Saint Petersburg, Russia
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Nenasheva E.A.,Ceramics Co. | Redozubov S.S.,GIRICOND Research Institute | Kartenko N.F.,RAS Ioffe Physical - Technical Institute | Gaidamaka I.M.,St. Petersburg State Mining Institute
Journal of the European Ceramic Society | Year: 2011

Ceramic samples based on ZnO-Nb2O5-TiO2 compositions have been prepared using solid state ceramic route. The work was carried out over a wide range of initial ZnNb2O6 and Zn0.17Nb0.33Ti0.5O2 compounds concentration. The crystal structure and microstructure developments were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the phase compositions of the samples present itself a columbite type and mixture of two phases-solid solutions of columbite and rutile types.The sintering behavior, permittivity, its temperature coefficients and quality factor had been characterized for ceramic samples in depending on compositions. The permittivity of the samples in this system is within the limits from 24 to 80, τe{open} from 150 to -560ppm/°C. For the samples with τe{open}~0, e{open}r~43.8 and Q·f=35000GHz at f=9GHz. The comparatively low sintering temperature (≤1080°C) and high dielectric properties in microwave range make these ceramics promising for application in electronics. © 2010 Elsevier Ltd.

Abdellatif A.S.,University of Waterloo | Taeb A.,University of Waterloo | Ranjkesh N.,University of Waterloo | Gigoyan S.,University of Waterloo | And 2 more authors.
International Journal of Microwave and Wireless Technologies | Year: 2014

This paper proposes a compact, low-loss, and low-cost phase shifter for millimeter-wave/sub-THz applications. The basic idea is to perturb the propagation constant of a high resistivity silicon image guide by high-dielectric constant barium lanthanide tetratitanates (BLT) ceramic loading. Three different BLT ceramic samples have been tested. The measured maximum phase-shift variation reaches 150° at 100 GHz with an average insertion loss of 2.85 dB and an insertion loss variation <0.7 dB for a sample of a 5-mm length. The proposed phase shifter has a bandwidth from 95 to 105 GHz. A low-cost fabrication technology has been developed and used to realize this phase shifter. Copyright © Cambridge University Press and the European Microwave Association 2014

Nenasheva E.A.,GIRICOND Research Institute | Kartenko N.F.,RAS Ioffe Physical - Technical Institute | Gaidamaka I.M.,Saint Petersburg State Mining Institute | Trubitsyna O.N.,Ceramics Co.Ltd | And 3 more authors.
Journal of the European Ceramic Society | Year: 2010

In this paper we report the influence of the composition and concentration of Mg-containing additions such as Mg2TiO4, MgO and a mixture of Mg2TiO4-MgO on ceramics based on a mixture of BaTiO3/SrTiO3. Phase relations, crystal structure, microstructures, microwave dielectric properties (ε, tan δ) and DC tunability have been studied over a wide range of frequencies. The temperature dependence of the dielectric properties has been measured as well. Among the compositions synthesized were low loss bulk ferroelectrics with dielectric constants in the range 150-800 and relatively high DC tunabilities (up to 1.49 under a DC electric field of 40 kV/cm). These materials can be used for high power tunable microwave devices. © 2009 Elsevier Ltd.

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