ADVANCED CERAMIC SYSTEMS FOR THE TELECOMMUNICATION INDUSTRY

1. ADVANCED CERAMIC SYSTEMS FOR THE TELECOMMUNICATION INDUSTRY Participants: TKI-Ferrit Development and Manufacturing Ltd. KŐPORC Development Ltd. Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences Head of the project: Anna Sztaniszlav TKI-Ferrit Ltd. H-1142 Budapest Ungvár u. 64-66 Hungary sztanisz@tki-ferrit.hu

2. Introduction: Microwave ferrite devices ( isolators, circulators) are irreplaceable components for the telecommunication industry. Transmission parameters (insertion loss, isolation, etc.) and the working temperature range of the ferrite devices depend strongly on the dielectric losses, other microwave parameters and temperature dependence of the microwave parameters of applied materials, such as the soft ferrites and dielectric ceramics which are used as circuit components or tuning elements.

3. What is “ferrite device”? It is a nonreciprocal passive unit, which is an irreplaceable component for the telecommunication industry.

4. Main components of ferrite devices: Ceramic dielectric Circuit unit ferrite

5. Main components of ferrite devices: ferrite Ceramic dielectric Circuit unit Tuning component

6. Main applied material systems in ferrite devices: • Permanent magnets • It is not a topic of this development • Soft ferrites (MeFe2O4), garnet materials(YFe5O12) • Ceramic dielectrics (BaO/TiO2, TiO2/ZrO2, MgTiO3/ZnTiO3)

7. Which material systems are investigated ? Soft ferrites (MeFe2O4), garnets (YFe5O12) Spinel ferrites MnxMgyFezO4 x+y+z=3 typical substitutions:: Al, Zn,… NiFe2O4 typical substitutions : Al, Co, Zn, Mn, Bi, .. Li0,5Fe2-0,5O4 typical substitutions : Zn, Ti, Bi, Mn, … Garnets Y3Fe5O12 typical substitutions : Al, Gd, Ca, V. In, Zr, Ho,… all cations, where the ionic radius is between 0,26 és 1,29 A Most important material parameters: saturation magnetisation dielectric constant ( min. 10, max. 20) magnetic (ΔH) and dielectric (tg δ)losses temperature dependence of the above mentioned parameters

8. Which material systems are investigated ? • Ceramic dielectrics • TiO2 based dielectrics ε= 80-100 • TiO2/ZrO2, ε= 16 • BaO/TiO2 ε= 40 • MgTiO3/ZnTiO3) ε= 26-80 • composites • applications: active circuit components (dielectric constant: 6-100) • tuning elements • most important parameters: • dielectric constant • dielectric losses • temperature dependence of the above mentioned parameters

9. Aim of this project: Harmonised development of the ferrite/garnet and ceramic dielectric systems to produce isolators, circulators with a very broad working frequency range, with very low (<0,2 dB) insertion loss with very broad working temperature range (-400C +800C) in the possibly smallest dimension

10. To cover the demand of the modern telecommunication • wireless systems (900 MHz, 1800 MHz, 2400 MHz,..) • TETRA systems : 400 MHz, 800 MHz),…... • radars, etc.

11. to develop multifunctional devices • to increase the working temperature range of the ferrite devices (-400C ÷ +850C) • to improve the transmission parameters(insertion loss :<0,2 dB) • by the reduction of the loss factors of the ferrites, ceramic dielectrics • to reduce the size and price of the devices • It depends on the dielectric constants • to increase the power handling of the devices (kW) • It depends on the chemical composition and morphology of the two material systems.

12. Material parameters have to be matched: • temperature dependence of the saturation magnetisation of the ferrite/garnet • temperature dependence of dielectric constant of the ceramic dielectric • dielectric losses of the ferrite/garnet and ceramic dielectrics • dielectric constant of the ferrite/garnet and ceramic dielectrics

13. TASKS : • Development of new material compositions : • To develop ferrites, garnets with different chemical compositions • To develop ceramic dielectrics with different chemical compositions • Technological development (advanced pressing methods) to get • Homogeneous grain size distribution • High density materials • Ferrites and garnets with very small grain sizes for special application (high power devices) by HIP technique / nanoferrite technique • Elaboration of new investigation methods (to investigate the chemical composition, chemical homogeneity, morphology) • Development of high sensitive methods • Development new evaluation software

14. Design and preparation of new ferrite devices . • Investigation of theoratical questions: • correlation between the different material parameters and the transmission parameters of the devices

15. Recent results: • Anna Sztaniszlav • Microwave Ferrite Research and Development in Central Europe • Ferrites. Proceedings of the ICF 8. Kyoto 2000. P.825-829 Invited • Anna Sztaniszlav, M. Balla, M. Farkas-Jahnke • Solid State Reactions in the Fe2O3-CaCO3-In2O3 System • Journal opf Materials Science 25. (1990) p. 2353-2358 • Anna Sztaniszlav, M. Balla, M. Farkas-Jahnke • Garnet Forming Solid State Reactions in FeYCaZrO Systems with Different Y-Fe Ratios • Physica Scripta 40. P. 321-324 (1989) • L. Bartha, P. Arató, A.L. Tóth, R. Porat, S. Berger, A. Rosen • Investigation of HIP Sintering of Nanocrystalline WCCo Powder • Journal of Advanced Materials 32, p. 23-26. (2000)