Double-slot antennas on extended hemispherical and elliptical silicon dielectric lenses

Optimization of Micromachined Millimeter-Wave Planar Silicon Lens Antennas With Concentric and Shifted Matching Regions

“…Previously reported lenses typically use matching regions of uniform thickness [3,[9][10][11], here referred to as concentric matching regions. In this paper, we present a new matching region geometry, referred to as a shifted matching region.…”

“…The reported lens antennas have many advantages, including large bandwidths [3], frequency-stable far-fields, beam scanning capabilities [2,6,7] and frequency-stable phase center [3]. Planar lenses have many similarities with non-planar lenses, where there are many good references, see e.g., [8][9][10][11][12][13]. High-resistivity silicon is an excellent dielectric material for millimeter-wave planar lenses, due to its very small losses and accurate micromaching fabrication processes [14,15].…”

“…High-resistivity silicon is an excellent dielectric material for millimeter-wave planar lenses, due to its very small losses and accurate micromaching fabrication processes [14,15]. However, homogeneous lenses of high permittivity materials, such as silicon, suffer from reflections at the airdielectric interface caused by the large difference in impedance compared to free-space (see e.g., [9]). To reduce such reflections, high-permittivity lenses are commonly designed with up to three λ/4-matching regions, i.e., regions with permittivity and thickness determined as single or multiple λ/4-transformers [3,[9][10][11].…”

“…However, homogeneous lenses of high permittivity materials, such as silicon, suffer from reflections at the airdielectric interface caused by the large difference in impedance compared to free-space (see e.g., [9]). To reduce such reflections, high-permittivity lenses are commonly designed with up to three λ/4-matching regions, i.e., regions with permittivity and thickness determined as single or multiple λ/4-transformers [3,[9][10][11]. The advantages in using up to three λ/4-matching regions for non-planar rotationally symmetric lenses have been described in [11], based on time-domain simulations.…”

Dielectric spherical lens antenna for wireless millimeter‐wave communications

“…The exact solution of the problem of scattering from a spherically stratified Luneburg microwave lens using spherical wave functions was derived by Sanford [6] and its solution using dyadic Green's function was formulated by Mosallaei et al [7]. The solution of a hemispherical dielectric lens fed by a double-slot feed, which is a derivation from the spherical dielectric lens, is described in [8].…”