General Electric Company

Paul Douglas Haig

Robert Steven Stormont

Eddy Benjamin Boskamp

Ricardo Becerra

Xiaoming Lou

John Francis Prendergast, Sr

Dashen Chu

Anthony D Defranco

Matthew M Meiller

A decoupling circuit for a radio frequency (RF) surface coil having a plurality of tuning capacitors includes at least two decoupling points and a DC source coupled to the at least two decoupling points. Each decoupling point is associated with one of the plurality of tuning capacitors. Each decoupling point includes a decoupling inductor connected in parallel with a tuning capacitor, a diode connected in series with the decoupling inductor and in parallel with the tuning capacitor, a resistor connected in parallel with the diode and at least one isolating inductor connected between the resistor and the diode to RF isolate the resistor. The value of the resistor in each decoupling point is selected to maintain a high quality factor (Q) of the RF surface coil and to reduce the switching speed of the decoupling circuit.

Circuit and apparatus for decoupling RF surface coils

A feedback circuit is provided for reducing the input impedance of a preamplifier circuit, such as for use with a sensing coil in an imaging system. The feedback circuit permits adjustment of the input impedance by balancing inductive and capacitive components of a feedback control circuit. The imaginary component of the input impedance may be adjusted independently of the real component, to provide a substantially zero input impedance, while allowing adjustment of the stability of the system. The circuitry may function in conjunction with a reactance matching circuit to reduce cross-talk in multiple sensing coil arrangements.

Method and apparatus for reducing input impedance of a preamplifier

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Milwaukee, WI, United States of America

Paul Douglas Haig