Open Split Ring Resonator Research Articles

Highly Sensitive Phase-Variation Microwave Sensor Operating in Transmission Based on an Open Split Ring Resonator (OSRR)

Highly Sensitive Phase-Variation Microwave Sensor Operating in Transmission Based on an Open Split Ring Resonator (OSRR)

Bound states in the continuum driven by multiple modes for high Q refractive index sensing in metasurfaces

Bound states in the continuum (BICs) have attracted much attention in the field of refractive index sensing. In this paper, we propose multi-mode symmetry-protected BICs (SP-BICs) and the Freidrich–Wintgen BIC (FW-BIC) in terahertz metasurfaces consisted of periodic open split ring resonators. Firstly, multi-mode SP-BICs are subject to the magnetic dipole, electric dipole (ED), and toroidal dipole (TD) modes. Moreover, we demonstrate the FW-BIC by strongly coupling the electric quadrupole and TD modes. For micron film sensing of the ED mode, simulation results show that the Q factor, the sensitivity of sensing (S), and the corresponding figure of merit can simultaneously reach 1561, 141 GHz/RIU, and 306, respectively. Our quasi-BICs have potential applications in micro-sensing.

Dual-Band/Dual-Mode Rat-Race/Branch-Line Coupler Using Split Ring Resonators

A novel dual-band/dual-mode compact hybrid coupler which acts as a dual-band branch-line coupler at the lower band and as a rat-race coupler at the higher band is presented in this paper. One of the most interesting features of the proposed structure is that outputs of the proposed coupler in each mode of operation are on the same side. This unique design is implemented using artificial transmission lines (ATLs) based on open split ring resonators (OSRR). The low-cost miniaturized coupler could be operated as a dual-band 90° branch-line coupler at 3.3 and 3.85 GHz and 180° rat-race coupler at 5.3 GHz. The proposed coupler could be utilized in the antenna array feeding circuit to form the antenna beam. The structure’s analytical circuit design based on its equivalent circuit model is provided and verified by measurement results.

Microfluidic reflective-mode differential sensor based on open split ring resonators (OSRRs)

AbstractThis paper proposes a differential sensor based on a pair of open split ring resonators (OSRR) operating in reflection. The output signal is thus the differential reflection coefficient of both resonators, intimately related to their dielectric loading. Thus, for identical loads in both sensing resonators, the individual reflection coefficients are equal, thereby providing an ideally null output signal. By contrast, when unequal dielectric loads truncate the symmetry, the reflection coefficients are different, resulting in a differential output signal related to the level of asymmetry. In order to ease the measurement of the output signal, a rat-race hybrid coupler is used. The OSRR sensing loads are connected to the coupled ports of the hybrid coupler, whereas the input signal is injected to the Δ-port, and the output signal is collected at the isolated port (Σ-port). By this means, the output signal, i.e. the differential reflection coefficient between both sensing loads, is obtained from the transmission coefficient of a simple two-port structure. For experimental validation purposes, the sensor is applied to the measurement of isopropanol content in aqueous solutions, and for that purpose, the sensitive regions are equipped with microfluidic channels.

Tunable terahertz metamaterial absorber actuated by thermomechanical bimaterial microcantilevers.

We report a tunable terahertz (THz) metamaterial absorber (MA) actuated by thermomechanical bimaterial microcantilevers. The THz MA, which is suspended on a silicon substrate by the bimaterial microcantilevers, is a sandwich structure with a bottom Al ground plane, middle air and SiNx dielectric layers, and a top Al rotationally symmetric open split ring resonator. Upon application of a current, a Ti heating resistor integrated on the SiNx dielectric layer induces the bimaterial microcantilevers to bend, causing the air layer thickness to change, modulating the absorption of the THz MA. The tunable THz MA exhibited a relative modulation depth of absorption of 28.1% at 0.69 THz and a thermomechanical sensitivity of 0.12°/K. This tunable THz MA has potential applications in filtering, modulation, control, and THz imaging.

