Radiation characteristics of an input decoupling network for switching DC-DC converters are analyzed by a set of electromagnetic (EM) simulations. Input decoupling network is a part of a DC-DC converter with a dominant contribution to its radiated emissions. The impact of geometrical parameters of an input decoupling network such as the dimensions of metal plates on a printed circuit board (PCB), thickness of a PCB, number of layers, number of vias and radius of vias on the maximum radiated fields is analyzed. Design guidelines for minimizing radiated emissions of an input decoupling network for switching DC-DC converters are summarized.