An optically transparent and flexible microwave absorber for X and Ku bands application

Tayde, Yakeen; Chaudhary, Kajal; Singh, Gaganpreet; Dhumal, Ayushi; Saikia, Mondeep; Srivastava, Kumar Vaibhav; Ramkumar, J.; Ramakrishna, S. Anantha

doi:10.1002/mop.32269

Cited by 17 publications

(10 citation statements)

References 12 publications

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“…Therefore, the requirement of achieving higher conductivity or low sheet resistance is not critical in designing the absorbers. This can be seen in the reported works, as many used resistive sheets of ITO [78,113,114,207] or graphene [20,[208][209][210][211] for the ground plane with an electrical conductivity ≈10 5 S m −1 . One major issue with the transparent absorbers is the relatively low optical transparency, which is ascribed to the multiple conducting layers in the design.…”

Section: Printed Transparent Absorbermentioning

confidence: 89%

Optically Transparent and Flexible Radio Frequency Electronics through Printing Technologies

Akhter

Vaseem

et al. 2022

Adv Materials Technologies

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on several nonplanar objects and worn by humans, they must be mechanically flexible. Moreover, to maintain the abundance of such wireless devices in a smart city and still maintain the aesthetics, it is desirable that they be optically transparent. Finally, to afford this IoT revolution, in which billions of devices are required, the cost of an individual device must be extremely low. As displayed in Figure 1, this new form of transparent RF electronics can help in many smart city applications without affecting the functions of the existing structures where they will be deployed. For example, specially designed periodic structures, namely reconfigurable intelligent surfaces (RIS), can enhance the 5G and beyond communication by increasing the coverage area, spectrum, and energy efficiency. [7] Transparent RIS integrated on buildings, cars, and train windows can optimize the reflection and transmission characteristics of the 5G signal according to the user positions via tunable and switchable devices. [8] Transparent antennas on cars can provide diverse connectivity for radio, GPS, television, smartphones, and so on while maintaining aesthetics. [9][10][11] This can likewise serve as a mainstream technology for autonomous cars, which would rely on radar antennas on the car body. Another example is a transparent frequency selective surface (FSS), which is a periodic structure for selectively shielding from unwanted frequency bands while allowing the bands of interest to pass through. [12][13][14][15][16][17] Other examples of transparent RF electronics include RF circuits, [18] EM absorbers, [19][20][21] RF shielding, [22][23][24][25] and RF energy harvesting. [26,27] A highly suitable approach to realize this new form of mechanically flexible and optically transparent RF electronics is via printing technologies. Printed electronics (PE), as the name suggests, are electronic devices manufactured using traditional printing technologies. Compared with conventional fabrication techniques, such as milling, photolithography, and etching, [11,18,20,28,29] printing has many merits that make it suitable for the subsequent generations of electronics, such as ease of mass production with simple procedures, lower costs, higher throughput, and the ability to work with flexible materials and substrates. PE technologies allow for the direct deposition of various materials, including conductors, semiconductors, and dielectrics, among others, on different flexible substrates to form 2D and 3D patterns. PE has been widely

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Section: Printed Transparent Absorbermentioning

confidence: 89%

Optically Transparent and Flexible Radio Frequency Electronics through Printing Technologies

Akhter

Vaseem

et al. 2022

Adv Materials Technologies

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“…To improve the microwave absorption bandwidths of MMAs, superposition of multiple resonant modes by means of gradually varied structures and stacking of multilayer meta-surfaces emerged as a solution. − Although their microwave absorption bandwidths were expanded, the optical transmittance of these MMAs dramatically decreased. Therefore, to attain a balance between optical transmittance and broadband microwave absorption, MMAs with indium tin oxide (ITO) have been developed and studied. − On the one hand, the performance of broadband MMAs depends heavily on the precise unit cell geometry, which leads to a low tolerance to manufacturing error and may affect the absorbing performance due to the inevitable errors during the complicated patterning preparation. On the other hand, ITO-based MAs suffer narrow optical transmission band. , Most of the reported ITO-based MAs only show good transparency in the visible region.…”

Section: Introductionmentioning

confidence: 99%

Optically Transparent Broadband Microwave Absorber by Graphene and Metallic Rings

Han

et al. 2022

ACS Appl. Mater. Interfaces

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The demand for optically transparent microwave absorbers has attracted increasing interest among researchers in recent years. However, integrating broadband microwave absorption and high optical transparency remains a challenge. This report demonstrates a scheme for broadband microwave absorbers, featuring a 90% absorption bandwidth of 10 GHz covering a frequency range of 25.2–35.2 GHz and high compatibility with good optical transparency in a wide band from the visible to infrared. The absorber is based on a Jaumann structure composed of two graphene sheets sandwiched by dielectric and backed by an arrayed-metallic-rings sheet. Guided by derived formulas, this absorber exhibits complete absorption if the sheet resistance of graphene is close to 500 Ω sq–1. The bandwidth and center frequency of the absorption spectra can be readily tuned simply via changes in the thickness of the dielectric between the graphene films and arrayed-metallic-rings sheet. Moreover, the absorber is insensitive to the incident angle of radiation and can achieve broadband and near-unity absorption even at oblique incidence. The graphene-based absorber proposed herein provides a viable solution for effectively integrating broadband and near-unity microwave absorption with high optical transparency, thereby enabling widespread applications in optics, communications, and solar cells.

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“…In general, conventional MAs composed of metallic patterns 5–7 or FSSs suffer from narrow absorption bandwidth. For the purpose of bandwidth enhancement, patterned resistive films, also called resistive FSSs 8 or frequency selective resistive films, are introduced to achieve broadband MAs 9–14 . Most of them are designed for the applications at L, S, X, and Ku bands, that is, 1–20 GHz, while few are involved in higher frequency bands.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐wideband metamaterial absorber based on frequency selective resistive film for 5G spectrum

Ruan

Meng

Zou

et al. 2022

Micro & Optical Tech Letters

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An ultra‐wideband metamaterial absorber (MA) is proposed for 5G communication, which features a resistive frequency selective surface printed on a PET (polyethylene terephthalate) layer and a ground layer of resistive film. The proposed MA can provide over 90% absorptivity in the frequency range of 11.2–42.8 GHz. Moreover, it is insensitive to polarization and wide incident angles. The effective medium theory and multi‐reflection interference theory are used to interpret the broadband absorption mechanism. The surface current distribution at three absorption peaks is investigated to further study the physical mechanism behind the wideband absorption. The measured results of the fabricated prototype are in good agreement with the simulation ones, thus verifying the robustness of the design. The presented MA can probably be used in electromagnetic shielding of 5G signals.

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An optically transparent and flexible microwave absorber for X and Ku bands application

Cited by 17 publications

References 12 publications

Optically Transparent and Flexible Radio Frequency Electronics through Printing Technologies

Optically Transparent and Flexible Radio Frequency Electronics through Printing Technologies

Optically Transparent Broadband Microwave Absorber by Graphene and Metallic Rings

Ultra‐wideband metamaterial absorber based on frequency selective resistive film for 5G spectrum

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