Array Of Complementary Split Ring Resonators Research Articles

A Dual-Scale CSRRs-Based Sensor for Dielectric Characterization of Solid Materials

A compact planar sensor is presented in this letter, which could measure the dielectric constants of solid materials at microwave and sub-THz frequencies, simultaneously. The lower band resonator is based on a complementary split ring resonator (CSRR), fed by a coplanar waveguide line on the board operating at 4.76 GHz, and the upper band sensor is a 3 × 3 CSRR array, excited by a pair of WR-10 open-ended waveguide probes operating at 112 GHz. The upper band CSRR array is nested in the lower band CSRR resonator, but their sensing functions are independent of each other. A coincident sensing area is obtained that needs a testing sample with small volume. Dielectric films composed of polydimethylsiloxane and barium-titanate with different volume fractions are used to verify the performance of the sensor in both frequency scales. The advantages of the proposed design, including compact size, high sensitivity, low sample volume, and dual-scale operation, make it a competitive solution for detecting solid materials with similar dielectric properties in a single frequency band, for application such as the food industry, material quality control, and biomedical.

High-efficiency modulation of broadband polarization conversion with a reconfigurable chiral metasurface

We demonstrate an electrically biased reconfigurable chiral metasurface for controlling the polarization conversion and asymmetric transmission in a broadband manner. The reconfigurable metasurface is constructed with coupled three-layer complementary split-ring resonator (CSRR) arrays and is loaded with tunable electronic components to achieve dynamic control of reconfigurable chiral coupling in the CSRRs by simply tuning the external voltage on the structure. It is found that the polarization conversion in the metasurface can be effectively and continuously tuned in both experiments and simulations in a broadband frequency range. Meanwhile, the reconfigurable metasurface shows an asymmetric transmission (AT) effect in a broadband range for a polarized wave. The proposed reconfigurable chiral metasurface based on the active tuning of connection in the meta-structure with few functional layers is confirmed as an effective strategy for multi-functional polarization manipulation. The reported broadband properties of the chiral metasurface are promising for polarization manipulation in optical bands and applications in wireless communication.

A 4 × 4 Array of Complementary Split-Ring Resonators for Label-Free Dielectric Spectroscopy

In this study, complementary split-ring resonator (CSRR) metamaterial structures are proposed for label-free dielectric spectroscopy of liquids in microplates. This novel combination of an array of sensors and microplates is readily scalable and thus offers a great potential for non-invasive, rapid, and label-free dielectric spectroscopy of liquids in large microplate arrays. The proposed array of sensors on a printed circuit board consists of a microstrip line coupled to four CSRRs in cascade with resonant frequencies ranging from 7 to 10 GHz, spaced around 1 GHz. The microwells were manufactured and bonded to the CSRR using polydimethylsiloxane, whose resonant frequency is dependent on a complex relative permittivity of the liquid loaded in the microwell. The individual microstrip lines with CSRRs were interconnected to the measurement equipment using two electronically controllable microwave switches, which enables microwave measurements of the 4 × 4 CSRR array using only a two-port measurement system. The 4 × 4 microwell sensor arrays were calibrated and evaluated using water-ethanol mixtures with different ethanol concentrations. The proposed measurement setup offers comparable results to ones obtained using a dielectric probe, confirming the potential of the planar sensor array for large-scale microplate experiments.

Dynamic switching of coaxial focus based on terahertz meta-lens.

We propose an active meta-lens that can dynamically switch the coaxial focus on three statuses with the external optical pump. The meta-lens composes of two concentric sets of complementary split-ring resonator (CSRR) arrays, which function at different focal lengths, atop the silicon on sapphire substrate. With specifically structured phase distribution, the meta-lens can form completely separated double foci simultaneously. Through illuminating the internal or external CSRR arrays individually with patterned optical pump, the meta-lens switches to single focus at different points. The proposed design provides a new avenue for developing terahertz multifunctional devices applied in microscope imaging and tomography.

Design, fabrication, and performance analysis of corporate feed filtenna array using complementary split ring resonators

AbstractThis paper presents the design of a unique “corporate feed‐microstrip filtenna array” to be used as “radiating antenna” of a wireless system. The filtenna is a basic patch antenna fed by 50 Ohms microstrip line, loaded with complementary split ring resonators (CSRRs). When the basic patch antenna is made to resonate at 1.8 GHz, it also introduces unwanted spurious radiations appear at 2.82 and 3.46 GHz. Hence, the array of CSRR consisting of five non‐identical CSRRs are loaded, offers the required wideband rejection characteristic, solving the problem of the basic patch antenna. The five CSRRs resonate at 1.97, 2.43, 2.9, 3.28, and 3.72 GHz, offering an overall rejection band from 2 to 4 GHz is obtained. Incidentally there is a signal attenuation introduced by the passive CSRR filter. To compensate the attenuation, an array of filtenna is designed, using corporate feed configuration. The patch antenna, CSRR filter and filtenna are designed and fabricated on an epoxy flame retardant glass substrate (FR4) having a thickness 'h' of 1.6 mm, dielectric constant 'εr' of 4.4 and loss tangent (tan δ) of 0.02. The simulations are carried out using the HFSS software. The performance of the overall receiving filtenna system, having the size of 13.37 cm × 11.94 cm, is satisfactory. Experiments are carried out using vector network analyzer, verifying the software results. This unique radiating antenna exhibits acceptable gain and noise free reception, much required by upcoming 4G/5G wireless applications, rectenna and medical sensor applications.

