Tapered coax launch structure for a near field communication system

{
  "publication_number": "US10171578B1",
  "country": "US",
  "kind": "B1",
  "title": "Tapered coax launch structure for a near field communication system",
  "abstract": "A system is provided in which a set of modules each have a substrate on which is mounted a radio frequency (RF) transmitter and/or an RF receiver. Each module has a housing that surrounds and encloses the substrate. The housing has a port region on a surface of the housing. Each module has a tapered near field communication (NFC) field confiner located between the substrate and the port region on the housing configured to guide electromagnetic energy produced by the RF transmitter to the port region so that it can be emanated to a port region of an adjacent module.",
  "claims": [
    "1. A system comprising: a module comprising: a substrate on which a radio frequency (RF) transmitter is mounted, the RF transmitter having an output terminal; a housing having a port region at a surface of the housing; and a tapered transmission line with a conductive element, the conductive element having a first end coupled to the output terminal of the RF transmitter and a second end that terminates at the port region, wherein a characteristic impedance of the tapered transmission line increases along a length of the tapered transmission line from the first end to the second end, and the tapered transmission line has an outside surface separated from the conductive element by a dielectric, in which the dielectric is air.",
    "2. A system comprising: a module comprising: a substrate on which a radio frequency (RF) transmitter is mounted, the RF transmitter having an output terminal; a housing having a port region at a surface of the housing; and a tapered transmission line with a conductive element, the conductive element having a first end coupled to the output terminal of the RF transmitter and a second end that terminates at the port region, wherein a characteristic impedance of the tapered transmission line increases along a length of the tapered transmission line from the first end to the second end, and the tapered transmission line has an outside surface separated from the conductive element by a dielectric, in which the outside surface is conductive and coupled to a ground reference of the substrate.",
    "3. The system of claim 1, wherein an axis along the length of the tapered transmission line is perpendicular to the substrate.",
    "4. A system comprising: a module comprising: a substrate on which a radio frequency (RF) transmitter and an RF receiver are mounted, the RF transmitter having an output terminal, and the RF receiver having an input terminal; a housing having first and second port regions at a surface of the housing; a first tapered transmission line with a first conductive element the first conductive element having a first end coupled to the output terminal of the RF transmitter and a second end that terminates at the first port region, wherein a characteristic impedance of the first tapered transmission line increases along a length of the first tapered transmission line from the first end to the second end, and the first tapered transmission line has an outside surface separated from the first conductive element by a first dielectric; and a second tapered transmission line with a second conductive element, the second conductive element having a third end coupled to the input terminal of the RF receiver and a fourth end that terminates at the second port region, wherein a characteristic impedance of the second tapered transmission line increases along a length of the second tapered transmission line from the third end to the fourth end, and the second tapered transmission line has an outside surface separated from the second conductive element by a second dielectric.",
    "5. A system comprising: a first module comprising: a substrate on which a radio frequency (RF) transmitter is mounted, the RF transmitter having an output terminal; a housing having a first port region at a surface of the housing; and a tapered transmission line with a conductive element the conductive element having a first end coupled to the output terminal of the RF transmitter and a second end that terminates at the first port region, wherein a characteristic impedance of the tapered transmission line increases along a length of the tapered transmission line from the first end to the second end, and the tapered transmission line has an outside surface separated from the conductive element by a dielectric; and a backplane with first and second locations for attaching the first module and a second module, respectively, so the first port region aligns with a second port region of the second module when the first and second modules are attached to the backplane.",
    "6. The system of claim 1, wherein the tapered transmission line fills a gap between the port region and the substrate.",
    "7. A system comprising: a module comprising: a substrate on which a radio frequency (RF) transmitter is mounted, the RF transmitter having an output terminal; a housing having a port region at a surface of the housing; and a tapered transmission line with a conductive element the conductive element having a first end coupled to the output terminal of the RF transmitter and a second end that terminates at the port region, wherein a characteristic impedance of the tapered transmission line increases along a length of the tapered transmission line from the first end to the second end, and the tapered transmission line has an outside surface separated from the conductive element by a dielectric, and the first end is coupled to a contact bump on the substrate, and the contact bump is offset laterally from the port region, and the tapered transmission line is skewed to fill a gap between the port region and the contact bump.",
    "8. The system of claim 1, wherein an electromagnetic field emanated from the tapered transmission line has a frequency in a range of 5-100 GHz.",
