Circular Split Ring Resonator Research Articles

BANDWIDTH ENHANCEMENT OF MICROSTRIP PATCH ANTENNA

This paper discusses bandwidth enhancement of microstrip patch antenna using metamaterial and defected ground structure. A patch antenna is designed and simulated for 2.45GHz. Substrate is used for this purpose is FR4 glass epoxy with dielectric constant of 4.4 thickness of 1.6mm.The shape used for conventional patch antenna is rectangular with inset feed. For metamaterial antenna circular split ring resonator are used. Metamaterial SRR and Defected Ground Structure is designed and simulated for 2.45GHz. After comparing both antennas bandwidth enhancement antenna is reported. High Frequency Structure Simulator is used for this purpose.

Design and development of metamaterial bandpass filter for WLAN applications using circular split ring resonator

Abstract In this paper, a metamaterial bandpass filter using Split Ring Resonators (SRR) is designed, analyzed, and developed for WLAN applications at 2.4 GHz frequency band. Here, metamaterial bandpass filters with and without Defected Ground Structure (DGS) are designed, analyzed and compared. The filter structure shows a considerable size reduction with 50% fractional bandwidth, quality factor of 2 and wide bandwidth. The simulation results of the proposed filters offered good insertion loss and return loss response. The filters have been modeled, fabricated and their performance has been evaluated using the Method Of Moment (MOM) based electromagnetic simulator IE3D. The dimensions of the proposed filter is 20 × 9 × 1.6 mm which is considerably reduced. The simulated and measured results projected that the proposed metamaterial filters are well suited for WLAN applications.

Wideband switchable dual-functional terahertz polarization converter based on vanadium dioxide-assisted metasurface

The terahertz technology has attracted considerable attention because of its potential applications in various fields. However, the research of functional devices, including polarization converters, remains a major demand for practical applications. In this work, a reflective dual-functional terahertz metadevice is presented, which combines two different polarization conversions through using a switchable metasurface. Different functions can be achieved because of the insulator-to-metal transition of vanadium dioxide (VO2). At room temperature, the metadevice can be regarded as a linear-to-linear polarization convertor containing a gold circular split-ring resonator (CSRR), first polyimide (PI) spacer, continuous VO2 film, second PI spacer, and gold substrate. The converter possesses a polarization conversion ratio higher than 0.9 and a bandwidth ratio of 81% in a range from 0.912 THz to 2.146 THz. When the temperature is above the insulator-to-metal transition temperature (approximately 68 °C) and VO2 becomes a metal, the metasurface transforms into a wideband linear-to-circular polarization converter composed of the gold CSRR, first PI layer, and continuous VO2 film. The ellipticity is close to −1, while the axis ratio is lower than 3 dB in a range of 1.07 THz–1.67 THz. The metadevice also achieves a large angle tolerance and large manufacturing tolerance.

Hyper-sensitive microwave sensor based on split ring resonator (SRR) for glucose measurement in water

A microwave sensor for glucose concentration measurement is presented. The proposed sensor is composed of two cells of circular split ring resonator (SRR) with a liquid holder put on both cells. Those resonators are coupled to a coplanar line forming a two-port network whose S-parameter response provide an information about the dielectric properties of the liquid that is under study. This paper presents a numerical simulation and experimental study of our new configuration of the resonators to assess the sensitivity of the sensor toward small change in glucose concentrations in water. An electronic prototype has been used to improve the detection; a resolution of 1.665 mmol/l is reached at the frequency 1.9 GHz. The obtained results have shown the effectiveness of this new configuration of resonators sensor for non-invasive measurement on the small change in dielectric parameter εr. Therefore, the proposed sensor is well fitted for real time measurement, non-destructive, precise, and low cost.

A multiband circular polarization selective metasurface for microwave applications

In this research article, a multiband circular polarization selective (CPS) metasurface is presented. A reciprocal bi-layered metasurface is designed by introducing the chirality in the structure. The top layer of the proposed metasurface is composed of circular split-ring resonator with a cross shape structure inside it. The same structure is printed on the bottom side of the proposed metasurface by rotating it at an angle of 90° to achieve chirality in the structure. The proposed metasurface is able to add CPS surface capability between 5.18 and 5.23 GHz for y-polarized incident wave. For the frequency band of 5.18–5.23 GHz, the transmission goes up to − 4 dB, while the polarization extinction ratio (PER) reaches up to − 27.4 dB at 5.2 GHz. Similarly, for x-polarized incident wave, three strategic CPS operating bands are achieved within the frequency ranges of 10.64–10.82 GHz, 12.25–12.47 GHz, and 14.42–14.67 GHz. The maximum PER of 47.16 dB has been achieved for the 14.42–14.67 GHz frequency band at 14.53 GHz. Furthermore, the response of the metasurface does not vary against oblique incidences up to 45°. The simple structure, angular stability, multiband and miniaturized size make this metasurface an outstanding applicant for polarization conversion and biomedical applications.

