Vehicle assembly comprising a radar sensor and a set of layers
The invention relates to a vehicle assembly for a vehicle, with the vehicle assembly including a radar sensor configured to transmit/receive radar waves. The radar sensor being placed facing a layer assembly. The layer assembly includes at least two dielectric layers, these dielectric layers including a primary layer and a secondary layer separated by a layer of air. The layer of air has a thickness equal to (m3×(λ/2))/cos(θ3), with θ3 an angle of incidence of exiting reflected waves striking the secondary layer and m3=1, . . . to N, N being an integer, the exiting reflected waves deriving from radar waves transmitted by the radar sensor.
1 . A vehicle assembly for a vehicle, the vehicle assembly comprising:
a radar sensor configured to transmit or receive a number of radar waves, the radar sensor being placed facing a layer assembly, and
the layer assembly, which includes at least two dielectric layers, said dielectric layers including primary layers and secondary layers where each primary layer and each secondary layer is separated by a layer of air;
wherein the layer of air has a thickness equal to ((m3+ε)×(λ/2))/cos (θ3), where λ is a wavelength, where ε includes a value between −0.25 and +0.25, where θ3 represents an averaged angle of incidence from a plurality of exiting reflected waves striking the secondary layer; and
where m3 is defined by a number selected in a range from 1 to N, N being a positive integer, said exiting reflected waves derived from each associated radar waves transmitted by the radar sensor;
wherein the primary layer has a thickness equal to (λ/(2×n1×cos β1))+(m1×λ), where β1 is a refracted angle corresponding to an angle of incidence θ1 of each transmitted radar wave and where n1 is a refractive index of the primary layer and m1 is an integer selected from 1 to N; and
wherein the thickness of the primary layer is defined by the angle of incidence θ1 equal to arctan (d1/(2e4)), where d1 is a distance between a transmitter antenna and a receiver antenna, and where e4 is a distance between the radar sensor and the primary layer.
2 . The vehicle assembly of claim 1 , wherein the radar sensor is a radar sensor employing millimeter waves (waves between 24 GHz and 300 GHz) or sub-microwaves (waves between 300 MHz and 81 GHz) or microwaves (waves between 1 GHz and 300 GHz).
3 . The vehicle assembly of claim 1 , wherein radar waves are transmitted in a frequency band comprised between 100 MHz and 3 GHz.
4 . The vehicle assembly of claim 1 , wherein the secondary layer has a thickness equal to (λ/(2n2 cos β2))+(m2×λ), with β2 represents a refracted angle corresponding to an averaged angle of incidence θ2 from a plurality of a radar waves exiting from the primary layer; and where n2 is a refractive index of the secondary layer and m2 is an integer selected from 1 to N.
5 . The vehicle assembly of claim 1 , wherein the primary layer is a decorative part and the secondary layer is an exit lens of a light-emitting device of the vehicle.
6 . The vehicle assembly of claim 5 , wherein the light-emitting device is a headlamp or a tail lamp.
7 . The vehicle assembly of claim 1 , wherein the primary layer is a luminous element of a logo and the layer is an exit lens of a logo of the vehicle.
8 . The vehicle assembly of claim 1 , wherein the primary layer is a radome and the secondary layer is a logo.
9 . The vehicle assembly of claim 1 , wherein the layer assembly includes a layer that is a radome, a layer that is a decorative part and a layer that is an exit lens of a light-emitting device.
10 . A layer assembly for a vehicle, the layer assembly configured to be placed facing a radar sensor and configured to transmit or receive radar waves, comprising:
at least two dielectric layers, said dielectric layers including primary layers and secondary layers where each primary layer and each secondary layer is separated by a layer of air;
wherein the layer of air has a thickness equal to (m3×(λ/2))/cos(θ3), where λ is a wavelength, wherein θ3 is an averaged angle of incidence from a number of exiting reflected waves striking the secondary layer, where m3 is defined by a number selected in a range from 1 to N, N being a positive integer, said exiting reflected waves derived from each associated radar waves transmitted by the radar sensor;
wherein the primary layer has a thickness equal to (λ/(2×n1×cosβ1))+(m1×λ), where β1 is a refracted angle corresponding to an angle of incidence θ1 of each transmitted radar wave and where n1 is a refractive index of the primary layer and m1 is an integer selected from 1 to N; and
wherein the thickness of the primary layer is defined by the angle of incidence θ1 equal to arctan (d1/(2e4)), where d1 is a distance between a transmitter antenna and a receiver antenna, and where e4 is a distance between the radar sensor and the primary layer.