Process for accurate radar cross-section evaluation using reconfigurable intelligent surfaces

1 . A radar cross-section (RCS) measurement system comprising:

a reconfigurable intelligent surface (RIS) transceiver positioned relative to a first illumination direction of a target under test (TUT);

a RIS reflector positioned relative to a second illumination direction of the TUT; and

a controller configured to:

control the RIS transceiver to transmit an electromagnetic (EM) wave towards the first illumination direction of the TUT and the RIS reflector,

control the RIS reflector to reflect the EM wave received from the RIS transceiver towards the second illumination direction of the TUT,

control the RIS reflector to reflect a scattering of the EM wave received from the second illumination direction of the TUT back to the RIS transceiver, and

compute the RCS of the TUT in the second illumination direction of the TUT based on the scattering of the EM wave received from the RIS reflector.

2 . The system of claim 1 , wherein the controller is further configured to compute the RCS of the TUT in the first illumination direction of the TUT based on a scattering of the EM wave received from the first illumination direction of the TUT.

3 . The system of claim 1 , further comprising:

a plurality of RIS reflectors including the RIS reflector and at least one additional RIS reflector, the plurality of RIS reflectors respectively positioned relative to a plurality of illumination directions of the TUT,

wherein the controller is further configured to:

control the plurality of RIS reflectors to reflect the EM wave received from the RIS transceiver towards the plurality of illumination directions of the TUT, control the plurality of RIS reflectors to reflect a plurality of scatterings of the EM wave received from the plurality of illumination directions of the TUT back to the RIS transceiver, and

compute a plurality of RCSs of the TUT in the plurality of illumination directions of the TUT based on plurality of scatterings of the EM wave received from the plurality of illumination directions of the TUT.

4 . The system of claim 3 , wherein the plurality of illumination directions includes at least six illumination directions, and the computed RCS of the TUT is a three-dimensional RCS computed with respect to the six illumination directions.

5 . The system of claim 1 , wherein the controller is further configured to control an angle of reflection of the RIS reflector by adjusting impedance of respective reflective elements of the RIS reflector.

6 . The system of claim 1 , wherein the RIS reflector is configured to receive EM waves and the controller is further configured to measure a bi-static radar RCS of the TUT by processing the scattering of the EM wave from the second illumination direction of the TUT received by the RIS reflector.

7 . The system of claim 1 , wherein the EM wave has vertical polarization or horizontal polarization and the controller is further configured to compute a vertical polarization RCS or a horizontal polarization RCS of the TUT.

8 . The system of claim 1 , wherein the controller is further configured to control the RIS transceiver and RIS reflector to control an angle of incidence of the EM wave on the TUT.

9 . The system of claim 1 , wherein the RIS transceiver transmits in a plurality of RF bands, and the RIS reflector reflects in the plurality of RF bands.

10 . The system of claim 1 , further comprising:

a support for statically positioning the TUT relative to the RIS transceiver and RIS reflector during the RCS measurement.

11 . The system of claim 1 , wherein the controller is configured to:

control the RIS transceiver to transmit the EM wave in a specified frequency band; and

control the RIS reflector to reflect the EM wave in the specified frequency band,

wherein the specified frequency band is adjustable.

12 . A radar cross-section (RCS) measurement system comprising:

a first reconfigurable intelligent surface (RIS) transceiver positioned relative to a first illumination direction of a target under test (TUT);

a second RIS transceiver positioned relative to a second illumination direction of the TUT; and

a controller configured to:

control the first RIS transceiver to transmit an electromagnetic (EM) wave towards the first illumination direction of the TUT and the second RIS transceiver,

control the second RIS transceiver to receive a scattering of the EM wave received from the TUT, and

compute the RCS of the TUT in the first illumination direction of the TUT based on the scattering of the EM wave received from the TUT.

13 . The system of claim 12 , wherein the controller is further configured to:

control the second RIS transceiver to transmit an EM wave towards the second illumination direction of the TUT and the first RIS transceiver,

control the first RIS transceiver to receive a scattering of the EM wave received from the TUT, and

compute the RCS of the TUT in the second illumination direction of the TUT based on the scattering of the EM wave received from the TUT.

14 . The system of claim 12 , further comprising:

a plurality of RIS transceivers including the first RIS transceiver, the second RIS transceiver and at least one additional RIS transceiver, the plurality of RIS transceivers respectively positioned relative to a plurality of illumination directions of the TUT,

wherein the controller is further configured to:

control the plurality of RIS transceivers to transmit and receive the EM wave towards the plurality of illumination directions of the TUT, and

compute a plurality of RCSs of the TUT in the plurality of illumination directions of the TUT based on plurality of scatterings of the EM wave received from the plurality of illumination directions of the TUT.

15 . The system of claim 14 , wherein the plurality of illumination directions includes at least six illumination directions and the computed RCS of the TUT is a three-dimensional RCS computed with respect to the six illumination directions.

16 . The system of claim 12 , wherein the controller is further configured to control an angle of reflection of the RIS reflector by adjusting impedance of respective reflective elements of the RIS reflector.

17 . The system of claim 12 , wherein the EM wave has vertical polarization or horizontal polarization and the controller is further configured to compute a vertical polarization RCS or a horizontal polarization RCS of the TUT.

18 . The system of claim 12 , wherein the controller is further configured to control the first RIS transceiver and the second RIS transceiver to control an angle of incidence of the EM wave on the TUT.

19 . The system of claim 12 , wherein the first RIS transceiver and the second RIS transceiver transmit in a plurality of RF bands.

20 . The system of claim 12 , wherein the TUT is statically positioned relative to the first RIS transceiver and the second RIS transceiver during the RCS measurement.