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EP0374376A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method for providing multiple coaxial cable connections to a radio-frequency antenna without baluns

Assignee: General Electric Co
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Filing: 1989-09-15
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Granted: —
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Expires: 2009-09-15
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Abstract

Abstract A method for providing plural coaxial cable connec­tions, each to a different portion of a single radio-fre­quency (RF) antenna without requiring the use of isolation means at any RF connection, determines at least a point within the antenna having a desired common potential adjacent to each of the different portions to which one of the coaxial cable connections is to be made; Then forms a separate seg­ment of each different portion which is located substantially at the common potential and is reactively separated from ad­jacent segments of the associated portion; and connects a shield conductor of an associated coaxial cable to the sepa­rate segment, while connecting a center conductor of that same associated coaxial cable to a selected one of the adja­cent segments of that different portion.

Inventors

  • 👤 Peter Bernard Roemer
  • 👤 William Alan Edelstein
  • 👤 Cecil Edward Hayes
  • 👤 Matthew G. Eash

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 13:03
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34046; G01R33/36; G01R33/3628

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 115 words
A method for providing plural coaxial cable connections, each directly to a different one of a plurality of different portions of a single radio-frequency (RF) an­tenna, without requiring isolation means at any RF connec­tion, comprising the steps of: (a) identifying each different antenna portion to which a coaxial cable is to be attached; (b) determining at least one point within the an­tenna adjacent to each of the cable connection portions and having a desired RF potential thereat; (c) coupling a shield conductor of each cable to an associated one of the at least one point; and (d) connecting a center conductor of an associated cable to a selected one of the plurality of different por­tions.
Claim 2
Independent Claim 115 words
A method for providing plural coaxial cable connections, each directly to a different one of a plurality of different portions of a single radio-frequency (RF) an­tenna, without requiring isolation means at any RF connec­tion, comprising the steps of: (a) identifying each different antenna portion to which a coaxial cable is to be attached; (b) determining at least one point within the an­tenna adjacent to each of the cable connection portions and having a desired RF potential thereat; (c) coupling a shield conductor of each cable to an associated one of the at least one point; and (d) connecting a center conductor of an associated cable to a selected one of the plurality of different por­tions.
Claim 3
Dependent Claim 30 words
The method of claim 1, wherein step (b) in­cludes the step of extending the desired RF potential point to at least one of a potential line and a potential surface.
Claim 4
Dependent Claim 66 words
The method of claim 2, wherein step (c) in­cludes the steps of: (c1) forming in each different portion a separate segment which is located substantially at the common potential; (c2) reactively coupling each separate segment to adjacent segments of the associated portion; and (c3) di­rectly connecting the shield conductor of the associated dif­ferent cable to that separate segment associated with the different portion for that cable.
Claim 5
Dependent Claim 50 words
The method of claim 3, wherein the antenna is an RF coil having a pair of opposed end rings, and each dif­ferent portion is an axial conductor connected between the end rings; and step (b) includes the step of locating the common potential line substantially midway between the end rings.
Claim 6
Dependent Claim 72 words
The method of claim 4, further comprising the steps of: forming a separate conductive segment in each axial conductor, substantially at the common potential line, by breaking the conductor and reactively isolating the broken segment from the adjacent parts of that axial conductor; and directly connecting the associated cable center conductor to that end of the axial conductor adjacent part chosen to prop­erly phase the connection with respect to the common poten­tial.
Claim 7
Dependent Claim 45 words
The method of claim 3, wherein the antenna is an array of a plurality of different RF coils, with each coil being a different portion; and step (b) includes the step of locating the common potential line substantially midway through each of the different coils.
Claim 8
Dependent Claim 77 words
The method of claim 6, further comprising the steps of: forming a separate conductive segment in a conduc­tor of each of the different coils, substantially at the com­mon potential line, by breaking the conductor and reactively isolating the broken segment from the adjacent parts of that conductor; and directly connecting the associated cable cen­ter conductor to that end of the adjacent part of the conduc­tor chosen to properly phase the connection with respect to the common potential.
Claim 9
Dependent Claim 144 words
The method of claim 2, wherein the antenna is an RF coil having a pair of opposed end rings, and each dif­ferent portion is a different axial conductor connected be­tween the end rings at different locations thereon; step (a) includes the step of identifying the cable center conductor attachment points as being along one of the end rings; step (b) includes the step of locating the common potential line substantially midway between the end rings; and step (c) in­cludes the steps of: (c1) connecting all of the cable shield conductors to a selected point on the common potential line; (c2) extending each cable generally along the common poten­ tial line to a selected associated different one of the axial conductors; and (c3) connecting each cable shield to the as­sociated axial conductor, between the common potential line and up to one of the end rings.
Claim 10
Dependent Claim 72 words
