Pair Of Split Ring Resonators Research Articles

TRIPLE BAND-NOTCHED UWB PLANAR MONOPOLE ANTENNA USING CIRCULAR SLOTS

In this study, a novel star-shaped antenna with partial ground plane was designed to achieve ultra-wideband (UWB) communications. To create the wireless local area network band notch (5.71-6.02 GHz), the ground plane contained two pairs of split ring resonators that were symmetrically arranged. The split ring resonators were placed on the patch to obtain a C-band notch (4.54-4.6 GHz). A circular slot was added to the patch in order to obtain an X-band notch for satellite communications (6.44-7.12 GHz). The suggested antenna is a strong option for a variety of UWB applications due to its excellent performance in triple notched bands, consistent gain, and radiation patterns in the operating bands.

Multi-state polarization switching and multifunction-integrated terahertz metadevice enabled by inverse resonance responses

Dynamical control of terahertz metadevices and integration of versatile functions are highly desired due to increasing practical demands. Here, we propose a multifunctional photosensitive Si hybrid metastructure consisting of twisted split-ring resonator pairs that could empower multi-state polarization switching and object-recognized imaging. The theoretical and simulated results show that inverse complete modulation of cross-polarized components could be realized via tuning the conductivity of the Si-bridge. The calculated ellipticity indicates that our metadevices possess the ability to convert linearly polarized light into left-hand circular-polarized or right-hand circular-polarized waves, as well as left-hand circular-polarized or right-hand circular-polarized into linearly polarized states. Combined with these properties, mono-parameter amplitude imaging and amplitude-phase synergistic encryption imaging are accomplished. Our research provides a new strategy to develop reconfigurable and multifunctional components in the terahertz regime.

Ultramicro-sensing of terahertz metamaterials implemented by using sample traps

A metamaterial sensor implemented by using sample traps based on terahertz electromagnetically-induced-transparency-like (EIT-like) effect is proposed. The basic unit structure of the sensor is composed of a metal wire and a pair of split ring resonators (SRRs), which are coupled to produce EIT-like effect. The full width at half maximum of transparency peak is 178 GHz obtained at 1.067 THz, and the maximum transmittance of the transparency peak is 89.71%. The sensing characteristics of the structure are studied, and the sensitivity per unit volume is <inline-formula><tex-math id="M3">\begin{document}$178\;{\rm{G}}{\rm{H}}{\rm{z}}/({\rm{R}}{\rm{I}}{\rm{U}}{\cdot} {{\rm{m}}{\rm{m}}}^{3})$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230080_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230080_M3.png"/></alternatives></inline-formula>. The analysis of electric field distribution at the resonant frequency point of the metamaterial indicates that the electric field at the gap of the SRRs on both sides is strongest. Sample traps are constructed at the gap where the electric field is strongest. The photoresist is filled into the sample traps as the object to be measured, and 50 GHz frequency offset is successfully measured, verifying that the sample trap structure can be applied to sensing. With samples placed in the sample traps, the sample volume is reduced to the ultra-micro level, and the sensitivity per unit volume is increased to <inline-formula><tex-math id="M4">\begin{document}$5538\;{\rm{G}}{\rm{H}}{\rm{z}}/({\rm{R}}{\rm{I}}{\rm{U}}{\cdot} {{\rm{m}}{\rm{m}}}^{3})$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230080_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20230080_M4.png"/></alternatives></inline-formula>, which is 31 times higher than original one. The successful identification of water, human skin and rat skin samples show that the metamaterial sensor implemented by using sample traps has potential applications in the field of ultra-micro detection.

