A theoretical investigation on the quarter-wavelength model — part 1: analysis

Ying, Lei; Liu, Yue; Drew, Michael G. B.

doi:10.1088/1402-4896/ac1eb0

Cited by 38 publications

(68 citation statements)

References 41 publications

(53 reference statements)

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“…We have previously shown that the minima of |RL(x1 -)| can be described accurately using wave cancellation theory WCT [7,8] and as a consequence, we qualitatively identified the flaws in the QWM [7,12,19]. Here, we verify the results of WCT using quantitative mathematics based on our own experimental data obtained from the film of composite BaFe 11.8 Ce 0.2 O 19 /polypyrene [25], as shown in Fig.…”

Section: A Quantitative Verification Of the Theoretical Results From ...supporting

confidence: 70%

“…The results conform to the inverse relationship needed to replace QWM [7,12,19,27]. If α P d is small, beams 3 r , 4 r , 5 r , etc.…”

Section: A Quantitative Verification Of the Theoretical Results From ...supporting

confidence: 69%

“…2 predicts that peaks a, b, c, and e in Fig. 1 occur at d = λ/4 which is consistent with the QWM, but the predicted peaks h and k do not conform since they occur at d = λ/2 [7,19].…”

Section: A Quantitative Verification Of the Theoretical Results From ...mentioning

confidence: 77%

“…It has been proposed that the theory of QWM is valid in all circumstances but it has been shown that it cannot be applied to magnetic materials at high frequencies because then the minima of |RL(x1 -)| occur at d = nλ/2 instead of (2n + 1)λ/4 [7,19]. Using data from BaFe 11.8 Ce 0.2 O 19 /polypyrene in MB, beam 1 r is approximately in phase with beam i at x 1for frequencies higher than 8.65 GHz (the step ∆ν used in the measurement is 170 MHz), as exemplified by the values of R M (x 1 -) or Z M /Z 0 in Table 1 for frequencies of 13.58 and 15.11 GHz.…”

Section: The Inverse Relationship Between Frequency and Film Thicknessmentioning

confidence: 99%

“…Even though the minima of |RL(x 1 -)| can be correctly predicted by the phase difference of beams t and 1 r at φ = (2n + 1)π [7,8], this condition cannot be taken to be equivalent to, and therefore replaced by the requirement that Z in (x 1 -) and Z 0 are in phase because the value of RL(x1 -) cannot always be predicted by |Zin -Z0| while the effect of |Zin + Z0| in the expression of RL(x1 -) is ignored [7]. In addition, ignoring the relevance of wave superposition in film has led to the development of the QWM which is flawed because a film contains interfaces whose phase effects are ignored [7,12,19]. The shortcomings in IM and the QWM have been highlighted previously using rigorous theoretical arguments from transmission-line theory.…”

Section: Introductionmentioning

confidence: 99%

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Microwave absorption of film explained accurately by wave cancellation theory

Liu

Yin

Drew

et al. 2023

Preprint

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It has been proved theoretically that in the field of microwave absorption, film and material are confused, and that the impedance matching theory (IM) which is usually applied to metal-backed film is inadequate. IM is defined by the difference between the absolute values of the input impedance of the film Zin and the characteristic impedance of open space Z0. Before the scientific community accepts any new theories, it is necessary to validate them with a variety of experimental data such as those obtained from films of different materials. By analysis of experimental data, it is shown here that the problems with IM cannot be solved even if different criteria such as the value of |Zin - Z0| or the phase difference between Zin and Z0 are used and therefore it needs to be replaced by wave cancellation theory. The analysis of published data in this work supports the following conclusions. The value of reflection loss RL is determined by energy conservation, specific to film since it is related to the amplitude of the resultant of the two beams reflected from the two interfaces in the film and the angular effect from the phase difference between the two beams is vital for understanding microwave absorption from film.

