An antenna assembly and an electromagnetic navigation system including such an antenna assembly are provided. The antenna assembly includes a substrate and multiple groups of planar antennas. Each of the planar antennas includes a multiple-loop trace deposited on one of multiple layers of the substrate. Each group includes a first, second, and third planar antenna. For each group, an innermost loop of the first planar antenna has a first linear portion and a second linear portion approximately perpendicular to the first linear portion, an innermost loop of the second planar antenna has a first linear portion and a second linear portion approximately perpendicular to the first linear portion and longer than the first linear portion, an innermost loop of the third planar antenna has a first linear portion and a second linear portion approximately perpendicular to the first linear portion and longer than the first linear portion.
