Anna Andreychenko1, Hugo Kroeze2, Dennis W. Klomp2, Jan J. Lagendijk1, Peter Luijten2, Cornelius A.T. van den Berg1
Travelling wave MR imaging exploits the RF shield of the scanner as a waveguide. When a patient is placed in the bore a strong impedance mismatch occurs between the hollow (where antenna is located) and loaded parts of the bore. It causes wave reflection and inefficient power is transferred to the target region. To avoid this impedance mismatch we propose to insert a quarter-wavelength coaxial waveguide between the antenna and load which gradually transforms impedance of the antenna to the load impedance. The effectiveness of this inset has been demonstrated both in the simulations and in-vivo experiments.