Multiple Split Ring Resonators Research Articles

A Compact Thin-Film Sensor Based on Nested Split-Ring-Resonator (SRR) Metamaterials for Microwave Applications

In this paper, we propose a novel metamaterial-based microwave thin-film sensor that incorporates multiple split ring resonators in a compact nested structure. The special feature of the proposed sensor is that the nested SRR structure has more split gaps than the classical SRR structure. The sensing performances are numerically investigated using a three-dimensional full-wave electromagnetic solver based on the finite integral method. The simulated results show that comparing with the traditional SRR structure, the nested SRR structure has low operating frequency (corresponding to a miniaturization by 22.6% in size), low nonlinearity error, and high sensitivity. At the same time, these results demonstrate that our metamaterial design may be well suited for biosensing. Moreover, the proposed structures provide more design flexibility. It can be extended to the terahertz frequency range, which will open a new route for metamaterial application toward sensing of chemical and biomedical molecules with different mass concentrations as well as detecting chemical reaction.

개방 루프 다중 분할 링 공진기를 이용한 0.13 um 전압 제어 발진기 설계

In this paper, a novel voltage-controlled oscillator(VCO) using the open loop multiple split ring resonator(OLMSRR) is presented for improving the phase noise, implemented in 130 nm CMOS technology. Compared with the conventional CMOS LC resonator, the proposed CMOS OLMSRR has the larger coupling coefficient value, which makes a higher Q-factor, and has improved the phase noise of the VCO. The proposed CMOS VCO based OLMSRR has the phase noise of -99.67 dBc/Hz @ 1 MHz in the oscillation frequency. Compared with the VCO using the conventional CMOS LC resonator and the proposed VCO using the CMOS OLMSRR structure has been improved in 7 dB. The prototype 24 GHz CMOS VCO is implemented in 130 nm CMOS and occupies a compact die area of .

Nested Metamaterials for Wireless Strain Sensing

We designed, fabricated, and characterized metamaterial-based RF-microelectromechanical system (RF-MEMS) strain sensors that incorporate multiple split ring resonators (SRRs) in a compact nested architecture to measure strain telemetrically. We also showed biocompatibility of these strain sensors in an animal model. With these devices, our bioimplantable wireless metamaterial sensors are intended, to enable clinicians, to quantitatively evaluate the progression of long-bone fracture healing by monitoring the strain on the implantable fracture fixation hardware in real time. In operation, the transmission spectrum of the metamaterial sensor attached to the implantable fixture is changed when an external load is applied to the fixture, and from this change, the strain is recorded remotely. By employing telemetric characterizations, we reduced the operating frequency and enhanced the sensitivity of our novel nested SRR architecture compared to the conventional SRR structure. The nested SRR structure exhibited a higher sensitivity of 1.09 kHz/kgf operating at lower frequency compared to the classical SRR that demonstrated a sensitivity of 0.72 kHz/kgf. Using soft tissue medium, we achieved the best sensitivity level of 4.00 kHz/kgf with our nested SRR sensor. Ultimately, the laboratory characterization and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> biocompatibility studies support further development and characterization of a fracture healing system based on implantable nested SRR.

Radiation Properties and Coupling Analysis of a Metamaterial Based, Dual Polarization, Dual Band, Multiple Split Ring Resonator Antenna

We demonstrate an electrically small antenna that operates at two modes, which correspond to two orthogonal polarizations. The antenna was single fed and composed of perpendicularly placed metamaterial elements and a monopole. One of the metamaterial elements was a multi split ring resonator (MSRR), and the other one was a split ring resonator (SRR). The elements' physical sizes were the same while the electrical sizes differed nearly by 1 GHz. This variety resulted in the dual mode operation at the 4.72 GHz and 5.76 GHz frequencies. When the antenna operated in the MSRR mode at 4.72 GHz for one polarization, it simultaneously operated for the SRR mode at 5.76 GHz, but for the perpendicular polarization. The efficiencies of the modes were 15% and 40%, and electrical sizes were λ/11.2 and λ/9.5, correspondingly. Finally, we numerically demonstrate the effect of coupling of the two resonators on the operation frequencies.

Electric and magnetic responses in the multiple-split ring resonators by electric excitation

We experimentally demonstrate both the electric and magnetic responses from the multiple-split-ring resonators (MSRRs) via normal reflectance measurements. All the fabricated MSRRs exhibit electric resonances under electric couplings but the magnetic resonances are only excited in MSRRs with odd numbers of splits from the asymmetrically electric couplings. Furthermore, the dependence of split numbers on the resonant positions and strengths is also investigated. In addition, the coupling mechanism of correlated resonances in the MSRRs can be well elucidated by the concept of standing-wave plasmonic resonances. Such scalable MSRRs present the tailored electromagnetic responses at desired frequencies, paving ways toward integrated nanophotonic applications.

