Floating segmented shield cable assembly
First Claim
1. Apparatus for transmitting signals in an RF field comprising:
- a source of RF signals to be transmitted;
a circuit ground;
a shielded cable comprising;
an inner conductor construction extending axially along the cable and providing electrical connection for transmission of signals between opposite ends of the cable;
an axially extending outer shield conductor disposed in spaced surrounding relationship around the inner conductor construction, the outer shield conductor extending continuously between the opposite ends of the cable;
the outer shield conductor being connected to the circuit ground;
the outer shield conductor fully enveloping the inner conductor construction so as to shield the inner conductor construction from said RF field;
the inner conductor construction being electrically insulated from the outer shield conductor by dielectric material interposed between;
a plurality of segmented shield conductor portions each surrounding the outer shield conductor and each having a length less than that of the cable;
the segmented shield conductor portions being arranged at locations along the cable;
the segmented shield conductor portions being electrically separated each from the others such that the segmented shield conductor portions float electrically relative to the other segmented shield conductor portions;
the segmented shield conductor portions being electrically separated from the outer shield conductor such that the segmented shield conductor portions float electrically relative to the outer shield conductor;
and a cable jacket enclosing the segmented shield conductor portions and the outer shield conductor.
9 Assignments
0 Petitions
Accused Products
Abstract
Signals in an RF field, such as that of an MRI system, are communicated through an inner conductor having an outer shield with a dielectric material therebetween and an outer cable jacket. Current in the shield caused by the RF field from the transmit body coil is reduced by providing a second dielectric material around the shield conductor and a plurality of segmented shield conductor portions formed of non-magnetic braid or wrapped non-magnetic foil tape outside the second dielectric material and inside the jacket at spaced positions along the cable, with the portions being electrically separated from each other and from the shield so that the segmented shield conductor portions act to shield the outer shield conductor to reduce the generation of current thereon while the electrical separation of the segmented shield conductor portions each from the others prevents the generation of a current along the portions.
103 Citations
30 Claims
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1. Apparatus for transmitting signals in an RF field comprising:
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a source of RF signals to be transmitted; a circuit ground; a shielded cable comprising; an inner conductor construction extending axially along the cable and providing electrical connection for transmission of signals between opposite ends of the cable; an axially extending outer shield conductor disposed in spaced surrounding relationship around the inner conductor construction, the outer shield conductor extending continuously between the opposite ends of the cable; the outer shield conductor being connected to the circuit ground; the outer shield conductor fully enveloping the inner conductor construction so as to shield the inner conductor construction from said RF field; the inner conductor construction being electrically insulated from the outer shield conductor by dielectric material interposed between; a plurality of segmented shield conductor portions each surrounding the outer shield conductor and each having a length less than that of the cable; the segmented shield conductor portions being arranged at locations along the cable; the segmented shield conductor portions being electrically separated each from the others such that the segmented shield conductor portions float electrically relative to the other segmented shield conductor portions; the segmented shield conductor portions being electrically separated from the outer shield conductor such that the segmented shield conductor portions float electrically relative to the outer shield conductor; and a cable jacket enclosing the segmented shield conductor portions and the outer shield conductor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of communicating signals in an RF field comprising:
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connecting the signals to be communicated to an elongate axially extending inner conductor construction of a communication cable; providing an axially extending shield conductor of the cable disposed in spaced surrounding relationship around the inner conductor construction, the shield conductor extending continuously between the opposite ends of the cable and being connected to a circuit ground for shielding the inner conductor construction from external fields; the inner conductor construction being electrically insulated from the shield conductor by dielectric material interposed between; and providing a cable jacket enclosing the shield conductor; wherein the inner conductor construction and the outer shield conductor are located in an RF field of sufficient intensity and over time period and of a wavelength which would generate heat therein; and reducing the amount of heat generated by; providing a plurality of segmented shield conductor portions, each surrounding the shield conductor and each having a length less than that of the cable; the segmented shield conductor portions being arranged at locations along the cable; the segmented shield conductor portions being electrically separated each from the others such that the segmented shield conductor portions float electrically relative to the other segmented shield conductor portions; and the segmented shield conductor portions being electrically separated from the shield conductor such that the segmented shield conductor portions float electrically relative to the shield conductor of the cable; where the segmented shield conductor portions act to shield the shield conductor to reduce the heating of the shield conductor in the RF field while the electrical separation of the segmented shield conductor portions each from the others reduces the generation of a current along the segmented shield conductor portions. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification