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.

Intelligently optimized arch-honeycomb metamaterial with superior bandgap and impact mitigation capacity

Engineering applications concurrently face challenges related to vibration, impact, load-bearing and energy absorption. Here, an arch-honeycomb metamaterial with split-ring resonators is proposed for wave attenuation and impact mitigation, with better energy absorption and lower initial peak stress. The split-ring resonators effectively induce bandgaps below 3 kHz, and the mechanisms of bandgap generation and polarization are studied through mode shapes, frequency contours and equivalent mass densities. Subsequently, a machine learning-based optimization framework is introduced to tailor the bandgaps, leading to a 155.59% increase in bandgap width. Furthermore, superior vibration isolation and impact mitigation are confirmed through experiments. Obvious attenuation peaks are observed in the bandgaps of the acceleration transmission spectrum in frequency domain. In time domain, the impact test demonstrates peak weakening and delay. The metamaterials offer advantages in wave attenuation, impact mitigation, load-bearing and energy absorption, providing valuable insights for the advancement of multifunctional metamaterials and their practical engineering applications.

Electromechanically Reconfigurable Terahertz Stereo Metasurfaces.

Dynamic terahertz devices are vital for the next generation of wireless communication, sensing, and non-destructive imaging technologies. Metasurfaces have emerged as a paradigm-shifting platform, offering varied functionalities, miniaturization, and simplified fabrication compared to their 3D counterparts. However, the presence of in-plane mirror symmetry and reduced degree of freedom impose fundamental limitations on achieving advanced chiral response, beamforming, and reconfiguration capabilities. In this work, a platform composed of electrically actuated resonators that can be colossally reconfigured between planar and 3D geometries is demonstrated. To illustrate the platform, metadevices with 3D Split Ring Resonators are fabricated, wherein two counteracting driving forces are combined: i) folding induced by stress mismatch, which enables non-volatile state design and ii) unfolding triggered by the strain associated with insulator-to-metal transition in VO2, which facilitates volatile structural reconfiguration. This large structural reconfiguration space allows for resonance mode switching, widely tunable magnetic and electric polarizabilities, and increased frequency agility. Moreover, the unique properties of VO2, such as the hysteretic nature of its phase transition is harnessed to demonstrate a multi-state memory. Therefore, these VO2 integrated metadevices are highly attractive for the realization of 6G communication devices such as reconfigurable intelligent surfaces, holographic beam formers, and spatial light modulators.

Non-Destructive Sensor for Glucose Solution Concentration Detection Using Electromagnetic Technology.

In this paper, a sensor using a complementary split ring resonator (CSRR) is proposed for non-destructive testing of blood glucose. By depicting the complementary split ring structure on the ground, the electromagnetic field strength between the split rings can be enhanced effectively. The structure size of the sensor by CSRR is determined by simulation, so that the insertion loss curve of the device has a resonance point at the frequency of 3.419 GHz. With a special holder created by three-dimensional (3D) printing technology, the test platform was established when the concentration of the solution varied from 0 mg/mL to 20 mg/mL. The experimental results indicate that there is an obvious linear relationship between the insertion loss S21 and the glucose concentration at the resonant frequency. Similarly, the measured real part and imaginary part of the S21 both vary with glucose concentration linearly. Based on the above experimental results, the feasibility of the sensor using a CSRR proposed in this paper for non-destructive detection of blood glucose is preliminarily verified.

Dynamic Properties of Coupled Nonlinear Split-Ring Resonators

In this paper, we delve into the dynamics of two and three coupled SRRs models, exploring their nonlinear properties such as stability, periodicity, or chaos. Additionally, we examine the energy function Hamilton within the context of these models. Numerical examples are provided to illustrate the obtained results and demonstrate the applicability of our findings.

