US-20260126545-A1 - FREQUENCY SELECTIVE SURFACE WITH TUNABLE RADAR CROSS SECTION

US20260126545A1US 20260126545 A1US20260126545 A1US 20260126545A1US-20260126545-A1

Abstract

A system for communication can include a frequency selective surface having a tunable radar cross section configured to receive an electromagnetic signal. The frequency selective surface can include an isolation layer, a plurality of conductive elements disposed on a first side of the isolation layer, and a plurality of tunable components, each coupled with a respective conductive element. A control system can be configured to adjust a bias voltage applied to the tunable components to modulate the radar cross section of the frequency selective surface and encode binary data in a reflected electromagnetic signal. A radar system can be configured to transmit the electromagnetic signal and receive the reflected electromagnetic signal. The frequency selective surface can operate within a frequency band corresponding to an operational frequency of the radar system to enable adaptive, reflected-signal communication.

Inventors

Jason Brett Evatt
Wesley R. Bonin
Kenneth Fritsch

Assignees

AIRBORNE OUTFITTERS LLC

Dates

Publication Date: 20260507
Application Date: 20251105

Claims (20)

1 . A system for communication, comprising: a frequency selective surface having a tunable radar cross section configured to receive an electromagnetic signal, the frequency selective surface comprising: an isolation layer; a plurality of conductive elements disposed on a first side of the isolation layer; and a plurality of tunable components, each tunable component coupled with a respective conductive element of the plurality of conductive elements; a control system configured to adjust a bias voltage applied to each tunable component of the plurality of tunable components to modulate a radar cross section of the frequency selective surface to encode binary data in a reflected electromagnetic signal following receipt of the electromagnetic signal by the frequency selective surface; a radar system configured to transmit the electromagnetic signal and receive the reflected electromagnetic signal; and the frequency selective surface is configured to operate within a frequency band corresponding to an operational frequency of the radar system.
2 . The system of claim 1 , wherein the frequency selective surface includes a ground layer disposed on a second side of the isolation layer opposite the plurality of conductive elements.
3 . The system of claim 2 , wherein the frequency selective surface includes a substrate layer disposed on the first side of the isolation layer.
4 . The system of claim 3 , wherein the substrate layer includes a member selected from a group consisting of a polymer, a ceramic, a glass, a composite, and combinations thereof.
5 . The system of claim 4 , wherein the substrate layer includes the polymer and the polymer includes a member selected from a group consisting of polytetrafluoroethylene, polyimide, polyethylene terephthalate, polycarbonate, and combinations thereof.
6 . The system of claim 4 , wherein the substrate layer includes the ceramic and the ceramic includes a member selected from a group consisting of alumina, silicon nitride, and combinations thereof.
7 . The system of claim 4 , wherein the substrate layer includes the glass and the glass includes a member selected from a group consisting of quartz, borosilicate glass, and combinations thereof.
8 . The system of claim 1 , wherein the plurality of conductive elements includes a member selected from a group consisting of an N-pole type element, a loop type element, a plate type element, and combinations thereof.
9 . The system of claim 8 , wherein the plurality of conductive elements includes the N-pole type element and the N-pole type element includes a member selected from a group consisting of a dipole, a tri-pole, a Jerusalem cross, a cross-dipole, a spiral, and combinations thereof.
10 . The system of claim 8 , wherein the plurality of conductive elements includes the loop type element and the loop type element includes a member selected from a group consisting of a multi-legged element, a circular loop, a square loop, a hexagonal loop, and combinations thereof.
11 . The system of claim 1 , wherein each tunable component of the plurality of tunable components includes a PIN diode.
12 . The system of claim 11 , wherein the control system is configured to adjust the bias voltage applied to each PIN diode to modulate the frequency selective surface between a high radar cross section state and a low radar cross section state.
13 . The system of claim 12 , wherein an increase to the bias voltage modulates the frequency selective surface to the low radar cross section state.
14 . The system of claim 12 , wherein a decrease to the bias voltage modulates the frequency selective surface to the high radar cross section state.
15 . The system of claim 12 , wherein the high radar cross section state represents a binary of 1.
16 . The system of claim 12 , wherein the low radar cross section state represents a binary of 0.
17 . The system of claim 1 , wherein the radar system comprises a signal processor configured to decode a variation in the reflected electromagnetic signal corresponding to the encoded binary data.
18 . A system for communication, comprising: a frequency selective surface having a tunable radar cross section configured to receive an electromagnetic signal, the frequency selective surface comprising: an isolation layer; a plurality of conductive elements disposed on a first side of the isolation layer; and a plurality of tunable components, each tunable element coupled with a respective conductive element of the plurality of conductive elements; a control system configured to adjust a bias voltage applied to each tunable component of the plurality of tunable components to modulate a radar cross section of the frequency selective surface to encode binary data in a reflected electromagnetic signal following receipt of the electromagnetic signal by the frequency selective surface; a radar system configured to transmit the electromagnetic signal and receive the reflected electromagnetic signal; and the frequency selective surface is configured to operate within a frequency band corresponding to an operational frequency of the radar system; wherein: the frequency selective surface includes a ground layer disposed on a second side of the isolation layer opposite the plurality of conductive elements, the frequency selective surface includes a substrate layer disposed on the first side of the isolation layer, each tunable component of the plurality of tunable components includes a PIN diode, the control system is configured to adjust the bias voltage applied to each PIN diode to modulate the frequency selective surface between a high radar cross section state and a low radar cross section state, an increase to the bias voltage modulates the frequency selective surface to the low radar cross section state, a decrease to the bias voltage modulates the frequency selective surface to the high radar cross section state, the high radar cross section state represents a binary of 1, the low radar cross section state represents a binary of 0, and the radar system comprises a signal processor configured to decode a variation in the reflected electromagnetic signal corresponding to the encoded binary data.
