Electromagnetic transmission characteristics of composite frequency selective surfaces coated with conductive polymer-silver paste

In this work, a kind of conductive polymer-silver paste was used to fabricate composite frequency selective surfaces (FSSs) with four-legged slot elements. Screen printing and 3D engraving process were carried out to coat the conductive polymer-silver paste onto the fabric preform and sculpt composite panels into composite FSSs, respectively. The substrates of the composite FSS were carbon and quartz glass fabrics, respectively. The equivalent electrical conductivity of the composite material FSS was measured and the results showed that it increased significantly after the fabrics printed by the conductive silver paste. Free space method was adopted to test the electromagnetic transmission characteristics of the composite FSS. Experimental results showed that the conductive silver paste was effective to decrease the minimum transmission loss of the composite FSS and the minimum transmission loss of the quartz glass fabric composite FSS was lower than that of the carbon ones. A finite element model was put forward to calculate the electromagnetic transmission characteristics of the composite FSS. The calculated results were in agreement with the experimental data. Effects of the equivalent electrical conductivity and the thickness of the composite substrate on the minimum transmission loss of the carbon fabric composite FSS were investigated.