Multiple Split Ring Resonators Research Articles

Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates With High Sensitivity

Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates With High Sensitivity

Evaluating the Impact of Geometric Dimensions of a Multi-Split Ring Resonator

In this paper, a metamaterial unit cell is designed and simulated based on the concept of multiple split-ring resonators (SRRs) in a compact size. The presented nested modified SRR resonator construct has the advantage of achieving more usable split gaps by increasing capacitance, resulting in a lower operational resonance frequency and improved sensitivity over typical SRR metamaterials. The impact of several split ring resonator geometric characteristics, such as the gap space, the width of the copper lines, the inner rings length, and the outer ring length on magnetic permeability and permittivity was analyzed. The modified metamaterial can be utilized for 5G mobile applications.

An Analysis of Split-Ring Resonators and Potential Barcode Application

This paper presents an analysis of various split-ring resonator (SRR) configurations coupled with coplanar waveguides (CPW). Three distinct resonant structures are presented, namely, the S-shaped split-ring resonator (S-SRR), the conventional split-ring resonator (SRR), and a pair of SRR. Among the examined resonant structures, it is observed that the S-SRR exhibits the smallest electrical size with the corresponding resonant frequency of 1.37 GHz, while the conventional SRR has the largest electrical size with the corresponding resonant frequency of 3.34 GHz. On the other hand, the resonant frequency of a dual SRR is 2.37 GHz. However, the transmission coefficient of a dual SRR is -11.43 dB, which is higher than S-SRR (-10.02 dB) and SRR (-8.18 dB). Furthermore, this study extends the analysis between a square dual SRR and a circular dual SRR with retained area. The square SRR demonstrates a lower resonance frequency (2.23 GHz) relative to its circular counterpart (2.37 GHz). The comparison also shows that the transmission coefficient of the square configuration is -13.88 dB, which is higher than its circular counterpart (-11.43 dB). The realization of a barcode application is achieved by loading multiple S-shaped split ring resonators (S-SRRs) with varying geometric parameters adjacently onto the transmission line. By individually rotating each of these S-SRRs, it becomes possible to alter the notch magnitude, thereby positioning it within a specific designated range corresponding to a particular code. In the case of a configuration involving rotations of (0°, 45°, 90°, 0°, 45°, 90°), this approach results in the creation of a barcode denoted as "100 010 000 100 011 000". This methodology enables the encoding of information in the form of distinctive resonant responses, providing a versatile and compact means of realizing barcode applications.

A multi-functional tunable terahertz graphene metamaterial based on plasmon-induced transparency

A graphene terahertz metamaterial composed of multiple square split ring resonators is proposed to realize the excellent functions of sensing and switching based on plasmon-induced transparency (PIT). The switch, operating at multiple frequencies can be easily achieved by adjusting the Fermi level of graphene, corresponding to a maximum amplitude modulation of 89.5 %. When the device is employed as a sensing platform, the multi-PIT effect can improve the sensitivity due to greater interactions between the metamaterial and analytes, leading to a maximum sensitivity of 380 GHz/RIU. These findings suggest that the proposed metamaterial can serve as a multipurpose device with broad applicability.

Enhanced second harmonic generation from a quasi-periodic silver dendritic metasurface

The preparation of the vast majority of nonlinear optical metal metasurfaces currently relies on complex top-down methods such as electron beam or ion beam etching, which are expensive and difficult to meet the requirement of large area preparation. In this paper, an easily prepared quasi-periodic silver dendritic metasurface model with high Q factor is established in the near-infrared band based on a simple and easy-to-operate electrochemical deposition method. The simulations prove that the silver dendritic metasurface has a high Q factor (exceeds 104) because of its strong electric field localization ability, which is analogous to the superposition of multiple split-ring resonators. It is demonstrated that the second harmonic generation (SHG) intensity of the dendritic metasurface at a large incident angle (such as 85°) is about 30 times that of the metasurface at a small incident angle when the x-polarized pump light is incident obliquely to break the centrosymmetry of the metasurface. The influences of the incident angle or dendritic structure’s dimensions on the Q factor and SHG efficiency have also been researched through a lot of simulation. This easily prepared quasi-periodic silver dendritic metasurface SHG device may provide a new avenue for the development and application of miniature, integratable nonlinear optical devices.

