Influence of dual-row loop array geometry on near field transmit properties at 300 MHz

We evaluated the performance of overlapped dual-row near-field arrays with radiative elements of axial length 80, 100, and 110 mm, after optimization of both array circuit and near-field behavior at 297.2 MHz. For each array geometry, human head-and-torso model position and optimization strategy, an array performance measure was evaluated. For different axial lengths of the elements, this measure was very similar when the distance between the crown of the head and the array axial center was kept constant. Reducing the distance between the crown of the head and the end of the array improved axial coverage for arrays with element axial length of 100 and 110 mm, at the cost of an intrinsic reduction of safety excitation efficiency.