Application of the Scattering Bond Graph Methodology for Composite Right/Left Handed Transmission Lines

The approach of the metamaterials based on the theory of transmission lines has an influence on the development of the radiofrequency domain, so the types and techniques of elaboration of these artificial lines are quite diversified. This paper will present two models of Artificial Transmission Line CRLH (Composite Right Left Handed) composed of a combination of resonators OSRR (Open Split Ring Resonators) and OSCRR (Complementary Open Split Ring Resonators). This paper will also show how the Scattering Bond Graph (SBG) study methodology allows to provide electromagnetic simulation results (Scattering parameters, phase response) more conducive to Bond Graph (BG) modeling, and will prove the possibility of having the most perfect line (solved the problem of impedance adaptation) and better understanding of the behavior of radiofrequency systems.

Compact Bandstop Half-Mode Substrate Integrated Waveguide Filter Based on a Broadside-Coupled Open Split-Ring Resonator

A shunt RLC resonant circuit obtained from a broadside-coupled open split ring resonator (BC-OSRR) is proposed. This BC-OSRR cell allows a parallel connection with planar waveguides. Hence, it has been applied to a half-mode substrate integrated waveguide (HMSIW) section. The analysis of the frequency response and electromagnetic field distribution of the HMSIW structure loaded with an appropriate BC-OSRR cell have shown two main behaviors. The first characteristic is a high-pass frequency response inherent to the HMSIW and the second is a transmission zero in the passband of the HMSIW, which is due to the resonance of the BC-OSRR cell. The First- and second-order prototypes have been designed and fabricated. The measured bandstop HMSIW filters using BC-OSRR achieve a 3-dB stopband bandwidth around 10% with more than 21-dB insertion loss. This BC-OSRR cell with low undesired radiation loss can be a new alternative for the implementation of compact bandstop filters in the planar technology.

A Metamaterial Inspired Compact Open Split Ring Resonator Antenna for Multiband Operation

In this work, a metamaterial inspired compact open split ring resonator (OSRR) antenna is investigated for multiband operation. The proposed antenna uses closely employed open split rings as a radiating element which provides efficient size reduction and broader bandwidth performance. The proposed antenna with the overall size of 27.5 ? 16.08 ? 1.6 mm3 is fabricated and tested. The measured results indicate that it covers 2.4/5.2/5.8 GHz (Wireless LAN), 5.5 GHz (WiMAX) and 7.4 GHz (X-band downlink) applications. The OSRR antenna has achieved size reduction of 38.83% and 52.83% compared to the split ring resonator and ring antennas respectively. It is observed that the proposed antenna produces better performance than the existing antennas in the literature.

Study of harmonic suppression using defected ground structure for OSRR antenna

In this study, a co-planar waveguide (CPW) fed open split ring resonator (OSRR) antenna with defected ground structure (DGS) is proposed to achieve harmonics suppression. The proposed antenna consists of OSRR structure and two modified F-shaped DGS (MFDGS), which is responsible for miniaturization and wide-band stop characteristics respectively. From the results of measured reflection coefficient, we observe that the proposed antenna structure is able to suppress higher frequencies between 3 GHz and 8 GHz. Particularly in the second frequency, suppression is attained up to 19 dB. Further analysis shows, the peak gain and radiation pattern of proposed structure is suppressed up to 20 and 30 dB respectively at second harmonic frequency. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1353–1358, 2016

A study of the ground plane effect in passband filters using OSRR cells

This paper presents the study of the ground plane effect in passband filters using metamaterial cells in Open Split Ring Resonators (OSRR) structures on microstrip substrates. Three different configurations have been proposed, namely: by removing partially the ground plane of the OSRR cell back end, by windows design over the ground plane at the back end of each cell and by placing a full ground plane. The conducted analysis shows that the filter transmission response featuring a ground plane including windows proved to be the most flattened with the middle bandwidth of the three configurations. On the other hand, the performance of these filters is similar to a conventional filter based on three-pole microstrip technology but with a considerable reduction in size of about 60%.

Compact and Wide Stopband Lowpass Filter Using Open Complementary Split Ring Resonator and Defected Ground Structure

