Dual Split Ring Resonator Research Articles

TeraHertz wideband cross-polarization conversion metasurface based on double split-ring resonator

This paper presents the design and analysis of a switchable metasurface for wideband cross-polarization conversion in the terahertz (THz) regime. A dual-split ring resonator (DSRR) connected with a narrow metallic strip is used to achieve wideband cross-polar conversion from 2–4.85 THz. Till date, this is the highest reported bandwidth for a THz cross-polarization conversion metasurface. This wideband operation is achieved by exciting the closely spaced resonant frequencies of the DSRR occurring at 2.22 THz, 2.78 THz, 3.96 THz, and 4.68 THz. Additionally, photoconductive silicon is integrated in between the gaps of DSRR for continuous tuning in the operating frequency range. The proposed polarization converter has a compact unit cell size of 0.29 λ0, where λ0 is the free space wavelength at the lowest cut-off frequency. The proposed cross-polarizer achieved excellent polarization conversion ratio (PCR) of ≥ 94% over the entire bandwidth and exhibits wide angular stability up to 45∘. With these advantages, the proposed metasurface has potential applications in THz communication systems, especially in the field of imaging and sensing.

Tunable terahertz slow light with hybrid coupling of a magnetic toroidal and electric dipole metasurface

We present a hybrid coupling scheme of a magnetic toroidal and electric dipole metasurface with suppressed radiation loss, which can produce the tunable plasmon-induced transparency (PIT) with an enhanced slow-light effect in the terahertz regime. The terahertz metasurface is constructed by nesting a dual-split ring resonator (DSRR) inside a ring resonator (RR) to exploit the destructive coherence of hybrid electromagnetic mode coupling at the PIT resonance. The polarization-dependence excitation performs the active tunability of a PIT-induced group slowing down by rotating the polarization angle, experimentally achieving a maximum group delay of 3.5 ps. Furthermore, the modified terahertz metasurface with a four-split ring resonator (FSRR) nested in an RR is prepared on photoconductive silicon, demonstrating the pump-controllable group delay effect at the PIT resonance. The large group delay from 2.2 to 0.9 ps is dynamically tunable by adjusting the pump power. The experimental results are in good accord with the theoretical simulations.

Circularly polarized array antenna based on dual split ring resonators (DSRRs)

Abstract A wideband circularly polarized (CP) array antenna has significant importance in modern communication system. In this paper, we proposed a wide band CP array by combing dual split ring resonators (DSRRs) to dual layer microstrip antenna. A 2 × 2 dual-layer microstrip antenna array is used to radiate wide band linearly polarized wave, and the 3 × 3 four-layer DSRRs is used as an external polarizer which converts linearly polarized wave to circularly polarized wave at distinct frequencies. The proposed array achieves an impedance bandwidth of 20% ranging from 4.57–5.57 GHz and AR bandwidth of 16.83% ranging from 4.57–5.41 GHz. The prominent futures of the proposed array are wide impedance bandwidth on desired frequencies. This new concept is theoretically and experimentally investigated to evaluate the performance of the proposed array, which allows a better prospect for the application of radar and satellite communication systems.

Analyses of Combined DSRR and EBG Structures Over SIW and HMSIW for Obtaining Band Pass Response

Effect of combination of dual split ring resonator and electromagnetic bandgap structures over substrate integrated waveguide and half-mode substrate integrated waveguide (HMSIW) transmission line sections to obtain band pass property is presented in this paper. Greater control over the insertion loss (IL) within the transmission pass-band as well as the stop band isolation of the BPF is obtained by detailed study on several parameters of the proposed structure. The proposed design is further miniaturized using HMSIW technique keeping other useful parameters unaltered. The BPF structure is designed considering Neltec NH9320 material of thickness 30 mils and dielectric constant of 3.2. The filter achieves very small IL and wider bandwidth covering major part of microwave Ku frequency bands (12–18 GHz) with good stopband isolation. The designs are fabricated and measured results come with close approximation with the simulated outcomes.

Design and Fabrication of 3D Printed Reconfigurable Metamaterial-inspired Structures

Abstract In this paper, 3D printing is used as an alternative manufacturing technique to fabricate metamaterial-inspired RF structures for liquid profiling. A dual split-ring resonator (SRR) based sensor tag is designed and integrated with a microfluidic channel for detecting different liquid samples. The sensor is 3D printed using a high-temperature resin and metallized using a custom developed metal patterning process. The sensor requires a very small volume of 8.6 μL of sample under test for detection. The resonance frequency of the SRR changes with change in sample loading and the shift is monitored for sample profiling. Different volatile organic compounds are introduced and the shift is monitored demonstrating the sensitivity of the proposed tag. The low-cost, real-time nature of the tag makes it an ideal choice for monitoring liquids along the supply chain.

