In the past years, both multilayer ceramic capacitors (MLCCs) and varistors (MLVs) have become continuously more important for RF- applications, e.g. in mobile phones or data processing. For the optimized use of MLCCs e.g. for noise reduction, suppression of harmonic frequencies and impedance matching, a better understanding of RF behaviour is increasingly demanded. The same holds for MLVs, which in addition to their use for ESD protection offer excellent EMI/ noise suppression capabilities. The scope and purpose of this paper is to describe the advanced abilities in RF designs of recently developed MLCC and MLV devices. The RF behaviour is assessed by s- parameter measurements up to 6 GHz and ECP- (equivalent circuit parameter -) modelling. Results are presented and compared for MLCCs with different case sizes and inner electrode types, and for MLVs with case size 0603 and arrays. For the MLCCs it is shown, that a significant increase of Q-factor can be obtained using newly developed copper inner electrode designs. For the multilayer varistors we demonstrate the ability of their capacitance to behave as RF filter with ECP model similar to MLCC. In addition, the influence of the operating temperature on resonance frequency and the ECP model has been evaluated and is discussed with respect to RF application needs.
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