Enhanced microwave absorption of rice husk‐based pyramidal microwave absorber with different lossy base layer

Lee, Yeng Seng; Soh, Ping Jack; You, Kok Yeow; Hoon, Wee Fwen; Yew, Lee Chia; Seng, G; Malek, F.

doi:10.1049/iet-map.2019.0571

Cited by 16 publications

(2 citation statements)

References 31 publications

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“…For low-frequency and high-frequency electromagnetic waves, surface multiple reflection attenuation (SMRA) can be carried out on the surface of the pyramid structure. At the same time, the internal multiple reflection attenuation (IMRA) can also be achieved by entering the absorber, so as to gain the broadband absorption . Therefore, the change of each part will have a great impact on the final MWAP.…”

Section: Resultsmentioning

confidence: 99%

Broadband and High-Efficiency Microwave Absorbers Based on Pyramid Structure

Sun

Zhang²,

et al. 2022

ACS Appl. Mater. Interfaces

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Microwave-absorbing materials with wide bandwidth and high absorptivity are increasingly playing an important role in overthe-air (OTA) testing. In this work, a kind of pyramid absorbing material was prepared using flame-retardant absorbers as the filler. In addition, a coating was used to further improve the flame-retardant properties of the microwave-absorbing material. To obtain excellent microwave absorption performance (MWAP), a high-frequency structure simulator (HFSS) was adopted to design structural materials. Here, the total height, the base height, the decapitation height of the pyramid tip, the distance between the pyramids, and other parameters were analyzed; then, the actual processing and molding were realized. The MWAP of −30 dB was achieved at 2.7−18 GHz, and the MWAP of −10 dB was also met at 2−18 GHz. In particular, the study also investigated the MWAP of large angle, which can meet the MWAP of −10 dB at 2−18 GHz and MWAP of −30 dB at 4−18 GHz. Most importantly, the absorption mechanism of the pyramid structure was explored. The influence of the tip was proved by the distribution of the electromagnetic field in the pyramid. It can be regarded as a multilayer microwave-absorbing material due to the impedance gradient of the pyramid, which can provide an effective research idea and method for future engineering applications.

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Section: Resultsmentioning

confidence: 99%

Broadband and High-Efficiency Microwave Absorbers Based on Pyramid Structure

Sun

Zhang²,

et al. 2022

ACS Appl. Mater. Interfaces

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“…−10 dB absorption for S 11 means 90.0% of the power of the incident electromagnetic wave is absorbed −20 dB absorption means 99.0% of the power is absorbed, and −30 dB absorption means 99.9% of the power is absorbed [8]. In literature, some eco-friendly and low-cost absorbers have been proposed [9,10], which keep a reasonable performance at the higher frequency, but have limitations in the lower part of the operating band. The reason is that graphite, especially its synthetic type, is not a 'green' product, having several environmental pollution issues [11,12], and higher energy consumption during fabrication [13].…”

Section: Introductionmentioning

confidence: 99%

Boosting the performance of low‐cost eco‐friendly pyramidal absorbers with a Salisbury screen

Sahraei,

Sadeghzadeh,

Aliakbarian

et al. 2024

IET Microwaves Antenna & Prop

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Instead of using expensive highly performing conventional pyramidal absorbers, in some cases, the use of absorbers based on very cheap eco‐friendly materials is an attractive alternative. The authors introduce a novel technique to improve the absorption bandwidth of these intrinsically low‐quality absorbers by adding a Salisbury screen at the base of the pyramidal absorber, which adds two extra design parameters. The first is the resistive sheet surface impedance, and the second is the resonance frequency of the Salisbury screen. By tuning these two parameters, better impedance matching can be obtained. This is verified with the help of a transmission line model, full‐wave simulations, and measurements. The method is applied to two different lower‐quality absorbers found in the literature. In the first absorber, the operating bandwidth is increased at the lower frequency side by 40%, and in the second one, this is about 90%. Finally, a prototype of an eco‐friendly combined absorber is designed and fabricated. The measurement validates the expected behaviour.

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A Review of Agricultural Product Characterization Using Microwave Sensor

Lee

You

Soh

et al. 2021

Lecture Notes in Electrical Engineering

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This paper presents a review on characterization of agricultural product using various type of microwave sensor. Interaction between EM waves with materials are described. Interaction between microwave and agricultural product are considering a wide range of frequencies and applications such as detection of dielectric properties, moisture content, heating mechanisms, and product control. Each of the Agricultural product has their unique dielectric properties, it can be characterized by frequency dependent parameters such as dielectric properties and moisture content. By analyzing the unique dielectric properties of the agricultural products, the moisture content and the heating mechanisms can be distinguished by measuring the changes in dielectric properties and concentration of agricultural products. Additionally, this paper also emphasis on a clear demarcation of open-ended coaxial probe, planar antenna, rectangular waveguide, and horn antennas as microwave sensor and their applications.

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Enhanced microwave absorption of rice husk‐based pyramidal microwave absorber with different lossy base layer

Cited by 16 publications

References 31 publications

Broadband and High-Efficiency Microwave Absorbers Based on Pyramid Structure

Broadband and High-Efficiency Microwave Absorbers Based on Pyramid Structure

Boosting the performance of low‐cost eco‐friendly pyramidal absorbers with a Salisbury screen

A Review of Agricultural Product Characterization Using Microwave Sensor

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