Circular Split Ring Resonator Research Articles

Planar microwave sensor for detection and discrimination of aqueous organic and inorganic solutions

A planar microwave sensor based on a coplanar waveguide (CPW) loaded with a circular split ring resonator (SRR) was developed for the detection and estimation of salts, sugars and organic acids in aqueous solution. The magnitudes of the spectra at resonance frequencies of 2.3–2.6 GHz were shown to provide a rapid and reliable way to measure concentrations of materials such as sucrose, sorbitol, glucose, fructose, CaCl2, NaCl, KCl, MgCl2, Na2CO3 and citric acid. We generated linear and nonlinear regression prediction models built from correlations between the magnitudes of the transmission coefficient (S21) and concentration of materials using coefficient of determination (R2). Principle component analysis (PCA) method was used for discrimination of liquid solution samples. The studies clearly showed sample concentrations in the range from 4 to 20% (w/V) were correlated with the magnitude of S21 and could be detected by using the proposed sensor. Aqueous solution samples could be discriminated into two groups based on magnitude of the spectra of S21 of different solutions at various concentrations. The proposed device can be used to distinguish between organic and inorganic materials in aqueous solution.

Design of miniaturized, low-loss and flexible multi-band metamaterial for microwave application

In this paper, a novel miniaturized low-loss metamaterial unit cell structure, called circular spiral split ring resonator (CSSRR), operating at microwave frequency regime is introduced. The miniaturization is realized with inductive loading by increasing the length of metallic spiral strips inside the structure. Due to inductive loading, the effective inductance-to-capacitance ratio, L/C, is increased as a consequence, low-loss behaviour is also obtained along with the compactness. Despite of miniaturization and low loss, the introduced structure exhibits multi-resonance property with two distinct e-negative (ENG) regions and one µ-negative (MNG) region over the X, Ku, and K microwave frequency bands. Particularly, the low-loss behaviour is observed for all three resonance frequencies of the proposed structure. Furthermore, the presented metamaterial is flexible and provides stable characteristics to bending as well as twisting effect.

Ultraviolet light-induced terahertz modulation of an indium oxide film.

Active ultraviolet light-induced terahertz modulation of an indium oxide film is investigated. A large absorption modulation of ~66% is achieved upon illumination with a low intensity UV laser (11 mW/cm2). The interaction between indium oxide and a flexible metamaterial structure is investigated owing to the large UV-induced enhancement of photo carriers observed in an indium oxide film. We are able to realize absorption peak shifts of 37 GHz by changing the UV excitation light intensity. We also propose a multi-frequency switch by building a circular metallic split ring resonator whose gaps are filled with silicon, germanium, and indium oxide. In future, a photo-excited tunable multi-frequency metamaterial switch can be realized by irradiating the structure with multi-wavelength laser beam.

A fractal quad-band antenna loaded with L-shaped slot and metamaterial for wireless applications

A novel concept of using fractal antenna with metamaterial and slot to achieve multiband operation is investigated. The antenna consists of an L-shaped slot, Sierpinski triangle (used as fractal) as the radiating part and metamaterial circular split ring resonator (SRR) as the ground plane. The introduction of metamaterial in the ground plane makes the antenna operate at 3.3 GHz (middle WiMAX). The etching of Sierpinski triangle and L-shaped slot in the radiating monopole perturbs the surface current distribution; thereby increasing the total current path length which tends the antenna to further operate at 5.5 (upper WiMAX), 7.3 (satellite TV) and 9.9 GHz (X-band), respectively. The extraction of medium parameter of a circular SRR through waveguide medium is discussed in detail. The antenna has a compact dimension of 0.33λ0 × 0.27λ0 × 0.01λ0 = 30 mm × 24.8 mm × 1.6 mm, at a lower frequency of 3.3 GHz. Under simulation, antenna operates at 3.3, 5.5, 7.3 and 9.9 GHz with S11 < −10 dB bandwidth of about 5.9% (3.24–3.44 GHz), 5.6% (5.31–5.62 GHz), 7.3% (6.99–7.52 GHz) and 3.02% (9.78–10.08 GHz), respectively. In measurement, antenna exhibit resonances at 3.1, 5.52, 7.31, 9.72 GHz with S11 < −10 dB bandwidth of about 3.5% (3.04–3.15 GHz), 5.01% (5.44–5.72 GHz), 13.2% (6.76–7.72 GHz) and 5.77% (9.42–9.98 GHz), respectively. Good impedance matching and stable radiation characteristics are observed across the operational bandwidth of the proposed configuration.