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Section: A Quantitative Verification Of the Theoretical Results From ...supporting

confidence: 70%

“…The results conform to the inverse relationship needed to replace QWM [7,12,19,27]. If α P d is small, beams 3 r , 4 r , 5 r , etc.…”

Section: A Quantitative Verification Of the Theoretical Results From ...supporting

confidence: 69%

“…2 predicts that peaks a, b, c, and e in Fig. 1 occur at d = λ/4 which is consistent with the QWM, but the predicted peaks h and k do not conform since they occur at d = λ/2 [7,19].…”

Section: A Quantitative Verification Of the Theoretical Results From ...mentioning

confidence: 77%

Section: The Inverse Relationship Between Frequency and Film Thicknessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microwave absorption of film explained accurately by wave cancellation theory

Liu

Yin

Drew

et al. 2023

Preprint

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Super‐Wideband Electromagnetic Absorbing TiC/SiOC Ceramic/Glass Composites Derived from Polysiloxane and Titanium Isopropoxide with Low Thickness (<1 mm)

Yang

Zhang

et al. 2022

Adv Eng Mater

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Herein, TiC/SiOC ceramic/glass composites with excellent electromagnetic wave (EMW) absorbing performance are fabricated by pyrolysis of polycarbosiloxane and titanium (IV) isopropoxide (TTIP). By taking advantage of the polymer‐derived route, the phase compositions and microstructures are easily tuned. The composites are investigated by X‐ray diffraction (XRD) analysis, scanning electron microscope, and transmission electron microscopy/energy dispersive spectroscopy. Nanoscaled TiC is formed and uniformly distributed without clustering within the SiOC matrix. Thermogravimetric Analysis (TGA) and in situ XRD results revealed good thermal stability and oxidation resistance mechanism. The presented material system (TiC/SiOC) shows a super‐wide microwave absorption bandwidth (EAB) of 13.5 GHz, including the entire Ka‐band (26.5–40 GHz) with a low thickness requirement (<1 mm). The superior EMW absorption properties of the ceramics are attributed to the optimal interface polarization, as well as the ordering, concentration, and interconnectivity of the conductive network, which all determine the electrical conductivity in the composites.

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The Developed Wave Cancellation Theory Contributing to Understand Wave Absorption Mechanism of ZIF Derivatives with Controllable Electromagnetic Parameters

Zhou,

He,

et al. 2023

Small

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How to better understand the influence of electromagnetic parameters on the absorbing properties of electromagnetic wave absorbers (EMAs) is an essential prerequisite for further synthesis and development of high‐performance EMAs. In this work, an improved wave cancellation theory is used as a guiding principle to prepare N‐doped carbon‐coated cobalt nanoparticles (Co@NC) using ZIF‐8@ZIF‐67 as the precursor, thus enabling controllable electromagnetic parameters by regulating the conduction loss and dipole polarization ability. The Co@NC generated by pyrolysis at 700 °C under H2 atmosphere presents an optimized absorption performance. Benefiting from developed wave cancellation theory, the thickness of the film can be accurately adjusted so that the difference between the amplitude of the reflected and transmitted electromagnetic waves is only 0.001 and the phase difference is 180.05°, thus achieving a minimum reflection loss (RLmin(dB)) of −64.0 dB. Meanwhile, a maximum effective absorption bandwidth of 5.4 GHz is achieved simultaneously attributing to its most suitable electromagnetic parameters. Accordingly, the current research based on wave cancellation theory significantly contributes to understand the relationships between electromagnetic parameters and wave absorption properties, therefore providing a theoretical insight into the further development of high‐performance EMAs.

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A theoretical investigation on the quarter-wavelength model — part 1: analysis

Cited by 38 publications

References 41 publications

Microwave absorption of film explained accurately by wave cancellation theory

Microwave absorption of film explained accurately by wave cancellation theory

Super‐Wideband Electromagnetic Absorbing TiC/SiOC Ceramic/Glass Composites Derived from Polysiloxane and Titanium Isopropoxide with Low Thickness (<1 mm)

The Developed Wave Cancellation Theory Contributing to Understand Wave Absorption Mechanism of ZIF Derivatives with Controllable Electromagnetic Parameters

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