Circular Split Ring Resonator (C-SRR) Array Integrated Frequency-Notched Horn-Filtenna With Wide and Strong Rejection Band

Linear-array of circular split ring resonators (C-SRR) integrated wideband notched filtering horn antenna with very strong rejection-band is proposed in this article. The linear C-SRR array, consisting of 3-sub arrays each having 4 identical C-SRR-elements, is printed on a dielectric substrate and is integrated into the throat or waveguide-section of the standard X-band horn (Narada 641). Staggered arrangement of the multiple C-SRRs based in-line filter contributes to the wideband notch filtering response with measured rejection band (S11 < 3-dB) of 315 MHz in proposed horn-filtenna. The realized horn-filtenna yields co- and cross- polar peak gain suppression of 35.42 dB and 24.6 dB at and around the centre of notch-band (9.8 GHz) while at the pass band of the C-SRR filter, the proposed antenna inherits the impedance and radiation characteristics of the standalone horn antenna. The proposed technique is simple, easy to integrate and can be used to eliminate adjacent band noise/interference for faithful reception of data without using any additional filter section.

A compact lowpass/dual-band bandpass filter for microwave application

A combination of lowpass and dual band bandpass filter with improved selectivity is presented in this manuscript. Two circular split ring resonators which are connected at the upper side, provide a lowpass filter characteristics. In order to achieve combined lowpass with dual passband response two L-shape stubs are incorporated into the lowpass filter structure. The parametric analysis of the proposed filter has been carried out using CST microwave studio. The numerical result shows a 3-dB cutoff frequency for lowpass at 1.22 GHz, first and second passband resonant frequencies are 2.44 GHz and 3.7 GHz respectively. The proposed filter is compact and overall size of the proposed filter is 32.9 mm?15mm.

Metamaterial-based sensor design using split ring resonator and Hilbert fractal for biomedical application

In this work, a novel approach is presented to design a metamaterial-based sensitive sensor for biomedical applications. The metamaterial-based sensor objective is to differentiate between different types of cancer cell lines (biological cells) based on their electrical properties. The sensor is designed by incorporating a single circular split ring resonator (SRR) and a Hilbert fractal curve. The SRR is designed based on its capacitive and inductive resonance properties, thereby making the SRR a favorable candidate for sensing applications. Moreover, the Hilbert fractal curve is introduced as a defected ground structure to move the resonance frequency of the SSR to lower band, and to increase sensor sensitivity. Different Hilbert curve orders are investigated. The fourth-order Hilbert curve is used in the final design as it showed the optimal performance among other orders. To verify the sensor functionality and selectivity, the proposed sensor is tested on three types of breast cancer cell lines, these are MCF7, MCF-7, and HS578T. Measurement results of the fabricated sensor compared well with simulated results obtained using high-frequency structure simulator (HFSS18).

Multiple-Cell Microfluidic Dielectric Resonator for Liquid Sensing Applications

This paper presents a high-sensitive planar microwave sensor based on the metamaterial technology, integrated with a microfluidic channel to be used for liquid sensing in a variety of biomedical applications. The sensor design comprises three cells of circular complementary split ring resonators (CSRRs) engraved on the ground plane of a dielectric substrate in a cascaded configuration. The sensing cells are excited with a time-varying electric field coupled from a planar microstrip-line (MTL) etched on the bottom side of the substrate. The proposed design of multiple coupled resonators would enhance the electric field intensity over a larger sensing region through the inter-resonator coupling, thus improving the overall sensitivity for detecting liquid samples of high permittivity and dielectric losses. The sensor exhibits a reject (band stop) filter behaviour with multiple resonances in the centimeter-wave band 1 – 6 GHz when loaded symmetrically with liquid samples. The sensor is fabricated on an FR4 dielectric substrate with a biocompatible microfluidic channel aligned appropriately over the sensing area to enable consistent and intact sensing of the liquid samples. The CSSR-sensor is numerically modeled and compared in performance to the single-cell CSRR for detecting small variations in the dielectric properties. The sensitivity, reliability, and repeatability of the proposed sensor are practically demonstrated by the in-lab measurements for different liquid samples using a Vector Network Analyzer (VNA) setup where distinctive resonant features (amplitude and frequency) are extracted from multiple resonance modes in the reflection and transmission responses. A high sensitivity is also demonstrated for monitoring glucose level variations in synthetic blood samples of concentrations (70 – 150 mg/dL) which are clinically-relevant to diabetes conditions. Beside its impressive capability in detecting small dielectric variations, the developed sensor features other favorable attributes including compact size, simple fabrication, affordable cost, non-ionizing nature, and minimal health risk or impact. Such key advantages could potentially promote the proposed sensor for integration with other microwave components in an embedded device for non-invasive monitoring of blood glucose for diabetes.

