Screen printed silver patterns on La0.5Sr0.5CoO3-δ - Epoxy composite as a strategy for many-fold increase in EMI shielding

The thermal, mechanical and dielectric properties of epoxy resin were improved substantially after making it a composite with the perovskite oxide conductors La0.5Sr0.5CoO3 - delta (LSCO). Nevertheless, the electromagnetic interference (EMI) shielding characteristics of the composites (in the X and Ku-band) were not up to the level for practical applications which prompted us to introduce a novel strategy to augment the level of shielding. On top surface of the composite sheets, predesigned silver (Ag) patterns (periodic structures like rectangular patterns parallel and perpendicular to the waveguide axis, mesh like patterns as well as blanket coating) were screen printed, which resulted in a dramatic 4-fold improvement in their EMI shielding effectiveness, with significant enhancements in the reflection and absorption shielding efficiency of the composite. Compared to the conventional way of adding silver to form epoxy-silver 0-3 composite above its percolation, the present method of screen printing needs only lesser amount of the conductor to generate a maximum shielding efficiency of 99%, with considerable easiness of processing.