Temperature compensated niobate microwave ceramics with the columbite structure, M2+Nb2O6
| Autor: | N McN Alford, Robert C. Pullar, K Okeneme |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Materials science
Settore ING-IND/22 - Scienza e Tecnologia dei Materiali Analytical chemistry Mineralogy Relative permittivity Dielectric engineering.material ) chemistry.chemical_compound Materials Chemistry Settore CHIM/03 - Chimica Generale e Inorganica Columbites Settore CHIM/07 - Fondamenti Chimici delle Tecnologie Doping Tcf (or τ Dielectric resonator Niobates Dielectric properties Microwave properties f Calcium titanate chemistry Ceramics and Composites engineering Electroceramics Temperature coefficient Columbite |
| Zdroj: | Journal of the European Ceramic Society. 23:2479-2483 |
| ISSN: | 0955-2219 |
| Popis: | Of the niobate ceramics with the formula M 2+ Nb 2 O 6 , several compounds (M 2+ =Zn, Mg, Ca and Co) have Qf values (at f =1–10 GHz) between 40 000 and 90 000 GHz, offering potential in dielectric resonator applications. However, their temperature coefficient of resonant frequency ( τ f ) values are too high for commercial development, at between −50 and −90 ppm. This paper details the doping of these materials with dielectric ceramics having a large positive τ f , in an attempt to reduce the overall τ f to zero, whilst maintaining a high quality factor ( Q ). It was also found that doping increased the relative permitivity ( e r ) of the niobates. Several materials have been made with near-zero τ f , such as 90% CoNb 2 O 6 /10% CaTiO 3 ( τ f =+2.0 ppm, e r =25.2 and Qf =21 700 GHz), and 94% CoNb 2 O 6 /6% TiO 2 ( τ f =+4.4 ppm, e r =29.6 and Qf =20 300 GHz) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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