Fully Metallic Flat Lens Based on Locally Twist-Symmetric Array of Complementary Split-Ring Resonators

In this article, we demonstrate how twist symmetries can be employed in the design of flat lenses. A lens design is proposed, consisting of 13 perforated metallic sheets separated by an air gap. The perforation in the metal is a two-dimensional array of complementary split-ring resonators. In this specific design, the twist symmetry is local, as it is only applied to the unit cell of the array. Moreover, the twist symmetry is an approximation, as it is only applied to part of the unit cell. First, we demonstrate that, by varying the order of twist symmetry, the phase delay experienced by a wave propagating through the array can be accurately controlled. Secondly, a lens is designed by tailoring the unit cells throughout the aperture of the lens in order to obtain the desired phase delay. Simulation and measurement results demonstrate that the lens successfully transforms a spherical wave emanating from the focal point into a plane wave at the opposite side of the lens. The demonstrated concepts find application in future wireless communication networks where fully-metallic directive antennas are desired.

New filter topology with a reflectionless feature based on slow-wave structures loaded with resonator arrays

We report a filter topology with reflectionless properties within the stopband. Based on a periodic-impedance coplanar waveguide (CPW) supporting slow waves and complementary split ring resonator (CSRR) arrays, a reflectionless bandstop filter is realized as an example. Energy within the stopband is dissipated in carefully arranged CSRR arrays instead of being reflected back, maintaining a well impedance match within the full frequency band. The design procedure, simulations, sample fabrication, and experiments are presented to vindicate the proposed reflectionless filter topology. It is foreseeable that based on our methodology, various wireless reflectionless filters can be designed to work from the radiofrequency to the optical band.

Complementary split ring resonator arrays for electromagnetic energy harvesting

This work demonstrates the viability of Ground-backed Complementary Split-Ring Resonator (G-CSRR) arrays with significant power conversion efficiency and bandwidth enhancement in comparison to the technology used in current electromagnetic energy harvesting systems. Through numerical full-wave analysis, we demonstrated correlation between either the resonance frequency or the input impedance of G-CSRR cells with the periodicity of the array. A comparative study of power harvesting efficiency through numerical analysis and laboratory measurement was presented where an array of G-CSRRs is compared to an array of microstrip patch antennas. We demonstrated that a G-CSRR array yields power conversion efficiency of 92%, which represents a significant improvement in comparison to the single G-CSRR reported in our earlier work.

Tunable Left-Handed Characteristics of Ferrite Rectangular Waveguide Periodically Loaded With Complementary Split-Ring Resonators

We propose, for the first time, a tunable left-handed (LH) waveguide consisting of an array of complementary split-ring resonators built on the broad wall of a rectangular waveguide filled with ferrite material. The left-handed behavior is caused by the negative permittivity of the complementary split-ring resonators together with the negative permeability of the transversely magnetized ferrite. The electromagnetic behavior of this structure is studied by means of an equivalent circuit model. From this model, the dispersion relation of the guide is derived and validated numerically by the finite element method. It is shown that this structure has a left-handed frequency band that can be tuned by changing the dc bias magnetic field applied to the ferrite. Compared to previous works, the fabrication requirements on this structure are not critical, which enhances its potential applicability.

CSRRS FOR EFFICIENT REDUCTION OF THE ELECTROMAGNETIC INTERFERENCES AND MUTUAL COUPLING IN MICROSTRIP CIRCUITS

This paper proposes an e-cient microstrip isolator fllter which suppresses the surface and lateral waves (SW and LW) in planar antenna arrays. The structure consists in a double or triple row of periodic and ∞ipped array of subwavelength Complementary Split Ring Resonators (CSRRs). The array of CSRRs is etched on a dielectric substrate backed by a metallic ground plane. These structures can both block the electromagnetic (EM) energy in one direction and guide it along the other transverse direction. In particular, the ∞ipped array of CSRRs presents wider bandgap characteristic (stopband ‚ 20%) than periodic array of CSRRs (» 16%) and conventional array of SRRs (‚ 12%). Then, the metamaterial fllter is inserted between two 6.1GHz probe-fed patch antenna elements separated by a distance of 0:8‚0. Excellent agreements between the simulated and the experimental results are obtained. In fact, a signiflcant reduction of the EM mutual coupling is achieved, more than 24dB, over a wide frequency bandwidth. Moreover, the proposed CSRR structures are compact, low complex and, as printed antennas, are very easy to manufacture. They have numerous applications in MIMO systems and directive phased arrays.