Abstract. A compact (0.16  g × 0.08  g ) and wide stop-band lowpass filter design using open complementary split ring resonator (OCSRR) and defected ground structure (DGS) is presented in this paper. Low pass filter is con-structed using two cascaded stages of OCSRR. Since the rejection bandwidth of the OCSRR is narrow, tapered dumbbell shaped DGS section is placed under the OCSRR to enhance the bandwidth. The cutoff frequency (f c ) of the proposed lowpass filter is 1.09 GHz. The rejection band-width of the filter covers the entire ultra wideband spec-trum. Hence the spurious passband suppression is achieved up to 10 f c . The designed filter has been fabri-cated and validated by experimental results. Keywords Lowpass filter, defected ground structure (DGS), open complementary split ring resonator (OCSRR) 1. Introduction On the motive of conventional filter design methods such as stepped impedance and open stub suffering from poor skirt characteristics and spurious passband, re-searchers have paid great attention over the past few years in designing a compact and sharp cutoff lowpass filters with spurious free wide stopband. Lowpass filter using different defected ground structures (DGS), photonic bandgap (PBG) structures and electromagnetic bandgap structures have been proposed in various literatures [1–9]. Sharp cutoff and low insertion loss lowpass filter using a complementary split ring resonator (CSRR) is reported in [3]. Cascaded stages of CSRR with open stub configura-tion, exhibiting sharp cutoff lowpass response are pre-sented in [4]. Planar photonic bandgap (PBG) structures involving compact microstrip resonating cell (CMCR) are utilized to design a lowpass filter with wide stopband [5]. Recently, a lowpass filter with very sharp transition band using OCSRR is demonstrated in [6]. In this paper, a new technique is proposed to reduce the size of the lowpass filter and to obtain the wide spurious free stopband. The lowpass filter is designed using open complementary split ring resonator and a tapered dumbbell shaped DGS is placed under the OCSRRs to extend the stopband. The proposed lowpass filter is smaller and outperforming the existing filters in terms of insertion loss level, roll off rate and rejection bandwidth. Figure 1 shows the schematic of OCSRR printed on the microstrip line. This structure is first proposed in [6] for designing a sharp cutoff lowpass filter with compact size. OCSRR is a negative image of the open split ring resonator. To study the frequency response characteristics of the OCSRR, this structure is designed on Rogers 5880 substrate with a dielectric constant of 2.2 and a substrate thickness of 0.381 mm and simulated using an Ansys full wave simulator.

A VARACTOR-TUNED BANDPASS FILTER USING OPEN SPLIT-RING RESONATORS

This paper presents a compact tunable bandpass filter that is based on open split ring resonator to achieve high out-of-band rejection. Exact equations and design procedures are given based on strict theoretical analysis. By loading the varactor diodes, the center frequency and bandwidth of the bandpass filter could realize reconfigurable. Then defected ground structure was adopted in the input and output ports for the sake of high out-of-band rejection. In order to verify the result of theoretical analysis, a compact tunable bandpass filter with defected ground structure, whose range of frequency was 1.61 GHz ∼ 1.82 GHz and range of relative bandwidth was 8.3% ∼ 24.8%, had been simulated and fabricated. Good agreement between the measured data and the anticipated results is achieved.

Applications of electrically tunable composite right/left handed transmission lines based on barium–strontium–titanate thick films and open resonators

This paper is focused on the study and applications of tunable composite right/left handed transmission lines (CRLH TL) based on open resonators. Specifically, it will be demonstrated that CRLH TL based on open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) can be tuned by means of barium–strontium–titanate thick-films. These artificial lines are applied to the design of tunable band-pass filters, phase shifters, dual-band impedance inverters and dual-band power dividers, where independent or simultaneous tuning of different resonators can be considered, depending on the application. The design methodology and different proof-of-concept demonstrators are reported.

Differential Bandpass Filter With Common-Mode Suppression Based on Open Split Ring Resonators and Open Complementary Split Ring Resonators

Differential (balanced) microstrip bandpass filters (BPFs) implemented by combining open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are proposed. The OSRRs are series connected in both strips of the differential line, whereas the OCSRRs are paired face-to-face and connected between both line strips in a symmetric configuration. For the differential mode, the OCSRRs are virtually connected to ground and the structure can be modeled, to a first-order approximation, by a cascade of series resonators (OSRRs) alternating with shunt resonators (OCSRRs), i.e., the canonical circuit model of a BPF. These filters have the ability to suppress the common mode by properly adjusting the metallic area surrounding the OCSRRs. An order-3 balanced Chebyshev BPF is designed and fabricated to illustrate the possibilities of the approach. The filter does not require vias (contrary to previous single-ended microstrip BPFs based on OSRRs and OCSRRs), filter dimensions are small, and the common mode is efficiently suppressed with more than 20 dB rejection within the differential filter pass band.

