# US 6,873,225 B2 · Diplexers with low pass filter having distributed and non-distributed (lumped) elements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,873,225 B2 - Document ID: US6873225B2 - Status: Granted - Kind: B2 - Application number: 10/414,677 - Filed: 2003-04-15 - Published: 2004-10-21 - Granted: 2005-03-29 - Earliest claimed: 2003-04-15 - Assignees: Microphase Corporation - Inventors: Mark Spielman; Necdet Ergul - Web page: https://patentgrep.com/patent/US6873225B2 ## CPC - H03H 7/463: {Duplexers} - H01P 1/213: combining or separating two or more different frequencies (H01P1/215 takes precedence) - H03H 7/0123: {comprising distributed impedance elements together with lumped impedance elements} - H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)} - H03H 7/1758: {Series LC in shunt or branch path (H03H7/1791 takes precedence)} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) ## Abstract A low pass filter comprises a first series of transmission line elements connected between an input and an output; and a second series of shunt elements connected from the transmission line elements to a ground of the filter. At least one of the shunt elements has a distributed portion and a lumped portion. The distributed portion may comprise a tube mounted tangentially on a printed circuit board. The lumped portion may comprises a coil with a first lead connected to the first series of transmission line elements, and a second lead extending into the tube. A tuning element is moveably disposed in the tube. The tuning element may have an opening for receiving the second lead of the coil. The low pass filter may be used in a diplexer with one or more high pass filters. The diplexer may include power transmission apparatus. ## Claims ### Claim 1 A low pass filter comprising: a first series of transmission line elements connected between an input and an output of said low pass filter; and a second series of shunt elements connected from said transmission line elements to a ground of said low pass filter, at least one of said shunt elements having a distributed portion and a lumped portion. ### Claim 2 (depends on 1) The low pass filter of claim 1, wherein said distributed portion comprises a tube. ### Claim 3 (depends on 2) The low pass filter of claim 2, wherein said lumped portion comprises a coil with a first lead connected to said first series of transmission line elements, and a second lead extending into said tube. ### Claim 4 (depends on 3) The low pass filter of claim 3, further comprising a tuning element moveably disposed in said tube. ### Claim 5 (depends on 4) The low pass filter of claim 4, wherein said tuning element has an opening for receiving said second lead of said coil. ### Claim 6 (depends on 4) The low pass filter of claim 4, wherein a respective tuning element has an opening for receiving said second lead of said coil. ### Claim 7 (depends on 1) The low pass filter of claim 1, wherein said shunt elements each comprise a tube, and said tubes are mounted on a printed circuit board. ### Claim 8 (depends on 7) The low pass filter of claim 7, wherein said tubes are mounted tangentially on said circuit board. ### Claim 9 (depends on 7) The low pass filter of claim 7, wherein said first series of transmission line elements include a wire connected between a first land on said printed circuit board and a second land on said printed circuit board, said wire having a portion positioned to extend in a direction parallel to a plane of said printed circuit board. ### Claim 10 (depends on 9) The low pass filter of claim 9, further comprising a support member extending from said circuit board for supporting said wire at a predetermined distance from said circuit board. ### Claim 11 (depends on 10) The low pass filter of claim 10, further comprising an insulating sleeve disposed around said wire, said sleeve being positioned to insulate said wire from said support member. ### Claim 12 (depends on 11) The low pass filter of claim 11, wherein said insulating sleeve and said support member form an additional shunt element of said low pass filter. ### Claim 13 (depends on 1) The low pass filter of claim 1, further comprising at least one lumped element connected in series with said first series of transmission line elements. ### Claim 14 (depends on 13) The low pass filter of claim 13, wherein said at least one lumped element comprises a coil. ### Claim 15 (depends on 13) The low pass filter of claim 13, wherein said lumped element is connected to lands on a circuit board. ### Claim 16 (depends on 15) The low pass filter of claim 15, wherein said shunt elements comprise tubes mounted on said circuit board. ### Claim 17 (depends on 16) The low pass filter of claim 16, wherein said lumped portion comprises a coil with a first lead connected to said first series of transmission line elements, and a second lead extending into one of said tubes. ### Claim 18 (depends on 17) The low pass filter of claim 17, further comprising a tuning element moveably disposed in each of said tubes. ### Claim 19 (depends on 1) The low pass filter of claim 1, wherein at least one of said first series of said shunt elements comprises a tube, further comprising: an electrical conductor connected to said first transmission line elements, and a tuning element movable within said tube, said tuning element having an opening for receiving said electrical conductor. ### Claim 20 (depends on 19) The low pass filter of claim 19, wherein said electrical conductor is a rod. ### Claim 21 (depends on 20) The low pass