The method of claim 8, wherein the coil end rings are separated into a plurality of segments, and each gap between adjacent segments is bridged by a capacitive ele­ment; and step (d) includes the step of directly connecting the center conductor of each cable to an end ring segment upon the opposite side of a capacitive element from the end ring segment to which the shield conductor of that cable is connected.
Claim 11
Dependent Claim 186 words
The method of claim 1, wherein the antenna is an RF coil having a pair of opposed end rings separated into a plurality of segments, and each gap between adjacent seg­ments is bridged by a capacitive element; step (a) includes the step of identifying the cable center conductor attachment points as being along a selected one of the end rings; step (b) includes the step of locating the common potential point upon the selected end ring and substantially midway between the attachment points; and step (c) includes the steps of: (c1) connecting all of the cable shield conductors to the common potential point; and (c2) connecting each cable shield along at least part of the end ring segment, between the com­mon potential point and an end of the end ring segment; and step (d) includes the step of connecting the center conductor of each cable to an end ring segment upon the opposite side of a capacitive element from the end ring segment upon the opposite side of a capacitive element from the end ring seg­ment to which the shield conductor of that cable is con­nected.
Claim 12
Dependent Claim 119 words
A radio-frequency (RF) antenna, comprising: a plurality of RF coils, each having a conductor segment separated from a remainder of the RF coil and having thereon on a common RF potential essentially equal to the RF potential on the separated segment of any other one of the RF coils; the coils being arrayed to cause the common potential segments lie upon one of a line and a surface; and a like plurality of coaxial cables, each associated with a different one of the RF coils, each having a shield conductor connected to the common potential segment of the associated RF coil, and having a center conductor directly connected to a selected point on the remainder of that RF coil.
Claim 13
Dependent Claim 119 words
A radio-frequency (RF) antenna, comprising: a plurality of RF coils, each having a conductor segment separated from a remainder of the RF coil and having thereon on a common RF potential essentially equal to the RF potential on the separated segment of any other one of the RF coils; the coils being arrayed to cause the common potential segments lie upon one of a line and a surface; and a like plurality of coaxial cables, each associated with a different one of the RF coils, each having a shield conductor connected to the common potential segment of the associated RF coil, and having a center conductor directly connected to a selected point on the remainder of that RF coil.
Claim 14
Dependent Claim 17 words
The antenna of claim 11, further comprising reactive means for bridging each gap in each RF coil.
Claim 15
Dependent Claim 23 words
The antenna of claim 12, wherein the reactive means bridging the gap across which the coaxial cable is con­nected is a capacitive element.
Claim 16
Dependent Claim 27 words
The antenna of claim 13, wherein the capaci­tance of the capacitive element is selected to match the ca­ble impedance to the RF coil at a selected frequency.
Claim 17
Dependent Claim 88 words
A radio-frequency (RF) antenna, comprising: an RF coil having a pair of opposed conductive end rings, each separated into a first plurality of segments, and a plurality of axial conductors, each extending between like-­positioned segments of the end rings; and a plurality of coaxial cables, each having a shield conductor connected to a selected one of a common potential point, a common potential line and a common potential surface upon the coil, and each having a center conductor directly connected to a different location upon the RF coil.
Claim 18
Dependent Claim 88 words
A radio-frequency (RF) antenna, comprising: an RF coil having a pair of opposed conductive end rings, each separated into a first plurality of segments, and a plurality of axial conductors, each extending between like-­positioned segments of the end rings; and a plurality of coaxial cables, each having a shield conductor connected to a selected one of a common potential point, a common potential line and a common potential surface upon the coil, and each having a center conductor directly connected to a different location upon the RF coil.
Claim 19
Dependent Claim 71 words
The antenna of claim 15, wherein a different one of the axial conductors is associated with each cable, each associated axial conductor having a segment thereof lo­cated at the common potential and separated from a remainder of that axial conductor; the associated cable shield conduc­tor being connected to the axial conductor segment and the associated cable center conductor being connected to a prede­termined location upon the remainder of that axial conductor.
Claim 20
Dependent Claim 37 words
The antenna of claim 16, further comprising reactive means for bridging each gap separating the segment and the remainder of any axial conductor; the cable center and shield conductors being connected across one of the reac­tive means.
Claim 21
Dependent Claim 30 words
The antenna of claim 17, wherein the RF coil is enclosed within an RF shield, and the cables are routed to the shield and the cable shield conductors connected thereto.
Claim 22
Dependent Claim 71 words
The antenna of claim 16, wherein a different one of the axial conductors is associated with each cable, each associated axial conductor having a location thereon at the common potential; all cable shield conductors being con­nected to the associated axial conductor between the common potential point thereon and an end thereof joined to one of the end ring segments; each cable center conductor being di­rectly connected to another end ring segment.
Claim 23
Dependent Claim 57 words
The antenna of claim 15, wherein a different segment of one end ring is associated with each cable; all cable shield conductors being connected to another segment of the same end ring, different from all associated segments, at which the common potential is defined; each cable center con­ductor being directly connected to the associated end ring segment.

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