Sharp Triple-Notched Ultra Wideband Antenna with Gain Augmentation Using FSS for Ground Penetrating Radar

A printed ultra-wideband antenna that provides wide bandwidth of 2.6–10.58 GHz, with sharp triple notches at 3.3–3.92, 5.1–5.4 and 5.68–6.02 GHz to eliminate the WiMAX and WLAN interferences, is proposed. Triple notches are implemented by embedding split ring shaped slot and unique circular split ring resonator pairs in the antenna. The antenna provides monopole like radiation patterns with gain variation of 2.5–5 dBi and average radiation efficiency of 86% in its pass band. Wide bandwidth of the antenna makes it well suited in low depth subsurface scanning ground penetrating radar (GPR) applications where better lateral resolution is desired. To improve the depth resolution, the antenna is integrated with reflective type frequency selective surfaces. Overall gain augmentation of 3 dBi with maximum gain increment of nearly 6 dBi at 5.5 GHz is achieved by adding the FSS. The antenna-FSS composite structure provides impedance band of 2.52–10.66 GHz with triple notches at 3.26–3.84, 5.1–5.38 and 5.66–5.95 GHz. Performance of the composite structure is evaluated in close proximity of sandy soil test bed by keeping thin aluminium sheet at the bottom of sand. Adequate VSWR, transfer function and group delay responses ensure the eligibility of proposed antenna to work for GPR.

Gain Augmentation of a Triple Notched Ultra-wideband Antenna using Compact Uniplanar Frequency Selective Surface for Ground Penetrating Radar

A simple structured, compact ultra-wideband (UWB) circular disk monopole antenna of dimension 35 × 30 × 0.8 mm3 that offers wide bandwidth from 2.64 to 9.36 GHz with sharp triple notch bands at 3.28–3.84, 5.08–5.44, and 5.62–6.06 GHz is integrated to the single-layer UWB frequency selective surface (FSS) that has unit cell dimension of 0.1136λL × 0.1136λL only where λL signifies the lower band-edge of UWB. Sharp triple notches are employed by embedding split-ring slot on circular patch and implanting dual circular split-ring resonator pairs at the backside of feed. Addition of FSS layer does not affect the antenna impedance band and offers significant antenna gain improvement by 2–4 dBi in the pass bandwidth with maximum gain of 8 dBi at 8.5 GHz. The antenna also provides high average radiation efficiency of 80%, improved radiation in the broadside direction and consistent group delay response in its pass band when integrated to the FSS layer. Working capability of proposed antenna-FSS structure is evaluated in proximity of soil test bed by keeping thin aluminum sheet at different buried levels. Adequate VSWR profile, linear transfer function response, and consistent group delay response in pass band ensure the eligibility of proposed antenna to work for ground penetrating radar.

A compact circularly polarized modified printed monopole antenna for wireless applications

ABSTRACT In this article, a new compact Circularly Polarized Antenna with wide operating bandwidth is proposed. The proposed structure consists of a Modified Circular Split Ring Resonator (MCSRR) as the radiating patch, which is fed by coplanar waveguide and loaded with 2 × 2 closed-ring resonantor (CRR) array on its FR4 epoxy substrate. The dimensions of the antenna are 0.329 λo x 0.329 λo x 0.024 λo (λo stands for the free space wavelength at center frequency of 4.94 GHz).The implementation CRR on modified printed monopole antenna leads to a wide measured impedance bandwidth of 2726 MHz with a peak gain of 5.09dBi and efficiency of 96.3% in the operating bandwidth. A prominent feature of the proposed antenna is that dual 3-dB axial ratio bandwidth of 430 MHz and 670 MHz is observed in the operating band, and thus, making it to be a promising candidate for recent day wireless applications. The simulated results was verified by measuring the characteristics of the fabricated antenna; the obtained results showed a good matching with the simulated results.

