Physicochemical Aspects of the Development of Microwave Dielectrics

Abstract

Microwave technology uses widely various dielectric materials. Dielectrics, the use of which reduces substantially the overall dimensions of microwave circuits, i.e. dielectrics with high permittivity (epsiv>20), are of special interest. The miniaturization effect is based on the epsiv <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> -fold reduction of electromagnetic wave length in dielectric; the planar dimensions of microwave microcircuits decrease by a factor of epsiv. Dielectrics with high permittivity are used as dielectric resonators, microcircuit substrates, filter capacitors, etc in microwave technology. Microwave dielectrics can be developed in several different ways, for example on the basis of monophase systems and by creating multiphase compositions. Monophase microwave dielectrics are developed on the basis of solid solutions using aliovalent substitution in one of the crystal sublattices and by making one of the sublattices mobile. At the same time, microwave dielectrics based on multiphase compositions can be developed by creating multi-layer resonant elements and by using volume temperature compensation. This paper will discuss briefly the above methods for developing microwave dielectrics in terms of literature data and the results by the author.