Complementary Ring Resonator Research Articles

Broadband complementary ring-resonator based terahertz antenna for 6G application

Broadband complementary ring-resonator based terahertz antenna for 6G application

High efficiency dielectric resonator antenna using complementary ring resonator for bandwidth enhancement

A complementary ring resonator (CRR) technique is used to improve the bandwidth of the dielectric resonator antenna (DRA) while maintaining other parameters such as the efficiency and the gain. Parametric experiments were conducted in order to demonstrate the suggested antenna's working guideline. The bandwidth of the proposed Antenna is boosted by 769 percent as compared to the antenna without the CRR technique. The proposed antenna has high efficiency of 94 percent and a tiny dimension of around 30×30×12 mm. The suggested antenna has a frequency range from 2.61 to 3.65 GHz, which is suitable for S-band applications. Computer simulation technology (CST) was used to implement the design and obtain the results.

Mutual Coupling Reduction of MIMO Antenna Array Using Meta-FCRR

In order to reduce mutual coupling interference of between both adjacent antenna elements, a practical scheme for metamaterial is reported in this paper. The study shows that the permittivity and permeability of metamaterial based on fold complementary ring resonator (FCRR) can well be anastomosed in electromagnetic field. The antenna array using co-planar waveguide mode to expound the multiple input multiple output (MIMO) performance are further proposed. The results of simulated antenna array with FCRR indicate that the coupling of about 30.5 dB, 14 dB and 20.2 dB are reduced at resonance frequency (at 2.4 GHz, 6.15 GHz and 9.2 GHz). Meanwhile the experimental measure results can meet the simulation data. Additionally, the envelope correlation coefficient (ECC), diversity gain (DG), voltage standing wave ratio (VSWR) are better characteristics in contrasting to without FCRR, making the solution viable for MIMO antenna arrays.

Metamaterial-enhanced infrared attenuated total reflection spectroscopy.

The use of Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) allows solid or liquid samples to be characterised directly without specific sample preparation. In such a system, the evanescent waves generated through total internal reflection within a crystal interact with the sample under test. In this work we explore the use of a mid-infrared metasurface to enhance the interaction between molecular vibrations and the evanescent waves. A complementary ring-resonator structure was patterned onto both silicon and SiO2/Si substrates, and the spectral properties of both devices were characterised using a FTIR-ATR system. Minima in reflectance were observed corresponding to the resonance of the metasurface on the silicon substrate, and to the hybrid resonance of phonon modes and metasurface resonances on the SiO2/Si substrate, in good agreement with simulations. Preliminary experiments were undertaken using mixtures containing trace amounts of butyl acetate diluted with oleic acid. Without the use of a metasurface, the minimum concentration of butyl acetate that could be clearly detected was 10%, whereas the use of the metasurface on the SiO2/Si substrate allowed the detection of 1% butyl acetate. This demonstrates the potential of using metasurfaces to enhance trace chemical detection in FTIR-ATR systems.

An ENG-Inspired Microwave Sensor and Functional Technique for Label-Free Detection of <italic>Aspergillus Niger</italic>

Aspergillus Niger is an airborne fungal pathogen which commonly affects the vegetation. More importantly, the toxins carried by its micrometer-sized spores can be easily inhaled through surrounding atmosphere and causes respiratory diseases in human. Thus, their detection in the surrounding media is important. In this paper, a microwave sensor based on epsilon negative structure is realized. The sensor has two complementary ring resonators in the horn-shape and U-shape. A label-free detection approach is presented in which a functionalized glass slide attached with fungi specific enzyme is mounted on the sensor. The air fringing fields of the complementary rings interact with the fungi immobilized glass slide to produce a change in the resonant frequency. A prototype sensor system is also proposed for low-cost measurement of sensor frequency response into equivalent DC signaling. The proposed sensor is suitable for real-time monitoring of fungal contamination of air in the industrial processes.

Broadband complementary ring-resonator based terahertz antenna.

A broadband terahertz antenna based on complementary ring-resonator is designed. The complementary ring-resonator is etched in the ground plane to stimulate the generation of a new resonant frequency. After loading the resonator, the bandwidth of the antenna can increase by 111% compared with the one without complementary ring. The cavity resonance theory is used to explain the performance and mechanism of the complementary ring resonator. The radius of the complementary ring is the major impact parameter that can significantly determine the new resonant frequency. This work provides a way to design the broadband terahertz antenna.

