Low loss dielectrics with controllable values of specific permittivity

The preparation of solid phase dielectric materials for filling functional volumes in microwave circuits is discussed. The objective is to produce filling material of known low loss and with a high operating temperature and known temperature coefficient of permittivity. Waxes, polymers, and ceramics are considered. It is concluded that a mixture of one of the polymers with a suitable ceramic is the most likely material. Mixtures of polystyrene and rutile are examined. It is concluded that this combination is the most suitable.