A compact printed ultra-wideband filtenna with low dispersion for WiMAX and WLAN interference cancellation

A printed monopole filtenna fed by a co-planar waveguide with U-shaped split slot on patch and circular split ring resonator pairs at the other side of feed is proposed in this letter. The compact filtenna of dimension 0.32λ × 0.215λ (λ denotes wavelength corresponding to 2.68 GHz) is capable of providing large bandwidth from 2.68 to 8.72 GHz with dual frequency notch bands over 3.28–3.84 and 4.95–6.02 GHz, primarily to eliminate the WiMAX and WLAN interferences. The dual notched antenna performances are evaluated by simulation and experimental measurement and compared to those of recently reported ultra-wideband (UWB) notched antennas. The proposed filtenna provides bidirectional E-plane and omni-directional H-plane radiation patterns with gain variation of 2–4.5 dBi and average radiation efficiency of 78% in its pass band. Also the filtenna offers minimal dispersion characteristic as stable group delay response, and linear variation of transfer function (S21) is achieved in its pass bandwidth.

New Compact Wearable Metamaterials Circular Patch Antennas for IoT, Medical and 5G Applications

The development of compact passive and active wearable circular patch metamaterials antennas for communication, Internet of Things (IoT) and biomedical systems is presented in this paper. Development of compact efficient low-cost wearable antennas are one of the most significant challenges in development of wearable communication, IoT and medical systems. Moreover, the advantage of an integrated compact low-cost feed network is attained by integrating the antenna feed network with the antennas on the same printed board. The efficiency of communication systems may be increased by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the printed antenna feed line. Design, design considerations, computed and measured results of wearable circular patch meta-materials antennas with high efficiency for 5G, IoT and biomedical applications are presented in this paper. The circular patch antennas electrical parameters on the human body were analyzed by using commercial full-wave software. The circular patch metamaterial wearable antennas are compact and flexible. The directivity and gain of the antennas with Circular Split-Ring Resonators (CSRR) is higher by 2.5dB to 3dB than the antennas without CSRR. The resonant frequency of the antennas without CSRR is higher by 6% to 9% than the antennas with CSRR. The computed and measured bandwidth of the stacked circular patch wearable antenna with CSRR for IoT and medical applications is around 12%, for S11 lover than −6dB. The gain of the circular patch wearable antenna with CSRR is around 8dBi.

Quad band metamaterial absorber based on asymmetric circular split ring resonator for multiband microwave applications

This article presents a metamaterial based on a modified asymmetric circular split ring resonator for absorber applications in the microwave regime. This metamaterial absorber (MMA) exhibits four absorption peaks to cover C, X, and Ku band applications. The MMA unit cell is formed on a low-cost FR4 substrate with electrical dimensions of 0.106 λ0 × 0.106 λ0, for which wavelength, λ0 is calculated at 4.1 GHz. The resonator of the unit cell is structured with three concentric intercoupled circular split rings with dimensions modified to obtain maximum absorption peaks of 97.9%, 99.1%, 99.5%, and 99.95% at 4.1, 6.86, 11.3, and 13.45 GHz, respectively. Metamaterial and absorber properties are investigated in the analysis of the surface current, electric, and magnetic fields. The unit cell exhibits single negative metamaterial properties with an effective medium ratio (EMR) of 9.15 and quality factor (Q factor) greater than 20. Beyond that, the equivalent circuit of the MMA unit cell is modeled and validated by comparing S11 obtained from Advanced Design System (ADS) and CST software. The MMA array’s absorption properties are also examined in the simulations. Measured results of the unit cell and array correspond well with the result of simulation in terms of absorption at intended frequencies. Given its good EMR, superior quality factor, and high maximum absorption, the MMA can be a good candidate for a multiband absorber in microwave applications like sensing, detecting, notch filtering and to decrease the indirect reverberation and reflections caused by the metallic part of the radar and satellite antennas.