Compact metamaterial-based single/double-negative/near-zero index resonator for 5G sub-6 GHz wireless applications

The concept, performance, and analyses of distinctive, miniaturized metamaterial (MTM) unit cell addressing the forthcoming Sub 6 GHz 5G applications are presented in this paper. Two circular split-ring resonators (CSRR) with two parallel rectangular copper elements in front of the design and a slotted square element in the background make up the suggested metamaterial. It has a line segment with tunable features that is positioned in the center of the little ring copper structure. The suggested design offers a significant operating frequency band of 220 MHz together with a resonance of transmission coefficient S21 at 3.5 GHz. Furthermore, in two (z & x) principal axes of wave propagation, wide-range achievement, single/double-negative (S/DNG) refractive index, negative permittivity, and near-zero permeability properties were demonstrated. Through varying central slotted-strip line length, resonance frequencies can be selectively altered. Moreover, the metamaterial has overall dimensions of 9 × 9 mm2 and is composed on a Rogers 5880 RT substrate. In order to create the suggested MTM's equivalent circuit, which shows similar coefficient of transmission (S21), a proposed design’s numerical simulation is carried out in the CST micro-wave studio. This simulation is after that put to comparison with manufacturing of the design.

A Terahertz Programmable Digital Metasurface Based on Vanadium Dioxide

Metasurfaces can realize the flexible manipulation of electromagnetic waves, which have the advantages of a low profile and low loss. In particular, the coding metasurface can flexibly manipulate electromagnetic waves through controllable sequence encoding of the coding units to achieve different functions. In this paper, a three-layer active coding metasurface is designed based on vanadium dioxide (VO2), which has an excellent phase transition. For the designed unit cell, the top patterned layer is composed of two split square resonant rings (SSRRs), whose gaps are in opposite directions, and each SSRR is composed of gold and VO2. When VO2 changes from the dielectric state to the metal state, the resonant mode changes from microstrip resonance to LC resonance, correspondingly. According to the Pancharatnam-Berry (P-B) phase, the designed metasurface can actively control terahertz circularly polarized waves in the near field. The metasurface can manipulate the order of the generated orbital angular momentum (OAM) beams: when the dielectric VO2 changes to metal VO2, the order l of the OAM beams generated by the metasurface changes from −1 to −2, and the purity of the generated OAM beams is relatively high. It is expected to have important application values in terahertz wireless communication, radar, and other fields.

Non‐Hermitian Broadside Coupled Split Ring Resonators with Directional Sensitivity (Advanced Optical Materials 17/2024)

Non‐Hermitian Broadside Coupled Split Ring Resonators with Directional Sensitivity (Advanced Optical Materials 17/2024)

A Wide Bandpass Elliptical Filtering Response Frequency-Selective Slab Based on Slotline- Backed Split-Ring Resonators

A Wide Bandpass Elliptical Filtering Response Frequency-Selective Slab Based on Slotline- Backed Split-Ring Resonators

A Multi-Frequency Low-Coupling MIMO Antenna Based on Metasurface

In this paper, a multi-frequency MIMO antenna for 5G and Wi-Fi 6E is presented. The antenna uses a cosine-shape monopole and split-ring resonator (SRR) structure for tri-band radiation, and frequency band expansion is achieved through SRR, folded split-ring resonators (FSRR) and Archimedean spiral metasurfaces for decoupling, with which a combination of surface wave and space wave decoupling is achieved. The Archimedean spiral metasurface unit can achieve space wave decoupling in the tri-band. By adopting the method of combining space wave decoupling and surface wave decoupling, the miniature antenna is achieved. The measured results closely align with the simulated results. Specifically, maintaining a reflection coefficient of −10 dB, the measured results indicate an increase in isolation of 3.5 dB, 36.47 dB, and 6.42 dB for the frequency bands of 3.45–3.55 GHz, 5.7–5.9 GHz, and 6.75–7 GHz, respectively. Additionally, the MIMO antenna demonstrates an average efficiency of approximately 89%, with an average envelope correlation coefficient (ECC) of 0.0025. Furthermore, the antenna’s peak gain increases by 4.3 dB at 3.5 GHz, 3.8 dB at 5.8 GHz, and 1.9 dB at 6.9 GHz upon integrating the metasurface. The proposed method and structure are anticipated to contribute significantly to decoupling in multi-frequency MIMO antennas.

