New Technique for Improving Modal Filter Performance by Using an Electromagnetic Absorber

This paper presents a novel technique for improving modal filter (MF) performance by using an electromagnetic absorber which shows a significant improvement in attenuation of ultra-wideband interference. The authors analyzed the effect of the absorber on the MF performance in suppressing conducted and radiated interferences (in the near and far fields). As an excitation, the authors used an ultra-wideband pulse of 155 ps (at 0.5 level) and then employed
$N$
-norms to estimate and characterize the decomposed pulses. It was experimentally demonstrated that the value of
$N_{1}$
decreased by a factor of 4.31,
$N_{2}$
– by a factor of 6.52,
$N_{5}$
– by a factor of 1.87. In terms of radiated interference in the near field, the improvement in attenuation of each norm achieved at least 2.81 times. The analysis of the characteristics in the far field showed that the use of the electromagnetic absorber allows reducing the transmission coefficient on average by 2.25 times at a distance of 1 m.