Balamati Choudhury¹, Sanjana Bisoyi¹, Pavani Vijay Reddy¹, Manjula S.¹ and R. M. Jha¹

CMC-Computers, Materials & Continua, Vol.39, No.3, pp. 179-215, 2014, DOI:10.3970/cmc.2014.039.179

Abstract The terahertz spectrum of electromagnetic waves is finding its position in various applications of day to day life because of its unique properties, including the penetration through opaque materials. Naturally occurring materials in this range are rare due to the display of a natural breakpoint of both electric, and magnetic resonances in these materials. However recent advances in artificially engineered materials, which show resonance in this region are able to harness desirable properties in the terahertz region. In this paper, terahertz design and fabrication issues have been explored along with their applications. A brief review More >

C.J. Stevens¹

CMC-Computers, Materials & Continua, Vol.33, No.1, pp. 1-18, 2013, DOI:10.3970/cmc.2013.033.001

Abstract Metamaterials offer new propagation modes for electromagnetic signals which have been explored as media for data exchange. They also offer a good prospect for efficient power transfer. This paper considers the limits on transferable power and their consequences in relation to magneto inductive waves in 1 and 2 dimensional magnetic metamaterial structures. The upper limit is found to be directly related to the voltage tolerance of capacitances used in the meta-material’s construction. Higher resonant frequencies offer better efficiency and higher maximum powers. For a proposed device operating in the Qi band (100-200k Hz) power transfer More >

Balamati Choudhury¹, Pavani Vijay Reddy¹, Sanjana Bisoyi¹, R. M. Jha¹

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 135-146, 2013, DOI:10.3970/cmc.2013.037.135

Abstract The terahertz region of the electromagnetic spectrum plays a vital role in biomedical imaging because of its sensitivity to vibrational modes of biomolecules. Advances in broadband terahertz imaging have been emerging in the field of biomedical spectroscopy. Biomedical imaging is used to distinguish between the infected (cancer) and the non-infected tissue, which requires broad band and highly efficient radar absorbing material (RAM) designs (to obtain high resolution image of the tissue). In this paper, a metamaterial broadband RAM design is proposed towards biomedical spectroscopy applications in the THz region. The particle swarm optimization (PSO) algorithm More >

Shiv Narayan¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.37, No.2, pp. 97-108, 2013, DOI:10.3970/cmc.2013.037.097

Abstract A novel metamaterial based FSS (frequency selective surfaces) structure is presented in this paper for wideband airborne radome applications. The proposed metamaterial-FSS structure consists of three layers, where a DPS (double positive sign) layer is sandwiched between a MNG (μ-negative) and ENG (ε- negative) layer, exhibits very good bandpass characteristics inside the operational band along with excellent roll-off characteristics outside the band. The EM performance analysis of the proposed structure has been carried out using transmission line transfer matrix (TLTM) method, which shows excellent bandpass characteristics over a wide frequency range. The transmission efficiency is More >

Shiv Narayan¹, Latha S.¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.34, No.2, pp. 131-142, 2013, DOI:10.3970/cmc.2013.034.131

Abstract The EM performance analysis of a multilayered metamaterial based radar absorbing structure (RAS) has been presented in this paper based on transmission line transfer matrix (TLTM) method for millimeter wave applications. The proposed metamaterial-RAS consists of cascaded DPS and MNG layers of identical configurations. It exhibits extremely low reflection (< 42 dB) at 95 GHz and absorbs more than 95% power of incident wave over the frequency range of 90.4- 100 GHz without metal backing for both TE and TM polarizations. In view of aerospace applications, the reflection, transmission, and absorption characteristics of the proposed More >

Balamati Choudhury¹, R. M. Jha¹

CMC-Computers, Materials & Continua, Vol.33, No.3, pp. 275-308, 2013, DOI:10.3970/cmc.2013.033.275

Abstract The exciting features of metamaterial in conjunction with transformation optics leads to various applications in the microwave regime with such examples as invisible cloak, frequency selective surfaces (FSS), radomes, etc. The concept of electromagnetic invisibility is very much important in aerospace platform. Hence to study the feasibility of implementation of this concept for stealth, an extensive literature survey of metamaterial cloaks has been carried out and reported in this paper along with the basic concept of cloaking. To make the review more effective, the technical papers are classified into three broad sections viz. mathematical modeling, More >

Balamati Choudhury1¹, Sanjana Bisoyi¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.31, No.3, pp. 201-228, 2012, DOI:10.3970/cmc.2012.031.201

Abstract Soft computing methods play an important role in the design and optimization in diverse engineering disciplines including those in the electromagnetic applications. The aim of these soft computing methods is to tolerate imprecision, uncertainties, and approximations to achieve a quick solution, which is both robust and economically viable. Soft computing methods such as genetic algorithm, neural network and fuzzy logic have been widely used by researchers for microwave design since the last decade. The metamaterial multilayer concept in conjunction with transformation optics leads to exciting applications in the microwave regime with such examples as invisible More >

Cherl-Hee Lee¹, Jonghun Lee¹

CMC-Computers, Materials & Continua, Vol.31, No.2, pp. 147-156, 2012, DOI:10.3970/cmc.2012.031.147

Abstract The guided modes are investigated in a five-layered slab waveguide with double claddings of metamaterials using a new graphical method. The dispersion equations in the symmetric and asymmetric five-layered slab waveguide are derived from the presented graphical method, and corresponding field distributions are plotted for the oscillating guided and surface guided modes. The energy flux distribution along the axis is plotted for the surface TE₁ mode. More >

Shiv Narayan¹, Shamala Joshi B¹, Raveendranath U. Nair¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.31, No.1, pp. 1-16, 2012, DOI:10.3970/cmc.2012.031.001

Abstract The electromagnetic design and performance analysis of dual/ multi-band metamaterial frequency selective surface (FSS) structures have been carried out for radome applications in microwave and millimeter wave frequency regimes. The proposed metamaterial FSS structure, consisting of cascaded MNG (mu-nega -tive) and DPS (double positive) layers, exhibits dual-band transmission responses at V-band and W-band. Excellent transmission efficiency (more than 95%) has been obtained over the frequency range 45.8-53.1 GHz at first resonance, and from 93.0-97.1 GHz at second resonance. The incorporation of additional DPS layer to the proposed metamaterial-FSS structure facilitates multiband bandpass characteristics at 30 More >

Chunyu Ren, Zhihai Xiang, Zhangzhi Cen

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.4, pp. 121-122, 2011, DOI:10.3970/icces.2011.016.121

Abstract Recently, many interesting conceptual devices have been proposed to manipulate the propagation of acoustic waves at will. This is mostly achieved through acoustic metamaterials designed by the coordinate transformation method [1]. However, such materials are usually required to be anisotropic and inhomogeneous, which hampers their realization in practice.

In this talk, we are going to introduce conformal mapping based transformation acoustics for 2D cases [2]. In this way, the resultant metamaterial parameters are isotropic, which greatly facilitates their implementation. More >