Sharp Rejection and Wide Stopband Microstrip Lowpass Filters using Complementary Split Ring Resonators

Chebyshev microstrip lowpass filters with improved performance, achieved by means of circular complementary split ring resonators (CSRR), are presented. The CSRR particles exhibit a frequency rejection bandwidth in the vicinity of their resonant frequencies that can be used to meliorate both the selectivity and stopband in microstrip lowpass filters. Two configurations have been used: a stepped-impedance model and a configuration using open-circuited stubs. Microstrip filters having 5, 7 and 9 poles were designed and fabricated. Selectivity values up to 86 dB/GHz and suppression levels reaching 60 dB in the stopband were obtained. The filters have cutoff frequencies around 2 GHz and rejection band up to 10 GHz. The insertion of the designed CSRR resonators in the ground plane of the filters removes all the transmission spurious observed in the analyzed frequency band. No considerable variation in the passband group delay is observed in the CSRR-based lowpass filters. It is also made a comparison among the filters designed in this and other referenced works, considering their number of poles and size. The measured results are in good agreement with the simulated ones.Â

Metamaterial inspired DNG superstrate for performance improvement of microstrip patch antenna array

To utilize the manipulation of wave properties by metamaterials, in this paper, a microstrip-fed patch antenna array, loaded with metamaterial superstrate, has been proposed. Under unloaded conditions, the conventional patch antenna array resonates at IEEE 802.16a 5.8 GHz Wi-MAX band with gain of 4.31 dBi and bandwidth of 425 MHz, whereas when each patch of this array is loaded with a metamaterial superstrate, composed with the pair of circular split ring resonators and wire strips, gain and bandwidth approaches to 11.9 dBi and 685 MHz, respectively, which corresponds to gain improvement by 7.6 dBi and bandwidth enhancement of 260 MHz. The proposed antenna is fabricated and tested to compare simulated and measured results. A good compliance is observed between these two results. Equivalent circuit model of the composite structure has been developed and analyzed.

Parametric enhancement of a novel microstrip patch antenna using Circular SRR Loaded Fractal Geometry

The improvement in the performance of a novel microstrip patch antenna through added stages of a fractal geometry and a circular split ring resonator for multiband operation is presented. In its first stage, a coaxial-fed novel shaped patch is developed over a 60mm×60mm×1.6mmFR4 epoxy substrate. The modification of the basic patch structure into a fractal geometry results into the addition of bands along with the parametric enhancement of reflection coefficient, gain and bandwidth. A further stamping of Circular Split Ring Resonator on reverse side of the substrate would result in significantly improved performance. The validation of the simulated results has been done and the measured set of data has been plotted against the simulated results graphically.

A Proposed Design of Unit Cell of Metamaterial for 5G Mobile Communication

In this manuscript a design of metamaterial unit cells which are new artificial materials made of periodic arrangement much smaller than the guided wavelength, are proposed which are suitable to work for 5G mobile communication working with millimeter frequency band at 28 GHz due the high demand for the frequency spectrum for mobile networks .The structures of unit cells were simulated using High Frequency Structure Simulator HFSS software. The design starts with the metamaterial structure which is composed of double rectangular (DRR) and circular split ring resonator (DSRR). The results of simulation showed very good results such as wide operating frequency band which is 1.34 GHz with very law radiation losses the unit cell designed to overrun the radiation losses which are appear with the work of metamaterials.

Pneumatically Actuated Tunable Terahertz Metamaterial Absorber With Dual-Side Tuning Capability

Aiming to achieve dual-side postfabrication performance tuning capability, a new tunable terahertz metamaterial absorber design with built-in pneumatic actuation mechanism was proposed, in which a circular split ring resonator with double-slit was adopted. Using multiphysics simulation, including electromagnetic and mechanical, the desired dual-side tuning on absorption peak has been successfully demonstrated by simply changing the direction as well as the amplitude of the applied pressure, agreeing well with theoretical expectation. In addition, detailed discussion about the design optimization strategy for the radius of the split ring resonator from the consideration on improving tuning range was also provided.

Multiband SRR loaded leaf-shaped Koch fractal with a modified CPW-fed antenna

ABSTRACTIn this article, a compact co-planar wave-guide (CPW) feed leaf-shaped Koch fractal antenna loaded with a circular split ring resonator (SRR) is presented. The proposed design consists of a leaf patch etched with Koch fractal (top) and an SRR loaded beneath the FR4, which are accountable for achieving multiple band characteristics, smallness, and fine impedance matching. The antenna dimension is 14×16×1.6 mm3 and is fabricated and tested. The testing results show that the design proposed, having −10 dB for 1.977, 3.19, 6.32, 8.814, 11.87, 15.69, and 18.3 GHz, respectively, covers L/S/C/X/Ku/K bands. It has good radiation characteristics for both E and H fields in all the operating bands and also it generates superior performances compared to the existing antenna in the reviews. The modified CPW-fed leaf-shaped Koch fractal SRR structure antenna is validated through negative permeability extraction and different parametric studies.

