Layer Of Split-ring Resonators Research Articles

Advancing frequency fine-tuning: a theoretical approach to a novel metamaterial-inspired Bi-layer resonator

This study presents a novel adjustable device designed for precise frequency tuning within the S-band of the microwave spectra. In addition to the geometrical design and dielectric behavior of the resonator, this study identifies an influential governing factor that affects the resonant frequency. The proposed method utilizes a bi-layer split ring resonator configuration implemented on a FR4 epoxy substrate with a dielectric constant of 4.4. The substrate is coated with a 35 μm- thick layer of copper and patterned as split ring resonator. Frequency tuning was achieved by spatially separating the two parallel split ring resonators in increments of 800 μm. This innovative approach allows for a shift in the resonant frequency range from 2.36 GHz to 2.61 GHz, covering the desired frequencies in the S-band for applications such as biomedical and wireless communications. This study demonstrates that the alteration in the frequency domain is dependent on the distance between the two layers of split ring resonators. Compared to existing frequency tuning mechanisms, this adjustable bi-layer split ring resonator offers numerous advantages including simplicity, cost-effectiveness, and high sensitivity. The research employs a combination of finite-element simulations and theoretical analysis to validate the findings.

Terahertz metamaterial perfect absorber with continuously tunable air spacer layer

We present a comprehensive investigation of a continuously tunable metamaterial perfect absorber operating at terahertz frequencies. In particular, we investigate a three-layer absorber structure consisting of a layer of split ring resonators and a metallic ground plane, with a central layer consisting of a mechanically tunable air-spaced layer. The absorber was characterized using terahertz time-domain spectroscopy in reflection (at normal incidence) as a function of spacer thickness from 0 to 1000 μm. Our experimental measurements reveal the detailed evolution of the absorption bands as a function of spacing, in excellent agreement with analysis using interference theory and simulation. Our Fabry-Pérot-like structure provides an avenue for achieving massive tunability in metamaterial absorber devices.

Wideband Low-Loss Magnetoelectric Dipole Antenna for 5G Wireless Network With Gain Enhancement Using Meta Lens and Gap Waveguide Technology Feeding

In this paper, a wideband magnetoelectric (ME) dipole antenna excited by a slot coupled to a fork-shaped printed ridge gap waveguide is proposed. To enhance the antenna gain, a meta lens consists of three layers of split ring resonators (SRRs) are integrated horizontally in front of the ME dipole antenna. Each slab contains a $3 \times 7$ array of SRR unit cells. The matching bandwidth is improved as a secondary effect of the lens. A $1 \times 4$ array is designed to provide more gain by adjusting the lens between the edge elements of the four-element array. The antenna is fabricated and tested. The measured results show that −10 dB $S_{11}$ is obtained between 26.5 and 38.3 GHz. The measure realized gain is better than 15 dBi over the frequency range of 28–38 GHz. A 90% radiation efficiency at 30 GHz is achieved.

FILTERING LENS STRUCTURE BASED ON SRRS IN THE LOW THZ BAND

A flltering lens for conical horns based on Metamaterials is presented. The paper focuses on a millimeter wave application. The metamaterial structure is composed of a printed layer of Split Ring Resonators (SRRs) on a substrate. The structure is used as a superstrate on the horn aperture. When the SRRs are excited, a fllter performance arises preventing radiation in the desired frequency bands. Besides the flltering property, also a lens behavior is achieved. In this way larger gain can be achieved in both E and H planes, reducing the 3dB beamwidth. A 6% i3dB stop band is achieved from 73.3GHz to 85.7GHz. Symmetrisation of the radiation pattern up to 3dB is accomplished and the focalization efiect is achieved by emulating a hyperbolical-plane lens. Thus, a simplifled system based on a conical horn can be designed by unifying the fllter and lens in one electromagnetic element.

Stopband Phenomena in the Passband of Left-Handed Metamaterials

Stopband phenomena are reported in the passband of left-handedmetamaterials. The samples with linear defect are designed by removingone layer of split ring resonators (SRRs). It is shown that theleft-handed transmission peaks have a distinct transform with therelative deviation of the SRRs centre from the wire centre δ,from a single left-handed peak, double left-handed peaks with differentmagnitude to no transmission peak, i.e. left-handed properties ofmetamaterials disappear. Numerical simulation shows that the change ofδ makes the effective permeability shift at a frequency range,where stopband occurs. It is thought that the stopband in left-handedpassband is due to the symmetry breaking between SRRs and wires in themetamaterials.

Magnetic response of split-ring resonators in the far-infrared frequency regime

We report on the fabrication, through photolithography techniques, and the detailed characterization, through direct transmission measurements, of a periodic system composed of five layers of photolithographically aligned micrometer-sized Ag split-ring resonators (SRRs). The measured transmission spectra for propagation perpendicular to the SRRs plane show a gap around 6 THz for one of the two possible polarizations of the incident electric field; this indicates the existence of a magnetic resonance, which is verified by detailed theoretical analysis. To our knowledge this is the first time that a system of more than one layer of micrometer-sized SRRs has been fabricated. The measured optical spectra of the Ag microstructure are in very good agreement with the corresponding theoretical calculations.

Reflection and phase of left-handed metamaterials at microwave frequencies

We experimentally investigated the reflection and phase of the left-handed metamaterials (LHMs) in a rectangular waveguide for the normally incident microwave. The samples are constructed by periodically arraying the copper split ring resonators (SRRs) and wires. It is found that for the LHMs with one-layered SRRs, a reflection peak with a depth of −3.3 dB (i.e. with the reflectivity of 47%) occurs in the left-handed range. The dependence of reflection phase on the frequency is different from that of the transmission phase, and the reflection phase has an inflexion at the reflection peaks. For the LHMs with three-layered SRRs, the depth of reflection peak increases with the row number, i.e. reflection is weakened, and the reflection peak has a shift with respect to the left-handed transmission peak. It is thought that the interaction between different layers of SRRs is the reason of the shift.