Double-sided open split ring resonator for compact microstrip band-pass filter design

A metamaterial structure, called the double-sided open split ring resonator (DOSRR), which combines two open split ring resonators (OSRRs) aligned over the opposite faces of the substrate in an inverted fashion is presented. A study of this resonator from full-wave electromagnetic and circuit simulations is performed. As with the OSRR cell, the DOSRR cell allows a series connection along a microstrip transmission line and it has a small electrical size. Moreover, the DOSRR cell has the ability to add a transmission zero in the out-of-band region without increasing its size. This DOSRR cell is used for the design of compact microstrip slow-wave-type band-pass filters. Two strategies based on circular windows etched at the bottom plane instead of square windows and U-shape slots etched in the microstrip transmission line are designed to increase the stop band and to add extra zeros in order to suppress the spurious band. The experimental results have confirmed the possibilities of this electrically small resonator (DOSRR) and the efficiency of both strategies to improve the out-of-band rejection.

Broadband Microstrip Bandpass Filter Based on Open Complementary Split Ring Resonators

Broadband bandpass filters based on open complementary split ring resonators (OCSRRs) coupled through admittance inverters, and implemented in microstrip technology, are reported. As compared to other broadband filters based on open split ring resonators (OSRRs), ground plane etching is not necessary in the proposed filters. The selectivity of the filters at the upper transition band is improved thanks to the presence of a controllable transmission zero. To demonstrate the potential of this approach, two illustrative prototype devices have been designed and fabricated.

Recent Advances in Metamaterial Transmission Lines Based on Split Rings

This paper is focused on metamaterial transmission lines based on split rings. Specifically, the considered lines are those based on the hybrid approach, where complementary split ring resonators (CSRRs) are combined with series gaps and shunt inductive stubs, and those implemented by loading a host line with open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs). The dispersion characteristics and the characteristic impedance of such lines, essential for design purposes, are analyzed to the light of the lumped element equivalent circuit models of the lines. Finally, it is shown that hybrid lines are useful for the design of power splitters with filtering capability, and OSRR/OCSRR-loaded lines are of interest for the design of wideband bandpass filters. The achieved performances are satisfactory and device dimensions small.

High-order coplanar waveguide (CPW) filters implemented by means of open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs)

In this paper, it is demonstrated that transmission lines loaded with a combination of open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are useful for the design of high-order band pass filters subjected to standard responses. Specifically, we present a 7-pole Chebyshev band pass filter in coplanar waveguide technology. The device is compact and filter performance is good, including a wide stopband response. With this work, we extend our previous work on the applications of OSRR- and OCSRR-loaded lines to the design of highly selective filters.

Compact, deep, and wide rejection bandwidth low‐pass filter using open complementary split ring resonator

AbstractA deep and wide rejection bandwidth, sharp cutoff and compact low‐pass filter design using open complementary split ring resonator (OCSRR), and open stub is presented in this article.OCSRR is counterpart of the open split ring resonator. The proposed low‐pass filter consist of two OCSRR connected in series. The open stubs are attached on both sides of the OCSRR. At the 3 dB cutoff frequency of 1.08 GHz, the proposed filter offers a sharp rejection and wide rejection bandwidth of more than 20 dB up to six times the cutoff frequency. The filter size is very small as 0.22 λg × 0.18 λg, where λg is the guided wavelength at the cutoff frequency. The proposed filter is fabricated and tested; the experimental results are found to be in good agreement with the simulation results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:845–848, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25874

Tunable coplanar waveguide band-stop and band-pass filters based on open split ring resonators and open complementary split ring resonators

In this study, the authors show that open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) can be loaded with varactor diodes in order to implement tunable filters in coplanar waveguide (CPW) technology. By loading a CPW with shunt-connected varactor-loaded OSRRs, a band-stop filter with tunable central frequency results. The electronically tunable band stop can be switched to a pass band by replacing the shunt resonators with varactor-loaded OCSRRs. To illustrate the possibilities of the approach, a tunable band-stop filter and a tunable band-pass filter have been designed and fabricated. The measured characteristics are in good agreement with the co-simulations (electric and electromagnetic) and with the circuit simulations of the electric model. The measured tuning range is roughly 120% for the stop-band structure (for varying voltages between 0 and 28 V) and over 30% for the band-pass filter (for varying voltages between 5 and 25 V).