Patent US4731585A successfully refreshed from Google Patents.
US4731585A
Expired / Lapsed
US
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Antenna coupling circuit for magnetic resonance imaging
Assignee: Toshiba Corp
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Filing: 1987-02-24
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Granted: 1988-03-15
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Expires: 2007-02-24
Abstract
Abstract A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry is provided which includes capacitive circuitry, resistive circuitry, and capacitive transformer circuitry. The capacitive circuitry is coupled in parallel with the antenna to provide capacitive reactance to the coupling circuitry. Resisitive circuitry is coupled in parallel with the antenna and with the capacitive circuitry to provide resistance R in the coupling circuit when an AC voltage at the resonant frequency of the coupling circuit is applied. Capacitive transformer circuitry is coupled in series with the antenna for transforming the resistance value R of the resistive circuitry into a transformed resistance value R'. This increases the apparent resistance of the coupling circuit in parallel with the antenna without increasing the actual resistance and power consumption of the coupling circuit.
Inventors
- 👤 Timothy R. Fox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:34
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/36; G01R33/3628; G01R33/3621
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: capacitive means, coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; resistive means, coupled in parallel with said antenna and with said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; and capacitive transformer means, coupled between said antenna and said receiver circuitry in series with said antenna, for transforming said resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 2
Dependent Claim
124 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: capacitive means, coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; resistive means, coupled in parallel with said antenna and with said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; and capacitive transformer means, coupled between said antenna and said receiver circuitry in series with said antenna, for transforming said resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 3
Dependent Claim
17 words
A coupling circuit as recited in claim 1, wherein the capacitive transformer means comprises a padder capacitor.
Claim 4
Dependent Claim
63 words
A coupling circuit as recited in claim 1, wherein the capacitive transformer means comprises first capacitive transformer means, coupled between the antenna and the receiver circuitry in series with the antenna on one side of said antenna, and second capacitive transformer means, coupled between said antenna and said receiver circuitry and in series with said antenna on the other side of said antenna.
Claim 5
Dependent Claim
19 words
A coupling circuit as recited in claim 3, wherein the first capacitive transformer means comprises a first padder capacitor.
Claim 6
Dependent Claim
19 words
A coupling circuit as recited in claim 3, wherein said second capacitive transformer means comprises a second padder capacitor.
Claim 7
Dependent Claim
201 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: first means for coupling a first terminal of said antenna to a first terminal of said receiver circuitry; second means for coupling a second terminal of said antenna to a second terminal of said receiver circuitry; capacitive means, coupled at a first end to said first coupling means and at a second end to said second coupling means and thereby being coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; resistive means, coupled at one end to said first coupling means and at the other end to said second coupling means and thereby being in parallel with said antenna and said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; and capacitive transformer means, coupled in series with said antenna in said first coupling means, for transforming said resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 8
Dependent Claim
201 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: first means for coupling a first terminal of said antenna to a first terminal of said receiver circuitry; second means for coupling a second terminal of said antenna to a second terminal of said receiver circuitry; capacitive means, coupled at a first end to said first coupling means and at a second end to said second coupling means and thereby being coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; resistive means, coupled at one end to said first coupling means and at the other end to said second coupling means and thereby being in parallel with said antenna and said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; and capacitive transformer means, coupled in series with said antenna in said first coupling means, for transforming said resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 9
Dependent Claim
17 words
A coupling circuit as recited in claim 6, wherein the capacitive transformer means comprises a padder capacitor.
Claim 10
Dependent Claim
224 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: first means for coupling a first terminal of said antenna to a first terminal of said receiver circuitry; second means for coupling a second terminal of said antenna to a second terminal of said receiver circuitry; capacitive means, coupled at a first end to said first coupling means and at a second end to said second coupling means and thereby being coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; and resistive means coupled at one end to said first coupling means and at the other end to said second coupling means, thereby being in parallel with said antenna and said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; first capacitive transformer means coupled in series with said antenna in said first coupling means; and second capacitive transformer means, coupled in series with said antenna in said second coupling means; said first and said second transformer means together transforming the resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 11
Dependent Claim
224 words
A coupling circuit for coupling an inductive coil antenna of a magnetic resonance imaging system to receiver circuitry, said coupling circuit comprising: first means for coupling a first terminal of said antenna to a first terminal of said receiver circuitry; second means for coupling a second terminal of said antenna to a second terminal of said receiver circuitry; capacitive means, coupled at a first end to said first coupling means and at a second end to said second coupling means and thereby being coupled in parallel with said antenna, for providing capacitive reactance in said coupling circuit; and resistive means coupled at one end to said first coupling means and at the other end to said second coupling means, thereby being in parallel with said antenna and said capacitive means, for providing resistance R in said coupling circuit when the inductive reactance of said coupling circuit is equal to the capacitive reactance of said coupling circuit; first capacitive transformer means coupled in series with said antenna in said first coupling means; and second capacitive transformer means, coupled in series with said antenna in said second coupling means; said first and said second transformer means together transforming the resistance value R of said resistive means into a transformed resistance value R', thereby increasing the apparent resistance of said coupling circuit in parallel with said antenna.
Claim 12
Dependent Claim
19 words
A coupling circuit as recited in claim 8, wherein the first capacitive transformer means comprises a first padder capacitor.
Claim 13
Dependent Claim
19 words
A coupling circuit as recited in claim 8, wherein the second capacitive transformer means comprises a second padder capacitor.
References Cited (Backward Citations)
US3603871A
Cited
US3735246A
Cited
US3870926A
Cited
US4129822A
Cited
US4249137A
Cited
US4327390A
Cited
US4371846A
Cited
US4633181A
Cited
US4628264A
Cited
US4620155A
Cited
US4649348A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |