# US 12,771,412 B2 · Monolithic butler matrix for beamforming applications utilizing nonvolatile radio frequency switches and planar wideband couplers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,771,412 B2 - Document ID: US12771412B2 - Status: Granted - Kind: B2 - Application number: 18/968,905 - Filed: 2024-12-04 - Published: 2026-06-04 - Granted: 2026-10-20 - Earliest claimed: 2024-12-04 - Assignees: Dell Products L.P. - Applicants: Dell Products L.P. - Inventors: Tejinder Singh; Navjot Kaur Khaira - Web page: https://patentgrep.com/patent/US12771412B2 ## CPC - H04B 7/043: {using best eigenmode, e.g. beam forming or beam steering} - H01Q 13/08: Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines - H01Q 21/0093: {Monolithic arrays} - H04B: TRANSMISSION - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract The technology described herein is directed towards Butler matrix that can be implemented in a monolithic planar structure design for low-cost and scalable manufacturing. One implementation design is for a device that integrates the quadrature couplers, crossover couplers, and fixed phase-shift meandered lines of the Butler matrix, with a switch and an antenna array in a planar layout that eliminates the need for multiple layers of metallization. The implementation uses monolithic nonvolatile phase change material-based radio frequency (RF) switch elements for dynamic beamforming, by routing RF signals through the Butler matrix based on controlling conductive and nonconductive states of the phase change material corresponding to selectable switch ports. This facilitates dynamic, power-efficient reconfiguration within the Butler Matrix for flexible beam steering. Also described are ultra-wideband quadrature couplers and crossover couplers with parametric design optimization variables, which facilitates ultra-compact device designs. ## Claims ### Claim 1 A system, comprising: a non-volatile radio frequency (RF) multiport switch comprising a common RF port and respective selectable RF ports above a substrate; an antenna array; and a Butler matrix that couples the common RF port to antenna elements of the antenna array, the Butler matrix being comprised in a metal layer above the substrate with a metal ground plane beneath the substrate, the Butler matrix comprising: delay elements, quadrature couplers, and crossover couplers, wherein the multiport switch is controllable to route an RF signal, obtained via the common RF port to one or more of the respective selectable RF ports, through the Butler matrix to the antenna array, to transmit the RF signal via a beamformed beam from the antenna array, and wherein the multiport switch comprises: respective phase change material junctions coupled to the respective selectable ports, and a controllable heater network comprising respective heating elements that transfer heat to the respective phase change material junctions, the controllable heater network being controlled to output heat via energy pulses to selectively change a first set of one or more of the respective phase change material junctions to a lower resistance state that electrically couples the common RF port to a first group of the respective selectable ports, and to selectively change a second set of the one or more of the respective phase change material junctions to a higher resistance state that electrically decouples the common RF port from a second group of the respective selectable ports. ### Claim 2 (depends on 1) The system of claim 1, wherein the RF signal is a first RF signal, wherein the beamformed beam is a first beamformed beam, and wherein the multiport switch is controllable to route a second RF signal, received at the antenna array via a second beamformed beam, through the Butler matrix to the common RF port. ### Claim 3 (depends on 1) The system of claim 1, wherein the antenna array is fabricated in the metal layer. ### Claim 4 (depends on 1) The system of claim 1, wherein each quadrature coupler of the quadrature coupler comprises: a top metallization layer corresponding to the metal layer above the substrate, the top metallization layer comprising: a metallic upper plane, a first port coupled to the metallic upper plane via a first microstrip line, a second port coupled to the metallic upper plane via a second microstrip line, a third port coupled to the metallic upper plane via a third microstrip line, and a fourth port coupled to the metallic upper plane via a fourth microstrip line, wherein the first port is opposite the third port, the first port is adjacent to the second port, and the first port is the adjacent to fourth port, a first slot in the metallic upper plane having a first slot width and a first slot length, and a second slot in the metallic upper plane having a second slot width and a second slot length, wherein the first slot crosses the second slot at an intersection point. ### Claim 5 (depends on 4) The system of claim 4, wherein the first slot is angled at substantially about forty-five degrees relative to the first microstrip line and the third microstrip line, wherein the second slot is substantially perpendicular to the first slot, wherein the first slot is length is greater than the second slot length, and wherein the intersection point of the first slot and the second slot is substantially centered relative to the metallic upper plane. ### Claim 6 (depends on 1) The system of claim 1, wherein each crossover coupler of the crossover couplers comprises: a top metallization layer corresponding to the metal layer above the substrate, the top metallization layer comprising: a first port, a second port, a third port, and a fourth port, wherein the first port is coupled to a first segment of a first microstrip line and the third port is coupled to a third segment of the first microstrip line, and wherein the second port is coupled to a second segment of a second microstrip line and the fourth port is coupled to a fourth segment of the second microstrip line, and wherein the first microstrip line and the second microstrip line cross at an intersection point in a cross-shaped pattern, inner partial couplers surrounding the intersection point, comprising a first inner partial coupler between the first segment and the fourth segment, a second inner partial coupler between the first segment and the second segment, a third inner partial coupler between the second segment and the third segment, and a fourth inner partial coupler between the third segment and the fourth segment, and an outer ring surrounding the inner partial couplers. ### Claim 7 (depends on 6) The system of claim 6, wherein the metal ground plane comprises a bottom metallization layer, associated with each crossover coupler, comprising a defined-size cutout area, and wherein the defined-size cutout area is determined by a height of the substrate. ### Claim 8 (depends on 1) The system of claim 1, wherein the Butler matrix comprises an 8×8 Butler matrix. ### Claim 9 (depends on 1) The system of claim 1, wherein the non-volatile RF multiport switch comprises eight respective selectable RF ports. ### Claim 10 A method, comprising: electrically coupling, by a system comprising at least one processor, a common radio frequency (RF) port of a nonvolatile RF switch to one or more selectable RF ports of the nonvolatile RF switch, wherein the common RF port is electrically