# US 12,763,485 B1 · Hybrid artificial magnetic conductor antenna reflector technology > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,763,485 B1 - Document ID: US12763485B1 - Status: Granted - Kind: B1 - Application number: 18/938,610 - Filed: 2024-11-06 - Granted: 2026-10-13 - Earliest claimed: 2024-11-06 - Assignees: The United States of America as represented by the Secretary of the Navy - Applicants: The United States of America Represented by the Secretary of the Navy - Inventors: David Rohde - Web page: https://patentgrep.com/patent/US12763485B1 ## CPC - H01Q 15/167: {comprising a gap between adjacent panels or group of panels, e.g. stepped reflectors} - H01Q 1/36: Structural form of radiating elements, e.g. cone, spiral, umbrella; {Particular materials used therewith}(H01Q1/08, H01Q1/14 take precedence) - H01Q 21/065: {Patch antenna array} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A Hybrid Artificial Magnetic Conductor (AMC) antenna reflector improves performance of an Archimedean spiral antenna across all bands. The AMC reflector provides uni-directional radiation over a 1-5 GHz frequency range. The AMC reflector provides at least 3 dB of gain compared to the same antenna without a reflector. The AMC reflector includes a traditional Perfect Electric Conductor (PEC) reflector portion, used to reflect higher frequencies, and a capacitively loaded AMC reflector portion, used to reflect lower frequencies. The AMC patch size and capacitor values are optimized for best response across the 1-2 GHz frequency range. The center, high frequency section of the AMC reflector portion is removed to provide an optimized standoff distance from the antenna to allow direct reflection from the PEC reflector portion. The AMC reflector reduces the PEC reflector thickness dimension and provides improved antenna pattern symmetry at higher frequencies. ## Claims ### Claim 1 An antenna reflector comprising: a ground plane; and an artificial magnetic conductor surface comprising a plurality of patches on said artificial magnetic conductor surface and having a central portion removed to expose said ground plane, wherein some of the plurality of the patches are capacitively loaded around the central portion of the artificial magnetic conductor surface. ### Claim 2 (depends on 1) The antenna reflector according to claim 1, further comprising a laminate structure attached to the ground plane; and a layer containing said plurality of the patches on top of said laminate structure. ### Claim 3 (depends on 2) The antenna reflector according to claim 2 wherein the antenna reflector includes a total reflector thickness of approximately 14 mm. ### Claim 4 (depends on 1) The antenna reflector according to claim 1, wherein said patches are square. ### Claim 5 (depends on 4) The antenna reflector according to claim 4, wherein a portion of said patches include a tab to attach a capacitor between adjacent patches. ### Claim 6 (depends on 1) The antenna reflector according to claim 1, wherein said artificial magnetic conductor surface is capacitively loaded approximately 48-73 mm from the center of said ground plane. ### Claim 7 (depends on 1) The antenna reflector according to claim 1, wherein said removed central portion is circular. ### Claim 8 (depends on 7) The antenna reflector according to claim 7, wherein the circular central portion has a radius of approximately 35 mm. ### Claim 9 (depends on 1) The antenna reflector according to claim 1, wherein said antenna reflector comprises a square surface approximately 288 mm×288 mm with 15 rows and 15 columns of patches. ### Claim 10 An antenna, comprising: a substrate; a feed element; and a radiating element being coupled to the feed element, wherein the radiating element is substantially parallel to said substrate, wherein said substrate comprises a dielectric material having a ground plane reflector and an artificial magnetic conductor reflector attached thereto, wherein said artificial magnetic conductor reflector is between said radiating element and said ground plane reflector, and wherein said artificial magnetic conductor reflector includes a central portion removed to allow direct reflection for said radiating element from said ground plane reflector. ### Claim 11 (depends on 10) The antenna according to claim 10, further comprising a transmitter being connected to said feed element, wherein said transmitter is configured to transmit at frequencies from 1-5 GHz. ### Claim 12 (depends on 10) The antenna according to claim 10, said radiating element comprising a spiral antenna. ### Claim 13 (depends on 10) The antenna according to claim 10, wherein said artificial magnetic conductor reflector comprises a plurality of patches connected to said ground plane. ### Claim 14 (depends on 13) The antenna according to claim 13, wherein said patches are square. ### Claim 15 (depends on 13) The antenna according to claim 13, wherein a portion of said patches include a tab to attach a capacitor between adjacent patches. ### Claim 16 (depends on 10) The antenna according to claim 10, wherein said artificial magnetic conductor reflector is capacitively loaded approximately 48-73 mm from the center of said ground plane. ### Claim 17 (depends on 10) The antenna according to claim 10, wherein said removed central portion is circular. ### Claim 18 (depends on 17) The antenna according to claim 17, wherein the circular central portion has a radius of approximately 35 mm. ### Claim 19 (depends on 10) The antenna according to claim 10, wherein said substrate comprises a square surface approximately 288 mm×288 mm with 15 rows and 15 columns of patches connected to said ground plane. ### Claim 20 (depends on 10) The antenna according to claim 10, wherein said substrate includes a thickness of approximately 14 mm.