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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:22 |
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Conference: Bucharest University Faculty of Physics 2005 Meeting
Section: Solid State Physics and Materials Science
Title:
Dielectric properties of Mg–doped ZST ceramics
Authors:
C.Berbecaru(1), H.V.Alexandru(1), A.Dutu(2), V. Ion(1), M.Mihailescu, A. Ioachim(2), L. Nedelcu(2), M. G. Banciu(2), M. I. Toacsen(2), D. Ghetu(2)
Affiliation:
(1) University of Bucharest, Faculty of Physics, Romania
(2) National Institute of Materials Physics, Bucharest-Magurele, Romania
E-mail
Keywords:
ceramic materials, microwave and millimeter wave, high-permittivity materials
Abstract:
The ceramic materials (ZST) are very attractive for microwave and millimeter waves applications, (dielectric resonators, filters, dielectric antennas, substrates for hybrid microwave integrated circuits, etc.), in commercial wireless technologies. The high dielectric permitivity, low losses and great quality factor of those ceramics reduce the size of the components in the specific applications. Particularly, the compounds exhibit an almost zero temperature coefficient and a great stability. The materials, has been prepared by solid-state reaction. The samples were sintered in the temperature range of oC for 2 hours. XRD patterns showed that the compound is single phase, with crystalline structure of the type, i.e. orthorhombic unit cell. The effect of MgO (0.2wt%) addition is to lower the sintering temperature in order to obtain well sintered samples with high value of bulk density. The dependence of the permitivity and loss, versus temperature, at 1 kHz for the samples sintered at oC and oC, respectively on the temperature oC interval were studied with a Hioki 3511-50 LCR HiTester bridge type. The material exhibits high permitivity values, very low losses and an intrinsic quality factor of at 6.5 GHz. The microwave (6.5 GHz) values of the permitivity agree very well with those performed at low 1 kHz frequency. ZST samples show an insignificant decrease from 1 kHz to 6.5 GHz of less than 1 %, which is completely covered by some experimental uncertainties. It can be seen an excellent thermal stability of the permitivity in the –100 ÷ +100 oC temperature range.
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