Sign apparatus for vehicle
Disclosed is a sign apparatus for displaying a sign for traffic or a vehicle, where the sign apparatus includes a display configured to display the sign and to permit a radar signal radiated from a source to pass, a filter configured to attenuate a signal of at least one frequency in the radar signal passing through the display and to allow a signal of a remaining frequency to pass, and a reflector configured to reflect the signal passing through the filter, wherein the reflected signal includes encoded identification information of the sign.
1 . An apparatus for displaying a sign comprising:
a display, comprising a transparent member, configured to display the sign and to permit a radar signal radiated from a source to pass;
a filter configured to attenuate a signal of at least one frequency in the radar signal passing through the display and to allow a signal of a remaining frequency to pass; and
a reflector configured to reflect the signal passing through the filter,
wherein the reflected signal comprises encoded identification information of the sign, and
wherein the display is located on the filter.
2 . The apparatus of claim 1 , wherein
the identification information has N digits;
a first digit to a last digit of the N digits correspond to different frequencies; and
the filter is further configured to attenuate a signal of a frequency corresponding to a digit having a first value and to allow a signal of a frequency corresponding to a digit having a second value to pass.
3 . The apparatus of claim 2 , wherein
the filter is further configured to attenuate a signal of a frequency corresponding to the first digit in response to the first digit having the first value, and to allow the signal of the frequency corresponding to the first digit in response to the first digit having the second value.
4 . The apparatus of claim 2 , wherein
the filter comprises unit cells, and
each of the unit cells comprises a resonator having a frequency corresponding to a digit having the first value as a resonance frequency.
5 . The apparatus of claim 1 , wherein
the filter comprises unit cells, and
each of the unit cells comprises a number of resonators corresponding to a number of first values in the identification information or equal to a multiple of the number of first values.
6 . The apparatus of claim 5 , wherein
each of the unit cells comprises resonators of different sizes, in response to the identification information having a plurality of first values.
7 . The apparatus of claim 6 , wherein
the resonators are positioned on different layers.
8 . The apparatus of claim 5 , wherein
a spacing between the unit cells corresponds to half a wavelength value of a center frequency of the radiated radar signal.
9 . The apparatus of claim 1 , wherein
the filter is spaced apart from the reflector by a first distance.
10 . The apparatus of claim 9 , wherein
the first distance is greater than a result of multiplying a wavelength value of a center frequency of the radiated radar signal with a value.
11 . The apparatus of claim 1 , wherein
the reflector comprises a trihedral corner reflector.
12 . The apparatus of claim 1 , wherein
the source comprises a radar sensor disposed in an autonomous vehicle.
13 . An apparatus for displaying a sign, the apparatus comprising:
a display, comprising a transparent member, configured to display the sign and to permit a radar signal radiated from a source to pass;
a filter comprising resonators, the filter configured to attenuate a signal of a resonant frequency of each of the resonators in the radar signal passing through the display and to allow a signal of a remaining frequency to pass; and
a reflector configured to reflect the signal passing through the filter,
wherein the reflected signal comprises encoded identification information of the sign, and
wherein the display is located on the filter.
14 . The apparatus of claim 13 , wherein
the identification information has N digits,
a first digit to a last digit of the N digits correspond to different frequencies, and
the resonant frequency is same as a frequency of a digit having a first value in the identification information.
15 . The apparatus of claim 13 , wherein
the filter comprises unit cells, and
each of the unit cells comprises one or more resonators of the resonators.
16 . The apparatus of claim 15 , wherein
a spacing between the unit cells corresponds to half a wavelength value of a center frequency of the radiated radar signal.
17 . The apparatus of claim 13 , wherein
the filter is spaced apart from the reflector by a first distance value.
18 . The apparatus of claim 17 , wherein
the first distance value is greater than a result of multiplying a wavelength value of a center frequency of the radiated radar signal with a value.
19 . The apparatus of claim 13 , wherein
the reflector comprises a trihedral corner reflector.
20 . The apparatus of claim 13 , wherein
the source comprises a radar sensor disposed in an autonomous vehicle.