Experiment on terahertz metasurfaces of metal split ring resonators with bound state in the continuum

A bound state in the continuum (BIC) is a wave that coexists with a continuous wave but remains localized. In the terahertz band, BIC can design devices with an ultra-high mass factor (Q factor), which is of great value for terahertz science and technology, so we designed a terahertz BIC metasurface structure composed of metal split ring resonators (SRRs). According to the symmetric protection principle of superlattice mode, the leakage process of BIC states to the far field is studied by changing the gap width of SRR. By introducing multiple SRRs and changing their arrangement, we obtain three superlattice modes and BIC states. The leakage of BIC states into the far field is observed experimentally, which means that observable quasi-BIC patterns are formed. We verify a feasible method that allows for flexible design and implementation of BIC.

Highly Efficient and Multiband Metamaterial Microstrip-Based Radiating Structure Design Showing High Gain Performance for Wireless Communication Devices

High-speed wireless communication devices need antennas to operate at multiple frequencies with high gain. The need for such antennas is increasing day by day. The proposed metamaterial superstrate antenna gives a high gain and multiband performance, which is required in high-speed wireless communication devices. The designed antenna is also applicable for C- and X-band communication devices. The structure consists of a simple patch and multiple split-ring resonator metamaterials on the superstrate region. The performance optimization is achieved by adjusting the feed position, varying the height of the superstrate layer and changing the thickness of metamaterial rings. The proposed design is analyzed for 4 GHz to 12 GHz. The performance analysis regarding the reflection coefficient, directivity, gain and electric field is observed. FR4 is used as a dielectric material that makes the design low-cost. The proposed design represents a minimum reflection coefficient response of −49 dB, a bandwidth of 490 MHz, a maximum electric field of 1.29 × 104 v/m, good directivity and a broader radiation pattern. The comparison between the simulated and the measured results is incorporated in the manuscript. A comparison of the presented design with other articles is included to check the novelty of the design. The proposed method helps to target applications such as WiFi, Earth observation and microwave links.

Study and Design of Bandstop Filtres Based on a Multiple Co-Directional Complementary Split Ring Resonator (CSRR)

The objective of this study is to enhance the performance of metamaterial filters. Indeed, the distinctive electromagnetic characteristics of metamaterials, along with their capacity to guide and manipulate electromagnetic waves in ways unattainable by natural materials, have rendered metamaterials progressively appealing in recent years. One type of metamaterial that has been studied extensively is the Split Ring Resonator (SRR) and its complementary counterpart (CSRR), Both of these structures possess dimensions significantly smaller than the wavelength. They demonstrate bandstop characteristics and exhibit negative permeability or negative permittivity in a narrow frequency range centered around their resonant frequencies. These frequency bands can be precisely and easily controlled in terms of frequency selectivity and rejection level by adjusting various parameters. As a result, these resonators are designed and optimized for use in the design of new filters. The obtained results confirm that the proposed metamaterial resonators significantly enhance the performance of the targeted applications.

A Multiband, Polarization-Controlled Metasurface Absorber for Electromagnetic Energy Harvesting and Wireless Power Transfer

A multiband, polarization-controlled energy harvesting metasurface is presented in this article for harvesting electromagnetic energy in the Wi-Fi bands. Inspired by the split-ring resonator (SRR), a metasurface of SRRs is designed by nesting multiple SRRs together. The novelty of the design lies in the controllable multiband polarization and adjustable absorption frequency, so as to achieve the active modulation of energy harvesting on the metasurface at different frequencies. The metasurface is composed of a periodic array of SRRs unit cells, an impedance-matched rectifier, and a load. Metasurface arrays and rectifier integration are proposed to reduce power losses, while the channels formed by the array enhance energy density and improve the ability to capture energy. Moreover, the design for the rectifier is capable of rectifying RF energy from multiple Wi-Fi bands simultaneously at low input RF power density. The finite array of <inline-formula> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> 5 SRRs absorber is fabricated and tested. Measurements in an anechoic chamber show that the fabricated prototype reaches the efficiency of 66.5&#x0025; at 2.4 GHz, 40.6&#x0025; at 5.2 GHz, 35.6&#x0025; at 5.8 GHz under transverse electric (TE) polarization, and 38.3&#x0025; at 5.3 GHz under transverse magnetic (TM) polarization when the incident power density is greater than 66 <inline-formula> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula>/cm².