Multifunctional Bandpass Filter/Displacement Sensor Component

This paper presents the design and realization of a multifunctional bandpass-filter/displacement-sensor using an edge-coupled microstrip bandpass filter loaded by a pair of split ring resonators (SRRs). It is shown that while the structure acts as a bandpass filter at its operating frequency, the phase of the reflection coefficient from a movable loading resonator at the resonance frequency of the resonator can be used for displacement sensing. With this aim, and to avoid any interference with the filter functionality, the resonance frequency of the SRRs is chosen within the stopband of the bandpass filter, where all the input signal is reflected back to the input port. Therefore, moving the loading resonators does not have any adverse effect on the filtering performance. To validate the concept, a fifth-order Chebyshev bandpass filter with a feed line loaded with a pair of SRRs is designed and the numerical evaluation of the proposed multifunctional bandpass-filter/displacement-sensor is provided. The proposed multifunctional component is also validated through fabrication and measurement. It is shown that the proposed component has a sensitivity of 8°/mm at the designed frequency of SRRs. However, the sensitivity can be increased by scaling the SRRs to resonate at a higher frequency within the upper stopband of the filter.

Characteristic-mode analysis of coupled split-ring resonators

Abstract The coupling between closely spaced split-ring resonators, when employed as sub-components of electromagnetic structures, is an important feature often leveraged upon to provide bulk material properties. In its contribution, this paper employs characteristic-mode analysis (CMA) to examine modal interactions intrinsic to the coupling between a pair of split-ring resonators. The analysis reveals the influence of feed impedance and rotational orientation of a pair of coupled SRRs on the excited resonant modes, which, in turn, determine the power transfer levels between both SRRs and the frequencies at which these occur. The insights provided suggest the aptness of rotational orientation and feed impedance as critical design parameters for the realization of SRR-based magneto-inductive waveguides and wireless power transfer setups.

Displacement Sensors Based on the Phase of the Reflection Coefficient of a Split Ring Resonator-Loaded Transmission Line

In this article, novel displacement sensors using a microstrip loaded with a pair of split ring resonators (SRRs) are proposed. It is shown that the phase of the reflection coefficient from the loading SRRs can be used for displacement sensing. The article also proposes a differential version of the sensor that benefits from a higher sensitivity and reference zero, which is useful for alignment purposes. It is further shown that the concept of interferometry can be used to convert the output variable of the sensor from changes in the phase to variations in the amplitude of the reflected wave, which can be easily measured. To this end, the proposed single-ended or differential sensors are used along with a branch-line coupler. The proposed sensing mechanism is validated through electromagnetic (EM) simulation of the structures. The concept is further validated through the fabrication and measurement of a prototype.

EBG and SRR Loaded Triple Band Notched UWB Antenna

A compact triple band notched ultra-wideband (UWB) monopole antenna is presented in this paper. Split Ring Resonator (SRR) structure is exploited in various forms like Complementary Split Ring Resonator (CSRR), Split Ring Resonator Pair (SRRP) and CSRR on Electromagnetic Band Gap (EBG) structure to produce triple band notched characteristics in UWB spectrum. The proposed antenna produces triple band notched functions with integration of all three types of SRR on primary antenna. The parametric analysis of each form of SRR is presented along with their current distribution effects on triple band notched antenna. The proposed antenna prototype is fabricated and measured results are also compared with simulated one to understand the discrepancies. The measured and simulated results are presented to investigate the band notching characteristics of suggested antenna in terms of VSWR and radiation characteristics.

Dual-band electromagnetically induced transparent metamaterial with slow light effect and energy storage

The realization of electromagnetically induced transparency (EIT) on metamaterials has special properties, such as strong slow-light, frequency-selection and so on, which have allowed EIT to be widely used in the fields of slow-light, optical storages and filters. In this paper, a metamaterial with two pairs of split ring resonators and one cut-wire is designed to achieve dual-band EIT effect at 0.5–2.14 GHz and 0.4–2.10 GHz with independently tunable bandwidths of 1.64 GHz and 2.7 GHz, respectively. The coupled Lorentz model is adopted to principally study the coupling characteristics between dark and bright modes. It is shown that the coupling strength between the dark and bright modes could be modulated by the coupling distance, which make the dual-band transparent window could be independently modulated by only changing the coupling distance between the bright and dark mode. The group delay and energy storage are also simulated by setting the Gaussian pulse signal passing through the EIT structure. The results show that the group delay of the designed EIT structure is 16.9 times that of the same thickness of dielectric material. The manufactured metamaterial is tested in a microwave anechoic chamber. The experimental and theoretical results are well consistent. These results could be beneficial for the development of EIT research toward some up-and-coming novel slow-light, optical storage, sensor and optical filter applications.

