Francisco Enilton Alves Nogueira, José Wagner de Oliveira Bezerra, Daniel Barros de Freitas, João Paulo Costa do Nascimento, Tallison Oliveira Abreu, Francisco Alekson Chaves Nobrega, Roterdan Fernandes Abreu, Marcos José Pereira Alves, Paulo Maria de Oliveira Silva, Ronaldo Glauber Maia de Oliveira, Felipe Felix do Carmo, Marcelo Antonio Santos da Silva, Ronaldo Santos da Silva, Antonio Sergio Bezerra Sombra
{"title":"La2Ti2O7-La4Ti9O24复合材料的介电性能在温度变化下具有较高的热稳定性","authors":"Francisco Enilton Alves Nogueira, José Wagner de Oliveira Bezerra, Daniel Barros de Freitas, João Paulo Costa do Nascimento, Tallison Oliveira Abreu, Francisco Alekson Chaves Nobrega, Roterdan Fernandes Abreu, Marcos José Pereira Alves, Paulo Maria de Oliveira Silva, Ronaldo Glauber Maia de Oliveira, Felipe Felix do Carmo, Marcelo Antonio Santos da Silva, Ronaldo Santos da Silva, Antonio Sergio Bezerra Sombra","doi":"10.1007/s41779-024-01106-7","DOIUrl":null,"url":null,"abstract":"<div><p>In this work, an experimental and numerical investigation of the dielectric properties in the radio frequency (RF) and microwave (MW) regions of the La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>—La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub> composites was conducted. X-ray diffraction demonstrated that there was a reaction between La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> (LTO) and TiO<sub>2</sub>, resulting in the formation of La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub>. Electrical studies in the RF region demonstrated that the composites presented a thermally activated process with activation energy values between 1.50 and 2.30 eV, indicating that the addition provided an increase in activation energy (E<sub>a</sub>). In the MW region, an increase in the permittivity (ε'<sub>r</sub>) and dielectric loss (tan δ) was observed with the increased presence of La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub>, as well as a change in the temperature coefficient (τ<sub>f</sub>). The materials were tested as dielectric resonator antennas (DRA), showing reflection coefficients below –10 dB, realised gain between 4.18 and 4.97 dBi, bandwidth varying from 73 to 207 MHz, and radiation efficiency above 75%. These results show that La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>—La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub> composites are promising candidates for use in electronic circuits in the radiofrequency and microwave regions.</p></div>","PeriodicalId":673,"journal":{"name":"Journal of the Australian Ceramic Society","volume":"61 3","pages":"887 - 895"},"PeriodicalIF":2.1000,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"High thermal stability of the dielectric properties of the La2Ti2O7—La4Ti9O24 composites under temperature variation\",\"authors\":\"Francisco Enilton Alves Nogueira, José Wagner de Oliveira Bezerra, Daniel Barros de Freitas, João Paulo Costa do Nascimento, Tallison Oliveira Abreu, Francisco Alekson Chaves Nobrega, Roterdan Fernandes Abreu, Marcos José Pereira Alves, Paulo Maria de Oliveira Silva, Ronaldo Glauber Maia de Oliveira, Felipe Felix do Carmo, Marcelo Antonio Santos da Silva, Ronaldo Santos da Silva, Antonio Sergio Bezerra Sombra\",\"doi\":\"10.1007/s41779-024-01106-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In this work, an experimental and numerical investigation of the dielectric properties in the radio frequency (RF) and microwave (MW) regions of the La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>—La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub> composites was conducted. X-ray diffraction demonstrated that there was a reaction between La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> (LTO) and TiO<sub>2</sub>, resulting in the formation of La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub>. Electrical studies in the RF region demonstrated that the composites presented a thermally activated process with activation energy values between 1.50 and 2.30 eV, indicating that the addition provided an increase in activation energy (E<sub>a</sub>). In the MW region, an increase in the permittivity (ε'<sub>r</sub>) and dielectric loss (tan δ) was observed with the increased presence of La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub>, as well as a change in the temperature coefficient (τ<sub>f</sub>). The materials were tested as dielectric resonator antennas (DRA), showing reflection coefficients below –10 dB, realised gain between 4.18 and 4.97 dBi, bandwidth varying from 73 to 207 MHz, and radiation efficiency above 75%. These results show that La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>—La<sub>4</sub>Ti<sub>9</sub>O<sub>24</sub> composites are promising candidates for use in electronic circuits in the radiofrequency and microwave regions.</p></div>\",\"PeriodicalId\":673,\"journal\":{\"name\":\"Journal of the Australian Ceramic Society\",\"volume\":\"61 3\",\"pages\":\"887 - 895\"},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2024-10-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the Australian Ceramic Society\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s41779-024-01106-7\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, CERAMICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Australian Ceramic Society","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s41779-024-01106-7","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
High thermal stability of the dielectric properties of the La2Ti2O7—La4Ti9O24 composites under temperature variation
In this work, an experimental and numerical investigation of the dielectric properties in the radio frequency (RF) and microwave (MW) regions of the La2Ti2O7—La4Ti9O24 composites was conducted. X-ray diffraction demonstrated that there was a reaction between La2Ti2O7 (LTO) and TiO2, resulting in the formation of La4Ti9O24. Electrical studies in the RF region demonstrated that the composites presented a thermally activated process with activation energy values between 1.50 and 2.30 eV, indicating that the addition provided an increase in activation energy (Ea). In the MW region, an increase in the permittivity (ε'r) and dielectric loss (tan δ) was observed with the increased presence of La4Ti9O24, as well as a change in the temperature coefficient (τf). The materials were tested as dielectric resonator antennas (DRA), showing reflection coefficients below –10 dB, realised gain between 4.18 and 4.97 dBi, bandwidth varying from 73 to 207 MHz, and radiation efficiency above 75%. These results show that La2Ti2O7—La4Ti9O24 composites are promising candidates for use in electronic circuits in the radiofrequency and microwave regions.
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