US4952878A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic resonance apparatus having an improved RF coil
Assignee: US Philips Corp
•
Filing: 1989-04-19
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Granted: 1990-08-28
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Expires: 2009-04-19
Abstract
Abstract An r.f. transmitter coil is coupled to individually or group-wise independently drivable antenna wire elements, each independently drivable element being driven by its own power amplifier via a sliding contact. An r.f. supply source is coupled to the inputs of the power amplifiers via an input network which provides a phase distribution among the r.f. signals supplied to the amplifiers for the coil to transmit with a circularly polarized r.f. field.
Inventors
- 👤 Wilhelmus R. M. Mens
- 👤 Peter H. Wardenier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:28
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/36; G01R33/3614; G01R33/34; G01R33/34046; G01R33/3607
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
73 words
A magnetic resonance apparatus having a magnet system for generating a stationary magnetic field, a gradient magnet system and an rf coil system, characterized in that the rf coil system comprises a coil which has means for an individually controllable drive of antenna wires or sub-groups of antenna wires of the coil and a power amplifier incorporated for each of the individually drivable antenna wires in the proximity of the corresponding antenna wire.
Claim 2
Dependent Claim
73 words
A magnetic resonance apparatus having a magnet system for generating a stationary magnetic field, a gradient magnet system and an rf coil system, characterized in that the rf coil system comprises a coil which has means for an individually controllable drive of antenna wires or sub-groups of antenna wires of the coil and a power amplifier incorporated for each of the individually drivable antenna wires in the proximity of the corresponding antenna wire.
Claim 3
Dependent Claim
37 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that the power amplifier comprises a MOS-FET transistor which is connected, via an input network having an inductance and a capacitance, to an rf supply source.
Claim 4
Dependent Claim
42 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that the rf coil comprises a number of antenna wires present on a cylinder surface about a central axis which are connected to ring conductors on each side via a capacitance.
Claim 5
Dependent Claim
23 words
A magnetic resonance apparatus as claimed in claim 3, characterized in that the ring conductors are constructed as flanges adapted to the cylinder.
Claim 6
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that the rf coil is enclosed radially by an electrically conductive screening sheath.
Claim 7
Dependent Claim
35 words
A magnetic resonance apparatus as claimed in claim 5, characterized in that the sheath serves as a reference potential for circuit elements of input networks and/or as a heat dissipating element for the power amplifiers.
Claim 8
Dependent Claim
26 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that the power amplifiers are connected to the corresponding antenna wires via axially adjustable contacts.
Claim 9
Dependent Claim
47 words
A magnetic resonance apparatus as claimed in claim 1, characterized in that a phase control device is incorporated in the supply for the individually drivable antenna wires for driving with successive phase differences a signal in the antenna wires for generating a circularly polarized rf transmitter field.
Claim 10
Dependent Claim
42 words
A magnetic resonance apparatus as claimed in claim 2, characterized in that the rf coil comprises a number of antenna wires present on a cylinder surface about a central axis which are connected to ring conductors on each side via a capacitance.
Claim 11
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 2, characterized in that the rf coil is enclosed radially by an electrically conductive screening sheath.
Claim 12
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 3, characterized in that the rf coil is enclosed radially by an electrically conductive screening sheath.
Claim 13
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 4, characterized in that the rf coil is enclosed radially by an electrically conductive screening sheath.
Claim 14
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 2, characterized in that the power amplifiers are connected to antenna wires via axially adjustable contacts.
Claim 15
Dependent Claim
24 words
A magnetic resonance apparatus as claimed in claim 3, characterized in that the power amplifiers are connected to antenna wires via axially adjustable contacts.
Claim 16
Dependent Claim
47 words
A magnetic resonance apparatus as claimed in claim 5, characterized in that a phase control device is incorporated in the supply for the individually drivable antenna wires for driving with successive phase differences a signal in the antenna wires for generating a circularly polarized rf transmitter field.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |