Negative Effective Permeability Research Articles

Electric and magnetic resonances inducing triple-stopband terahertz metamaterial filter

A polarization insensitive triple-stopband terahertz metamaterial filter is proposed. This filter consists of a flexible polyimide substrate and periodically arranged copper structures on its top. The shape of the metal unit is a “田” inside a square ring. The simulation results show that the resonant frequencies of the filter are 0.107, 0.23, and 0.271 THz; the stopband depths are −35.56 dB, −42.7 dB, and −37.485 dB; the 3 dB bandwidths are 34, 53, and 32 GHz; and the relative bandwidths are 31.78%, 23%, and 11.8%, respectively. Effective parameter analysis demonstrates that the first resonance originates from the negative effective permittivity and positive effective permeability, but the reason for the latter two resonances is opposite to the first. The surface current distributions indicate that the first resonance is electric type, while the latter two resonances are the lower and higher orders magnetic resonances, respectively. Then, we verify the triple-stopband characteristic of the filter based on the equivalent circuit. Finally, the analysis reveals that the performance of the filter is independent of the incident polarization angle. This filter has the characteristics of multi-frequency, broadband, deep stopband, polarization insensitivity, and simple structure, which can be used in terahertz communication, detection, and other fields.

Millimeter wave negative refractive index metamaterial antenna array

In this paper, a novel negative refractive index metamaterial (NIM) is developed and characterized. The proposed metamaterial exhibits negative effective permittivity (εeffe) and negative effective permeability (µeffe) at millimeter wave frequency of 28 GHz. This attractive feature is utilized to enhance the gain of a microstrip patch antenna (MPA). Two thin layers of 5 × 5 subwavelength unit cell array of NIM are placed above a single MPA to enhance the gain of the antenna. Each unit cell has an area of 3.4 × 3.4 mm2. A gain increase of 7.9 dBi has been observed when using the proposed NIM as a superstrate. Furthermore, the NIM array is placed over a 2 × 2 array of MPAs with four ports to demonstrate versatility of the metamaterial. The total size of the 2 × 2 antenna array system with N-MTM is about 61.1 × 34 × 16mm3 (5.71λ × 3.18λ × 1.5λ, where λ is the free-space wavelength at 28 GHz). The measurement result indicate that the maximum gain of the antenna array is 13.5dBi. A gain enhancement of 7.55 dB in E-Plane and 7.25 dB in H-Plane at the resonant frequency of 28 GHz is obtained. The proposed antenna structure is suitable for 5G millimeter wave communications, in particular, for possible implementation in future millimeter wave access points and cellular base stations.

Electronically controlled left-handed metamaterial based on memristor/ferrite multilayer at microwaves

The paper focuses on exploring the left-handed microwave properties of a double negative metamaterial formed by utilizing elements from two natural materials: (a) thin-layer ferrite, which exhibits effective negative permeability, and (b) thin-layer TiO2 (memristor), which exhibits effective negative permittivity. Both of these natural materials possess negative constitutive parameters within the frequency band where they exhibit left-handed properties. We have defined the conditions under which a backward wave appears in the double negative frequency band. We analyze a left-handed metamaterial (LHM) for the microwave frequency band formed by a multilayer structure from the above-mentioned materials. We have theoretically demonstrated the transparency of this LHM. Furthermore, we demonstrate the ability to control the electromagnetic properties of the metamaterial. This can be achieved not only by applying both static magnetic and static electric fields but also by solely using a static electric field. The latter is one of the main advantages of this structure for technological implementation. We discuss potential applications of the designed structure as a component of microwave electronics. The capability to control various resistance states of nanoscaled TiOX with low voltage offers further control over the properties of the left-handed metamaterial.

Left-handed metamaterial based on circular split ring (CSRR) resonator for microwave sensing Application

This paper presents a new metamaterial structure specifically designed to operate in the L, S, and C frequency bands. It is characterized by a small unit cell size of 15mm × 15 mm. The metamaterial's electromagnetic properties are thoroughly examined, utilizing FR-4 substrate material and copper circular split ring resonators (CSRRs). The Computer Simulation Technology (CST) software uses the finite integration technique (FIT) to precisely model the effective parameters over a frequency range of 0–6 GHz. In simulations and experiments, the structure demonstrates negative refractive index, effective permittivity, and effective permeability. The electric and magnetic field distributions within the unit cell are accurately characterized using vector fields. In addition, the equivalent circuit is simulated and depicted using ADS software, with comparisons drawn between the measured data and the simulated data. The experimental validation, conducted using six varying thicknesses of FR4 materials, verifies the resemblance between the simulated and the measured transmission coefficients. Moreover, the effective medium ratio (EMR) of the metamaterial is calculated to be 12.74, indicating its promising capabilities for microwave sensing applications. The examination of the sensor model uncovers such metrics as quality factors, frequency detection resolution (FDR) values, and sensitivities, all of which enhance our comprehension of the material's performance. This discovery has the potential to advance the development of sensing metamaterials, which could significantly impact various applications and enhance research in the field.

