Zhuoma Wang¹, Ruoyan Li^2,3, Wenjing Ye^2,*, Yijun Liu³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.09236

Abstract An acoustic diffuser refers to a device that spreads sound energy uniformly in all directions. Such a device plays a very important role in architectural acoustics, i.e., concert halls and auditoriums. Many designs such as the wellknown Schroeder diffusers [1] have been proposed and developed throughout the past several decades. However, most of these conventional designs achieve uniform sound diffusion by using different air trenches to create a phase shift profile following a specific sequence such as maximum length sequence or quadratic residue sequence derived from the number theory [1,2]. As such, these diffusers have considerable thicknesses, which makes them… More >

Haoyi Cheng¹, Jingwen Guo¹, Wenjing Ye^1.*, Xin Zhang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09237

Abstract With their thin thicknesses and unprecedent wave manipulation capabilities, acoustic metasurfaces have a great potential to be applied in a wide range of applications. Most existing metasurfaces are passive devices. Although passive devices are easy to implement and consume no energy, one major shortcoming of passive devices is their fixed and limited functionality, which greatly limits their application scope. To increase the functionalities of a metasurface and yet still maintain its passivity, we propose to use the wave frequency as a tuning freedom to realize multiple functionalities in one single passive device. Specifically, the passive metasurface will be designed to… More >

Zaka Ullah^1,*, Muath Al Hasan1¹, Ismail Ben Mabrouk², Muhammad Junaid³, Fawad Sheikh⁴

CMC-Computers, Materials & Continua, Vol.75, No.2, pp. 3453-3464, 2023, DOI:10.32604/cmc.2023.034704

Abstract With the advancement of technology, shielding for terahertz (THz) electronic and communication equipment is increasingly important. The metamaterial absorption technique is mostly used to shield electromagnetic interference (EMI) in THz sensing technologies. The most widely used THz metamaterial absorbers suffer from their narrowband properties and the involvement of complex fabrication techniques. Materials with multifunctional properties, such as adjustable conductivity, broad bandwidth, high flexibility, and robustness, are driving future development to meet THz shielding applications. In this article, a theoretical simulation approach based on finite difference time domain (FDTD) is utilized to study the absorption and shielding characteristics of a two-dimensional… More >

Haoran Wei, Tian Ji, Jianqing Huang^*

Journal of Renewable Materials, Vol.11, No.2, pp. 731-743, 2023, DOI:10.32604/jrm.2022.022283

Abstract Simultaneous broadband absorption and polarization conversion are crucial in many practical applications, especially in terahertz communications. Thus, actively tunable metamaterial systems can exploit the graphene-based nanomaterials derived from renewable resources because of the flexible surface conductivity and selective permeability of the nanomaterials at terahertz frequencies. In this paper, we propose a graphene-based active tunable bifunctional metasurface for dynamic terahertz absorption and polarization conversion. The graphene ring presents a certain opening angle (A) along the diagonal of the xoy plane. When A = 0°, the proposed metasurface behaves as a broadband absorber. Numerical results show the feasibility of achieving this polarization-insensitive… More >

Si Chen¹, Yuhao Zhou¹, Sarah Mohrmann², Haiyan Fu¹, Yuying Zou¹, Zheng Wang^1,*

Journal of Renewable Materials, Vol.10, No.11, pp. 2791-2803, 2022, DOI:10.32604/jrm.2022.021531

Abstract Based on the efficient sound absorption characteristics of Helmholtz resonance structures in the range of medium and low frequency acoustic waves, this paper investigates an effective solution for light timber construction walls with acoustic problems. This study takes the light timber construction wall structure as the research object. Based on the Helmholtz resonance principle, the structure design of the wall unit, impedance tube experiment and COMSOL MULTIPHYSICS simulation calculation were carried out to obtain the change rule of acoustic performance of the Helmholtz resonance wall unit structure. The research results show that the overall stability of sound insulation of the… More > Graphic Abstract

Omar A. Saraereh^*

CMC-Computers, Materials & Continua, Vol.73, No.1, pp. 1055-1066, 2022, DOI:10.32604/cmc.2022.030193