Designing and Validation of Miniaturized CPW Based Microwave Notch Filter Using Loaded Modified Multiple Split Ring Resonator (MSRR)

In this article, a coplanar waveguide (CPW) based compact low loss notch filter (NF) with sharp roll–off is proposed. At the beginning, the proposed NF is designed using an array of conventional Multiple Split Ring Resonator structure (MSRR), then it is replaced by modified MSRR structure in array to improve the sharpness factor in dB/GHz. This array of modified MSRR structure is behaving like a metamaterial unit cell. The proposed NF operates at resonant frequency of 2.56 GHz with 3 dB fractional bandwidth (FBW) of 4.68%, a roll-off factor (ROF) of 672 dB/GHz, and passband insertion loss of 0.35 dB. A parametric study has been done to obtain the relationship between the ring perimeter of the MSRR and the resonant frequency of the NF. Finally, a dual-band notch filter (DBNF) is designed by using an array of four modified MSRR structures. The EM simulated, circuit simulated, and measurement results of the proposed structure are in good agreement with each other. The proposed CPW based NF is useful for various applications like LTE (2600 MHz), Wimax (2500 MHz), and FCC ID (2.68 GHz).

Array Design of 300 GHz Dual-Band Microstrip Antenna Based on Dual-Surfaced Multiple Split-Ring Resonators.

To meet the increasing need of high-data-rate and broadband wireless communication systems, the devices and its circuits R&D under Millimeter, Sub-Millimeter, or even Terahertz (THz) frequency bands are attracting more and more attention from not only academic, but also industrial areas. Most of the former research on the THz waveband (0.1–10 THz) antenna design is mainly focused on realizing high directional gain, such as horn antennas, even though the coverage area is very limited when comparing with the current Wi-Fi system. One solution for the horizontally omnidirectional communication antenna is using the structure of multiple split-ring resonators (MSRRs). Aiming at this point, a novel 300 GHz microstrip antenna array based on the dual-surfaced multiple split-ring resonators (DSMSRRs) is proposed in this paper. By employing the two parallel microstrip transmission lines, different MSRRs are fed and connected on two surfaces of the PCB with a centrally symmetric way about them. The feeding port of the whole antenna is in between the centers of the two microstrip lines. Thus, this kind of structure is a so-called DSMSRR. Based on the different size of the MSRRs, different or multiple working wavebands can be achieved on the whole antenna. Firstly, in this paper, the quasi-static model is used to analyze the factors affecting the resonance frequency of MSRRs. Simulation and measured results demonstrate that the resonant frequency of the proposed array antenna is 300 GHz, which meets the design requirements of the expected frequency point and exhibits good radiation characteristics. Then, a dual-band antenna is designed on the above methods, and it is proved by simulation that the working frequency bands of the proposed dual-band antenna with reflection coefficient below −10 dB are 274.1–295.6 GHz and 306.3–313.4 GHz.

Submersible High Sensitivity Microwave Sensor for Edible Oil Detection and Quality Analysis

A high sensitivity complementary multiple split ring resonator (CMSRR) based submersible microwave sensor for edible oil detection and quality analysis is proposed. The main part of the sensor is the CMSRR loaded flared microstrip patch, and the proposed single-port structure is quite attractive for liquid detection. The proposed sensor was fabricated and measured to operate at 8.49 GHz with very high Q factor, which agrees very well with the simulated results obtained by High Frequency Structure Simulator (HFSS). A strong electric field can be observed along the sides of CMSRR at resonance, creating a sensing region sensitive to changes in the nearby dielectric material. By simply immersing the sensor into some familiar oil samples and heated peanut oil, the device’s resonance and peak attenuation change greatly. The measured results have proven the improved sensitivity of the proposed sensor on the liquid samples compared with the methods described in the literature. The complex permittivity of the oil samples can be estimated by establishing an approximate model in HFSS. Two empirical formulas were built and fitted to estimate the complex permittivity of unknown several oil samples and heated peanut oil samples. The estimated dielectric constants agree well with the existing data. The estimated error is within 1.4% and the measured sensitivity is up to 7.25%. The proposed sensor has advantages, being compact, inexpensive, reliable, easy to operate, and highly sensitive, and has potential applications in oil detection and quality analysis.

