Dielectric and High Temperature Superconducting Materials for Microwave Communication Systems

Informacje na temat projektu

Identyfikator umowy o grant: BRPR950084

Projekt został zamknięty

Data rozpoczęcia 1 Stycznia 1996

Data zakończenia 31 Grudnia 1998

Finansowanie w ramach

• Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Koszt całkowity € 0,00

Wkład UE Brak danych

Koordynowany przez

Thomson-CSF
France

Exploitable results

Dielectric and High Tc Superconducting Materials for Microwave Communication Systems

Resonators are the basic bricks of filters and oscillators. At centimetre wavelengths (i.e. strictly speaking frequencies from 3 to 30 GHz, usually extended to 1-100 GHz), so-called "microwave" resonators are made of dielectric and conducting or superconducting materials with different configurations - lumped elements: inductors L and capacitors C as for lower frequencies - lines: coaxial, microstrip, stripline... - metallic cavities - metal coated ceramics - dielectric resonators DR From a circuit point of view, a resonator is defined by - the resonant frequency fr set by the geometrical dimensions of the resonator (in the centimetre range) and by the permittivity ? of the dielectric material. - the quality factor Q equal to the inverse of the relative resonant line-width ?f/f which depends on both the loss tan? of the dielectric material and the surface resistance Rs of the (super)conducting material. - the characteristic impedance Zc and coupling factors Ze or ? defined by the connections to the circuit. The resonator parameters are directly related to the material parameters and to the geometry. These different kinds of resonators can be evaluated according to their size and to their electrical characteristics. The choice depends on the application. MMIC for instance are poised to lumped elements with poor Q (unless superconductors are used), while the other applications seek for the highest Q within the smallest volume. In order to meet this requirement, two ways are considered: - dielectric resonators - superconducting resonators These are the core of DiHiMiCo project. The study is focused on these two objects and on their evolution versus temperature T. High Temperature Superconducting materials (HTS) indeed must be cooled below 90K and the behaviour of both HTS and DR versus T is a major issue which is addressed in DiHiMiCo. The effort starts from the materials and the effect of processing variables on the performance through a careful selection and analysis procedure.