Tunable dielectric composite and method for the production thereof


The present invention relates to composite dielectric materials with low dielectric losses and high tunability of the relative dielectric permittivity, in the form of thick films to be used and integrated in circuits, as passive components of tunable devices, for application at radio and microwave frequencies, and methods for the production thereof, specifically with the combination of the electrophoretic deposition method with the sol gel method for manufacturing said thick composite films, composed of a dielectric phase with low dielectric losses (high Q), such as the rare earth barium titanates BaO-Re2O3-TiO2 (Re = Nd, Sm, La, in particular), the neodymium titanate (BaNd2Ti5O14, BNT), and of a dielectric phase with a tunable dielectric permittivity that is tunable by the electric field, as components of the solid solution between barium titanate and strontium titanate BaTiO3 - SrTiO3, such as (Ba0.5 Sr0.5) TiO3 (BST), in particular.

Innovative aspects & main advantages

The present invention describes a new tunable dielectric composite that comprehends a tunable dielectric material and a non tunable dielectric material composed of one or more of the: barium titanate rare earth bronzoids family materials, BaO-Re2O3-TiO2, being Re = Nd, Sm, La, among others; MgTiO3; Ba2Ti9O20; Zr0.8TiSn0.2O4; Ba(Mg1/3Ta2/3)O3; or similar; or their compositions and of a dielectric with a tunable dielectric permittivity with the electric field, as compounds of the solid solution between barium titanate and strontium titanate BaTiO3 – SrTiO3, as (Ba0.5 Sr0.5)TiO3 (BST), namely.
The present invention is useful to make compatible, in the same film, low dielectric losses with a high tunability of the dielectric permittivity, which properties do not exist in a unique material and fundamental for devices operating at high frequencies; the miniaturization of high frequency devices; and the possibility of application to many other electroceramic systems, anticipating the broadening of the existent applications and the fabrication of new electronic devices for high frequency applications.


The present invention seeks to produce thick films of dielectric materials of optimized properties (low dielectric loss and high Q) for use in, for example, varactors, tunable filters, phase shifters, co-planar and linear phase array antennas. The present invention can also produce multilayer thick films in order to enable the manufacture of vertical tunable capacitors of high capacity and low costs. These capacitors, as well as planar capacitors form the basis of tunable filters and resonators of high power.


Dielétrico compósito sintonizável e processo de fabrico

Our Inventors


Universidade de Aveiro
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