Effects of filling factor on near field transmit properties for a dual-row array at 300 MHz

We evaluated the performance of purely cylindrical and conical-cylindrical non-overlapped dual-row near-field head arrays with radiative elements of axial length 70 and 80 mm. Increasing the filling factor using a conical row does not ensure an increase of the RF magnetic field averaged over the entire human brain. For the geometries, excitation conditions and volume of interest that were investigated, the conical shape resulted in an intrinsic reduction of safety excitation efficiency.