Compact Circular CSRR Loaded Koch Fractal Inspired Frequency Band Reconfigurable Antenna

A compact frequency band reconfigurable dual-mode antenna utilizing both Koch fractal geometry and circular complementary split ring resonators (CSRRs) is presented in this paper. The proposed antenna can be electrically switched into both dual- and single-band resonance modes. A Koch curve derivative novel fractal curve is used to design the patch boundary of the antenna. Two optimized circular CSRRs are loaded inside the antenna geometry to achieve double-band resonance. The antenna operates at both 5.1[Formula: see text]GHz (upper WLAN band) and 9.6[Formula: see text]GHz ([Formula: see text]-band) in dual resonance mode and resonates only at 8[Formula: see text]GHz ([Formula: see text]-band) in single resonance mode. A properly biased RF-range PIN diode placed at the slotted ground plane reconfigures the antenna in two operating modes by switching into its ON–OFF states. The antenna is fabricated on cost-efficient epoxy (FR-4) substrate consuming the maximum dimension of [Formula: see text] which is much more compact than the conventional rectangular patch antennas designed for similar bands. Stable radiation characteristics with reduced cross-polarization are achieved at all the resonant bands of the antenna. A prototype of the proposed antenna is fabricated and measured. The simulated results are in good agreement with the measured ones.

Simulation Study of Metamaterial Effect towards Ultra Wide Band Antenna

In this paper, the design of a metamaterial ultra-wideband (UWB) antenna with a goal towards application in microwave imaging systems for detecting unwanted cells in human tissue, such as in cases of breast cancer, heart failure and brain stroke detection is proposed. The metamaterial unit cell is constructed using circular split ring resonator (CSRR) technique and wire, to attain a design layout that simultaneously exhibits both a negative magnetic permeability and a negative electrical permittivity and attached as superstrate in front of the UWB antenna. This design results in an astonishing negative refractive index that enables amplification of the radiated power of this reported antenna, and therefore, high antenna performance. A Rogers (RT5880) substrate material is used to design and print this reported antenna, and has the following characteristics: thickness of 0.51 mm, relative permeability of one, relative permittivity of 2.70 and loss tangent of 0.02. The metamaterial antenna is design to be operated at frequency between 300MHz to 30GHz which is suitable for biomedical application such as Microwave Imaging. The overall metamaterial antenna size is 90 mm × 50 mm × 0.51 mm. The design and simulation has been carried out using Computer Simulation Technology Microwave Studio (CST MWS).

Simulated Triple Circular Split-Ring Resonator Metamaterial Unit Cell for THz application

Metamaterial used widely nowadays to overcome the limitation of the natural material in manipulating the electromagnetic wave and radiation. Split-Ring Resonator (SRR) have been used widely as a design to manipulate the electromagnetic waves but none of them used for higher frequency such as light frequency. Therefore, the objective of this paper is to design SRR unit cell that is capable to bend the light wave. The negative value of material properties obtained from the simulation of the metamaterial at three different part which are at phase=0, real value and imaginary value. CST Microwave Studio 2018 used as a simulation software. The results show all the negative value of material properties obtained at different frequency range. However, the negative value of material properties at phase=0 and imaginary part is obtained at same frequency range. While for real part, the negative value for all material properties occurred at different frequency range. This SRR design is suitable to manipulate the lights radiation waves.

Study of Circular Complementary Split Ring Resonator on a Heterogeneous Substrate Material

A circular patch loaded with a circular complementary split ring resonator (CSRR) is fabricated on a heterogeneous substrate material. The CSRR helps to reduce the size of antenna up to 44.26%. A 2.4 GHz ISM band circular patch antenna is constructed, fabricated and identified as prototype for wireless applications. We investigate how the loading of triple circular complementary split ring resonator on a heterogeneous substrate can reduce the size of antenna and improve the bandwidth and gain compared to conventional microstrip patch antenna. Further, the design is compared for different heights and width of Air and Taconic RF-30 dielectric substrate which is used to prepare a heterogeneous substrate material.

Split ring resonator inspired THz antenna for breast cancer detection

A circular split ring resonator inspired (THz) antenna for breast cancer detection is proposed in this paper. The proposed metamaterial antenna is made from a simple rectangular patch antenna loaded with a Circular Split Ring Resonator (CSRR) structure in the ground plane. The design equations for the CSRR along with its equivalent circuit and permittivity calculations are also discussed in this paper. The experimental technique for detection of tumor in human breast model are also offered in this paper. The proposed circular split ring resonator inspired antenna operates at 1.5 THz resonant frequency with the VSWR ≤ 1.5 along with 24.2 dBi of gain and 90% of efficiency. The proposed circular split ring resonator inspired (THz) antenna could be a suitable candidate for a breast cancer detection application.