A compact CRLH metamaterial with wide band negative index characteristics

Abstract

Metamaterials are the artificial materials that may have a negative refractive index and results in extraordinary properties which are not found in nature. This research focusses on designing a compact-sized artificial material for negative characteristics of permittivity, permeability and refractive index over the wide range of frequencies. The metamaterial design is evaluated for single negative, double negative and double positive behaviours over a broad range of frequencies to investigate the gap and gapless transitions from backward to forward wave propagation. The dispersion diagram of the material is also investigated for left or right hand behaviour of the material. The equivalent circuit diagrams along with circuit simulations of the parameters are also presented for detailed analysis and understanding. The designed metamaterial behaves like a double negative material for low frequencies and double positive material for high frequencies. The approach is verified using CST microwave studio simulation and the results obtained are validated using the rectangular waveguide measurement method.

ENG and NZRI Characteristics of Decagonal-Shaped Metamaterial for Wearable Applications

“…It is apparent from this table that the NRW method produced a relatively lower refractive index compared to the results obtained from the RTR method. This agrees with the findings reported in [12], which indicates the known ambiguities in extracting refractive index values using the NRW method. Despite the slight variations based on the different extraction methods, values of the ENG and NZRI textile-based unit cells are generally almost identical for all unit cell array structure types.…”

“…For the ENG materials, the permittivity is negative with positive permeability. In contrast, permeability is negative with positive permittivity for MNG materials [12]. Besides antenna designs, researchers have applied these unique properties of MTMs for different applications including wireless health monitoring [13], invisibility cloaking [14], bendable artificial magnetic conductors (AMC) [15], filters [16], sensors [17], and absorbers [18].…”

“…Besides antenna designs, researchers have applied these unique properties of MTMs for different applications including wireless health monitoring [13], invisibility cloaking [14], bendable artificial magnetic conductors (AMC) [15], filters [16], sensors [17], and absorbers [18]. Furthermore, the refractive index of a material, which depends on the permittivity and permeability can decide the extent of reflection and refraction in a material [12]. The near-zero refractive index (NZRI) property can also enhance the gain as reported in [19].…”

Electrically Tunable Left-Handed Textile Metamaterial for Microwave Applications

“…This was performed by extracting the scattering parameters from the structure when it is excited at normal incidence [ 33 , 34 ]. The RTR method was chosen instead of the Nicolson–Ross–Weir (NRW) method to avoid its known phase ambiguity [ 28 ]. First, the S-parameters (i.e., reflection coefficient ( S 11 ) and the transmission coefficient ( S 21 )) were defined within the frequency of interest (i.e., between 1 and 15 GHz).…”

“…To extract the parameters of the MTMs, the robust reflection-transmission (RTR) method was adopted. The 2 × 2 array structure was then chosen to be experimentally validated using the waveguide (WG) port measurement technique [ 28 ]. Simulations and measurements showed tunable DNG characteristics within the range of 2.74 to 5.51 GHz.…”