A planar CPW fed UWB antenna with dual rectangular notch band characteristics incorporating U‐slot, SRRs , and EBGs

In this article, a planar ultra-wideband (UWB) antenna with dual rectangular notchband characteristics (ie, 5.94-7.50 GHz and 8.02-10.46 GHz) is presented. The two-notch bands are chosen based on various wireless applications operating in C-band and X-band. The size of the antenna is very compact (25 × 25 × 1.6 mm3) and is designed on a low-cost FR4 substrate. Co-planar waveguide (CPW) feed and beveling techniques are utilized for achieving the UWB operation. In order to yield the first rectangular notch, a U-slot and a pair of split-ring resonators are embedded into the radiating patch and the backside of the design, respectively. The coupling between these two structures is adjusted so as to achieve a rectangular band-notch operation. The second rectangular notch has been achieved by introducing the two mushroom type electromagnetic band-gap structures on the opposite side of the CPW feed. The parametric analysis for controlling band notches, time-domain analysis, and filter synthesis is also presented. Finally, simulated as well as measured results of S11, gain, radiation pattern, group delay, and total efficiency are demonstrated to show the suitability of this design for UWB systems.

Terahertz Plasmon-Induced Transparency Effect in Parallel Plate Waveguide

Recently reported metamaterial analogues of plasmon-induced transparency are very promising in designing novel optical components, such as slow-light devices and optical switches. However, most of the previous works mainly focus on manipulating the PIT effects using planar structures in the free space under normal incidence, where the resonances are mostly induced by the incident electric fields. Here, we present a PIT analogue in a waveguide system in the terahertz regime by inserting coupled split-ring resonator pairs into a tapered parallel plate waveguide. Different from the free-space cases, the incident magnetic fields can also play an important role here. By carefully arranging the relative orientations of the coupled split-ring resonators in each pair, giant modulation of the PIT effect is observed. This straightforward approach may enable novel devices for integrated terahertz devices.

A compact UWB antenna with triple band notch reconfigurability

AbstractA compact ultrawideband (UWB) antenna with reconfigurable triple band notch characteristics is proposed in this paper. The antenna consists of a coplanar waveguide-fed top-cut circular-shaped radiator with two etched C-shaped slots, a pair of split-ring resonators (SRRs) on the backside and four p-type intrinsic n-type (PIN) diodes integrated in the slots and SRRs. By controlling the current distribution in the slots and SRRs, the antenna can realize eight band notch states with independent switch ability, which allows UWB to coexist with 5G (3.3–4.4 GHz)/WiMAX (3.3–3.6 GHz), WLAN (5.15–5.825 GHz), and X-band (7.9–8.4 GHz) bands without interference. By utilizing a nested structure of C-shaped slots and SRRs on the backside, a compact size of 18 × 19.5 mm2 is achieved along with multimode triple band notch reconfigurability. The antenna covers a bandwidth of 3.1–10.6 GHz. A prototype is fabricated and tested. The simulated and experimental results are in good agreement.

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 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.

Analysis and design of a compact ultra-wideband antenna with WLAN and X-band satellite notch

<span lang="EN-US">A compact design of ultra-wideband (UWB) antenna with dual band-notched characteristics based on split-ring resonators (SRR) are investigated in this paper. The wider impedance bandwidth (from 2.73 to 11.34 GHz) is obtained by using two symmetrical slits in the radiating patch and another slit in the partial ground plane. The dual band-notch rejection at WLAN and X-band downlink satellite communication system are obtained by inserting a modified U-strip on the radiating patch at 5.5 GHz and embedding a pair of rectangular SRRs on both sides of the microstrip feed line at 7.5 GHz, respectively. The proposed antenna is simulated and tested using CST MWS high frequency simulator and exhibits the advantages of compact size, simple design and each notched frequency band can be controlled independently by using the SRR geometrical parameters. Therefore, the parametric study is carried out to understand the mutual coupling between the dual band-notched elements. To validate simulation results of our design, a prototype is fabricated and good agreement is achieved between measurement and simulation. Furthermore, a radiation patterns, satisfactory gain, current distribution and VSWR result at the notched frequencies make the proposed antenna a suitable candidate for practical UWB applications.</span>

