An interface device enables an intracavity probe to be used with a magnetic resonance (MR) system for the purpose of obtaining images or spectra of a region of interest within a cavity of a patient. The probe includes a shaft, a balloon at one end thereof, and a coil loop within the balloon. The coil loop preferably includes two drive capacitors and a tuning capacitor, all of which in series. A junction node between the drive capacitors serves as a ground for electrically balancing the coil loop. Diametrically opposite the junction node, the tuning capacitor enables the coil loop to resonate at the operating frequency of the MR system. Across each drive capacitor is connected an output cable having an electrical length of SL+n(λ/4). The output cables terminate in a plug that is used to connect the coil loop to the interface device.
