Balun for use in magnetic resonance imaging (MRI) systems and an MRI system that employs the balun

A magnetic resonance imaging (MRI) system comprising:

• N radio frequency (RF) receive coils, each RF receive coil being configured to detect an RF signal having a frequency of interest and to output a magnetic resonance (MR) signal, where N is a positive integer that is greater than or equal to one;
• N amplifiers, each amplifier configured to amplify an MR signal outputted by a respective RF receive coil to produce an amplified MR signal;
• at least one RF receiver;
• and
• a plurality of coaxial cables interconnecting outputs of the amplifiers with inputs of the RF receiver, wherein the amplified MR signals are carried on the coaxial cables from the outputs of the amplifiers to the inputs of the RF receiver, each coaxial cable having a balun comprising:
• a device made of a dielectric material, the device having an outer surface;
• a first inductor formed by winding a portion of the respective coaxial cable L times about the outer surface to form the first inductor, where L is a positive integer that is greater than or equal to 1;
• and
• a resonant circuit having at least a second inductor and at least a first capacitor that are electrically coupled to one another, wherein the first inductor is configured to magnetically couples common-mode noise at the frequency of interest into the resonant circuit, the resonant circuit and the first inductor configured to provide the coaxial cable with a coupled impedance, and wherein at the frequency of interest, the coupled impedance has a high value for suppressing common-mode signals propagating in the respective coaxial cable.

A magnetic resonance imaging (MRI) system comprising:

• N radio frequency (RF) receive coils, each RF receive coil being configured to detect an RF signal having a frequency of interest and to output a magnetic resonance (MR) signal, where N is a positive integer that is greater than or equal to one;
• N amplifiers, each amplifier amplifying an MR signal outputted by a respective RF receive coil to produce an amplified MR signal;
• at least one RF receiver;
• and
• a plurality of coaxial cables interconnecting outputs of the amplifiers with inputs of the RF receiver, wherein the amplified MR signals are carried on the coaxial cables from the outputs of the amplifiers to the inputs of the RF receiver, each coaxial cable having a balun comprising:
• a device made of a dielectric material, the device having an outer surface;
• and
• a first inductor formed by winding a portion of the respective coaxial cable multiple times about the outer surface to form a first inductor layer and winding the portion of the respective coaxial cable multiple times about the first inductor layer to form a second inductor layer on top of the first inductor layer, the first and second inductor layers comprising a first inductor, and wherein a parasitic capacitance exists in between the windings, the parasitic capacitance and a first inductance of the first inductor being configured to provide a resonant circuit that has a parallel impedance at the frequency of interest for suppressing common-mode signals propagating in the coaxial cable.