Magnetostatic waves in metallic rectangular waveguides filled with uniaxial negative permeability media

The propagation characteristics of magneto-quasistatic waves, more commonly, known as magnetostatic waves in a long, metallic rectangular waveguide filled with a metamaterial slab are comprehensively investigated. The metamaterial slab consists of split-ring resonators as an anisotropic uniaxial medium with transversal negative effective permeability. Some analytical relations and numerical validations on the characteristics of these waves are presented. The results include the dispersion relations, mode patterns (field distributions) that can be supported by such media, and their corresponding cutoff frequencies, group velocities, power flows, and storage energies of magnetostatic waves. The findings from the present research study can be advantageous to advance the synthesis and development of negative permeability materials with peculiar features in guiding structures.

Double-Split Rectangular Dual-Ring DNG Metamaterial for 5G Millimeter Wave Applications

This article presents the design and analysis of a low profile double-negative (DNG) metamaterial unit structure for 5G mmWave (millimeter wave) applications. The structure, comprised of double-slotted rectangular ring patches, experiences the peak current value near the magnetic resonance, causing the metamaterial to resonate at 28 GHz where it exhibits negative effective permittivity and permeability. The 3.05 mm × 2.85 mm compact structure is designed over a substrate Rogers RT/Duroid 5880 to attain better effective medium ratio (EMR) in the 5G frequency range (27.1–29.2 GHz). A rigorous parametric study is conducted to obtain the proposed design. Full-wave electromagnetic simulation software tools CST and HFSS are used to generate the scattering parameters for the analysis. The Nicolson–Ross–Wier method is used to observe the negative effective permittivity and permeability. In addition, different output quantities, e.g., surface current and electric and magnetic field distribution, are investigated. The structure is further tested with 1 × 2, 2 × 2, and 4 × 4 arrays, where the results show adequate agreement to be considered for 5G mmWave applications.

High-Sensitivity Grooved CSRR-Based Sensor for Liquid Chemical Characterization

In this work, a new complimentary split ring resonator (CSRR)-based sensor is proposed to sense chemical concentrations. A groove is created in the dielectric ring region of the CSRR to place the hollow tube containing the material under test (MUT). By placing the MUT in the region of high field concentration, higher sensitivity is achieved. The proposed novel and simple design alleviates the requirement of complex fluidic channels and space needed to place the MUT. The fabrication process is also simple with efficient utilization of the sensor’s sensitive region. The CSRR is excited uniquely through a transmission line with periodically placed capacitive gaps in series. By placing the capacitive gaps, effective negative permeability and permittivity are simultaneously achieved, and the structure exhibits metamaterial [composite right/left-handed transmission line (CRLH-TL)] left-handed behavior. Greater coupling of electromagnetic energy from the transmission line to the resonator is achieved by increasing the capacitive gap widths, which renders higher sensitivity. The main sensing parameter is the shift in the frequency of the transmission coefficient notch arising due to the placement of chemicals of varying concentrations throughout the ring region in the hollow tube. The sensor dimension is 4 cm (0.012 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> ) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 cm (0.012 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> ), with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> being the guide wavelength. The large sensing bandwidth obtained is 1320 MHz that corresponds to high sensitivity of 14.66 MHz/unit change in concentration and 21.44 MHz/unit change in permittivity. The sensor is cheap and small, and the sensing process is simple offering instantaneous results.

Scannable Leaky-Wave Antenna Based on Ferrite-Blade Waveguide Operated Below the Cutoff Frequency

This article proposes a scannable leaky-wave antenna (LWA). The antenna consists of a ferrite-blade waveguide with a longitudinal slot on the upper wall, which has a tunable composite right-/left-handed (CRLH) property. The left-handed (LH) behavior of this structure is based on the negative effective permeability of the ferrite material and the negative effective permittivity of the waveguide excited below its cutoff frequency. First, based on the modal analysis and calculated dispersion relation, the unbalanced CRLH response of the ferrite-blade waveguide is investigated. Second, an LWA is presented by using a longitudinal slot on the upper wall of the proposed ferrite-blade waveguide, where the tunable balance CRLH response is achieved and analyzed by the transverse resonance method (TRM). The proposed LWA can provide backward, broadside, and forward radiations by a change in the operation frequency or the magnetic bias, independently. The given results show a +59° to -57° sweep in the radiation beam when the magnetic bias of the ferrite changed from 1400 to 1600 Oe at the sampling frequency of 6.4 GHz. Moreover, the results show that the frequency tuning range is more than 600 MHz (6.2-6.8 GHz). The peak gain and efficiency of the proposed antenna are 7.1 dBi and 78.5% at 6.6 GHz, respectively.

All-dielectric bulk isotropic double-negative metamaterials

We propose the design of all-dielectric isotropic micro- or nanoparticles which, when used as structural elements of a metamaterial, can simultaneously provide negative effective electric permittivity and negative magnetic permeability. The particles comprise three dielectric layers with specially adjusted parameters that ensure simultaneous excitation of the electric and magnetic Mie dipole modes. The layer parameters were found by Mie scattering analysis and then verified by the simulations, which confirmed the double-negative behavior of the metamaterial at up to visible light frequencies. The isotropy of such particles suggests the possibility of using them in a double-negative liquid metamaterial.

Effect of Metamaterial Cells Array on a Microstrip Patch Antenna Design

Abstract In this paper, a microstrip patch antenna (MPA) design was developed to verify the performance of a metamaterial cell array (MTM) Capacitive Loaded Loop (CLL) immersed in the substrate. The metamaterial was obtained from metal laminates designed inside a dielectric material, with dimensions carefully calculated to have the effective negative permittivity and permeability, consequently the negative refractive index, in a certain frequency range. In this case, the geometric control of the unit cell parameters allowed its organization in a periodic arrangement to be immersed in the MPA substrate. Simulated and experimental results were obtained and compared for some parameters of the antenna, which showed a good relationship between MTM and MPA performance.

Unbalanced CRLH behavior of ferrite-loaded waveguide operated below cutoff frequency

ABSTRACT This paper proposes a new unbalance composite right/left handed (CRLH) transmission line that consists of a normally magnetized ferrite-loaded rectangular waveguide. The left-handed (LH) behavior of this structure is based on the negative effective permeability of the ferrite material and the negative effective permittivity of the hollow metallic waveguide at the frequencies below the cutoff. By increasing the frequency and passing through the cutoff frequency, this structure behaves as a right handed (RH) transmission line. As a main advantage of the proposed structure, the CRLH response of this transmission line can be tuned by changing the magnetic bias of the ferrite layer. This tunable CRLH transmission line can be used to design a tunable microwave filter or a tunable leaky wave antenna (LWA) with backfire-to-endfire scanning capability. Compare to previous CRLH metamaterial structures, the proposed structure has an easy design and a wide frequency range of tunability.

Tunneling modes induced by interface states in 1D photonic crystals with single negative materials

We investigate the electromagnetic wave propagating in one dimensional photonic crystals with alternating layers of negative permittivity materials and negative permeability metamaterials. The band structure and transmission spectra are obtained. In the negative effective permittivity and negative effective permeability regime, we find new interface modes propagating along the interfaces between the two different media with even and odd parities, respectively. For the oblique incident case, the new propagation modes result in the emergence of a transmission band within the zero-ϕeff gap of these photonic crystals. By adjusting the plasma density or the thickness of the plasma layer, the zero-ϕeff gap as well as the transmission band of the interface modes can be tuned, which can facilitate the design of tunable filters at the microwave frequency range.

Circularly Polarized Array with Enhanced Isolation Using Magnetic Metamaterials

This article proposes a 2 × 2 circularly polarized array with enhanced isolation that could be used in the adaptive anti-jamming system for China’s Beidou Navigation Satellite System (BDS), and a compact dual-band microstrip antenna for GPS and GLONASS is designed at the center part of the array for multiple modes operation. The substrate integrated split ring resonators with negative effective permeability are used as the magnetic metamaterials. Four groups of the magnetic metamaterials are placed between the BDS antenna elements, which could constrain the EM filed in the area of the active element, and then significantly reduce the mutual coupling among the elements. The results tell that the isolation among the BDS elements are improved by more than 10 dB, and the performance of radiation patterns and the axial ratio of each BDS elements are also apparently improved compared to the array without magnetic metamaterials.

Electrodynamic improvements to the theory of magnetostatic modes in ferrimagnetic spheres and their applications to saturation magnetization measurements

Electrodynamic theory applied to the analysis of TEn0p mode resonances in ferromagnetic spheres placed either in metallic cavities or in the free space is compared with Walker-Fletcher's theory of so-called magnetostatic modes. The influence of the diameter of the sample, its permittivity and the permittivity of the surrounding media on the resonance frequencies of a few modes is analyzed. It is shown that the dominant resonances are essentially related either to negative values of the diagonal component of the permeability tensor or, for clockwise circularly polarized magnetic fields, to negative effective permeability. The electrodynamic theory is used to determine the saturation magnetization (Ms) from measured TEn01 frequency differences. Measurements on different samples confirmed that Ms can be determined using an electrodynamic approach with uncertainties of the order of 2% regardless of sample sizes, metal enclosures or static magnetic field values.

