Structural, Thermal and Dielectric Properties of Low Dielectric Permittivity Cordierite-Mullite-Glass Substrates at Terahertz Frequencies

Abstract

Glass–ceramic composites containing cordierite, mullite, SiO2 glass and SiO2-B2O3-Al2O3-BaO-ZrO2 glass were fabricated in a process comprising solid state synthesis, milling, pressing and sintering. Thermal behavior, microstructure, composition and dielectric properties in the Hz-MHz, GHz and THz ranges were examined using a heating microscope, differential thermal analysis, thermogravimetry, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis, impedance spectroscopy, transmission method and time domain spectroscopy (TDS). The obtained substrates exhibited a low dielectric permittivity of 4.0–4.8. Spontaneously formed closed porosity dependent on the sintering conditions was considered as a factor that decreased the effective dielectric permittivity.

Ultra-low temperature cofired ceramics based on Li2WO4as perspective substrate materials for terahertz frequencies

“…The intrinsic losses of a ceramic material increase with the damping coefficient of the structural vibrations increasing [54,55]. Higher dielectric losses in the THz range than in the GHz range are both predicted theoretically and found experimentally in our previous works for other ceramic materials [31,48,52] and by other researchers for commercial LTCC materials [46].…”

“…Table S1 in the ESM presents the comparison of the LTCC low dielectric permittivity materials sintered at temperatures higher than 800 ℃ , which had been earlier characterized in the THz range. The dielectric permittivity of the developed ULTCC materials shown in Table 2 (5.0-6.4 at 1 THz) is lower or close to that of the commercial Ferro A6M LTCC glass-ceramics at 1 THz (ε r ′ = 6.06) [46] and other polycrystalline LTCC substrate materials based on willemite, zinc borate, copper borates, and calcium magnesium silicate (5.1-7.7) [31,[47][48][49][50][51] and a little higher than those of the glass-ceramic composites based on cordierite and mullite (3.9-4.7) [52,53], listed in Table S1 in the ESM.…”

(1E,3E)-1,4-Dinitro-1,3-butadiene—Synthesis, Spectral Characteristics and Computational Study Based on MEDT, ADME and PASS Simulation

“…What is more, CNDs can be also applied in reactions of [3+2] cycloaddition (32CA) with various three-atom components (TACs) [ 26 ]. As a consequence, it is possible to obtain symmetric biheterocycles ( Scheme 2 ) which may successfully be used in medicine [ 27 ] as well as in optoelectronics [ 28 ] as highly efficient photovoltaic materials [ 29 ] or solar cells [ 30 ] and also a useful organic ingredient improving the structural, thermal and dielectric properties in glass-ceramic composites for the dielectric industry in Low Temperature Cofired Ceramic (LTCC) Technology [ 31 , 32 , 33 ].…”

The Potential of Bacilli-Derived Biosurfactants as an Additive for Biocontrol against Alternaria alternata Plant Pathogenic Fungi

“…Capacitance methods are fast, capable of in-line measurement providing living cell numbers, and less sensitive to external influences. The Incyte capacitance sensor by Hamilton (Bonaduz, Switzerland) measures permittivity at several frequencies, resulting in a permittivity profile vs. frequency called dielectric spectroscopy; this allows for the almost continuous determination of living cell numbers [ 18 ]. At the same time, it also follows the conductivity, which may correlate to the pH changes in the broth mainly caused by primary metabolites.…”