AlN-based lossy ceramics for high average power microwave devices: performance–property correlation

Mikijelj, Biljana; Abe, David K.; Hutcheon, R. M.

doi:10.1016/s0955-2219(03)00146-8

Cited by 41 publications

(22 citation statements)

References 3 publications

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“…It is obviously that this strong peak cannot be found either in Ni-Al alloy or in AlN [14]. The (Ni, Al)/AlN nanoparticle is a such perfect system, because the metallic-dielectric nanocomposite with the polarized charges can play the role of dipoles, as demonstrated in the silver nanoparticles dispersed in an aluminum oxide thin film [32].…”

Section: Resultsmentioning

confidence: 99%

“…i) AlN is an excellent electromagnetic loss material as its own dielectric properties [13]. It has attracted special commercial interests to replace the toxic beryllium oxide (BeO) ceramics in microelectronics applications and high-frequency integrated devices [14]. ii) The anisotropic shapes of AlN nanostructures are benefit to the generation of electric dipoles and the enhancement of dipole moments.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Polarization in Tadpole-Shaped (Ni, Al)/Aln Nanoparticles and Microwave Absorption at High Frequencies

Huang¹,

Xue²,

Lü³

et al. 2011

PIER B

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Abstract-Tadpole-shaped (Ni, Al)/AlN nanoparticles were synthesized via evaporating Ni-Al alloy in a mixed atmosphere of N 2 and H 2 . As a counterpart, the spherical-shaped (Ni, Al)/Al 2 O 3 nanoparticles were also prepared from the same target alloy while in a mixture of Ar and H 2 . The electromagnetic parameters of as-made nanoparticles/paraffin composites were then investigated in the frequency range of 2-18 GHz. Excellent microwave absorption can be obtained for the tadpole-shaped (Ni, Al)/AlN-paraffin composite at high frequencies and in a thin layer, which is thought to be the result of the enhanced polarization in the anisotropic tadpole-shaped nanoparticles. With the increasing of the composite thickness, the frequency of effective reflection loss shifts towards lower frequencies due to an improved impedance match and absorption.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced Polarization in Tadpole-Shaped (Ni, Al)/Aln Nanoparticles and Microwave Absorption at High Frequencies

Huang¹,

Xue²,

Lü³

et al. 2011

PIER B

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“…Two additives, Bi 2 O 3 (99.9%, Aldrich Co.) and a glass, were added to the proper mixture of BaTiO 3 and AlN. For the oxide additive, the bulk samples were prepared by adding a fixed content of 3 wt.% Bi 2 O 3 , pressing at ∼80 MPa, and firing at 1200 • C for 6 h in air atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…thermal conductivity (140-230 Wm −1 K −1 ), low thermal expansion coefficient (4-4.5 ppm K −1 ) and non-toxicity [1][2][3][4]. This material has been mainly used as a substrate particularly for high power applications requiring thick film-based integrated hybrid structures.…”

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confidence: 99%

Dielectric properties of the BaTiO3-AlN-additive system

et al. 2006

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The mixed system of BaTiO 3 and AlN has been investigated in terms of dielectric properties and microstructure. Two different types of additives, bismuth oxide and bismuth borosilicate glass, were used to lower sintering temperature. First, the addition of a fixed content (3 wt.%) of Bi 2 O 3 provided densification at 1200 • C where monotonous decreases of dielectric constant were found with increasing the content of AlN. On the other hand, the bismuth borosilicate glass was effectively used to decrease firing temperature to 850 • C, which is suitable for thick film capacitor applications. A practical demonstration of thick film capacitors using a Ag electrode on a 96% alumina substrate indicated that the optimum composition of 76BaTiO 3 -20AlN-4glass may be adequate for generating k of 79.4 and tan δ of 0.014 at 1 MHz as a result of the low temperature firing of 850 • C in air atmosphere.

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“…BeO-based materials, which have a high thermal conductivity, are suitable to high average power electronic tube, but BeO is toxic and has thus limited applications [1]. AlN is being considered as a potential material alternative to BeO [2], because of its excellent comprehensive performance such as high thermal conductivity, high electrical resisitivity, low-outgassing rates being consistent with high vaccum environments, thermal expansion coefficient matching with silicon, and excellent mechanical properties [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of spark plasma sintering AlN-W composite ceramics

Wang

Jia

et al. 2011

Rare Metals

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In order to develop AlN composites suitable for high average power electronic tube, AlN-W materials were prepared by spark plasma sintering. The effects of manufacture parameters on dielectric loss tangent and permittivity constant were investigated, which include powder-mixed method, milling time of high-energy ball milling, starting powder particle size, sintering temperature and holding time and adding amount of the conductive second phase. The results showed that AlN-W materials sintered at the temperature of 1700°C holding for 5 min with 10 vol.% W showed the best dielectric loss tangent larger than 0.81 at the frequency 1 kHz-1 MHz. In addition, magnetic stirring mixed powder and lower sintering temperature led to the better properties because of the higher porosity. The samples sintered from the starting AlN powder with smaller particle size also had the better properties.

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AlN-based lossy ceramics for high average power microwave devices: performance–property correlation

Cited by 41 publications

References 3 publications

Enhanced Polarization in Tadpole-Shaped (Ni, Al)/Aln Nanoparticles and Microwave Absorption at High Frequencies

Enhanced Polarization in Tadpole-Shaped (Ni, Al)/Aln Nanoparticles and Microwave Absorption at High Frequencies

Dielectric properties of the BaTiO3-AlN-additive system

Dielectric properties of spark plasma sintering AlN-W composite ceramics

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