ON THE NEW TYPES OF COMPOSITE METAMATERIALS

This paper is the review of our study published in J Appl Phys 115, 233509 (2014) and J Mater Sci 53, 2034 (2018). In it, we examined the possibility of fabricating the metamaterial, which is both gyrotropic and of the simultaneously negative permittivity and permeability. Our idea was to use the three-component mixture of ingredients, where one of them is responsible for the negative effective permeability µeff of hypothetical metamaterial, while all three are responsible for the negative value of effective permittivity εeff. At first we considered the following composite: the first component was the “swarm” of single-domain ferromagnetic nanoparticles, immersed in a mixture of other two, silver and mercury cadmium telluride. Then, as fabrication of the Hg1-x Cdx Te is related to using mercury which is very poisoning, we tried to exclude this material substituting it by Pb1-x Snx Te. Additionally, taking into account that silver is relatively expensive material, we have also used Cu and Al particles as the cheaper substitute of it. We have shown by computer simulations that by the proper fitting of the parameters, e.g., the radius of nanoparticles, their magnetic moments, the relative concentration of ingredients, etc., it is possible to obtain the double-negative metamaterial, that is with negative refraction index in a relatively broad range of temperatures and magnetic fields. The last seems to be very promising in terms of practical applications of metamaterials.

Analysis of Wireless Power Transfer Using Superconducting Metamaterials

A spiral superconducting metamaterial with an effective negative permeability is presented for efficient wireless power transfer (WPT) using magnetic resonant coupling. The S-parameters of superconducting metamaterials unit cell with respect to different resonance frequencies are obtained by the finite element simulation. The effective permeability of the unit cell of superconducting metamaterials is derived by the S-parameter method, and an analysis of the resonant modes is performed by full-wave simulation. The 3 × 3 planar superconducting metamaterials slab is designed by the proposed unit cell to verify their effects in a WPT system. The effects of superconducting on efficiency enhancement are analyzed by both S-parameter and magnetic field distribution simulation. The optimal position of the superconducting metamaterials is acquired by analyzing the transfer efficiency. We show with simulation results that the transfer efficiency of the system can be improved significantly by the superconducting metamaterials through enhanced evanescent wave coupling and with the lower loss properties of the superconductor.

Tunneling of Microwave Radiation through Three-Layer Structures Containing Ferrite Layer

Tunneling of microwave radiation through a symmetric three-layer structure in which the central ferrite layer is interfaced with two layers of a material with negative permittivity is considered. Conditions for perfect tunneling (i.e., transmission with zero reflection) are analyzed for normal incidence. It is shown that the transmittance of the structure can be controlled using external magnetic field that provides magnetization of the ferrite layer. A broad transmission band with a width of several gigahertzes in which almost perfect tunneling is implemented can exist in the frequency range corresponding to the negative effective permeability of the ferrite material.

Туннелирование СВЧ излучения через трехслойные структуры, содержащие ферритовый слой

AbstractTunneling of microwave radiation through a symmetric three-layer structure in which the central ferrite layer is interfaced with two layers of a material with negative permittivity is considered. Conditions for perfect tunneling (i.e., transmission with zero reflection) are analyzed for normal incidence. It is shown that the transmittance of the structure can be controlled using external magnetic field that provides magnetization of the ferrite layer. A broad transmission band with a width of several gigahertzes in which almost perfect tunneling is implemented can exist in the frequency range corresponding to the negative effective permeability of the ferrite material.

Negative effective permeability metamaterial using multi-layer ceramic capacitors

Negative effective permeability metamaterial using multi-layer ceramic capacitors

Design of a modified single-negative metamaterial structure for sensing application

A new topology of modified negative effective permeability material (NEPM) are studied by adding a small similar form with different angles to the basic single split-ring resonators. We report our work conducted on the design, simulation and micro-fabrication of sensing system based on a modified split-ring resonator (MSRR) structure around 140 GHz operation frequency. Once the NEPM cells are excited, the reflection and transmission coefficients from the excitation mechanism can be measured by using quasi-optical technique with normal incidence. It has been shown that our proposal NEPM exhibits a high resonant frequency which is extraordinarily sensitive to the changes of the geometries and the properties of metal shape. By applying the new design of square Plus symbol (+) curve to the SRRs, more condensed size and higher sensitivity can be attained compared to conventional SRRs. Furthermore, the enhancement of sensitivity of the new design is also exposed. The considered sample double defect corner square modified form (DCD2) is fabricated in our lab using a conventional printed circuit board process with 2 μm aluminum and validated by comparing simulated profiles with measurements.