    "9. A method of transmitting a signal in a system, the method comprising: generating a first radio frequency (RF) signal in a module; generating a second RF signal in the module; conducting the first RF signal through a first signal line to a first contact point; conducting the second RF signal through a second signal line to a second contact point; confining and directing the first RF signal by a first tapered near field communication (NFC) field confiner from the first contact point to a first port region of the module, wherein the first tapered NFC field confiner has a first characteristic impedance value at the first contact point and a second characteristic impedance value at the first port region; confining and directing the second RF signal by a second tapered NFC field confiner from the second contact point to a second port region of the module, wherein the second tapered NFC field confiner has a third characteristic impedance value at the second contact point and a fourth characteristic impedance value at the second port region; emanating a first RF electromagnetic field in response to the first RF signal from the first port region of the module; and emanating a second RF electromagnetic field in response to the second RF signal from the second port region of the module.",
    "10. The method of claim 9, wherein the module is a first module and the method further comprises: receiving the emanated first RF electromagnetic field at a third port region of a second module adjacent the first module; confining and directing a resultant RF signal by a third tapered NFC field confiner from the third port region to a third contact point, wherein the third tapered NFC field confiner has a fifth characteristic impedance value at the third contact point and a sixth characteristic impedance value at the third port region; and providing the resultant RF signal to an RF receiver of the second module.",
    "11. The system of claim 1, wherein the tapered transmission line is a tapered near field communication (NFC) field confiner.",
    "12. The system of claim 2, wherein the tapered transmission line is a tapered near field communication (NFC) field confiner.",
    "13. The system of claim 2, wherein an axis along the length of the tapered transmission line is perpendicular to the substrate.",
    "14. The system of claim 2, wherein the tapered transmission line fills a gap between the port region and the substrate.",
    "15. The system of claim 2, wherein an electromagnetic field emanated from the tapered transmission line has a frequency in a range of 5-100 GHz.",
    "16. The system of claim 4, wherein the first and second tapered transmission lines are tapered near field communication (NFC) field confiners.",
    "17. The system of claim 4, wherein a first axis along the length of the first tapered transmission line is perpendicular to the substrate, and a second axis along the length of the second tapered transmission line is perpendicular to the substrate.",
    "18. The system of claim 4, wherein the first tapered transmission line fills a first gap between the first port region and the substrate, and the second tapered transmission line fills a second gap between the second port region and the substrate.",
    "19. The system of claim 4, wherein an electromagnetic field emanated from the first tapered transmission line has a frequency in a range of 5-100 GHz.",
    "20. The system of claim 5, wherein the tapered transmission line is a tapered near field communication (NFC) field confiner.",
    "21. The system of claim 5, wherein an axis along the length of the tapered transmission line is perpendicular to the substrate.",
    "22. The system of claim 5, wherein the tapered transmission line fills a gap between the first port region and the substrate.",
    "23. The system of claim 5, wherein an electromagnetic field emanated from the tapered transmission line has a frequency in a range of 5-100 GHz.",
    "24. The system of claim 7, wherein the tapered transmission line is a tapered near field communication (NFC) field confiner.",
    "25. The system of claim 7, wherein an axis along the length of the tapered transmission line is perpendicular to the substrate.",
    "26. The system of claim 7, wherein the tapered transmission line fills a gap between the port region and the substrate.",
    "27. The system of claim 7, wherein an electromagnetic field emanated from the tapered transmission line has a frequency in a range of 5-100 GHz."
  ],
  "description_excerpt": "This disclosure generally relates to the use of near field communication (NFC) in place of physical/ohmic contacts for communication among system modules.\n\nNear Field Communication (NFC) is a wireless technology allowing two devices to communicate over a short distance of approximately 10 cm or less. Various protocols using NFC have been standardized internationally within NFC Forum specifications and defined in ISO/IEC 18092, ECMA-340, and ISO 14443, for example. NFC allows a mobile device to interact with a subscriber's immediate environment. With close-range contactless technology, mobile devices may be used as credit cards, to access public transportation, to access secured locations, and many more applications. Contactless systems are commonly used as access control ID's (e.g. employee badges), as well as payment systems for public transportation etc. More recently, credit cards are beginning to include NFC capability.\n\nTypical NFC systems rely on low-frequency signals with structures such as coils or capacitive plates with large fringing electric or magnetic fields to facilitate signal transfer over a short distance. However, these low frequencies limit data rate. To increase data rate, the frequency of the carrier must be increased, and a large bandwidth around that carrier must be allocated.\n\nPermittivity is a material property that expresses a measure of the energy storage per unit meter of a material due to electric polarization (J/V 2)/(m). Relative permittivity is the factor by which the electric field between the charges is decreased or increased relative to vacuum.",
  "cpc": [
    "H04L 67/1063",
    "H04B 5/0031",
    "H04B 5/0062",
    "H04B 5/0068",
    "H04B 5/02",
    "H04B 5/20",
    "H04B 5/45",
    "H04B 5/48",
    "H04B 5/70",
    "H04B 5/77"
  ],
  "ipc": [
    "H04B 5/20",
    "H04B 5/48",
    "H04L 29/08"
  ],
  "assignees": [
    "Texas Instruments Inc"
  ],
  "inventors": [
    "Benjamin Stassen Cook",
    "Nathan Brooks",
    "Swaminathan Sankaran",
    "Bradley Allen Kramer",
    "Mark W. Morgan",
    "Baher Haroun"
  ],
  "filing_date": "2017-06-29",
  "publication_date": "2019-01-01",
  "grant_date": "2019-01-01",
  "priority_date": "2017-06-29",
  "application_number": "US-201715638146-A",
  "family_id": "64734921",
  "cited_by_count": 114,
  "citations": [
    "US20080153416A1",
    "US20140285281A1",
    "US9590699B1"
  ]
}