The dielectric properties of some ceramic substrate materials at terahertz frequencies

Ma, Mengyao; Wang, Yi; Navarro‐Cía, Miguel; Liu, Feng; Zhang, Faqiang; Liu, Zhifu; Li, Yongxiang; Hanham, Stephen M.; Hao, Zhang‐Cheng

doi:10.1016/j.jeurceramsoc.2019.06.012

Cited by 50 publications

(27 citation statements)

References 26 publications

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“…It is worth noting that for the samples sintered in the same temperature of 1050 °C, the dissipation factor of the glass–ceramic composites in the THz range were higher than those in the GHz band. Such an effect was also reported by other authors [ 35 ] for a few substrate materials. For Al 2 O 3 and Si 3 N 4 polycrystalline samples, tan δ (dissipation factor) determined by the TDS method was two times higher at 1 THz than at 200 GHz.…”

Section: Resultssupporting

confidence: 89%

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

et al. 2021

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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.

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Section: Resultssupporting

confidence: 89%

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

et al. 2021

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“…For commercially available LTCC materials, the values of dielectric permittivity in the range 4-7 and tanδ below 0.012 at 1 THz are considered low values, suitable for millimeter wave systems. The dielectric properties of CuB 2 O 4 and CuB 2 O 4 -Cu 3 B 2 O 6 ceramics in the 0.14-0.7 THz range are comparable with those reported for the commercial LTCC material Ferro A6M at 1 THz (ε r ' = 6.06, tanδ = 0.012) [45]. We plan to use the developed powders based on copper borates for tape casting and the fabrication of multilayer LTCC substrates appropriate for very high frequency applications in future work.…”

Section: Dissipation Factorsupporting

confidence: 81%

Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

et al. 2021

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New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

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“…To retrieve the dielectric constant of sandpaper over the complete low THz range, we used the Menlo Systems THz time-domain spectrometer TERA K15 Mark II in a quasi-optical configuration along with a material parameter extraction algorithm [ 36 ], similarly to [ 37 ]. This retrieval algorithm minimizes the difference between the measured (defined as ratio of the sample spectrum to the reference spectrum computed by Fourier transform of the corresponding waveforms) and theoretical complex transfer functions using the Nelder-Mead simplex algorithm, whereby the thickness- and frequency-dependent complex refractive index of the sample are extracted after numerical optimization.…”

Section: Experimental Methodologymentioning

confidence: 99%

Study of Low Terahertz Radar Signal Backscattering for Surface Identification

Sabery

Bystrov

Navarro‐Cía

et al. 2021

Sensors

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This study explores the scattering of signals within the mm and low Terahertz frequency range, represented by frequencies 79 GHz, 150 GHz, 300 GHz, and 670 GHz, from surfaces with different roughness, to demonstrate advantages of low THz radar for surface discrimination for automotive sensing. The responses of four test surfaces of different roughness were measured and their normalized radar cross sections were estimated as a function of grazing angle and polarization. The Fraunhofer criterion was used as a guideline for determining the type of backscattering (specular and diffuse). The proposed experimental technique provides high accuracy of backscattering coefficient measurement depending on the frequency of the signal, polarization, and grazing angle. An empirical scattering model was used to provide a reference. To compare theoretical and experimental results of the signal scattering on test surfaces, the permittivity of sandpaper has been measured using time-domain spectroscopy. It was shown that the empirical methods for diffuse radar signal scattering developed for lower radar frequencies can be extended for the low THz range with sufficient accuracy. The results obtained will provide reference information for creating remote surface identification systems for automotive use, which will be of particular advantage in surface classification, object classification, and path determination in autonomous automotive vehicle operation.

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The dielectric properties of some ceramic substrate materials at terahertz frequencies

Cited by 50 publications

References 26 publications

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

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

Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

Study of Low Terahertz Radar Signal Backscattering for Surface Identification

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