Radar system for a vehicle
The present disclosure relates to a radar system featuring a reduced radio cross-section (RCS). This is achieved by providing a radar system comprising one or more antenna structures and a spatially modulated surface structure, wherein the spatially modulated surface structure is configured to generate, from incident radar waves, a first portion of reflected waves and a second portion of reflected waves, wherein the first portion of reflected waves is out of phase in relation to the second portion of reflected waves.
1 . A radar system, comprising:
a structure comprising a first surface and a second surface, the first surface and the second surface being non-overlapping regions of a common plane;
at least one antenna structure occupying the first surface; and
at least one spatially modulated surface occupying the second surface of the structure,
wherein the at least one spatially modulated surface is configured to generate, from incident radar waves, a first portion of reflected waves and a second portion of reflected waves, wherein the first portion of reflected waves is out of phase in relation to the second portion of reflected waves,
wherein the at least one spatially modulated surface comprises a plurality of elements, protruding and/or receding from a baseline surface of the radar system, and each element of the plurality of elements has a height or depth of at least 1 millimeter as measured from the baseline surface, and
wherein the at least one spatially modulated surface is formed by a manufacturing technique suitable for producing three-dimensional shapes.
2 . The radar system according to claim 1 , wherein the first portion of reflected radio waves is reflected with a phase shift of (2n−1)×180° with a tolerance of ±90° compared to the second portion of reflected radio waves, where nϵZ+.
3 . The radar system according to claim 1 , wherein the at least one antenna structure is configured for emitting a signal of a predefined wavelength, ; and wherein a spatial dimension of the plurality of elements is adapted to be within (2n−1)× /2 of the predefined wavelength, where nϵZ+.
4 . The radar system according to claim 1 , wherein each of the plurality of elements has a predetermined shape that alternates and/or repeats along a predetermined direction on the baseline surface of the radar system.
5 . The radar system according to claim 1 , wherein a cross-sectional shape of at least some of the plurality of elements is a sinusoidal and/or another geometric shape.
6 . The radar system according to claim 1 , wherein at least one of the plurality of elements extends along a predetermined direction along the baseline surface.
7 . The radar system according to claim 6 , wherein the predetermined direction corresponds to a polarization of the at least one antenna structure.
8 . The radar system according to claim 6 , wherein the predetermined direction corresponds to a radiation direction of the at least one antenna structure.
9 . The radar system according to claim 1 , wherein one or more of the plurality of elements is a concave or convex hemisphere.
10 . The radar system according to claim 1 , wherein at least some of the plurality of elements have a same shape and are distributed across at least a portion of the baseline surface of the radar system.
11 . The radar system according to claim 1 , wherein at least some of the plurality of elements are repeatedly arrayed across at least a portion of the baseline surface of the radar system.
12 . The radar system according to claim 1 , wherein the at least one spatially modulated surface occupies at least 5-10% of the baseline surface of the radar system not occupied by the at least one antenna structure.
13 . The radar system according to claim 1 , wherein the at least one spatially modulated surface is made from, coated, or plated in a metal.
14 . A vehicle comprising a radar system according to claim 1 .
15 . The radar system according to claim 1 , wherein the at least one spatially modulated surface is a two-dimensional shape longer in a first dimension than in a second dimension,
wherein the at least one antenna structure is positioned at the second dimension of the at least one spatially modulated surface, and
wherein the at least one spatially modulated surface extends along a direction of transmission and/or polarization of the at least one antenna structure in the first dimension.
16 . The radar system according to claim 2 , wherein the phase shift is caused by the protruding and/or receding elements of the at least one spatially modulated surface.