Exploring the Impact of Split Ring Resonator Metamaterial Structure Integration on 4X4 MIMO Antenna Performance in Sub-6GHz Bands for 5G Applications

This research delves into the realm of antenna engineering, with a specific focus on examining the performance of 4x4 MIMO antennas with and without integration of split ring resonator metamaterial structure. The objective is to comprehend the influence of split ring resonator metamaterials on antenna characteristics within the 6 GHz frequency range. Employing CST Studio Suite software, comprehensive simulations are conducted to evaluate various parameters including gain, directivity, radiation efficiency, S-parameters, power distribution, VSWR, and total efficiency. In the frequency band up to 6GHz, observed gain values were 24.62dB without split ring resonator metamaterial integration and ranging from 6dB to 27dB with integration. Through a systematic comparison, the study aims to delineate the precise effects of split ring resonator metamaterials on antenna performance, thereby offering valuable insights into their potential for enhancing MIMO antenna systems.

MCML-BF: A Metal-Column Embedded Microstrip Line Transmission Structure with Bias Feeders for Beam-Scanning Leakage Antenna Design.

This article proposes a novel fixed-frequency beam scanning leakage antenna based on a liquid crystal metamaterial (LCM) and adopting a metal column embedded microstrip line (MCML) transmission structure. Based on the microstrip line (ML) transmission structure, it was observed that by adding two rows of metal columns in the dielectric substrate, electromagnetic waves can be more effectively transmitted to reduce dissipation, and attenuation loss can be lowered to improve energy radiation efficiency. This antenna couples TEM mode electromagnetic waves into free space by periodically arranging 72 complementary split ring resonators (CSRRs). The LC layer is encapsulated in the transmission medium between the ML and the metal grounding plate. The simulation results show that the antenna can achieve a 106° continuous beam turning from reverse -52° to forward 54° at a frequency of 38 GHz with the holographic principle. In practical applications, beam scanning is achieved by applying a DC bias voltage to the LC layer to adjust the LC dielectric constant. We designed a sector-blocking bias feeder structure to minimize the impact of RF signals on the DC source and avoid the effect of DC bias on antenna radiation. Further comparative experiments revealed that the bias feeder can significantly diminish the influence between the two sources, thereby reducing the impact of bias voltage introduced by LC layer feeding on antenna performance. Compared with existing approaches, the antenna array simultaneously combines the advantages of high frequency band, high gain, wide beam scanning range, and low loss.

Dual-band microwave sensor based on cross-finger MCSRR Research

This paper presents a low-cost, easy-to-fabricate microwave resonant sensor for characterising the dielectric properties of solids. The designed sensor is based on a Rogers RT/duriod 5880 substrate with a cross-finger treated Multiple Complementary Split-Ring Resonator (MCSRR) structure etched on it, and this resonance unit is used to place the Material Under Test (MUT). The sensor operates at 5.8 GHz and 8.3 GHz resonant frequencies and uses offset resonance to detect the dielectric properties of different solids. The relationships established by the simulation were experimentally verified by the fabricated sensor. The percentage error between the calculated dielectric constant and the reference dielectric constant is less than 9.58% for a certain thickness of the sample to be tested, which verifies the feasibility of the proposed loaded cross-finger MCSRR sensor. Therefore, this sensor is expected to be a cost-effective and convenient solution.

Flexible wavefront manipulation using exceptional points generated by non-interleaved metasurfaces

Precise modulation of the optical wavefront is the main way in which metasurfaces act, and the exceptional point (EP) topological phase provided by non-Hermitian metasurfaces offer an additional degree of freedom for the metasurface design. Here, we design an F-shaped non-interleaved metasurface whose unit cell consists of two basic resonators – a nanowire and a split ring resonator (SRR). By adjusting the strength and coupled-mode of these two resonators, the 2π phase accumulation enclosing the EP, the asymmetric transport properties, and the evolution of wavelength-dependent EP are observed. These properties allow for flexible wavefront manipulation in polarization, amplitude and wavelength dimensions. We simulate and demonstrate a spin-decoupled metasurface hologram, a dual-wavelength decoupled metasurface hologram, as well as a dual-wavelength metasurface for near-field nanoprinting and far-field holography. Non-Hermitian topological metasurfaces can be conveniently combined with other wavefront manipulation mechanisms, showing promising applications in the design of nanophotonic devices.

