Split Ring Resonator Elements Research Articles

Radiation Characteristics of Artificial Magneto-Dielectric Antenna Loaded with Split-Ring Resonator Array

This study proposes a simple artificial magneto-dielectric (MD) antenna with a split-ring resonator (SRR) loaded in an array configuration. This SRR element is used to realize the MD characteristic that is beneficial for antenna miniaturization. The simulation of material permittivity and permeability is conducted to ensure that the proposed SRR-array configuration has the expected MD characteristic. Configurations of SRR in arrays of 3×3, 5×5, 7×7, and 9 × 9 are realized to obtain its radiation characteristics when embedded in the antenna ground plane. A rectangular patch antenna is used in this study. Based on the simulation, the proposed antenna with an SRR array of 5×5 achieves excellent MD characteristics with high permittivity and permeability of 32.44 and 51.39, respectively. Furthermore, a microstrip antenna loaded with the SRR 5×5 arrays are fabricated on RT/duroid 5880 substrate. It has a dimension of 0.31λ0 × 0.26λ0. The simulation and measurement results of the proposed antenna show a fractional bandwidth of 4.79% and 5.2% at 1.5 GHz; and a maximum gain of 5.20 dB and 4.95 dB, respectively. Good agreement between the simulated and the measured results was achieved.

Sub wavelength plasmonic nano-antenna with modified SRR structure for Fano resonance

The optical electric field enhancement in the normal direction is noticed for Plasmonic and Fano mode at Nano antenna, therefore, we have modeled four various designs for Sub-wavelength Plasmonic and Nano-antenna with modified Split Ring Resonator (SRR) by adding new capacitors and SRR element to achieve the Fano resonance mode in various incident wave angles. Here, for all structures, the E-field enhancements at resonances are compared and design parameters effect on Fano resonance is debated. The incident wave direction is studied for making multi Fano resonance in all prototype structures and the extinction cross section comparison for 0°, 45° and 90° is revealed that the FANO resonances are related to the polarization angle of the incident wave and size of the gaps in Nano particles. SiN Substrate is selected with refractive index of 1.98 and silver with Johnson optical characteristic has been used for modeling of the metal layer. It has been observed that the |E2|/|Eint2| increased to 200000 at Fano resonances and the parametric studies showed that the gap size controls the Fano resonance frequency.

Planar holographic metasurfaces for terahertz focusing.

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.

Analysis of a Compact and Superdirective Metamaterial-Inspired Monopole Antenna

The directivity of a metamaterial-inspired compact (0.145λ0) monopole antenna was investigated. The proposed structure is composed of a split-ring resonator (SRR) parasitic element placed in the vicinity of a monopole antenna. Two configurations denoted by A1 and A2 were considered depending on the position of the slot in the SRR element. By analyzing simulated and measured results, the superdirectivity (7.5 dBi for A1 and 9 dBi for A2) of the structure was discussed. It is found that the monopole-SRR and/or ground plane-SRR coupling effects may be responsible for the superdirectivity of the structure.

A COMPACT SPLIT RING RESONATOR ANTENNA FOR WIRELESS COMMUNICATION SYSTEMS

In this paper, we report a new design of a compact antenna based on the use of split ring resonator (SRR). The designed antenna consists of two SRRs, with the same geometrical parameters, printed symmetrically on both sides of the dielectric substrate. Excitation of the SRR element is performed by adequately placing the access microstrip lines with respect to the conflnement plane of the split rings. The resonance frequency of the antenna is essentially deflned by geometrical parameters of the SRR, which makes it suitable for a broad range of applications spanning from mobile terminals to WLAN and WPAN systems. The flnal result is low proflle, and can be easily integrated with other RF front-end circuits in a PCB.

Role of coupling of discrete breathers in split-ring-resonator-based metamaterials

Through detailed quantum calculations, the presence of classical discrete breathers and, subsequently, a two-phonon bound state (TPBS) or quantum breather (QB) state have already been shown in nonlinear photonic materials such as ferroelectrics. The latter was done in a periodic boundary condition in terms of the variations of TPBS parameters against impurity that is related to nonlinearity. Metamaterials are also nonlinear optical materials for applications as a split-ring-resonator (SRR) in antenna arrays. By using a Klein–Gordon approach, first multi-solitons and classical breathers are shown. For QBs, by using a periodic boundary condition, the variation of the TPBS parameters with coupling within the SRR elements is observed. Finally, in a non-periodic boundary condition approach, the temporal evolution of the number of quanta is shown eventually in order to derive the critical time of redistribution of quanta that is proportional to the QB's lifetime in femtoseconds, which also shows variation with coupling in the SRR system.