Experimental retrieval of the negative parameters “Permittivity and Permeability” based on a circular split ring resonator (CSRR) left handed metamaterial

This paper presents a simulation and experimental retrieval negative permittivity and permeability based on a circular split ring resonator left handed material (LHM). The LHM structure consists of five circular split ring resonators on one side of dielectric substrate and a set of wire couples on other side. CST Microwave Studio is used to model the LHM structure to calculate the scattering parameters (S11 and S21) from which the complex permittivity, permeability and refractive index can be retrieved. MATLAB is used for verification of obtained negative values of structure’s parameter. The circuit was manufactured and measured. The experimental results well agree with the simulated ones.

Coupling Between Metamolecular Modes and Lattice Diffraction Modes of Metamaterials in Terahertz Region

The coupling between plasmonic modes and lattice diffraction modes of circular split-ring resonators in terahertz (THz) region has been analyzed by changing the lattice constants. We discovered a blue shift of the individual eigenmode in short lattice constants, which is due to the longitudinal coupling of two adjacent eigenmodes from neighboring unit cells. We found an anti-crossing effect in long lattice constants for both TM and TE incidence as the lattice diffraction modes is fused with the plasmonic modes to form hybrid modes. Moreover, these hybrid modes are more sensitive to the refractive index change than the pure modes, which shows the promise to increase the sensitivity of metamaterials by coupling.

Multiband SRR loaded Koch star fractal antenna

The Split ring resonator [SRR] loaded Koch star fractal antenna for multiple Freq band apps is presented. The CPW-Fed ant consists of Circular Split Ring Resonator [CSRR] which is fixed on reverse side of the substrate and iterated Koch star which is stamped on top of the FR4. The Koch fractal SRR antenna with a compacted size of 12×14mm2 is fabricated and tested. The multiple Freq for antenna measured capitulate with a −10dB at 1.88/6.54/7.88/12.20/15.08GHz bands and cover up the Freq spectrum of GSM, WiMAX, IEEE 802.11a (WLAN)/b/g, IEEE 802.16e, ITU, S/C/X/Ku and K band, correspondingly. The extraction method of −ve permeability for the projected circular slit resonator is examined in detail. The antenna projected to have significant recompense, plus low profile, miniaturization capability with good S11 and VSWR is accepting for the functional frequency bands.

Fluid, Strain and Rotation Sensing Applications by Using Metamaterial Based Sensor

We propose a design of a metamaterial based sensor to be used in various applications including micro-fluid, strain and rotation sensing. The structure has a simple geometry composed of a single circular split ring resonator (CSRR) and it is possible to adjust the resonance frequency in the region of desired band. The resonance frequency is carefully selected so that the materials to be sensed have linear dielectric curves at that particular frequency range which iscrucial to design accurate sensing characteristic. Three importantapplications are investigated, namely density, rotation and tension sensing. First one is a fluid sensor in which the structure successfully distinguishes the density of ethyl alcohol ratio in pure water andethyl alcohol mixture. Secondly, strain sensing is carried out by observing the resonance frequency shift depending on the iron rod thickness which is placed in the center of the hole in the middle of the structure. The last application is determination of the rotation angle in a precise manner. Depending on a metal placed in the resonator with different theta angles ( − 90 ⩽ θ ⩽ 90), the structure responses in different resonance frequencies. The structure demonstrates sensitive and very precise results in terms of the rotation angle.

A MINIATURIZED VOLKSWAGEN LOGO UWB ANTENNA WITH SLOTTED GROUND STRUCTURE AND METAMATERIAL FOR GPS, WIMAX AND WLAN APPLICATIONS

A novel concept of using slotted ground structure and a single circular split ring resonator (SRR) to achieve multiband operation from a miniaturized UWB antenna is presented in this paper. Initially, a miniaturized Volkswagen logo ultrawideband (UWB) antenna having −10 dB impedance bandwidth of about 124% (2.9–12.4 GHz) in simulation and 116.7% (3.1–11.8 GHz) under measurement is designed. This miniaturization leads to about 10% increment in −10 dB reflection coefficient bandwidth and about 66.71% reduction in the volume of the proposed UWB antenna as compared to the conventional circular antenna. In order to reconfigure the proposed UWB antenna to operate it at 1.5 (GPS), 3.5 (WiMAX), 5.2 and 5.8GHz (WLAN) frequency bands, slotted ground structure with metamaterial is used. The proposed metamaterial is a circular SRR consisting of a single circular ring and is placed on the slotted ground structure of the proposed antenna to achieve 1.5GHz band. The proposed configuration has a volume of 0.290λ0 × 0.290λ0 × 0.015λ0 (30 × 30 × 1.6mm3) at a lower resonating band of 2.9GHz and is fabricated on a widely available FR4 substrate with a loss tangent of 0.02 and dielectric constant of 4.4. Simulated and experimental results show that the proposed design yields S11 < −10 dB at the targeted frequencies. Good impedance matching, stable radiation characteristics with cross-polarization level less than −15 dB (both in E and H planes), VSWR < 2, average gain of 3.09 dBi and radiation efficiency of more than 85% are observed at the designed band when the antenna is fabricated and tested.

