Rectangular Split Ring Resonator Research Articles

A compact quad element human face‐shaped wideband MIMO antenna for 5G applications

SummaryThis article presents a quad element wideband multiple‐input multiple‐output (MIMO) antenna consisting of human face‐shaped patch radiators with defected ground structure (DGS) having rectangular split ring resonator (RSRR) in ground surface. The measured bandwidth of the proposed MIMO antenna is 3.0–6.5 GHz, and the isolation between the ports is more than 16 dB. Additionally, simulated diversity characteristics like the channel capacity loss (CCL), channel capacity (CC), total active reflection coefficient (TARC), mean effective gain (MEG), and envelope correlation coefficient (ECC) are investigated with the measured value and observed to be within the acceptable ranges over the operating frequency band. The suggested antenna can be used in the wireless local area network (WLAN) (i.e., 4.9–5.725 GHz), wireless fidelity (Wi‐Fi) (i.e., 5.15–5.85 GHz), and 5G under 6 GHz (3.3–5.0 GHz) frequency ranges.

Terahertz metal-graphene hybrid metamaterial for active manipulation of electromagnetically induced transparency

The dynamic tuning of terahertz (THz) electromagnetically induced transparency (EIT) offers significant potential in rapidly changing THz regulation fields, such as the next generation wireless communication, switching, and sensing. In this work, we demonstrate a THz EIT metamaterial by combining a circular and a rectangular split-ring resonator (CSRR and RSRR) based on the bright-bright mode coupling. The introduction of graphene into the EIT structure enables active tuning, and reveals two distinct regulation mechanisms in the metal-graphene hybrid EIT metamaterial: 1. the internal coupling effect diminishes with the increase of the Fermi level in the CSRR-graphene integration; 2. the surface electric field undergoes redistribution in the RSRR-graphene integration. These two dynamic regulation mechanisms are well confirmed by the simulated electric field distribution. As a result, the transmittance within the EIT window of the hybrid metamaterial can be precisely modulated, exhibiting a significant modulation depth of >85%. Notably, the integration with graphene in the RSRR allows for simultaneous modulation of resonances on either side of the EIT peaks, which expands more THz modulation channels. This work enriches the design and implementation methods for active THz EIT and shows potential applications in THz dynamic application scenarios.

Sensor and slow light based on plasmon-induced transparency in carbon nanotube rectangular split-ring resonator metamaterials

Sensor and slow light based on plasmon-induced transparency in carbon nanotube rectangular split-ring resonator metamaterials

Boosting Second Harmonic Generation Efficiency and Nonlinear Susceptibility via Metasurfaces Featuring Split-Ring Resonators and Bowtie Nanoantennas.

This work investigates a metasurface design to achieve remarkable second harmonic generation (SHG) conversion efficiency and enhance effective nonlinear susceptibility using the finite element method. The elements of the designed structure are composed of a rectangular split-ring resonator Ag film, a bowtie-shaped Ag nanoantenna, and a pair of Bi bars that induce nonlinear optical phenomena due to the nonuniform distribution of the electric and magnetic fields within the device surface. The simulation results agree perfectly with the theory and demonstrate outstanding achievements in terms of SHG conversion efficiency (η) and effective nonlinear susceptibility (χeff(2)). Specifically, the metasurface reaches a peak η value of 4.544×10-8 and an effective nonlinear susceptibility of 3.4×104 pm/V. This work presents a novel and versatile design to achieve high η and χeff(2) in an SHG metasurface.

The chiroptical properties of plasmonic dimer metamaterials based on the extended Born–Kuhn model

Plasmonic dimer metamaterials have been widely utilized in the study of chiral nanophotonics due to their special chiroptical properties. The chiroptical properties of simple rod-like dimer metamaterials can be intuitively described by the Born–Kuhn (BK) model, in which the coupling parameter between oscillators is commonly used as a constant. However, the BK model is limited for complex dimer metamaterials because the behavior of the oscillators is constrained by the geometry of the structure. In this paper, inspired by equivalent LC-coupled circuits, we develop the BK model to predict the chiroptical properties of the split-ring resonator (SRR) dimer metamaterials, where the coupling of oscillators depends on both the twist angle of the SRR dimers and the frequency of the incident light. Using the extended BK model, we predict that there exists a special twist angle, which will cause the chirality of the SRR dimer metamaterials to reverse. More importantly, in such specific spatial configurations, the SRR dimer metamaterials with rectangular slits not only retain the enhancement of the chiral near-field, but also limit the chiroptical far-field response because the interactions of electricity and magnetism cancel each other out. In addition, combined with simulation calculations, we find that the rectangular SRR dimer metamaterials have strong robustness within a certain range of structural regulation. Our work will be helpful for the design and optimization of optical logic elements, chiral sensor components, and coding devices.