ELECTROMAGNETICALLY INDUCED ABSORPTION IN METAMATERIALS IN THE INFRARED FREQUENCY

In this paper, the author studies, through numerical simulation, the classical analog of the electromagnetically induced absorption/re∞ection (EIA) in a planar metamaterial structure in the near infrared spectral region. The structure is designed by transforming an electromagnetically induced transparency (EIT) structure into an EIA structure using Babinet's principle. The structure exhibits a coupling between a bright mode (a complementary ring resonator (CRR)) and a dark mode (pair of parallel straight slits) imprinted on a glass substrate. A narrow absorption window, induced in a wide transparent window, is achieved by the structure and the strength of coupling is tuned by the degree of breaking symmetry and relative displacement of the two mode elements. Electromagnetically induced transparency (EIT) is a quantum mechanical phenomenon in which an absorption is transformed into a transparency, and this is associated with strong dispersion that reduces the group velocity (1{3). This phenomena has many potential applications in signal processing, optical flltering and sensing technologies (4{7). The classical analog of the EIT has been achieved and reported by many researchers using a planar metamaterial structures that are generally composed of two metallic elements imprinted on a dielectric substrate. The two elements are metallic resonators that act either as two bright modes or a bright and dark mode. A bright mode element couples strongly with the incident excitation fleld while the dark element does not couple with the incident fleld but couples with the magnetic fleld induced by the bright element. Several EIT metamaterial structures have been employed and reported in the microwave, terahertz and optical frequency regions (8{14). In this paper, we propose a new EIT structure that achieves a more pronounced narrow transparency window sandwiched between two absorption bands compared with a similar structure proposed in (14). Also compared with (14), the structure proposed here is independent of the polarization orientation with respect to the bright mode element. Then we transform this structure into an EIA structure using Babinet's principle (15,16), where a narrow absorption/re∞ection window is sandwiched between two transparency bands. The structures proposed here may be used as obscurant particles that allow the passage of a speciflc window/windows of the electromagnetic spectrum and obscure the neighboring frequencies, for this reason the transmission spectrum will be discussed and addressed for the potential obscurant applications. Although the orientational average response of the structure is what matters, it is of good beneflt to get the behavior in a given orientation. The EIT structure is composed of a metallic ring resonator (RR) which acts as a bright mode and a pair of metallic rods that act as a dark mode. Here we overlap the RR wide antenna resonance and the narrow line width quadrupole rod resonance, which in turn produces the EIT-like efiect. The structure is transformed into an EIA structure by replacing the metallic RR and the pair of rods resonator with complementary ring resonator (CRR) and

Fractal-Shaped Metamaterials and Applications to Enhanced-Performance Devices Exhibiting High Selectivity

Novel single negative metamaterial (MTM) transmission lines (TLs) are presented and studied in microstrip technology. They consist of a host TL in the conductor strip and a fractal-shaped complementary ring resonator (CRR) etched in the ground plane. Two types of fractal-shaped CRR are involved including the Moore and Hilbert. It is found that fractal perturbation in CRR results in lower and more transmission zeros in comparison with conventional CRR using nonfractal geometries. The single negative-permeability or -permittivity of these MTM TLs which associated with the resultant multitransmission zeros occurs by turns and should benefit devices with high selectivity requirement. Potential application of these MTM cells are illustrated by two examples, one is the microstrip stepped-impedance transformers (SIT) operating at 3.5 GHz with two edged attenuation poles to introduce selectivity; the other one is the Hi-Lo microstrip low-pass filter (LPF) with cutoff frequency 2.5 GHz exhibiting improved selectivity (77.3 dB/GHz). By constructing the low-impedance sections as hybrid prefractal shape and crown square, both the SITs and LPF obtained additional bandwidth enhancement and good matching. Consistent results between simulation and measurement have confirmed the design concept.

Hilbert-shaped complementary ring resonator and application to enhanced-performance low pass filter with high selectivity

In this article, a novel single negative metamaterial (MTM) transmission line (TL) consisting of a Hilbert-shaped complementary ring resonator (H-CRR) on the ground plane is initially presented and studied in depth. Then based on the proposed MTM TL, a novel six-section Hi-Lo microstrip low-pass filter (LPF) with a cut-off frequency 2.5 GHz is developed, fabricated, and measured. Measurement results indicate that: by integrating H-CRR, the selectivity has been significantly improved which is 77.3 dB/GHz due to the single negative permittivity; by etching a crown square on low-impedance section, the bandwidth characterized by 20 dB return loss was obviously enhanced by 26.2% and the maximal sidelobe level of in-band return loss was reduced from 22 to 24.6 dB. What' more, the developed LPF achieved a 36.3% size reduction with respect to its conventional counterpart. The design concept, which was confirmed by the measurement data, is of practical value and can be popularized in other microwave devices where high selectivity is requested. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.

Characteristics of complementary ring-resonator add/drop filters modeling by using graphical approach

In this paper, the filtering characteristics of the two kinds of complementary ring-resonator add/drop filters are modeled and investigated. A graphical approach with signal flow graph is employed here for the analytical derivation of the optical transfer functions in Z-domain of filters. The characteristics of the complementary circuits including the transmittance and group delay of the drop port with respect to the input port are simulated. The present analysis is restricted to directional couplers characterized by two parameters, the power coupling coefficient κ and power coupling loss γ. Explicit expressions for the phase delay, the full-width at half maximum, the Q-factor and the finesse are also given. Using appropriate coupling coefficients, the filtering characteristics can be optimized.