{"title":"介电负载微波天线用铌酸铋微晶玻璃","authors":"M. Mirsaneh, B. Zalinska, O. Leisten, I. Reaney","doi":"10.1109/ISAF.2008.4693751","DOIUrl":null,"url":null,"abstract":"Dielectrically-loaded quadrifillar-helix (D-LQH) antennas are used in applications such as global positioning systems and satellite radio where high gain is required for direct communication with satellites. The current generation of D-LQH antenna are made from hollow cylinders of medium permittivity (15Ç,ßå¿rÇß80), high quality factor (Qf), temperature stable ceramics coated with a helical Cu metallisation. To reduce the processing costs of the ceramic core, a castable bismuth niobate glass-ceramics (30% Bi2O3, 30% Nb2O5, 30% B2O3 and 10% SiO2, in mol%) has been developed. On crystallisation at 600°C, a nano-dendritic, pyrochlore-structured phase evolves with å¿r = 41 and Qf = 226. This phase is unstable at >700°C and is initially replaced by triclinic-BiNbO4 (BN) (700 Ç¿Ï 900°C) and then by orthorhombic BN (>900°C). Optimum properties for antenna core applications occur at 920°C heat treatment with å¿r = 15, Qf = 8000 GHz at which point the temperature ! coefficient of resonant frequency is ¿60 MK-1.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Bismuth niobate glass-ceramics for dielectrically-loaded microwave antenna applications\",\"authors\":\"M. Mirsaneh, B. Zalinska, O. Leisten, I. Reaney\",\"doi\":\"10.1109/ISAF.2008.4693751\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Dielectrically-loaded quadrifillar-helix (D-LQH) antennas are used in applications such as global positioning systems and satellite radio where high gain is required for direct communication with satellites. The current generation of D-LQH antenna are made from hollow cylinders of medium permittivity (15Ç,ßå¿rÇß80), high quality factor (Qf), temperature stable ceramics coated with a helical Cu metallisation. To reduce the processing costs of the ceramic core, a castable bismuth niobate glass-ceramics (30% Bi2O3, 30% Nb2O5, 30% B2O3 and 10% SiO2, in mol%) has been developed. On crystallisation at 600°C, a nano-dendritic, pyrochlore-structured phase evolves with å¿r = 41 and Qf = 226. This phase is unstable at >700°C and is initially replaced by triclinic-BiNbO4 (BN) (700 Ç¿Ï 900°C) and then by orthorhombic BN (>900°C). Optimum properties for antenna core applications occur at 920°C heat treatment with å¿r = 15, Qf = 8000 GHz at which point the temperature ! coefficient of resonant frequency is ¿60 MK-1.\",\"PeriodicalId\":228914,\"journal\":{\"name\":\"2008 17th IEEE International Symposium on the Applications of Ferroelectrics\",\"volume\":\"101 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2008-12-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"2008 17th IEEE International Symposium on the Applications of Ferroelectrics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1109/ISAF.2008.4693751\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/ISAF.2008.4693751","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Bismuth niobate glass-ceramics for dielectrically-loaded microwave antenna applications
Dielectrically-loaded quadrifillar-helix (D-LQH) antennas are used in applications such as global positioning systems and satellite radio where high gain is required for direct communication with satellites. The current generation of D-LQH antenna are made from hollow cylinders of medium permittivity (15Ç,ßå¿rÇß80), high quality factor (Qf), temperature stable ceramics coated with a helical Cu metallisation. To reduce the processing costs of the ceramic core, a castable bismuth niobate glass-ceramics (30% Bi2O3, 30% Nb2O5, 30% B2O3 and 10% SiO2, in mol%) has been developed. On crystallisation at 600°C, a nano-dendritic, pyrochlore-structured phase evolves with å¿r = 41 and Qf = 226. This phase is unstable at >700°C and is initially replaced by triclinic-BiNbO4 (BN) (700 Ç¿Ï 900°C) and then by orthorhombic BN (>900°C). Optimum properties for antenna core applications occur at 920°C heat treatment with å¿r = 15, Qf = 8000 GHz at which point the temperature ! coefficient of resonant frequency is ¿60 MK-1.
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