Low‐phase noise VCO using output matching network based on novel harmonic control circuit

AbstractIn this article, a novel voltage‐controlled oscillator (VCO) using the output matching network based on the novel harmonic control circuit is presented for reducing the phase noise without the reduction of the frequency tuning range. The phase noise suppression is achieved by the harmonic control circuit having the short impedances for the second‐ and third‐harmonic components. The high‐Q resonator has been used for reducing the phase noise but has the problem that the frequency tuning range has been also reduced by the increase of the Q value of the resonator. However, the frequency tuning range of the proposed VCO has not been reduced because the phase noise has been reduced without the high‐Q resonator. The microstrip square open loop multiple split ring resonator has been used with the proposed harmonic control circuit for better phase noise property. The phase noise of this VCO has been −127.5 to −126.33 dBc/Hz @ 100 kHz in the tuning range, 5.744–5.865 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1838–1842, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24510

Studies on Multiple-inclusion Magnetic Structures Useful for Millimeter-Wave Left-Handed Metamaterial Applications

Analytical model equations have been derived from the fundamental principles for effective relative permeability of circular multiple-inclusion magnetic structures like multiple split-ring resonators, spiral resonators and labyrinth resonators, useful for LHM applications. Tailoring of their resonant frequency, their bandwidth and their effective negative permeability is investigated. Thereafter, a suitable structure for operation at millimeter-wave frequency has been explored. When such microstructures are used in a periodic array, the dependence of resonant frequency and bandwidth on the lattice parameter has further been studied.

Microstrip Square Open-Loop Multiple Split-Ring Resonator for Low-Phase-Noise VCO

In this paper, we present a novel voltage-controlled oscillator (VCO) using the microstrip square open-loop multiple split-ring resonator for reducing the phase noise of VCO. We realize the microstrip square open-loop multiple split-ring resonator by combining the multiple split-ring resonator with the microstrip square open-loop structure. Compared with the conventional microstrip square open-loop resonator, the microstrip square open-loop multiple split-ring resonator has strong coupling between the microstrips of the open-loops with the multiple split-ring resonators, which makes for a high Q value of the resonator. The phase noise and the tuning range of the proposed VCO are -124.5 to -122.0 dBc/Hz at 100 kHz and 5.746 to 5.84 GHz. The figure-of-merit (FOM) of this VCO is -203.96 to -201.6 dBc/Hz at 100 kHz in the same tuning range.

Employment of Artificial Magnetic Metamaterials to Effectively Reduce the Back-Lobe of Patch Antennas

In this article, we present the employment of a proper set of artificial magnetic inclusions to dramatically reduce the back-lobe of patch antennas. The layout consists of a regular microstrip antenna surrounded by split-ring resonators (SRRs). These artificial magnetic inclusions are designed in order to resonate at the antenna operating frequency so that the surface waves are blocked and the front-to-back ratio of the antenna is increased. A numerical investigation of the near-zone magnetic field is conducted in order to propose a suitable arrangement of the SRRs around the antenna, aimed to obtain an effective 2D-isotropic suppression of the surface waves. Since inclusions located at the periphery of the structure resonate at a higher frequency, multiple split-ring resonators (MSRRs) are also used in order to reduce the resonant frequency of the peripheral inclusions. Finally, full-wave numerical simulations confirming the effectiveness of the proposed design and showing how the resonating artificial magnetic inclusions surrounding the antenna effectively suppress the back-lobe are presented.

Equivalent-Circuit Models for the Design of Metamaterials Based on Artificial Magnetic Inclusions

In this paper, we derive quasi-static equivalent-circuit models for the analysis and design of different types of artificial magnetic resonators-i.e., the multiple split-ring resonator, spiral resonator, and labyrinth resonator-which represent popular inclusions to synthesize artificial materials and metamaterials with anomalous values of the permeability in the microwave and millimeter-wave frequency ranges. The proposed models, derived in terms of equivalent circuits, represent an extension of the models presented in a recent publication. In particular, the extended models take into account the presence of a dielectric substrate hosting the metallic inclusions and the losses due to the finite conductivity of the conductors and the finite resistivity of the dielectrics. Exploiting these circuit models, it is possible to accurately predict not only the resonant frequency of the individual inclusions, but also their quality factor and the relative permeability of metamaterial samples made by given arrangements of such inclusions. Finally, the three models have been tested against full-wave simulations and measurements, showing a good accuracy. This result opens the door to a quick and accurate design of the artificial magnetic inclusions to fabricate real-life metamaterial samples with anomalous values of the permeability.

A compact ultra‐wideband slot antenna with multiple notch frequency bands

AbstractA compact printed ultra‐wideband slot antenna with superior multiple band‐notched characteristics is presented. The size of the UWB slot antenna is minimized, and multiple split ring resonators are printed inside the inner patch to achieve multiple notch frequency bands. As a practical example, a UWB antenna (working from 2.4 to 10.1 GHz) etched with two sets of split ring resonators are fabricated and its VSWR and radiation patterns are measured. The measured results agree well with the simulation, and the two notch frequency bands are centered at 3.65 and 5.75 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3056–3060, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22892

Design of Spiral and Multiple Split-Ring Resonators for the Realization of Miniaturized Metamaterial Samples

We present the design of miniaturized resonant inclusions to be employed in the practical realization of metamaterial samples with anomalous values of the real part of the permeability. Such inclusions, in fact, can be employed in the design of both mu-negative (MNG) materials and artificial magnetodielectrics (with negative and high-positive values of the real part of the permeability, respectively). The inclusions here considered are the multiple split-ring resonators (MSRRs), that represent a straightforward extension of the commonly used split-ring resonators (SRRs), and the spiral resonators (SRs), that enable a greater miniaturization rate. Some physical insights on the resonance mechanism and on the inherent saturation of the resonant frequency when increasing the number of the rings of the MSRRs and the number of the turns of the SRs are given in the paper. New and accurate analytical design formulas, based on a quasi-static model, for both MSRRs and SRs are derived and tested through a proper comparison with the existing formulas and full-wave numerical results. Both MSRRs and SRs are shown to be useful to reduce the electrical dimensions of the resonant inclusions when synthesizing artificial metamaterials.