Dielectric properties of pure alumina from 8 GHz to 73 GHz

Marco, Damien Di; Drissi, Khalil El Khamlichi; Delhote, Nicolas; Tantot, Olivier; Geffroy, Pierre-Marie; Verdeyme, Serge; Chartier, T.

doi:10.1016/j.jeurceramsoc.2016.05.047

Cited by 38 publications

(15 citation statements)

References 13 publications

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“…Although at mmWave bands beyond 60 GHz, the majority of implementations are based on fully-integrated CMOS devices (Table IV), Hemour et al proposed the highest PCE rectenna at 94 GHz with over 3× PCE improvements over CMOS implementations [25]. Despite being implemented on a very low loss alumina substrate (alumina's 60 GHz tanδ<0.001 [88]), it was observed that the surface current losses peaked in the matching network [25]. The rectenna had an overall size of 0.55λ 2 which, despite being larger than fully-integrated CMOS rectennas, is still usable for applications such as swarm micro-robotics.…”

Section: Design and Matching Of Mmwave Rectifiersmentioning

confidence: 99%

Millimeter-Wave Power Harvesting: A Review

Wagih

Weddell

Beeby

2020

IEEE Open J. Antennas Propag.

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The broad spectrum available at millimeter-wave (mmWave) bands has attracted significant interest for a breadth of applications, with 5G communications being the main commercial drive for mmWave networks. Wireless power transmission and harvesting at mmWave bands have attracted significant attention due to the potential for minimizing the harvesting antenna size, allowing for more compact rectennas. For a fixed antenna size, the received power increases with frequency. Nevertheless, several challenges lie in realizing high efficiency antennas and rectifiers at mmWave bands. This paper reviews the recent advances in mmWave rectenna design at a component-and system-level. Low-cost antennas and components for mmWave power harvesting, such as high efficiency scalable rectifiers on polymers and high radiation efficiency antennas on textiles, are reviewed. Both the antenna and rectifier can be realized using low-cost fabrication methods such as additively-manufactured circuits and packages, in addition to digital integrated circuits (ICs) for the rectifiers. Finally, this paper provides an overview of future antenna design challenges and research directions for mmWave power harvesting.

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Section: Design and Matching Of Mmwave Rectifiersmentioning

confidence: 99%

Millimeter-Wave Power Harvesting: A Review

Wagih

Weddell

Beeby

2020

IEEE Open J. Antennas Propag.

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“…Figure 8b shows a comparision of DC breakdown strengths of the pure XLPE and XLPE/uncoated α-Al2O3 nanocomposites containing 0.2 wt %, 0.5 wt %, 1.0 wt %, and 2.0 wt % Why can coated α-Al 2 O 3 nanosheets greatly increase the DC breakdown strength of nanocomposites? This may have been because the insulating coated α-Al 2 O 3 nanosheets were intrinsic electrical insulating nanopaticles [37]. Secondly, the redistribution of space charge in the insulation material causes electric field homogenization and decreases the free volume of XLPE [38].…”

Section: Electrical Properties Testing Results Of Xlpe/α-al 2 O 3 Nanmentioning

confidence: 99%

Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites

Guo

Xing²,

Zhao

et al. 2020

Materials

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This paper describes the effects of α-Al2O3 nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al2O3 nanocomposites. The α-Al2O3 nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al2O3 nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al2O3 nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 × 10−13 S/m to 1.04 × 10−13 S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al2O3 nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al2O3 nanocomposites.

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“…Concerning mechanical properties, the hardness (H) was determined on mirror polished surfaces using a diamond Vickers indenter (Buelher MicroMet 6040) for a load of 50 g during 15 s. The elastic properties (Young's modulus E, shear modulus G, and Poisson's ratio ν) were determined by pulse echography technique operating in infinite medium mode at 10 MHz on a 8 mm diameter disc-shaped specimen exhibiting a thickness of 1.2 mm Microwave dielectric properties (permittivity and losses) were extracted via a resonant method described in details in Ref. [34], where the dielectric resonator is placed inside a cylindrical cavity in copper. For such measurements, series of dense KNbTeO 6 ceramic pellets were specifically prepared.…”

Section: Characterization Methodsmentioning

confidence: 99%

New KNbTeO6 transparent tellurate ceramics

Dolhen

Carreaud

Delaizir

et al. 2020

Journal of the European Ceramic Society

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New transparent defect pyrochlore KNbTeO 6 ceramics were successfully prepared by Spark Plasma Sintering (SPS) of same composition polycrystalline powders elaborated by classic solid-state reaction from oxide precursors (K 2 CO 3 , Nb 2 O 5 , TeO 2 ) and followed by high energy milling powders. As such precursors are not available as commercial nanopowders, a suitable process has been developed by combining solid-state reactions and high energy milling. The determination of appropriate consolidation conditions and sintering parameters of the green body such prepared, are described in this paper. The resulting ceramic is transparent in both the visible and near infrared range (up to 5.5 μm). The maximum of transmittance is reached in the near infrared region around 2500 nm with a value of 78 % (1 mm thick sample), close to the maximum theoretical value of transmittance. This transparent KNbTeO 6 ceramic demonstrates a homogeneous and dense microstructure with an average grain size less than 500 nm. A small content of secondary phase has been detected by nanoscale observations without drastic effects on transparency. This ceramic exhibits very good mechanical properties similar to the Y 2 O 3 transparent ceramic, as well as interesting dielectric properties in the microwave range. This innovative method should drive the development of new transparent materials with technologically relevant applications.

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Dielectric properties of pure alumina from 8 GHz to 73 GHz

Cited by 38 publications

References 13 publications

Millimeter-Wave Power Harvesting: A Review

Millimeter-Wave Power Harvesting: A Review

Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites

New KNbTeO6 transparent tellurate ceramics

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