High-Sensitivity Triple-Band Absorber Based on Graphene Rectangular Split Ring Resonator and Cross-structure

High-Sensitivity Triple-Band Absorber Based on Graphene Rectangular Split Ring Resonator and Cross-structure

Angle-independent wideband metamaterial microwave absorber for C and X band application

Abstract In this article, an angle-independent wideband metamaterial microwave absorber (MMA) for C (4–8 GHz) and X (8–12 GHz) band frequency is presented. The unit cell of the proposed MMA consists of outer and inner structure associated with lumped resistors. The outer structure consists of rectangular split-ring resonator, whereas the inner structure consists of circular split-ring resonator. The structure is made up of three layers, in which top and bottom layers are made up of copper acting as a conducting material. The middle layer is made up of FR-4 acting as a dielectric substrate. The resonating structure at the top is designed in such a way that wideband absorption is achieved in the range from 6.11 to 13.52 GHz. The wideband absorption within the range approaches almost unity having a bandwidth of 7.41 GHz. Three different peaks are considered in the range of interest having maximum absorption of 0.94, 0.94, and 0.99 at frequencies of 6.76, 11.15, and 13.07 GHz, respectively. The structure is analyzed with respect to the effective parameters, i.e., effective permittivity ( ${\varepsilon _{{\textrm{eff}}}}$ ) and effective permeability ( ${\mu _{{\textrm{eff}}}}$ ), to prove that the structure acts as a metamaterial. Electric field and current distribution are plotted at three different peaks to prove the mechanism of wideband absorption. Normal and oblique incidence are plotted to determine that the structure is behaving as an angle independent. The simulated structure is fabricated on FR-4 substrate and measured inside an anechoic chamber. Finally, to prove the novelty of the work, the proposed structure is compared with the already reported MMA. The proposed MMA finds practical applications in radar cross section reduction, terrestrial communication, keyless entry system, space communication, radar, and baby monitor.

A Wideband Circularly Polarized Antenna Based on Anisotropic Metamaterial

This article presents a novel circularly polarized (CP) antenna based on an anisotropic metamaterial. The antenna is capable of performing linear-to-circular polarization conversion over a wideband of frequencies in the X-band (8–12 GHz). The proposed antenna was constructed from a metamaterial-based polarizer mounted above the aperture of a rectangular waveguide. The polarizer was oriented at 45° to E-plane of the waveguide. The proposed polarizer is composed of multiple metamaterial layers. The unit cell of the proposed polarizer consists of a single dielectric slab incorporating a series of rectangular split ring resonators that are printed on both sides of the slab. Impedance matching layers (IML) are introduced to enhance the axial-ratio (AR) bandwidth. The polarizer has a low profile in terms of electrical length (thickness of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.41 \lambda _{0}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at 10.5 GHz). A full-wave electromagnetic simulator was used to verify the anisotropic characteristics of the unit cell. This was achieved by showing that the metamaterial exhibits two different refractive indices along the orthogonal components of the incident electric field. The prototype of the proposed design is fabricated and measured to validate the performance. The measured results agree with the simulated ones and demonstrated a wide impedance bandwidth of 62.4% ranging from 7.08 to 13.5 GHz with a 3 dB AR bandwidth of 29.9% (9.25–12.5 GHz).

Electrically small asymmetric coplanar strip‐fed metamaterial‐inspired antenna for WLAN and satellite‐based applications

AbstractThis article presents an electrically small asymmetric coplanar strip (ACS)‐fed metamaterial‐inspired antenna for multiband operation. The design employs a simple monopole, a set of rectangular split ring resonator (SRR), an inverted U‐shaped stub, and a rectangular complimentary split ring resonator (CSRR) in the ground plane to realize four operating bands. The antenna operates at 2.46, 5.8, 6.78, and 10.46 GHz with a bandwidth of 270 MHz, 340 MHz,180 MHz, and 1.16 GHz, respectively. The proposed structure has an electrical size of at 2.46 GHz. The experimental results are found to be in close proximity to the simulated ones. The presented electrically small antenna possesses a radian sphere (ka) of 0.68 and achieves an adequate gain of 2.37dBi with requisite radiation characteristics suitable for WLAN and satellite‐based applications.