19 . A method for communication, comprising: providing a system for communication, comprising: a frequency selective surface having a tunable radar cross section configured to receive an electromagnetic signal, the frequency selective surface comprising: an isolation layer; a plurality of conductive elements disposed on a first side of the isolation layer; and a plurality of tunable components, each tunable component coupled with a respective conductive element of the plurality of conductive elements; a control system configured to adjust a bias voltage applied to each tunable component of the plurality of tunable components to modulate a radar cross section of the frequency selective surface to encode binary data in a reflected electromagnetic signal following receipt of the electromagnetic signal by the frequency selective surface; a radar system configured to transmit the electromagnetic signal and receive the reflected electromagnetic signal; and the frequency selective surface is configured to operate within a frequency band corresponding to an operational frequency of the radar system transmitting an electromagnetic signal toward the frequency selective surface; adjusting the bias voltage applied to the plurality of tunable components of the frequency selective surface to modulate the radar cross section to encode binary data in the reflected electromagnetic signal; and decoding the binary data from the reflected electromagnetic signal.
20 . The method of claim 19 , wherein modulating the radar cross section includes switching the frequency selective surface between a high radar cross section state representing a binary of 1 and a low radar cross section state representing a binary of 0.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63/716,265, filed on November 5, 2024. The entire disclosure of the above application is incorporated herein by reference. FIELD The present technology relates to frequency selective surfaces with tunable radar cross section capabilities and, more particularly, to a system and method for modulating an electromagnetic property of a frequency selective surface for communication. INTRODUCTION This section provides background information related to the present disclosure which is not necessarily prior art. A frequency selective surface is an engineered structure that can interact with electromagnetic waves in a frequency-dependent manner. The frequency selective surface can include a patterned arrangement of conductive elements supported by a dielectric or composite substrate, forming a surface capable of filtering, reflecting, absorbing, or transmitting specific frequency bands of incident radiation. Because of this selective interaction, the frequency selective surface can function as a spatial filter, reflector, or absorber that can provide controlled electromagnetic responses across microwave, millimeter-wave, and other frequency ranges. These characteristics can make the frequency selective surface useful in applications such as antennas, radomes, electromagnetic shielding, sensing, and radar systems. The frequency selective surface can exhibit fixed electromagnetic characteristics that are determined by geometry and materials. While effective in static environments, the frequency selective surface can lack adaptability to changing conditions, signal requirements, or operational objectives. To address this limitation, tunable frequency selective surfaces can be provided that incorporate controllable elements capable of altering surface impedance or resonance properties. These tunable designs can enable adjustment of reflection or transmission characteristics across selected frequency bands for more flexible electromagnetic management. Both static and tunable frequency selective surfaces, however, can encounter performance and integration challenges. Certain tunable frequency selective surfaces can suffer from limited tuning range, high insertion loss, and slow response times, which can reduce their effectiveness in practical applications. Integration with radar or communication platforms can be complicated by interactions with automatic gain control systems or by variations in signal stability. Accordingly, there is a need for a system and method for communication utilizing a frequency selective surface having a tunable radar cross section that can provide reliable, dynamic, and controllable modulation of electromagnetic properties to encode binary data while maintaining compatibility with existing electronic architectures. SUMMARY In concordance with the instant disclosure, systems and methods for communication utilizing a frequency selective surface having a tunable radar cross section, have surprisingly been discovered. The present technology includes articles of manufacture, systems, and processes that relate to communication utilizing a frequency selective surface having a tunable radar cross section that can provide reliable, dynamic, and controllable modulation of electromagnetic properties to encode binary data while maintaining compatibility with existing electronic architectures. In certain embodiments, a system for communication is provided. The system can include a frequency selective surface having a tunable radar cross section configured to receive an electromagnetic signal. The frequency selective surface can include an isolation layer, a plurality of conductive elements disposed on a first side of the isolation layer, and a plurality of tunable components. Each tunable component can be coupled with a respective conductive element. A control system can be configured to adjust a bias voltage applied to each tunable component to modulate the radar cross section of the frequency selective surface and encode binary data in a reflected electromagnetic signal. A radar system can be configured to transmit the electromagnetic signal and receive the reflected electromagnetic signal. The frequency selective surface can operate within a frequency band corresponding to an operational frequency of the radar system. In certain embodiments, a method for communication is provided. The method can include transmitting an electromagnetic signal toward a frequency selective surface having a tunable radar cross section. A bias voltage applied to a plurality of tunable components of the frequency selective surface can be adjusted to modulate the radar cross section and encode binary data in a reflected electromagnetic signal. Modulating can include switching the frequency selective surface between a high radar cross section state representing a binary one and a low radar cross section state representing