coupled to a conductor, and wherein the one or more selectable RF ports are connected to the conductor via a phase change alloy material junction between the selectable RF port and the conductor, the electrically coupling comprising: determining which of the one or more selectable RF ports to electrically couple to the common RF port via the conductor; for each selectable RF port determined to be a selectable RF port to electrically couple to the common RF port, determining whether the phase change alloy material junction between the selectable RF port and the conductor is in a conductive state or a nonconductive state, and, in response to the phase change alloy material junction being determined to be in the nonconductive state, controlling a heating element corresponding to the selectable RF port to change the phase change alloy material junction to a conductive state that electrically couples the selectable RF port to the conductor and a Butler matrix coupled to the conductor; and for each selectable RF port determined not to be a selectable RF port to electrically couple to the common RF port, determining whether the phase change alloy material junction between the selectable RF port and the conductor is in a conductive state or a nonconductive state, and, in response to the phase change alloy material junction being determined to be in a conductive state, controlling a heating element corresponding to the selectable RF port to change the phase change alloy material junction to the nonconductive state that electrically decouples the selectable RF port from the conductor and the Butler matrix. ### Claim 11 (depends on 10) The method of claim 10, wherein the common RF port is an input port that obtains an RF signal as input, and wherein the electrically coupling comprises determining at least one of one the one or more selectable RF ports as at least one corresponding output port for coupling the RF signal to an antenna array coupled to the Butler matrix. ### Claim 12 (depends on 11) The method of claim 11, further comprising: obtaining, by the system, beamforming information corresponding to beamforming a beam corresponding to the RF signal from the antenna array, and wherein the determining of which of the one or more selectable RF ports to electrically couple to the common RF port via the conductor is based on the beamforming information. ### Claim 13 (depends on 10) The method of claim 10, wherein the common RF port is an output port, and wherein the electrically coupling comprises determining at least one of one the one or more selectable RF ports as at least one corresponding input port for coupling an RF signal obtained at the Butler matrix via an antenna array coupled thereto. ### Claim 14 (depends on 10) The method of claim 10, wherein the controlling of the heating element comprises pulsing the heating element with a first voltage or current pulse to change the phase change alloy material junction to the conductive state, or pulsing the heating element with a second voltage or current pulse to change the phase change alloy material junction to the nonconductive state. ### Claim 15 A device, comprising: a Butler matrix comprising a top metallization layer corresponding to a metal layer above a substrate, and metal ground plane beneath the substrate, the Butler matrix comprising quadrature couplers, crossover couplers and delay elements integrated into the top metallization layer, wherein each quadrature coupler of the quadrature coupler comprises: a metallic upper plane in the top metallization layer, a first port coupled to the metallic upper plane via a first microstrip line, a second port coupled to the metallic upper plane via a second microstrip line, a third port coupled to the metallic upper plane via a third microstrip line, and a fourth port coupled to the metallic upper plane via a fourth microstrip line, wherein the first port is opposite the third port, the first port is adjacent to the second port, and the first port is the adjacent to fourth port, a first slot in the metallic upper plane having a first slot width and a first slot length, and a second slot in the metallic upper plane having a second slot width and a second slot length, wherein the first slot crosses the second slot at an intersection point, and wherein each crossover coupler of the crossover couplers comprises: a fifth port, a sixth port, a seventh port, and an eighth port, wherein the fifth port is coupled to a first segment of a fifth microstrip line and the seventh port is coupled to a third segment of the fifth microstrip line, and wherein the sixth port is coupled to a second segment of a sixth microstrip line and the fourth port is coupled to a fourth segment of the sixth microstrip line, and wherein the fifth microstrip line and the sixth microstrip line cross at an intersection point in a cross-shaped pattern, inner partial couplers surrounding the intersection point, comprising a first inner partial coupler between the first segment and the fourth segment, a second inner partial coupler between the first segment and the second segment, a third inner partial coupler between the second segment and the third segment, and a fourth inner partial coupler between the third segment and the fourth segment, and an outer ring surrounding the inner partial couplers. ### Claim 16 (depends on 15) The device of claim 15, further comprising: a radio frequency (RF) switch comprising: a common RF port and respective selectable RF ports, respective phase change material junctions coupled to the respective selectable ports, and a controllable heater network comprising respective heating elements that transfer heat to the respective phase change material junctions, the controllable heater network being controlled to output heat via energy pulses to selectively change a first set of one or more of the respective phase change material junctions to a lower resistance state that electrically couples the common RF port to a first group of the respective selectable ports, and to selectively change a second set of the one or more of the respective phase change material junctions to a lower resistance state that electrically decouples the common RF port from a second group of the respective selectable ports. ### Claim 17 (depends on 16) The device of claim 16, wherein the common RF port and the respective selectable RF ports are integrated into the top metallization layer. ### Claim 18 (depends on 16) The device of claim 16, further comprising: a thermally conductive dielectric layer between the respective phase change material junctions and the respective heating elements. ### Claim 19 (depends on 16) The device of claim 16, wherein, for each quadrature coupler: the first slot is angled at substantially about forty-five degrees relative to the first microstrip line and the third microstrip line, the second slot is substantially perpendicular to the first slot, the first slot length is greater than the second slot length, and the intersection point of the first slot and the second slot is substantially centered relative to the metallic upper plane, wherein each crossover coupler is associated with a portion of the metal ground plane, and wherein the portion comprises a defined-size cutout area. ### Claim 20 (depends on 15) The device of claim 15, wherein an antenna array is fabricated in the metal layer.