Design and analysis of a dual-band THz metamaterial sensor with high refractive index sensitivity

A terahertz metamaterial comprised of an array of cross rectangular split-ring resonators (CRSRR) was proposed and analyzed for sensing applications, and it exhibited two resonances in the frequency range of 0.2–3 THz. The resonant frequencies of different resonant modes were explained using equivalent circuit models. Furthermore, the influence on equivalent capacitance and inductance of the circuit with respect to different geometrical dimensions of the CRSRR structure were analyzed, and the results indicated that the resonant frequencies of the proposed metamaterial can be designed as the desired value by adjusting the CRSRR unit geometry. In addition, the sensing performances of the metamaterial were calculated based on the optimized structure, showing that it had high refractive index sensitivity of 309 and 730 GHz/RIU at two resonant frequencies, respectively. Meanwhile, such ability to operate at two frequency bands enabled the designed sensor could characterize the identical samples at different frequencies, thereby increasing the sensing sensitivity and decreasing the impact of environmental disturbance. Our study opens up new prospects in the design of terahertz metamaterial sensors with high sensitivity in a multi-band range, which is essential to meet increasing needs in terahertz sensing.

Metamaterial sensor based on reflected mirror rectangular split ring resonator for the application of microwave sensing

In this research paper, a new reflected mirror rectangular split-ring resonator-shaped metamaterial sensor is proposed for the detection of materials and thickness of the materials. The metamaterial structure is designed in the same dimension as the opening of the X-band waveguide as if a total guided electromagnetic wave penetrates the structure, and its size is 22.86 × 10.16 mm2. Computer simulation technology (CST) microwave studio is used to design the metamaterial structure and the obtained reflection coefficient is validated with the advanced design system (ADS) results. Various parametric analysis has been done to optimize the design and size of the structure. Three materials FR-4, Rogers RO4350B, Rogers, and RT5880 have been attached to the metamaterial sensor and have shown the overall results both experimentally and theoretically. The resonance frequency shifted 120 MHz between FR-4 and Rogers RO4350B, and 250 MHz shifted between FR-4 and Rogers RT5880. Three different thicknesses of the FR-4 have been used to see the response of the metamaterial sensor. The resonance frequency shifted 80 MHz between 1.6 and 1.3 mm thickness of the FR-4, and 110 MHz shifted between 1.6 and 1 mm thickness of the FR-4. The simulated and measured outcomes are quite similar. The sensitivity of the structure is 1.29 and the quality factor (Q-factor) is 435, the figure of merit (FOM) is also analyzed, and its value is 561.15. Since the proposed sensor has high sensitivity, high Q-factor, and shows better performance, hence it can be used in industry to detect the various materials and thickness of the materials.

CPW-fed metamaterial inspired compact multiband antenna for LTE/5G/WLAN communication

Abstract In this work, metamaterial (MTM) inspired a compact CPW-fed antenna with triple operating band is proposed. A rectangular Split Ring Resonator (SRR) is unified in a circular slot of the polygon-shaped radiator in MTM inspired antenna. The antenna exhibits three operating band which are based on metamaterial characteristics of unit cell. The CPW-fed antenna is ensuing 10 dB impedance bandwidth varies from 2.28 to 2.38 GHz, 3.07 to 3.78 GHz, and 5.05 to 7.03 GHz, whereas notch band exist from 2.39 to 3.06 GHz frequency. Metamaterial behaviour leads into the bandwidth enhancement as well as miniaturization in lower operating band with electric length of 0.14λ 0 × 0.21λ 0. The antenna archives the peak gain of 1.49 dB at 2.34 GHz, 2.04 dB at 3.32 GHz, and 4.14 dB at 6.5 GHz frequency. The measured results authenticate the simulated outcomes and consequently the proposed antenna can be pertinent in LTE, WLAN, and 5G communications.