Tunable SRR-based substrate for a microstrip patch antenna

In this paper, a microstrip patch antenna over an artificial substrate composed of split-ring resonator (SRR) elements is introduced. As the SRR-based substrate provides miniaturization for the patch, metallic loadings placed between the rings of the SRR elements offer frequency-tuning capability. Practical switch models are employed in lieu of those loadings to demonstrate dynamic control of the operational frequency. The full-wave analysis and design of the proposed tunable patch were carried out using CST Microwave Studio, and the cross-comparisons were provided via Ansoft HFSS. Preliminary measurements are also presented, demonstrating the prospective performance of the proposed design.

A wide-angle planar metamaterial absorber based on split ring resonator coupling

A wide-angle planar metamaterial structure exhibiting strong absorption is presented. The structure functions as a near-perfect absorber with the incident electric field propagating not only across but also along the gaps of individual split ring resonator (SRR) elements. It is the coupling of adjacent SRRs that provides capacitance necessary to excite the LC resonance for absorption. Both simulations and experiments are shown in this paper. The experimental results indicate that when the electric field propagates along the gaps of individual SRR elements, the structure obtains 1.6-GHz-wide absorption with absorptivity larger than 90% at small incident angles. The proposed structure offers a potential way to create azimuth-independent broadband metamaterial absorber.

Electric tunability of microwave permeability dispersion behaviors of metamaterials

By embedding a capacity-variable diode into a split ring resonator (SRR), it is found that the effective capacitance of such an SRR element can be varied by the biased voltage of diode. Therefore the resonance frequency and effective permeability of an SRR element can be tuned. Based on these results, a smart microwave magnetic metamaterial is proposed. Employing the finite-difference time-domain and retrieval method, the variations of resonance frequency and permeability of the SRR element are simulated and calculated by changing the biased voltage. It is found that with the decrease of capacitance due to the increase of biased voltage, the resonance frequencies are shifted towards lower values, and so are the resonance frequencies of permeability dispersion. Finally, the difference in permeability dispersion behavior between SRR structure and natural magnetic material (for instance, ferrite) has been pointed out.

Growth of Tl2Ba2CaCu2O7 thin films on curved substrates for metamaterial applications

Recent developments in the field of magnetic metamaterials have shown that coupled split-ring resonator (SRR) structures can manipulate magnetic fields on a scale shorter than the wavelength of the electromagnetic radiation [1]. In particular, stacks of copper/dielectic SRR structures can be used as high Q filters or as waveguides in near field imaging applications [2]. However, major improvements in the sensitivity of such devices would be achieved by fabricating the SRR elements from high temperature superconducting (HTS) films on appropriate dielectric substrates. In order to produce a stack of superconducting/dielectric SRR structures, the ideal method involves patterning them into an HTS film grown on the curved surface of a dielectric cylinder. To our knowledge this has not previously been attempted on the small scale required for these applications. The desired feature sizes range from a few millimetres for filter applications down to about 10μm for high resolution imaging applications. We report here our initial attempts at the growth of Tl2Ba2CaCu2O7 (Tl-2212) thin films on the surface of LaAlO3 and MgO single crystal cylinders of diameter 3mm and length 5mm. Scanning Electron Microscopy, Electron Backscatter Diffraction and a novel X-ray Diffraction technique have been used to study the microstructure and analyse the growth morphology of the Tl-2212 films in this unusual geometry. Simulations have been carried out on an axial array of SRR structures that could be fabricated from these HTS/dielectric cylinders.

Negative magnetic permeability of split ring resonators in the visible light region

Negative magnetic permeability of split ring resonator (SRR) is theoretically investigated in the visible light region. In our calculations, we considered the delay of the current inside the metal SRR in order to estimate the permeability of the SRR precisely. From the results, the silver SRR array with small capacitance exhibits negative permeability in all the visible range. The dependence of the permeability on the filling factor of the SRR elements is also discussed.