Compact spoof surface plasmonic waveguide with controllable cutoff frequency and wide stop band

To adjust the transmission band while keeping the width of a spoof surface plasmon polariton (SSPP) waveguide unchanged, periodic cells with T-shaped conductor branches on both sides are used. By controlling the top lateral strips of branches, the adjustable range of cutoff frequencies can reach approximately 3.5 GHz. Thus, compromised regulation of the field confinement and transmission loss is easily achieved, improving the transmission performance of SSPP modes. By loading open conductor rings onto T-shaped branches to construct a split ring resonator (SRR), a band-rejection filter is realized. When multiple SRRs with gradient lengths are loaded onto one side of the SSPP waveguide, a broad stop band with a relative bandwidth of 18% is achieved. The proposed structures are also advantageous for the miniaturization of microwave circuits.

Tunable toroidal Fano resonance in the multiple split-ring resonators metamaterials

We investigate the tunable toroidal Fano resonance in the multiple split-ring resonators (SRRs) metamaterial. The toroidal Fano resonance is theoretically and experimentally demonstrated. The Fano resonance can be excited by introducing a big-SRR in the multiple small-SRRs. Fano resonance results from the mutual coupling between toroidal and magnetic dipoles. The Fano lineshape can be tuned by changing the size of big-SRR. Moreover, the authors discover that the direction of toroidal dipole also can be tuned by properly controlling the size of big-SRR. The strength of Fano resonance can be enhanced by introducing two small-SRRs. The double Fano resonances can be excited by tuning the size ratio between two small-SRRs. The structure provides more dielectric information of the analyte. In the design, by introducing two small-SRRs in the structure and using Fano resonance, the sensitivity has been improved. The two small-SRRs structure increases the sensitivity of the final design, up to two times compare to the one small-SRRs structure. The tunable toroidal Fano resonance offers the potential for application in the microwave and terahertz sensing.

Numerical investigation of liquid metamaterial-based superstrate microstrip radiating structure

In this paper, we present a novel microstrip antenna system that combines liquid and metamaterial properties to achieve higher gain, higher operating bandwidth, and multiple operating frequency bands. This is achieved by stacking multiple liquid-based-metamaterial superstrate passive structures over the active patch. The circular active microstrip patch antenna is loaded with two layers (stacked one-above-the-other) of passive superstrate patches to improve the antenna system performance. Initially, to test and compare the concept-hypothesis, the superstrate is loaded with a conventional copper-based multiple split-ring resonators superstrate passive patch, followed by the liquid counterpart - liquid-based multiple split-ring resonators (liquid-metamaterial) superstrate passive patch, to achieve higher antenna system performances. The study shows that; compared to the copper-based superstrate, the liquid-based superstrate loading increases reflectance response, Gain, the operational bandwidth, and also open vistas for multiple frequency operation of the antenna system. Attention is drawn to the fact that the antenna system gain is enhanced by the liquid-based multiple split-ring resonators superstrate incorporated microstrip patch antenna system with high gain. Position of patches is arranged in two ways. Firstly arranged in center position one another and in secondly they are arranged in one-sided. By shifting patches in one-sided reflectance response will enhance that covers different strategic applications in the Wearable, Bio-monitoring, C-band and other extended wireless communication applications.

Bridge multiple split ring resonator sensor for microwave liquid characterization

A planar bridge multiple split-ring resonators (BMSRR) with a microfluidic sensor is a real-time nondestructive sensor designed based on bridge split ring topology. This sensor has the ability to characterize liquid solvents using the extraction of polynomial fitting technique and bridge connector elements were added to enhance the quality factor and sensitivity. The characterization of liquid samples is analysed and numerically expressed based on their dielectric properties and loss tangent with a minimum volume of samples. The unloaded Q-factor improves more than 400 over the bandwidth at an operating frequency of 2.3 GHz.