Design of electromagnetic cloak with sequentially connected rectangular split ring resonators for S-band applications

&lt;abstract&gt; &lt;p&gt;An electromagnetic (EM) invisible cloak is designed and analyzed with serially interconnected split ring resonators (SRRs). The cloak consists of an array of a network of split ring resonators which operates at a 3 GHz resonating frequency. The split ring resonators are connected with transmission line and are wrapped around the cylindrical object. Cloak coupled with EM waves gets transferred around the cylindrical object and received to the other side of transmission. Scattering cross section (SCS) is analyzed for both cases, which results in the effect of resonance. The total scattering cross section of the cloaked object is reduced by using SRRs. The simulated and measured results are in great agreement with each other. The transmission-line-connected SRR cloak is useful for S-band applications specifically at 3 GHz resonance.&lt;/p&gt; &lt;/abstract&gt;

A new design of UHF tag antenna for clothing identification using SRR

In this paper, we present a new antenna for radio frequency identification (RFID) tag operating in the Moroccan ultra high frequency (UHF) band around 868 MHz, this antenna is designed on a flexible plastic substrate of relative permittivity 3 and low tangential losses which is 0.002. The proposed tag is designed to identify clothing in supermarkets. The tag antenna has a miniature size of 38 mm in length and 26 mm in width. This miniature size was obtained by using two rectangular split ring resonator (RSRR). The impedance matching of the RFID chip with the antenna was carried out by a double T-matching structure. The antenna is designed, simulated and optimized using computer simulation technology (CST) microwave studio software and good results have been obtained in terms of impedance matching, gain and read range.

Quadruple Band-Notched Compact Monopole UWB Antenna for Wireless Applications

A printed quadruple band-notched ultra-wideband (UWB) antenna characteristic is presented. The designed UWB antenna has a size of 32 mm × 30 mm × 1.6 mm and covers an impedance bandwidth off 2.9–14.5 GHz for the entire frequency band. The entire frequency band maintains voltage standing wave ratio (VSWR) &lt;2, except at WiMAX (3.1–3.6 GHz), WLAN (4.92–6.12 GHz), downlink of X-band for satellite communication systems (7.5–8.4 GHz), and X-band (10.2–11 GHz). By inserting a pair of L-shaped slots into the radiating element, a H-shaped resonator and rectangular split-ring resonators are closely arranged to the microstrip feed-line, alongside the measured impedance bandwidth of 129%. The fabricated antenna radiation pattern and return loss is presented.

A ring monopole quad band antenna loaded with metamaterial and slots for wireless applications

The present wireless applications demand a compact, multi-operated, and stable radiation pattern antenna with good gain and impedance matching performance. To accomplish this requirement. In this paper, we propose a compact metamaterial structure loaded quad band antenna. The structural specifications/layout of the antenna consists of a circular ring monopole fed by a microstrip line. The ground part of the antenna is loaded with a metamaterial rectangular split-ring resonator (RSRR), an L-shaped slot, and two horizontally placed rectangular slots parallel to each other. No external matching circuit is utilized and impedance matching is solely controlled by the placement of slots. The antenna shows operation at 2.1 GHz (2.01-2.24 GHz, a bandwidth of 230 MHz (WLAN)), 4.5 GHz (4.35-4.66 GHz, a bandwidth of 310 MHz (C-band)), 5.5 GHz (5.37-5.77 GHz bandwidth of 400 MHz (WiMAX)), and 7.2 GHz (7.08-7.33 GHz, a bandwidth of 250 MHz (satellite band)). The antenna exhibits good gain and stable radiation pattern in both the plane and thus can be utilized for aforementioned applications.

An electrically small inverted L‐shaped asymmetric coplanar strip‐fed antenna with split‐ring resonator for multiband applications

SummaryIn this paper, an electrically small inverted L‐shaped asymmetric coplanar strip‐fed antenna with a split‐ring resonator structure is proposed for multiband applications. It possesses an extended monopole antenna and a rectangular split‐ring resonator (RSRR) structure. A monopole is responsible for generating the first and last resonance frequencies. Similarly, the RSRR structure produces center frequency (5.5 GHz) among three resonance frequency bands and improves impedance matching at a higher frequency. The antenna has an electrical size of 0.176 λ0 × 0.096 λ0 × 0.012 λ0. The proposed antenna has a triband resonance response at 2.45, 5.5, and 7.5 GHz with a bandwidth of 560 MHz, 680 MHz, and 3 GHz, respectively, which covers WiBro (2.3 GHz), WLAN (2.4/5.2 GHz), WiMAX (2.5/5.5 GHz), X‐band downlink (7.4 GHz), and ITU band (8.5 GHz). The antenna design is simulated and validated with measured results and has better radiation characteristics in all the required frequency bands. The presence of metamaterial property in the proposed RSRR is analyzed. The design is an electrically small antenna, and it has a radian sphere (ka) = 0.64. Further, the proposed antenna performances are compared with the various existing literature.