Abstract Wireless data traffic has expanded at a rate that reminds us of Moore’s prediction for integrated circuits in recent years, necessitating ongoing attempts to supply wireless systems with ever-larger data rates in the near future, despite the under-deployment of 5G networks. Terahertz (THz) communication has been considered a viable response to communication blackout due to the rapid development of THz technology and sensors. THz communication has a high frequency, which allows for better penetration. It is a fast expanding and evolving industry, driven by an increase in wireless traffic volume and data transfer speeds. A THz modulator based on a… More >

Mubashir Ashfaq¹, Shahid Bashir^1,*, Syed Imran Hussain Shah², Nisar Ahmad Abbasi³, Hatem Rmili^4,5, Muhammad Abbas Khan⁶

CMC-Computers, Materials & Continua, Vol.72, No.2, pp. 3601-3611, 2022, DOI:10.32604/cmc.2022.025558

Abstract This article presents a Sub-6 GHz microstrip patch antenna (MPA) with enhanced gain using metamaterial (MTM) superstrate. The source MPA operates at 4.8 GHz and has a peak gain of 5.3 dBi at the resonance frequency. A window-shaped unit cell is designed and investigated through the material wave propagation technique. The unit cell shows an Epsilon Near Zero (ENZ)-Mu Very Large (MVL) behavior around 4.8 GHz. The unit cell has a fourfold geometry which makes it a polarization independent metamaterial. A double layer antenna is designed by placing a 4 × 4 MTM slab as a superstrate above the MPA at a… More >

Kabir Hossain^1,2, Thennarasan Sabapathy^1,2,*, Muzammil Jusoh^1,2, Ping Jack Soh^1,3, Samir Salem Al-Bawri⁴, Mohamed Nasrun Osman^1,2, Hasliza A. Rahim^1,2, Danai Torrungrueng⁵, Prayoot Akkaraekthalin⁶

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 1677-1693, 2022, DOI:10.32604/cmc.2022.022227

Abstract This paper introduces a decagonal C-shaped complementary split-ring resonator (CSRR) textile-based metamaterial (MTM). The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ₀ × 0.255λ₀ at 3 GHz. Its stopband behaviour was first studied prior analysing the negative index properties of the proposed MTM. It is worth noting that in this work a unique way the experiments were completed. For both simulations and measurements, the proposed MTM exhibited negative-permittivity and negative-refractive index characteristics with an average bandwidth of more than 3 GHz (considering 1.7 to 8.2 GHz as the measurements were carried out within this range). In simulations, the MTM… More >

Samir Salem Al-Bawri¹, Mohammad Tariqul Islam^2,*, Kabir Hossain^3,4, Thennarasan Sabapathy^3,4, Muzammil Jusoh^3,4

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 611-628, 2022, DOI:10.32604/cmc.2022.021244

Abstract This paper presents a textile-based C-shaped split-ring resonators (SRR) metamaterial (MTM) unit cells with an electrical tunability function. The proposed MTM was composed of two symmetrical C-shaped SRR combined with a central diagonal metal bar, whereas the RF varactor diode is placed on the backside of the splitted ground plane. Stopband behavior of single and array MTM unit cells were analyzed while the achieved negative index physical characteristics were widely studies. Though four different MTM arrays (i.e., 1 × 1, 1 × 2, 2 × 1, and 2 × 2) were analyzed in simulation, a 2 × 2-unit cell array… More >

Huy Hung Tran^1,2, Khoa Nguyen-Dang^1,2,*, Niamat Hussain³

CMC-Computers, Materials & Continua, Vol.68, No.2, pp. 2487-2498, 2021, DOI:10.32604/cmc.2021.016027

Abstract A single-layer design of non-uniform metasurface (MS) based circularly polarized (CP) antenna with wideband operation characteristic is proposed and investigated in this paper. The antenna is excited by a truncated corner squared patch as a primary radiating CP source. Then, a non-uniform MS is placed in the same layer with the driven patch. Besides increasing the impedance bandwidth, the non-uniform MS also generates two additional CP bands in the high frequency band, leading to significantly increase the antenna’s overall performances. The use of non-uniform MS distinguishes our design from the other CP MS based antennas in literature, in which the… More >