Small-Size Coaxial Resonant Applicator for Microwave Heating Assisted Additive Manufacturing

Li, Nanya; Link, Guido; Engler, Moritz; Jelonnek, John

doi:10.1109/tmtt.2021.3105431

Cited by 7 publications

(2 citation statements)

References 19 publications

(17 reference statements)

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“…Microwave cavity resonators are widely used in accelerator and microwave technology [1][2][3]. Particle accelerators, klystrons and other microwave devices for generating and amplifying microwave power, measuring equipment, for instance, EPR (electron paramagnetic resonance) spectroscopy [4,5], dielectric spectrometry [6][7][8][9], radar, radio navigation equipment, communication equipment [10][11][12], medical applications [13][14][15] -the scope of the microwave cavity resonators is quite wide.…”

Section: Introductionmentioning

confidence: 99%

Graphene passivation effect on copper cavity resonator preserves Q-factor

Nuriakhmetov

Chernousov²,

Sakhapov³

et al. 2023

Nanotechnology

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Proposed resonator design and measurement technique is a promising solution to estimate the value of materials surface conductivity. In the developed device, there are no mechanical connections, that interrupt the flowing microwave currents, which eliminates losses due to poor metal contact and related measurement errors. The main losses (60%) in the resonator are concentrated in a small sample under study - RES, which ensures high sensitivity to changes in surface conductivity. The influence of annealing the copper cavity resonator surface conducting microwave currents, as well as the effect of graphene coating on its intrinsic quality factor and frequency, was experimentally studied. Technological procedures for modifying a copper surface such as annealing in an H2/Ar atmosphere at a temperature of 1070°C and subsequent coating with graphene by chemical vapor deposition (CVD) method are studied. The modification of copper resonator surface texture during heat treatment in hydrogen and argon atmospheres has been studied. It is shown that during annealing, the resonator quality factor increases. The increase of the quality factor was associated with a decrease of resistance of copper, with the growth of crystalline grains, this effect disappears when the resonator is exposed to an air atmosphere. It was found that the graphene coating does not make a significant contribution to the change in the quality factor, but prevents the active growth of the oxide layer and prevents impurities deposition on the copper surface from the atmosphere. Thus, after annealing in hydrogen atmosphere and subsequent coating with graphene, the increased quality factor is retained. The considered procedures can be used to increase and stabilize the resonators quality factor, to eliminate oxidation and contamination of their surface. The results of this work can be used in the designing of microwave devices to study the thin films surface impedance.

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Section: Introductionmentioning

confidence: 99%

Graphene passivation effect on copper cavity resonator preserves Q-factor

Nuriakhmetov

Chernousov²,

Sakhapov³

et al. 2023

Nanotechnology

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“…areas of drying porous and non-porous materials, sintering of ceramics and processing of carbon fibers [6]. In drying applications, the goal is to maintain a stable product output moisture level.…”

Section: Introductionmentioning

confidence: 99%

Multistatic Uniform Diffraction Tomography Derived Structural-Prior in Bayesian Inversion Framework for Microwave Tomography

Omrani

Yadav

Link

et al. 2022

IEEE Trans. Comput. Imaging

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In this work, a quantitative Bayesian inversion framework for microwave tomography (MWT) is coupled with a multistatic uniform diffraction tomography (MUDT) method to improve the imaging quality. The method is applied for an industrial use-case of MWT in which we estimate the 2-D spatial distribution of moisture (in terms of dielectric constant) in a polymer foam. In essence, we modify the prior information in the single-frequency Bayesian inversion framework using highresolution complementary structural information of the imaging domain from a qualitative approach MUDT utilizing broadband frequency-domain data. This way of obtaining structural prior information is effective as it utilizes the data from the same microwave sensor setup in contrast to the frequency-hopping approach, priors derived for other imaging modalities or radarbased techniques with the co-located sensor using, for example, uniform diffraction tomography (UDT) inversion framework. Proposed algorithm performance is tested for different moisture scenarios in the polymer foam with 3D numerical and experimental data from our developed MWT system. It is shown that the proposed approach significantly improves the reconstruction accuracy for the considered cases over just using the Bayesian inversion approach.

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