High-efficiency compact SRR–CSRR–SIW antenna based on CRLH-TL

A high-efficiency compact split-ring resonator (SRR)–complimentary split-ring resonator (CSRR)–substrate integrated waveguide (SIW) rectangular resonator antenna based on a composite right/left-handed transmission line is presented in this paper. A four-element rectangular CSRR structure is etched on the front of the antenna, and a four-element rectangular SRR structure is loaded on the back of the metal to correspond with each other, thus forming a composite right/left-handed transmission line structure. By meandering technique, a rectangular CSRR is etched on the front of the metal surface to reduce the frequency and realize the miniaturization of the antenna. Combined with SIW rectangular resonator, the high-efficiency compact antenna is finally realized. Simulation and experimental results show that the −10 dB impedance bandwidth of the SRR–CSRR–SIW rectangular resonator antenna is 5.26∼5.29 GHz (1.14%) and 9.07∼9.15 GHz (0.88%). The resonance frequency is 5.26 and 9.11 GHz. The gains are 5.33 and 5.25 dBi. The antenna can be widely used in WLAN and WiMAX.

Dual-band metasurface for broadband asymmetric transmission with high efficiency

In this paper, a dual-band asymmetric transmission metasurface for linearly polarized wave is designed, analyzed, and verified experimentally for operation in S- and C-bands. The metasurface is established by a bi-anisotropy structure with three metallic layers separated by dielectric spacers. Symmetric rectangular split-ring resonators are adopted in the top and bottom metallic layers while modified metal strip with stepped widths is utilized in the middle. Both asymmetric transmission capability and operation bandwidth are remarkably improved. According to simulation, the design yields an asymmetric transmission parameter above 0.8 within two operation bands: 2.53–2.56 and 3.80–4.71 GHz, fractional bandwidths of 1.18% and 21.39% can be deduced, respectively. The oblique incidence property is further analyzed, which demonstrates robustness response to incidence up to 50°. Two operation bands, 2.53–2.56 and 3.87–4.78 GHz, are also validated through measurement. The corresponding bandwidths 1.18% and 21.04% show tiny discrepancy related to simulated results, which validate the reliability of the design. Comparisons with other recent published results show that this structure provides relative low profile, wider operation band with high asymmetric transmission efficiency. The proposed metasurface could be applied for electromagnetic interference suppression and polarization control for modern radar and satellite communication systems and can be scaled to operate for higher frequencies with considerable bandwidth and efficiency.

Compact Ultrawide Band Metamaterial-Inspired Split Ring Resonator Structure Loaded Band Notched Antenna

A novel compact size ultrawide band planar antenna with band notched characteristics is present. The band rejection characteristic is achieved by loading a pair of metamaterial inspired rectangular split ring resonator (SRR) near the feed line and by etching the SRR slots on a radiating patch. The simulated and measured results reveal that the proposed antenna exhibits the impedance bandwidth over the ultrawide band (UWB) frequency range from 3.1 to 14 GHz with the voltage standing wave ratio less than 2 except for band stop bands at 3.29 to 3.7 GHz (WiMAX band), 3.7 to 4.10 GHz (C-band), 5.1 to 5.9 GHz (WLAN band), and 7.06 to 7.76 GHz (downlink X-band satellite communication), respectively. The proposed antenna fabricated on low-cost FR-4 substrate has compact size of 24 × 20 × 1.6 mm3. The simulation results are compared with measured results and demonstrate good agreement with stable gain over pass bands. The proposed antenna also exhibits dipole-like radiation pattern in E-plane and omni-directional pattern in H-plane. These results led to conclusion that the presented antenna is a suitable candidate for ultrawide band UWB applications with desired band notch characteristics.