Magnetic Metamaterials: A comparative study of resonator geometry and metal conductivity

In this work, split ring resonators based metamaterials are studied for microwave, terahertz and infrared frequency regimes. Two different geometries, circular and rectangular split ring resonators based metamaterials are investigated numerically for different frequency regimes. Our study indicates that the effect of metal conductivity and resonator geometry shows very little impact on the fundamental resonance mode. However the higher order modes go through significant frequency tuning because of the change in resonator geometry. We have further shown that the metal conductivity is an important parameter for the metamaterials employed in infrared domains.

Planar Microwave Sensor for Theranostic Therapy of Organic Tissue Based on Oval Split Ring Resonators.

Microwave sensors in medical environments play a significant role due to the contact-less and non-invasive sensing mechanism to determine dielectric properties of tissue. In this work, a theranostic sensor based on Split Ring Resonators (SRRs) is presented that provides two operation modes to detect and treat tumor cells, exemplary in the liver. For the detection mode, resonance frequency changes due to abnormalities are evaluated, and in the treatment mode, microwave ablation is performed. The planar sensor structure can be integrated into a needle like a surgery tool that evokes challenges concerning size limitations and biocompatibility. To meet the size requirements and provide a reasonable operating frequency, properties of oval shaped SRRs are investigated. By elongating the radius of the SRR in one direction, the resonance frequency can be decreased significantly compared to circular SRR by a factor of two below 12 GHz. In order to validate the detection and treatment characteristics of the sensor, full wave simulations and measurements are examined. Clear resonance shifts are detected for loading the sensor structures with phantoms mimicking healthy and malignant tissue. For treatment mode evaluation, ex vivo beef liver tissue was ablated leading to a lesion zone 1.2 cm × 1 cm × 0.3 cm with a three minute exposure of maximum 2.1 W.

Ultra‐wideband monopole antenna for multiband and wideband frequency notch and narrowband applications

A new design concept of a multi-configuration antenna providing both frequency notched ultra-wideband and multiple narrowband functionality from a coplanar waveguide fed circular monopole antenna is presented in this study. The proposed multiple antenna configurations are achieved by loading the feed section of the antenna with circular split ring resonator pair of varying dimensions and inner ring orientations and shorting copper strips. Fabricated prototypes were measured and compared with simulation and good agreement is obtained for both impedance and radiation characteristics.

New generation chiral metamaterials with small and flat chirality over a certain frequency band based on circular split ring resonators for microwave filter applications

There are many studies in literature on chiral metamaterials (MTMs) to obtain large chiralities with dynamic optical activities. With this regard, this new generation planar chiral MTM study focuses on a small, non-dispersive (constant/flat) chirality admittance over an indicated frequency band which has not been investigated so far in literature. This new generation planar chiral MTM provides a small and a constant/fixed chirality which is mostly ignored by the scientists. This study numerically and experimentally investigates and examines these new generation MTMs based on circular split ring resonators (SRRs) with an increased capacitance in details. Obtained results show that the suggested structure can provide a small and constant/flat chirality admittance over a certain frequency band and hence it can be used to design myriad novel electromagnetic (EM) devices such as transmission and antireflection filters, polarization rotators for any desired frequency regions.

NETWORK IMPLEMENTATION OF PHOTONIC CRYSTAL CIRCULAR SPLIT RING RESONATOR BASED ADF

Photonic Crystal based optical devices have attained a widespread attention for ultra-fast communications and Photonic Integrated Circuits. In this paper, Two Dimensional Photonic Crystal Circular Split Ring Resonator (PCCSRR) based Add Drop Filter is proposed and designed. The normalized transmission spectra of circular Photonic Crystal Split Ring Resonator are taken using 2D Finite Difference Time Domain method. The Photonic Band Gap is calculated by Plane Wave Expansion method. The resonant wavelength, coupling/ dropping efficiency and Q factor of the ADF are 1490nm, 100 % and 243nm, respectively. The overall size of the device is much smaller that is 10.4μm × 11.4μm which is highly suitable for photonic integrated circuits and all optical photonic network applications. In addition, the proposed device is incorporated in the point to point networks and its network parameters such as Bit Error Rate, Quality factor, receiver sensitivity are examined.