# US 12,216,299 B2 · Epoxy-based infrared filter assembly and associated fabrication devices and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,299 B2 - Document ID: US12216299B2 - Status: Granted - Kind: B2 - Application number: 18/541,230 - Filed: 2023-12-15 - Published: 2024-04-25 - Granted: 2025-02-04 - Earliest claimed: 2021-08-17 - Assignees: Fermi Research Alliance, LLC - Applicants: Fermi Research Alliance, LLC - Inventors: Gabriel Spahn - Web page: https://patentgrep.com/patent/US12216299B2 ## CPC - G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation} - G01K 11/006: {using measurement of the effect of a material on microwaves or longer electromagnetic waves, e.g. measuring temperature via microwaves emitted by the object (G01K17/003, G01J5/00 take precedence; measuring the effect of a material on X-, gamma- or particle radiation G01K11/30)} - G01T 1/1606: {with other specified detectors not provided for in the other subgroups of G01T1/16} - G02B 1/04: made of organic materials, e.g. plastics (G02B1/08 takes precedence) - G01J 5/0802: Optical filters - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract Epoxy-based inline infrared (IR) filter assembly, and manufacture and use of the same. Co-axial infrared filter assemblies comprise a substantially cylindrical filter body forming a central cavity characterized by opposing holes at each end. The filter body forms an outer conductor, and SMA connectors coupled to the opposing holes at each end of the body are electrically coupled to form an inner conductor positioned along a long axis of the filter body. An infrared absorbing material (such as castable epoxy resin) fills the central cavity of the filter body. Methods for producing the co-axial infrared filter include pressing SMA connectors into the respective ends of the filter body, electrically coupling the SMA connectors, and filling the filter body with epoxy. Electronic systems for operating a dark matter detector include a feedline comprising a coaxial filter configured to advantageously block infrared noise. ## Claims ### Claim 1 A co-axial infrared filter comprising: a body having a wall forming an outer conductor characterized by a filling hole, and a cylindrical central cavity having an open first end and an open second end; and a first Subminiature version A (SMA) connector mechanically coupled to the open first end of the body and a second SMA connector mechanically coupled to the open second end of the body, wherein a respective connector pin of each of the first SMA connector and the second SMA connector are positioned along a long axis of the body and electrically coupled proximate the filling hole to define an inner conductor. ### Claim 2 (depends on 1) The co-axial infrared filter according to claim 1, wherein the body further comprises copper. ### Claim 3 (depends on 1) The co-axial infrared filter according to claim 1, wherein the body further comprises an exterior surface cross-section shape selected from the group consisting of circular, triangular, square, pentagonal, hexagonal, septagonal, and octagonal. ### Claim 4 (depends on 1) The co-axial infrared filter according to claim 1, further comprising an infrared absorbing epoxy material configured to fill, as added through the filling hole, the cylindrical central cavity of the body. ### Claim 5 (depends on 4) The co-axial infrared filter according to claim 4, wherein the infrared absorbing epoxy material further comprises a magnetically loaded epoxy. ### Claim 6 (depends on 5) The co-axial infrared filter according to claim 5, wherein the magnetically loaded epoxy further comprises a castable epoxy resin. ### Claim 7 (depends on 4) The co-axial infrared filter according to claim 4, wherein the infrared absorbing epoxy material is further characterized by a passband frequency range of 4 to 8 GHz. ### Claim 8 (depends on 1) The co-axial infrared filter according to claim 1, wherein the first SMA connector is of a knurled SMA connector type. ### Claim 9 (depends on 1) The co-axial infrared filter according to claim 1, further comprising an SMA cap configured to couple to the first SMA connector. ### Claim 10 (depends on 1) The co-axial infrared filter according to claim 1, wherein the inner conductor is characterized by a radius range of 0.01 inch to 0.05 inch. ### Claim 11 (depends on 1) The co-axial infrared filter according to claim 1, wherein a cavity radius from the long axis to an inner surface of the body is 0.100 inch to 0.150 inch. ### Claim 12 (depends on 1) The co-axial infrared filter according to claim 1, wherein the cylindrical central cavity is 0.2 inch to 0.5 inch in length. ### Claim 13 (depends on 12) The co-axial infrared filter according to claim 12, wherein the cylindrical central cavity is 0.375+/−0.05 inch in length. ### Claim 14 (depends on 1) The co-axial infrared filter according to claim 1, wherein the cylindrical central cavity has an inner diameter range of 0.150 inch to 0.300 inch. ### Claim 15 A method for producing a co-axial infrared filter comprising: mechanically pressing a first Subminiature version A (SMA) connector into a first end opening of a hollow filter body and mechanically pressing a second SMA connector into a second end opening of the hollow filter body to define a cylindrical central cavity; forming a continuous conductor along a long axis of the hollow filter body by electrically coupling a respective connector pin of each of the first SMA connector and the second SMA connector; and filling, using a filling hole in the hollow filter body, the cylindrical central cavity with an infrared absorbing epoxy material. ### Claim 16 (depends on 15) The method according to claim 15, wherein the mechanically pressing the first SMA connector and the second SMA connector into the hollow filter body further comprises positioning the filter body in a pressing jig. ### Claim 17 (depends on 16) The method according to claim 16, wherein the mechanically pressing the first SMA connector and the second SMA connector into the hollow filter body further comprises fittedly receiving, using an SMA connector slot of the pressing jig, the first SMA connector. ### Claim 18 An electronic system comprising: a detector; and a feedline comprising an infrared filter assembly comprising: a body having a wall forming an outer conductor characterized by a filling hole, and a cylindrical central cavity having an open first end and an open second end; a first Subminiature version A (SMA) connector mechanically coupled to the open first end of the body and a second SMA connector mechanically coupled to the open second end of the body, wherein a respective connector pin of each of the first SMA connector and the second SMA connector are positioned along a long axis of the body and electrically coupled proximate the filling hole to define an inner conductor; and an infrared absorbing epoxy material configured to fill, as added through the filling hole, the cylindrical central cavity of the body. ### Claim 19 (depends on 18) The system according to claim 18, wherein the detector further comprises a superconducting substrate. ### Claim 20 (depends on 18) The system according to claim 18, further comprising a refrigeration component configured to maintain the detector at a temperature less than 3 degrees Kelvin (K).