Computational Characterization of a Composite Ceramic Block for a Millimeter Wave Heat Exchanger

Kumi, Petra; Venne, Jonathan S.; Yakovlev, Vadim V.; Hilario, Martin S.; Hoff, Brad; Rittersdorf, I. M.

doi:10.1007/978-3-030-44101-2_7

Cited by 3 publications

(1 citation statement)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies of the W-band (75-110 GHz) dielectric properties of the present AlN:Mo system, having Mo concentrations ranging from 0.25 to 4 vol%, were limited to temperatures below 550 • C [8]; however, predicted operating parameters for an envisioned mm-wave heat exchanger experiment involve cycling to substantially higher temperatures (600 • C-1000 • C) for multiple hours in air. To ensure that numerical models used for designing high-temperature mm-wave heat exchanger susceptors [11][12][13] adequately represent the electromagnetic behavior of these materials in expected usage conditions, dielectric property data for the proposed susceptor materials are required for temperatures up to 1000 • C, requiring novel modifications to an existing high-temperature, freespace, permittivity characterization system [14] that extend the original (550 • C) temperature limit of the system.…”

Section: Introductionmentioning

confidence: 99%

High temperature W-band complex permittivity measurements of thermally cycled ceramic-metal composites: AlN:Mo with 0.25 to 4.0 vol% Mo from 25 °C to 1000 °C in air

Cohick¹,

Schaub²,

Hoff³

et al. 2021

Meas. Sci. Technol.

View full text Add to dashboard Cite

An apparatus for measuring the W-band (75–110 GHz) complex permittivity of dielectrics at 1000 °C was developed. This apparatus allows for measurements at approximately twice the temperature of previously published high temperature free-space measurement systems while maintaining similar precision. Challenges were addressed related to high temperature measurements, including temperature uniformity, the accuracy of temperature measurements, and preventing temperature related changes to mm-wave measurement systems. The details of complex permittivity extraction from the measured S-parameters are discussed. Sources of error related to permittivity measurement and mathematical models were identified and are discussed in detail herein. Thermally-cycled, mm-wave absorbing, aluminum nitride ceramic composites containing varying levels of molybdenum additives were measured over the range of 25 °C–1000 °C. These measurements were compared to the same composites before thermal cycling. It was found that ceramic composites are largely stable after thermal cycling in terms of dielectric properties despite the presence of visible surface modifications.

show abstract