Ultra-wideband antennas for combined magnetic resonance imaging and UWB radar applications

Magnetic resonance imaging (MRI) is one of the most highly appreciated medical diagnostic techniques worldwide. Recent developments aim at adding the capability of creating focused images of moving objects. Among the potential navigator techniques required for such an improved MRI is ultra-wideband (UWB) radar. We have studied the performance of UWB antennas for biomedical imaging inside the 3-Tesla MRI system at PTB Berlin. The strong static and time variant magnetic fields give rise to severe mechanical and electrical interactions due to the induced electromagnetic forces. On the other side, the high magnetic field homogeneity required for MR scans can also be affected adversely by the presence of the UWB antennas. The requirements resulting for the design of MRI compatible antennas have been identified and implemented in terms of a novel type of double-ridged horn antenna. We describe the design of the antenna and its performance for magnetic resonance imaging.