filter of claim 20, further comprising: a circuit board on which said tube is mounted, and a pin extending from said circuit board, an end of said rod being soldered to said pin. ### Claim 22 A filter comprising: a first series of transmission line elements connected between an input and an output of said filter; and a second series of shunt elements connected from said transmission line elements to a ground of said filter, at least one shunt element including a tube and a conductor extending into said tube, said tube being mounted on a circuit board. ### Claim 23 (depends on 22) The filter of claim 22, further comprising a tuning element moveably disposed in each said tube. ### Claim 24 (depends on 23) The filter of claim 23, wherein said tuning element has an opening for receiving a respective conductor. ### Claim 25 A diplexer comprising: a low pass filter including: a first series of transmission line elements connected between an input and an output of said low pass filter; and a second series of shunt elements connected from said transmission line elements to a ground of said low pass filter, at least one of said shunt elements having a distributed portion and a lumped portion; and a high pass filter connected between said input of said low pass filter and a first high pass filter output. ### Claim 26 (depends on 25) The diplexer of claim 25, further comprising an additional high pass filter connected between said output of said low pass filter and a second high pass filter output. ### Claim 27 (depends on 26) The diplexer of claim 26, wherein each of said high pass filters serves as an impedance transformer. ### Claim 28 (depends on 26) The diplexer of claim 26, wherein the first high pass filter output and second high pass filter output match a lower impedance than that of said input of said low pass filter and said output of said low pass filter. ### Claim 29 (depends on 28) The diplexer of claim 28, wherein said lower impedance is fifty ohms. ### Claim 30 (depends on 25) The diplexer of claim 25, wherein said high pass filter serves as an impedance transformer. ### Claim 31 (depends on 25) The diplexer of claim 25, wherein the high pass filter output matches a lower impedance than that of said input of said low pass filter and said output of said low pass filter. ### Claim 32 (depends on 31) The diplexer of claim 31, wherein said lower impedance is fifty ohms. ### Claim 33 (depends on 25) The diplexer of claim 25, wherein said low pass filter is adapted to carry electrical power from an electrical power source between said input and an output of said low pass filter. ### Claim 34 (depends on 33) The diplexer of claim 33, wherein said first series of transmission line elements carry said power. ### Claim 35 (depends on 33) The diplexer of claim 33, further comprising a power management circuit for receiving and distributing said power. ### Claim 36 (depends on 35) The diplexer of claim 35, wherein said power management circuit comprises: a choke having a first terminal connected to said output of said low pass filter, and bypass capacitance connected from a second terminal of said choke to ground of said diplexer. ### Claim 37 (depends on 36) The diplexer of claim 36, wherein said bypass capacitance comprises: a first relatively large capacitor, and a second smaller capacitor for providing a low impedance for high frequency signals. ### Claim 38 (depends on 36) The diplexer of claim 36, further comprising a power protection element connected in parallel with said capacitance. ### Claim 39 (depends on 38) The diplexer of claim 38, wherein said power protection element is a sidactor. ### Claim 40 (depends on 36) The diplexer of claim 36, further comprising a power connector connected in parallel with said capacitance. ### Claim 41 (depends on 25) The diplexer of claim 25, wherein said distributed portion comprises a tube. ### Claim 42 (depends on 41) The diplexer of claim 41, wherein said lumped portion comprises a coil with a first lead connected to said first series of transmission line elements, and a second lead extending into said tube. ### Claim 43 (depends on 42) The diplexer of claim 42, further comprising a tuning element moveably disposed in said tube. ### Claim 44 (depends on 43) The diplexer of claim 43, wherein said tuning element has an opening for receiving said second lead of said coil. ### Claim 45 (depends on 25) The diplexer of claim 25, wherein said shunt elements each comprise a tube, and said tubes are mounted on a printed circuit board. ### Claim 46 (depends on 45) The diplexer of claim 45, wherein said tubes are mounted tangentially on said circuit board. ### Claim 47 (depends on 45) The diplexer of claim 45, wherein said first series of transmission line elements include a wire connected between a first land on said printed circuit board and a second land on said printed circuit board, said wire having a portion positioned to extend in a direction parallel to a plane of said printed circuit board. ### Claim 48 (depends on 47) The diplexer of claim 47, further comprising a support member extending from said circuit board for supporting said wire at a predetermined distance from said circuit board. ### Claim 49 (depends on 48) The diplexer of claim 48, further comprising an insulating sleeve disposed around said wire, said sleeve being positioned to insulate said wire from said support member. ### Claim 50 (depends on 49) The diplexer of claim 49, wherein said insulating sleeve and said support member form an additional shunt element of said low pass filter.