Dissertation > Excellent graduate degree dissertation topics show

Development and Application of Microwave Dielectric Ceramics Based on the Principle of Microwave Energy

Author: ZhengJianSen
Tutor: XiongZhaoXian
School: Xiamen University
Course: Materials Science
Keywords: Microwave dielectric ceramics Microwave energy RFID antenna Microwave heating
CLC: TQ174.1
Type: Master's thesis
Year: 2009
Downloads: 258
Quote: 1
Read: Download Dissertation

Abstract


In this thesis, in the view of the synthesis materials,Ba5(Nb0.85Sb0.15)4O15 Ca0.65Ti0.65La0.35Al0.35O3 ceramics were prepared via conventional mixing oxide route, and the effects of sintering aid and processing factors on chemical structure and dielectric properties of the samples were systematically investigated. In addition, in the view of the device design and manufacturing techniques, different kinds of microwave dielectric ceramics, including MgTiO3-CaTiO3, Ca0.65Ti0.65La0.35Al0.35O3, Ba(Mg0.2/3Zn0.8/3Nb2/3) and BaO-La2O3-TiO2 ceramics were explored for the applications of mobile communication and microwave heating based on the principle of microwave energy.Chemicals of H3BO3, MnCO3 and CeO2 were used as sintering additives to lower the sintering temperature for Ba5(Nb0.85Sb0.15)4O15, i.e.,BSN, ceramics. The sintering behavior, microstructure and microwave properties were investigated by XRD, SEM and network analyzer. With 1lwt% H3BO3 and 0.15wt% MnCO3 addition, the BSN ceramics sintered at 940℃get excellent microwave dielectric properties of anεrvalue of 29.28, a Q×f value of 17,113GHz, and aτf value of +10.34ppm/℃. Microwave dielectric properties are adjusted for the ceramic Cao.65Tio.65Lao.35Alo.35O3 + lwt% H3BO3 + 0.15wt%-0.75wt%CeO2 sintered between 900℃and 940℃for 2 h, with values of Q×f≈16,000-23,000GHz,εr≈28-31 andτf≈+8+18ppm/℃.The influence of CuO and MnCO3 additives on the sinterability, microstructure and microwave dielectric properties of Ca0.65Ti0.65La0.35Al0.35O3, i.e., CTLA, ceramics was investigated. The results indicated that the density and dielectric properties of CTLA ceramics could be improved by both low-level doping of CuO （up to 1 wt%） and MnCO3 （up to 0.75wt%）. The sintering temperature of CTLA ceramics with addition of CuO/MnCO3 could be effectively reduced from 1450℃to 1320℃due to the liquid phase effects. Excellent microwave dielectric properties were achieved for the ceramic Ca0.65Ti0.65La0.35Al0.35O3 + 0.75wt% CuO/MnCO3 sintered at 1320℃for 2 h, with values of Q×f≈32,800GHz,εr≈43 andτf≈+10ppm/℃.Meanwhile, gel-casting forming process was successfully used to fabricate microwave ceramic substrates. The dielectric properties of MgTiO3-CaTiO3 ceramics prepared by gel-casting were compared with those by dry press forming. In addition, two kinds of microwave antennas were also developed with the gel-casting forming process.A new method was presented for calculating frequency and Q-factor of dielectric resonator. A novel laser trimming procedure was utilized to adjust the frequency of practical ceramics for dielectric resonators aiming better performance. Experimental results showed that the resonant frequency increased after laser etching applied on either upper or lower surface of resonator; meanwhile, the Q-factor of dielectric resonator was improved.Finally, some results, such as BaO-La2O3-TiO2，Ba(Mg0.2/3Zn0.8/3Nb2/3) and MgTiO3-CaTiO3 ceramics were applied for microwave products supported by the National High-Tech Research and Development Plan of China （Plan 863） under Grant No. 2001AA325100.

Related Dissertations

  1. Synthesis Reseach on α’-Sialon-AlN-BN Composites Powders by Microwave and Conventional Heating,TB383.3
  2. Microwave heating system based on single-chip control,TP273
  3. Study and Design of Magnetron Power Source in Microwave Heating Equipment,TM924
  4. Asphalt Pavement Recycling and Maintenance Technology,U416.217
  5. Research and Implementation of Video Recoder System Combined with RFID Identification Function,TP274.2
  6. Wideband RFID Tag Antenna Design,TP391.44
  7. DSRC-ETC system RF transmitter circuit RFID antenna design,TN83
  8. Analysis and Research on Antenna Radiation Field of RFID System,TP391.44
  9. Study on Microwave Heating Technology and Equipment on the Utilization of Old Asphalt Mixture,U414
  10. Microwave-Assisted Synthesis and properties of methane combustion catalyst,O643.36
  11. Microwave high temperature automatic control system,TP273.5
  12. Physical Modification of the Soybean Protein Concentrate by Alcohol Extraction,TS201.21
  13. Technology Research on Improving the Stable Quality during Storage of Green Tea,TS272.51
  14. Study of the Quick Analysis Method of Cd～（2+）, Cu～（2+）, Pb～（2+） and NO3～- in Wheat Flour,TS211
  15. Preparation, Structure and Dielectric Properties of Some Perovskite-Like Microwave Dielectric Ceramics,TQ174
  16. Preparation and Properties Research of MgO-ZnO-TiO2 System Microwave Dielectric Ceramics,TQ174
  17. The asphalt mixtures microwave heating system optimization,U414
  18. Study of Preparation and Microstructure Characterization of Barium Zinc Niobate Microwave Dielectric Ceramics Thin Films by RF Magnetron Sputtering,O484.4
  19. Controlled Pyrolysis of Waste Printed Circuit Boards Assisted by Microwave,X705
  20. Migration Dynamics of Tinuvin P of PP during Microwave Treatment,TQ325.14

CLC: > Industrial Technology > Chemical Industry > Silicate > Ceramic Industry > Basic theory
© 2012 www.DissertationTopic.Net  Mobile