The design of optimised planar thick film filters

This paper presents planar thick film components and their practical implementations to filters. Different thick film LC filter geometries were designed, printed on alumina, fired and characterized in the HF range. They were asymmetric to input and output terminations, and to positive and negative (or ground) applied voltages and HF signals. L-inductive, C-capacitive parameters were distributed using different planar thick film constructions: inductor windings were printed as the top electrode of capacitor and vice versa, planar capacitors were printed between the windings. In addition, four types of optimised planar thick film filter are built using dielectric and ferrite middle layer. As a result, the groups of cells were realized on 0,5x1, 1x1 inch alumina substrate as DIL (dual-in-line package) matrix to serve as filter arrays in EMI (Electromagnetic Interference) suppression.