequencies. In this paper, we will address this issue by introducing a new class of metal-only modulated MTS, which can be easily fabricated by additive manufacturing or micro-machining for millimeter-wave and sub-THz applications.

Metal-only Reflecting Luneburg Lens Design for Sub-THz Applications

“…Since we envisage a future fabrication by DRIE, n eq (ρ) of the original model [4] has been appropriately adapted. A maximum of four etching steps is selected to avoid increasing the fabrication complexity [3]. This means that the refractive index can only take five values along the lens radius, since the final step with n eq = 1 does not require any etching.…”

“…To work at the aforementioned frequency range one has to select accurate fabrication processes that also guarantee low losses. To this end, Si wafers can be micro-machined with micrometer accuracy by deep reactive ion etching (DRIE) and then metallized by sputtering Au to avoid dielectric losses [3]. On the other hand, beam-steering is pivotal at these bands to ensure an accurate beam alignment in longrange point-to-point scenarios.…”