Patent ID: 8138762

Claim:
An RF coil array for use in a magnetic resonance system for detecting MR signals from a subject comprising: a plurality of separate RF coil elements arranged in an array for receiving RF signals from the subject, each of the coil elements having a conductive loop with a plurality of capacitors and with a pair of ends across one of the capacitors at which the signal is extracted; at least one of the coil elements having a pre-amplifier circuit for receiving the signal from the pair of ends of the coil element for amplification of the signal to submit to a signal analysis system; the pre-amplifier circuit including a transistor and conditioning components in advance of the transistor arranged to determine a required impedance for the pre-amplifier circuit; the conditioning components including an inductance and a capacitance; said at least one of the coil elements having a preamplifier decoupling network connected across the pair of ends at said one of the capacitors for generating a high impedance across the pair of ends so as to inhibit coupling in the coil from signals in adjacent and non-adjacent coils and coil elements of the array; wherein the decoupling circuit comprises a capacitance including said at least one capacitor which co-operates with the inductance of the conditioning circuit element to form a parallel resonant circuit to generate said high impedance; and wherein the capacitance and the coil element are arranged with impedance values selected to define an output impedance which substantially matches the required impedance of the pre-amplifier circuit.