Provided is printed circuit board for minimizing dielectric losses experienced by a low-current portion of an electric circuit. The printed circuit board includes a first substrate supporting an electrically-conductive material patterned to form a conductive pathway between electric circuit components, and a surface-mount guard pad provided on a substantially-planar exposed surface of the first substrate and covering at least an area of the exposed surface including a footprint of the low-current portion on the first substrate. A second substrate is also provided with one or more electrically conductive pads that are surface mounted to the guard pad to couple the second substrate to the guard pad. The second substrate also supports a signal trace included in the low-current region for conducting a low-current signal.