Balun circuit for radio frequency coils in magnetic resonance systems
First Claim
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1. A balun circuit arrangement for coupling radio frequency coil means in a magnetic resonance system to the RF transmitter-receiver, said RF coil means comprising:
- an inductor coil;
tuning capacitor means coupled to said inductor coil means for tuning said inductor coil to a desired resonant frequency for use in systems; and
matching capacitor means coupled to said tuning capacitor for matching the characteristic impedance of the RF coil to the characteristic impedance of the MR system,said balun circuit arrangement comprising;
(a) a two conductor first cable means for coupling said RF coil means to said RF transmitter-receiver;
(b) coupling means for coupling said first cable means across said matching capacitor and said tuning capacitor;
(c) said coupling means including balun means for connecting one conductor of said two conductor cable means to said inductor coil at the point of coupling of said tuning capacitor means and said inductor coil to short skin currents in said first cable means and to simultaneously prevent said currents from reaching said RF coil means, and(d) said balun means being a second cable means that is substantially one quarter wavelength in length at the tuned resonance frequency of said RF coil means.
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Abstract
A balun circuit arrangement for radio frequency (RF) coils in magnetic resonance (MR) systems. The balun circuit arrangement comprises a conductor having a length equal to a quarter wavelength at the tuned resonance frequency of the (RF) coil.
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Citations
7 Claims
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1. A balun circuit arrangement for coupling radio frequency coil means in a magnetic resonance system to the RF transmitter-receiver, said RF coil means comprising:
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an inductor coil; tuning capacitor means coupled to said inductor coil means for tuning said inductor coil to a desired resonant frequency for use in systems; and matching capacitor means coupled to said tuning capacitor for matching the characteristic impedance of the RF coil to the characteristic impedance of the MR system, said balun circuit arrangement comprising; (a) a two conductor first cable means for coupling said RF coil means to said RF transmitter-receiver; (b) coupling means for coupling said first cable means across said matching capacitor and said tuning capacitor; (c) said coupling means including balun means for connecting one conductor of said two conductor cable means to said inductor coil at the point of coupling of said tuning capacitor means and said inductor coil to short skin currents in said first cable means and to simultaneously prevent said currents from reaching said RF coil means, and (d) said balun means being a second cable means that is substantially one quarter wavelength in length at the tuned resonance frequency of said RF coil means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification