High Frequency Dielectric Response of Calcium Aluminate Cements: Potential Packaging Substrate Materials

1987 ◽  
Vol 108 ◽  
Author(s):  
Paul Sliva ◽  
M. Leffler ◽  
M. Bliss ◽  
L. E. Cross ◽  
B. E. Scheetz
Keyword(s):  
Dielectric Permittivity ◽  
Calcium Aluminate ◽  
Dielectric Response ◽  
Room Temperature ◽  
Perturbation Methods ◽  
Microwave Frequency ◽  
Far Infrared ◽  
Poly Vinyl Alcohol ◽  
Relative Dielectric Permittivity ◽  
Dielectric Permittivity And Loss

ABSTRACTDielectric permittivity and loss tangent were measured on: 1) pressed disks of four different calcium aluminate cements shear mixed with water and poly(vinyl alcohol) and cured at room temperature and 2) laminates of SECAR 71 cement sintered at 1450°C. Post resonance and perturbation methods were used for microwave frequency measurements. Far infrared dielectric response of the cements was determined by FTIR in the diffuse reflectance mode. The real and imaginary parts of the relative dielectric permittivity were obtained via a conventional Kramers-Kronig analysis.

scholarly journals Paving the Way to Eco-Friendly IoT Antennas: Tencel-Based Ultra-Thin Compact Monopole and Its Applications to ZigBee

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3658
Author(s):  
María Elena de Cos Gómez ◽  
Humberto Fernández Álvarez ◽  
Alicia Flórez Berdasco ◽  
Fernando Las-Heras Andrés
Keyword(s):  
Dielectric Permittivity ◽  
Frequency Band ◽  
Loss Tangent ◽  
Relative Dielectric Permittivity ◽  
Iot Applications ◽  
Half Wave ◽  
And Performance ◽  
Dielectric Permittivity And Loss ◽  
Range Test ◽  
The Way

An ultrathin, compact ecofriendly antenna suitable for IoT applications around 2.45 GHz is achieved as a result of exploring the use of Tencel fabric for the antenna’s design. The botanical ecofriendly Tencel is electromagnetically characterized, in terms of relative dielectric permittivity and loss tangent, in the target IoT frequency band. To explore the suitability of the Tencel, a comparison is conducted with conventionally used RO3003, with similar relative dielectric permittivity, regarding the antenna dimensions and performance. In addition, the antenna robustness under bent conditions is also analyzed by measurement. To assess the relevance of this contribution, the ultrathin ecofriendly Tencel-based antenna is compared with recently published antennas for IoT in the same band and also, with commercial half-wave dipole by performing a range test on a ZigBee-based IoT testbed.

Dielectric relaxation and microwave loss in the La(Mg1/2Ti1/2)O3–(Na1/2Bi1/2)TiO3 perovskite ceramics

2007 ◽  
Vol 22 (10) ◽  
pp. 2676-2684 ◽  
Author(s):  
A.N. Salak ◽  
V.M. Ferreira ◽  
L.G. Vieira ◽  
J.L. Ribeiro ◽  
R.C. Pullar ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Dielectric Response ◽  
Far Infrared ◽  
Phonon Modes ◽  
Resonant Frequencies ◽  
Microwave Dielectric ◽  
Wide Range ◽  
Microwave Loss ◽  
Perovskite Ceramics ◽  
Dielectric Permittivity And Loss

Dielectric response of the perovskite ceramics (1–x)La(Mg1/2Ti1/2)O3–x(Na1/2Bi1/2)TiO3 [(1–x)LMT–xNBT] (0 ⩽ x ⩽ 0.6) has been characterized at radio, microwave, and far infrared frequency ranges. Temperature variations of the dielectric permittivity and loss estimated by different methods were compared and analyzed. It was revealed that the low temperature dielectric response of the compositions with x ⩾ 0.2 is frequency-dependent over a wide range (102–109 Hz) below the resonant frequencies of the polar phonon modes. Contributions of different factors (both extrinsic and intrinsic) to the microwave dielectric loss of the ceramics were considered. The dielectric relaxation has been associated with the amount of bismuth in the system. The relaxation in LMT–NBT was considered in the context of similar effects observed in other Bi-containing, A-site disordered oxygen-octahedral compositions.

scholarly journals Особенности структуры и диэлектрических свойств керамик на основе титаната натрия-висмута

2018 ◽  
Vol 60 (3) ◽  
pp. 426
Author(s):  
Е.Д. Политова ◽  
Н.В. Голубко ◽  
Г.М. Калева ◽  
А.В. Мосунов ◽  
Н.В. Садовская ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Relative Dielectric Permittivity ◽  
Dielectric Losses ◽  
Relaxor Behavior ◽  
Temperature Dependences ◽  
Ferroelectric Phase Transitions ◽  
Formation Specific

AbstractThe phase formation, specific features, and the dielectric properties of the ceramics of compositions from the region of morphotropic interface in the (Na_0.5Bi_0.5)TiO_3–BaTiO_3 system modified by Bi(Mg_0.5Ti_0.5)O_3 and also low-melting additions KCl, NaCl–LiF, CuO, and MnO_2 that favor the control of the stoichiometry and the properties of the ceramics have been studied. The ceramics are characterized by ferroelectric phase transitions that are observed as jumps at temperatures near 400 K and maxima at T _m ~ 600 K in the temperature dependences of the dielectric permittivity. The phase transitions at ~400 K demonstrate the relaxor behavior indicating the existence of polar domains in the nonpolar matrix. An increase in the content of Bi(Mg_0.5Ti_0.5)O_3 favor a decrease in the electrical conductivity and dielectric losses of the samples, and the relative dielectric permittivity at room temperature ε_rt is retained quite high, achieving the highest values ε_rt = 1080–1350 in the ceramics modified with KCl.

scholarly journals High-Pressure Spectroscopy Study of Zn(IO3)2 Using Far-Infrared Synchrotron Radiation

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Akun Liang ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Ibraheem Yousef ◽  
Catalin Popescu ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Synchrotron Radiation ◽  
Infrared Radiation ◽  
Room Temperature ◽  
Far Infrared ◽  
Low Pressure ◽  
Pressure Response ◽  
Spectroscopy Study ◽  
Far Infrared Radiation

We report the first high-pressure spectroscopy study on Zn(IO3)2 using synchrotron far-infrared radiation. Spectroscopy was conducted up to pressures of 17 GPa at room temperature. Twenty-five phonons were identified below 600 cm−1 for the initial monoclinic low-pressure polymorph of Zn(IO3)2. The pressure response of the modes with wavenumbers above 150 cm−1 has been characterized, with modes exhibiting non-linear responses and frequency discontinuities that have been proposed to be related to the existence of phase transitions. Analysis of the high-pressure spectra acquired on compression indicates that Zn(IO3)2 undergoes subtle phase transitions around 3 and 8 GPa, followed by a more drastic transition around 13 GPa.

AC conductivity and dielectric permittivity of TGS and urea doped TGS crystals at microwave frequency

1994 ◽  
Vol 158 (1) ◽  
pp. 87-92 ◽  
Author(s):  
S. C. Mathur ◽  
D. C. Dube ◽  
D. S. Rawat ◽  
A. S. Bhalla
Keyword(s):  
Dielectric Permittivity ◽  
Ac Conductivity ◽  
Microwave Frequency
Sign in / Sign up

Export Citation Format

Share Document