Low-pass EMI Filter Based on Modal Distortions, Internal Reflections and
Magnetodielectric Cover
Abstract
The letter introduces the first highly miniaturized low-pass filter that
combines the use of modal distortions, internal reflections, and
magnetodielectric cover. The filter is implemented on an FR-4 printed
circuit board with compact external dimensions of 17x14x0.25 (mm)
covered with an elastic magnetodielectric material. We conducted
electrodynamic simulations of this filter using FDTD in Keysight EMPro
and FEM in COMSOL Multiphysics. To validate the simulation results, the
filter prototype was designed, manufactured, and tested. The EMI
attenuation in the range from 4 to 20 GHz was more than 42 dB. The
standing wave coefficient in the passband did not exceed 1.5. The
effectiveness of broadband and mesoband interference suppression was
evaluated using N-norms analysis. Signal integrity was
analyzed by exciting a pseudo-random bit sequence with data rates of
0.25 and 0.5 Gbps at the input of the filter. The examination of
N-norms and eye diagrams confirms that the filter can be
employed to protect signal circuits.