A miniaturized dual-band ZOR antenna using epsilon negative transmission line loading

A miniaturized dual-band CPW-fed metamaterial antenna is presented and developed in this paper. Zeroth-order mode is originated by realizing open-ended composite right/left-handed transmission line. A dual split ring resonator is introduced to obtain another mode. The antenna is operated in the frequency region 1.60–1.64 and 2.76–2.79 GHz. Shunt inductance is offered by means of thin stripline connecting ground planes. It is demonstrated that by applying metamaterial loading (thin stripline) proposed antenna is capable to achieve 51.9% miniaturization with respect to the antenna without metamaterial loading. The presented antenna has an electrical size of 0.162 λ0 × 0.108 λ0 × 0.008 λ0 at f0 = 1.62 GHz. The antenna exhibits simulated gain of 1.05 and 2.59 dB in the broadside directions at 1.62 and 2.78 GHz, respectively. Beside that this antenna offers dipolar-type pattern and omnidirectional pattern in the xz-and yz-planes respectively at both bands, which is beneficial to be used in modern wireless applications. The design methodology of the proposed antenna is described with the help of current distributions and parametric analysis.

Novel Multi-Broadband Plasmonic Absorber Based on a Metal-Dielectric-Metal Square Ring Array

We numerically analyzed a simple and novel design of multi-broadband plasmonic absorber which consists of a planar array of thin gold square ring structures on dielectric/metal substrate. Several optimized designs of the metasurface screen are proposed to absorb wide range of the electromagnetic spectrum, which includes single ring, single split ring, ring inside split ring, and dual split ring resonators, respectively. Moreover, simulation results demonstrate that by changing the dimensions of the metasurface screen and the middle dielectric spacer, multi-broadband absorption resonant peaks having absorption bandwidth of about 570 nm above 50% absorption and bandwidth of about 93 nm above 90% absorption are obtained in the visible and near-infrared regime. The proposed design has potential applications in imaging and detection.

Multiple band notch and Dual-Band filter using concentric and contiguous split ring resonators (CCSRR)

A novel, compact, multiple band notch filter and dual-band filters are presented. Contiguous and concentric split ring resonators (SRRs) and Ring resonator are used to achieve desired multiple narrow band notches. These band notches have been designed to avoid the undesired interference between co-existing wireless channels. The dual-band filter consists of a dual SRR having splits on the opposite sides with Inductive Short Stub Split Ring Resonator. Even- and odd-mode analyses have been performed to calculate the resonance frequencies. Three transmission zeros are achieved between the two passbands by both dominant electric or dominant magnetic coupling and also cancellation effect of electric and magnetic coupling. This results in high passband selectivity and improved band-to-band isolation. The proposed dual-band pass filter has the advantages of being compact with more degree of freedom to achieve desired passbands by controlling the electric and magnetic coupling independently. Proposed filter is implemented on RT/Duroid 5880 (εr = 2.2) substrate of thickness 0.785 mm and surface area of 0.27λg × 0.27λg. Insertion loss of the proposed filter at notch bands is high (>13 dB) and low (<0.8 dB) in pass band. Measured results correlate with the simulated results and thus ensure that the proposed filter is a suitable candidate to mitigate interference caused by the co-existing and emerging wireless technologies.

Multifunctional Microstrip Array Combining a Linear Polarizer and Focusing Metasurface

Although microstrip reflectarrays/transmitarrays have been extensively studied in the past decades, most previous designs were confined to monofunctional operations based on either transmission or reflection. In this communication, we propose a scheme to design multifunctional arrays that can simultaneously exhibit the functionalities of a reflectarray and a transmitarray on the basis of the appealing feature of a polarizer we discovered (i.e., constant phase difference between its cross-polarization transmission and copolarization reflection within a broadband). To demonstrate the proposed scheme, we designed and fabricated a multifunctional device comprising a $15 \times 15$ array of twisted complementary dual-split ring resonators, each carefully designed to exhibit the desired transmission phase satisfying a parabolic distribution. Feeding the device by a Vivaldi antenna at its focus, we numerically and experimentally demonstrated that our system functioned as a directive emitter working in a transmission/reflection mode for cross-polarization/copolarization radiation at low/high frequencies, and it can radiate directively in both directions with different polarizations at intermediate frequencies. The half-power beamwidth of the array antenna was $\sim 15^{\circ }$ , which is 40° narrower than that of a bare Vivaldi antenna. Moreover, the gain was higher than 13 dB in all cases studied, which is at least 7 dB higher than that of the Vivaldi antenna.

Phase Modulation Using Dual Split Ring Resonators

In this paper, we studied phase modulation numerically using metamaterials such as stacked structures of dual split ring resonators (DSRRs). To demonstrate the modulation, a vertical and a planar design were considered, where the wave vectors were parallel and perpendicular to the proposed structures creating 70 degrees and 80 degrees of phase change, respectively. In both of the designs modulation was brought about by changing the effective index of the structure through switching between the open and short states of the DSRRs while maintaining high transmission. One of the attractive features of our design was the thin layers of DSRRs, where for the vertical and planar models the DSRRs layers were 5 mm and 2.28 mm respectively. The numerical results obtained by simulation matched well with the theoretical prediction.

EXPERIMENTAL DEMONSTRATION OF METAMATERIAL-BASED PHASE MODULATION

Phase modulation is critical due to its applicability in varied RF devices such as phased array antennas, radars to name a few. In this paper, we report experimental data on phase modulation in the X-band frequency using tunable metamaterials such as a planar design of stacked dual split ring resonators (DSRRs) of 3 mm thickness at 8.5 GHz. Modulation was brought about by switching between the open and closed states of the rings causing a net change in the effective refractive index and thereby producing a phase variation. One and two dimensional free-space scanning experiments were carried out where a phase modulation of 62 degrees was demonstrated. The measured data matched well with the numerically simulated results.