# US 7,746,189 B2 · Waveguide circulator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,189 B2 - Document ID: US7746189B2 - Status: Granted - Kind: B2 - Application number: 12/212,723 - Filed: 2008-09-18 - Published: 2010-03-18 - Granted: 2010-06-29 - Earliest claimed: 2008-09-18 - Assignees: Apollo Microwaves, Ltd. - Inventors: Mahfoud Hocine; Marco Caplin - Web page: https://patentgrep.com/patent/US7746189B2 ## CPC - H01P 1/39: Hollow waveguide circulators - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) ## Abstract A waveguide circulator comprising at least three waveguide arms intersecting at a junction, at least one ferrite element positioned within the junction, an impedance transformer and a recessed transformer. At least a portion of each of the at least three waveguide arms and the junction define a first wall and a second wall that are positioned in an opposing relationship. The impedance transformer is positioned in proximity to the at least one ferrite element and projects from the first wall. The recessed transformer is positioned in proximity to the impedance transformer and is recessed within the first wall. ## Claims ### Claim 1 A circulator, comprising: a) at least three waveguide arms intersecting at a junction, at least a portion of said at least three waveguide arms and said junction defining a first wall and a second wall that are positioned in an opposing relationship; b) at least one ferrite element positioned within said junction; c) an impedance transformer positioned in proximity to said at least one ferrite element, said at least one impedance transformer projecting from said first wall; and d) a recessed transformer positioned in proximity to said impedance transformer, said recessed transformer being recessed within said first wall. ### Claim 2 (depends on 1) A circulator as defined in claim 1, wherein said impedance transformer is integrally formed with said first wall. ### Claim 3 (depends on 1) A circulator as defined in claim 1, wherein each of said at least three waveguide arms comprises a rectangular tube, wherein opposing inner walls of said rectangular tubes create at least a portion of said first wall and said second wall. ### Claim 4 (depends on 3) A circulator as defined in claim 3, wherein said impedance transformer is a first impedance transformer in a set of two impedance transformers, said two impedance transformers being positioned respectively on said first wall and said second wall in an opposing manner. ### Claim 5 (depends on 4) A circulator as defined in claim 4, wherein each of said two impedance transformers includes at least three transformer arms that extend into respective ones of said at least three waveguide arms. ### Claim 6 (depends on 4) A circulator as defined in claim 4, wherein said recessed transformer is a first recessed transformer in a set of three recessed transformers, wherein each of said three recessed transformers is recessed within a first wall of a respective one of said at least three waveguide arms. ### Claim 7 (depends on 6) A circulator as defined in claim 6, wherein said first wall and said second wall are separated by a certain distance, wherein a distance between said two impedance transformer is less than said certain distance, and wherein a distance between two opposing ones of said recessed transformers is greater than said certain distance. ### Claim 8 (depends on 6) A circulator as defined in claim 6, wherein said set of three recessed transformers is a first set of three recessed transformers, said circulator further comprising a second set of three recessed transformers, wherein each of said recessed transformers in said second set of three recessed transformers is recessed within a second wall of a respective one of said at least three waveguide arms. ### Claim 9 A waveguide circulator comprising three waveguide arms each comprising a first wall and a second wall, said three waveguide arms intersecting at a junction that includes at least one ferrite element therein, each of said three waveguide arms comprising: i) an impedance transformer projecting from said first wall; and ii) a recessed transformer that is recessed within said first wall. ### Claim 10 (depends on 9) A waveguide circulator as defined in claim 9, wherein said first wall and said second wall are opposing inner walls of a rectangular waveguide arm. ### Claim 11 (depends on 10) A waveguide circulator as defined in claim 10, wherein each of said three waveguide arms further comprises: a) an impedance transformer projecting from said second wall; and b) a recessed transformer that is recessed within said second wall. ### Claim 12 (depends on 11) A waveguide circulator as defined in claim 11, wherein said impedance transformer projecting from said first wall and said impedance transformer projecting from said second wall each include three transformer arms that extend respectively from said junction into said at least three waveguide arms. ### Claim 13 (depends on 11) A waveguide circulator as defined in claim 11, wherein said first wall and said second wall are separated by a certain distance, wherein a distance between said impedance transformers is less than said certain distance, and wherein a distance between two opposing ones of said recessed transformers is greater than said certain distance. ### Claim 14 A method, comprising: a) providing a waveguide circulator comprising: i) at least three waveguide arms intersecting at a junction, the at least three waveguide arms and the junction defining a first wall and a second wall that are positioned in an opposing relationship; ii) at least one ferrite element positioned within the junction; and iii) at least one impedance transformer within the waveguide circulator in proximity to the at least one ferrite element, said impedance transformer projecting into the junction; b) providing at least one recessed transformer into the first wall of the waveguide circulator. ### Claim 15 (depends on 14) A method as defined in claim 14, wherein providing the at least one recessed transformer into the first wall of the circulator comprises machining the at least one recessed transformer into the first wall of the circulator. ### Claim 16 (depends on 14) A method as defined in claim 14, wherein the circulator comprises a first portion and a second portion that are coupled together, said method further comprising separating the first portion of the circulator from the second portion prior to machining the at least one recessed transformer into the first wall.