Improve planar multiple split-ring sensor for microwave detection applications

In this paper, a sub-wavelength resonance sensor is proposed to microwave detection applications. A meta-material element—multiple split ring resonators (MSRR) is used to improve the sensitivity of the sensor. Therefore, the sensor is based on micro-strip technology and consists of a micro-strip and a MSRR. It is observed that the strongest electric field of the sensor can achieve to 105 V/m. So the sensor is very sensitive to capture changes of dielectric signals. Some experiments were carried out using the fabricated sensor, and a network analyzer (AV3609D) with liquids under test (LUT) inserted the sensor. Furthermore, primary finite element analysis and test results are used to compare the MSRR-based and a general complementary split ring resonator (CSRR)-based sensing sensor, demonstrating sensitivity improvement of up to 1.3 times. The proposed MSRR-based sensor has stronger coupling between the micro-strips of the open-loops of the MSRRs, which can reduce the reflection and dimension of the sensor. Therefore, this sensor is well suited for low-cost, real-time, and CMOS compatible sensing technologies.

A Metamaterial-Inspired Dual-Band High-Sensitivity Microwave Sensor Based on Multiple Split Ring Resonators for Sensing Applications

This paper introduces the design, manufacture, and evaluation of a compact metamaterial-inspired sensor, aiming at detecting dielectric properties of small liquids in a microwave measurement system. The proposed sensor is based on a microwave-coupled multiple split ring resonators (MSRR). The sensing principle is based on field perturbation theory. Then the sensor's resonance characteristics will change when the sensor is loaded with the materials under test (MUT). We have demonstrated that the sensor has a very high sensitivity to sensing the dielectric variations of its surroundings. When the resonance occurs, the strongest electric field intensity of the sensor is better than 105 V/m. The proposed sensor is simulated and optimized using ANSYS high frequency structure simulator (HFSS) to ensure its operating frequency is near 3 GHz and 4.5 GHz. Measurement results agree well with the simulation results. Some experiments show that this sensor can detect the dielectric property of liquids with very small volumes (∼12.56 mm3).

High absorbance performance of symmetrical split ring resonator (SRR) terahertz metamaterial based on paper as spacer

Paper is a fascinating material for electronic platform devices due to being an inexpensive and environment friendly material. Terahertz wave is able to penetrate paper, thus paper-based terahertz metamaterial will be great terahertz devices. Creating multiple symmetrical Split Ring Resonator (SRR) on upper side paper and depositing metallic plane on back side paper yield terahertz metamaterial absorber. The maximum of absorbance peak for numerical and analytical results are 98% at 0.92 THz and 99% at 0.92 THz, respectively. The superposition of multiple reflections of terahertz wave generated on paper and yielding destructive interference phenomenon. Numerical and analytical works have been carried out in this works and showed good agreement.

Plasmonic multi channel filter based on split ring resonators: Application to photothermal therapy

In this study, we developed and analyzed a multichannel filter based on multiple plasmonic split ring resonators. In the proposed structure, split ring resonators were coupled to T-shaped and straight waveguides. The field distribution and transmission characteristics were investigated using the finite-difference time-domain method. In the proposed filter, the split ring resonators, and straight and T-shaped waveguides were made of air situated in a silver background. The proposed structure can confine light to sub-wavelength dimensions and it can be utilized in photonic integrated circuits. The results showed that the proposed structure functioned as a typical filter and the electromagnetic wave energy at different wavelengths could be trapped in different insulator rings. The sensitivity factors and dependence of the multichannel filter on the coupling lengths (Li) and ring widths (Ci) were also investigated. Based on the linear relationships with the refractive indices and resonance wavelengths in the ring resonators, sensitivity factors could be obtained for different rings. By increasing the refractive index, the resonance wavelengths exhibited considerable red shifts. The proposed structure with high transmission efficiencies and resonance wavelength ranges (near infrared) will be useful in highly integrated optical circuits, photothermal therapy, and cancer treatment.