A Non-Magnetic RF Balun Designed at 128 MHz Centre frequency for 3 T MRI Scanners

In this work, a non-magnetic RF balun is implemented for 3 T magnetic resonance imaging (MRI) scanners operating at 128 MHz to transform a balanced input signal from a dipole or loop antenna into an unbalanced output signal. It is fabricated on a low-cost, copper cladded four-layer printed circuit board (PCB), FR4 with a thickness of 1.57 mm and a copper thickness of 35 μm, with overall footprint of 11.6 mm × 12.2 mm. A comparison among the ADS RF momentum simulations and the measured results indicates a good agreement with the measured insertion and return losses of better than -1 dB and -13 dB, respectively, in a 50 Ω termination setting.