Research On Electromagnetic Wave Absorption Performance Of Honeycomb Structure Composites

In order to meet people’s higher requirements in the field of electromagnetic wave protection,this paper prepared absorbing honeycomb structure material with carbonyl iron and carbon black as the main absorbent,and explored the way to improve the wave absorbing performance by means of absorbent composite and absorber filling honeycomb.Scanning electron microscope(SEM)and transmission electron microscope(TEM)were used to observe the microstructure of carbonyl iron(CIP)and carbon black(CB).Honeycomb absorber was prepared with CIP,CB and CIP/CB as absorbents.At the same time,the glass fiber reinforced plastics(GFRP)panel was added to the honeycomb to make honeycomb structure composites.In order to explore more ways to improve absorbing performance,prepared the EPS coated CB absorbing ball,CB/C@EPS and CB were filled in the cavity of the carbonyl iron structure absorbing honeycomb.At the same time,analyzed the impact of absorption performance improvement for filling absorbent in honeycomb,and studied the C@EPS filling rate on the properties of absorbing effect.Studies on absorbents show that CIP is a typical magnetic loss absorber,and the magnetic loss mode is natural resonance loss.CB is a typical resistive absorber,which mainly relies on its nano-size effect and the eddy current generated by itself to dissipate electromagnetic waves.It was found that the absorption performance of honeycomb was improved after the combination of CIP and CB,the absorption peak decreased,the effective absorption bandwidth(RL<-5dB)became wider,and the absorption performance was improved more obviously with the increase of CB content.With the addition of the GFRP panel,the absorption performance of the honeycomb is further improved,and the matching frequency moves to the lower frequency,which can almost achieve the full frequency band below-5dB absorption.It is found that the filling of absorbent in honeycomb cavity is also an effective way to improve the absorbing property.The EPS ball has wave penetrability,which can be adjusted by mixing it with carbon black.After CB/C@EPS absorber is filled into the honeycomb cavity,the wave absorbing performance of the material is greatly improved.At the same time,it was found that the filling rate of the C@EPS ball was not positively correlated with the absorption performance and the effect of 30% filling rate and 70% filling rate on the absorption performance was not the same,and the effect of the filling rate became smaller and smaller with the enhancement of the absorbing ability of honeycomb structure composite.In addition,because of the different filling rate,the affected electromagnetic wave frequency band is also different,which provides a research direction for further functional research of absorbing materials.