Design and development of graphene-based double split ring resonator metasurface biosensor using MgF2-gold materials for blood cancer detection

Design and development of graphene-based double split ring resonator metasurface biosensor using MgF2-gold materials for blood cancer detection

Aging Characterization of Modified Insulating Paper Based on the Transmission Characteristics of Microstrip Resonant Sensors

In this paper, the aging characterization of a kind of insulating paper modified by magnetron sputtering MgO particles based on a microstrip resonant sensor was presented. Firstly, the modified insulating paper with 0, 15 and 30 min MgO particle sputtering times was prepared by a magnetron sputtering device. After that, the properties of the modified insulating paper with different sputtering times were analyzed through microscopic characterization, infrared spectrum, polymerization degree, dielectric constant, AC breakdown strength and thermal aging experiments. The results show that the dielectric constant of the modified insulating paper decreased obviously, the AC breakdown strength increased and the thermal aging resistance was better after 15 min of sputtering. The overall performance of the modified insulating paper after 30 min of sputtering is reduced due to excessive sputtering. In addition, microstrip resonant sensors are introduced to characterize the thermal aging degree of the modified insulating paper, and two microstrip resonant sensors are prepared: a complementary split ring resonator (CSRR) and an interdigital-capacitor-shaped defected ground structure resonator (IDCS-DGS). The resonance frequency deviation of the modified insulating paper samples after aging was measured by microstrip resonance sensors to show the influence of aging temperature on aging degree. The experimental results show that the test results of the microstrip resonance sensors are in good agreement with the traditional characterization methods and can characterize the various aging stages of the modified insulating paper to a certain extent, which proves the feasibility of the characterization method.

Penta-band negative permittivity metamaterial with split disc ring resonator for s, c, x and Ku band applications

Penta-band negative permittivity metamaterial with split disc ring resonator for s, c, x and Ku band applications

Hydrogel-based radio frequency H2S sensor for in situ periodontitis monitoring and antibacterial treatment

Periodontitis, a chronic disease, can result in irreversible tooth loss and diminished quality of life, highlighting the significance of timely periodontitis monitoring and treatment. Meanwhile, hydrogen sulfide (H2S) in saliva, produced by pathogenic bacteria of periodontitis, is an important marker for periodontitis monitoring. However, the easy volatility and chemical instability of the molecule pose challenges to oral H2S sensing. Here, we report a wearable hydrogel-based radio frequency (RF) sensor capable of in situ H2S detection and antibacterial treatment. The RF sensor comprises an agarose hydrogel containing conjugated silver nanoparticles-chlorhexidine (AG-AgNPs-CHL hydrogel) integrated with split-ring resonators. Adhered to a tooth, the hydrogel-based RF sensor enables wireless transmission of sensing signals to a mobile terminal and a concurrent release of the broad-spectrum antibacterial agent chlorhexidine without complex circuits. With the selective binding of the AgNPs to the sulfidion, the RF sensor demonstrates good sensitivity, a wide detection range (2–30 μM), and a low limit of detection (1.2 μM). Compared with standard H2S measurement, the wireless H2S sensor can distinguish periodontitis patients from healthy individuals in saliva sample tests. The hydrogel-based wearable sensor will benefit patients with periodontitis by detecting disease-related biomarkers for practical oral health management.

Compact design of MIMO antenna with split ring resonators for UWB applications

In recent times, the Multiple-Input Multiple-Output (MIMO) system has played a vital role in wireless communication. MIMO antenna uses multiple antennas on both the sides of the transmitter and receiver. Mutual coupling occurs between two antenna elements to reduce the performance. The passage of current in the same direction on both neighbouring sides of the antennas increases the rate of mutual coupling. To decrease the mutual coupling, Split Ring Resonators (SRR) are located on the MIMO antenna. In this research paper, a MIMO antenna with SRR for Ultra Wide Band (UWB) applications with different frequency notches is proposed. Also, bandwidth and isolation are considered essential metrics for MIMO antennas. In the proposed 4 × 4 MIMO antenna design, SRR is located at the antenna's two sides, and the defected ground structure is on the bottom portion with a permittivity of 4.4 (FR4 substrate). The defected ground structure is proposed with stubs to enhance the characteristics of bandwidth and create notch bands in the frequency range of 3.1 GHz to 10.6 GHz. Placing SRRs adjacent to the feed line enhances the gain performance. The experimental results show that the ECC of the proposed antenna is less than 0.25, DG is higher than 9.8 dB, and the peak realized gain for 9.38 GHz is 11.3 dB, which is more reliable than other antenna designs. Therefore, experimental outcomes of the proposed antenna design enhance the applicability of band notching for wideband communication.

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