Active Reconfigurable Ultra-Wideband Antenna With Complementary Frequency Notched and Narrowband Response

An active reconfigurable ultra-wideband antenna exhibiting complementary frequency notched and narrowband responses is proposed in this paper. The frequency responses are achieved on a CPW fed single element printed monopole antenna loaded with a pair of split ring resonators (SRR) and PIN Diodes. The SRRs and PIN Diodes embedded on the Coplanar Waveguide (CPW) feed works as an inline filter, when activated, exhibits frequency reconfigurability by transforming a frequency notched wideband antenna into a narrowband antenna. Different biasing conditions (reverse and forward) on the loaded PIN diodes toggle between frequency-notched and narrow band response of the antenna. Prototypes are fabricated and the measured impedance and radiation characteristics are presented. This concept offers multi-antenna functionality using a single radiator without any modification or addition to the radiator geometry.

Compact UWB monopole antenna with quadruple band notched characteristics

ABSTRACTA compact planar Ultrawideband (UWB) monopole antenna with quadruple band notch characteristics is proposed. The proposed antenna consists of a notched rectangular radiating patch with a 50 Ω microstrip feed line, and a defected ground plane. The quadruple band notched functions are achieved by utilising two inverted U-shaped slots, a symmetrical split ring resonator pair (SSRRP) and a via hole. The fabricated antenna has a compact size of 24 mm × 30 mm × 1.6 mm with an impedance bandwidth ranging from 2.86 to 12.2 GHz for magnitude of S11 < −10 dB. The four band notched characteristics of proposed antenna are in the WiMAX (worldwide interoperability for microwave access) band (3.25–3.55 GHz), C band (3.7–4.2 GHz), WLAN (wireless local area network) band (5.2–5.9 GHz) and the downlink frequency band of X band (7–7.8 GHz) for satellite communication are obtained. The measured and simulation results of proposed antenna are in good agreement to achieve impedance matching, stable radiation patterns, constant gain and group delay over the operating bandwidth.

Design of a Quad-Band Monopole Antenna with Independent Frequency Control

A coplanar waveguide (CPW)-fed I-shaped monopole antenna with independent frequency control characteristic is presented for simultaneously satisfying the global positioning system (GPS), wireless local area network (WLAN), and worldwide interoperability for microwave access (WiMAX) applications. It is printed on an FR4 substrate with a single-layered metallic structure and the overall dimensions are [Formula: see text][Formula: see text]mm3. The proposed antenna consists of an I-shaped monopole, a pair of split-ring resonators (SRRs), and a coplanar ground plane. The unique advantage of this study is that the four frequency bands are generated individually by different radiating elements. That is, each of them can be controlled independently with little interference from others, which brings added convenience to the antenna design, optimization and debugging processes. Simulated and measured results both demonstrate that it can cover the 1.575[Formula: see text]GHz GPS (1.57–1.59[Formula: see text]GHz); 2.4/5.2/5.8[Formula: see text]GHz WLAN (2.4–2.485, 5.15–5.35 and 5.725–5.825[Formula: see text]GHz) and 3.5/5.5[Formula: see text]GHz WiMAX (3.40–3.60 and 5.25–5.85[Formula: see text]GHz) applications with satisfactory radiation patterns and acceptable gains.

Experimental Breast Phantom Imaging with Metamaterial-Inspired Nine-Antenna Sensor Array.

An experimental system for early screening of a breast tumor is presented in this article. The proposed microwave imaging (MI) system consists of a moveable array of nine improved negative-index metamaterial (MTM)-loaded ultrawideband (UWB) antenna sensor with incorporation of a corresponding SRR (split-ring resonator) and CLS (capacitively loaded strip) structure, in a circular array, the stepper motor-based array-mounting stand, the adjustable phantom hanging platform, an RF switching system to control the receivers, and a personal computer-based signal processing and image reconstruction unit using MATLAB. The improved antenna comprises of four-unit cells along one axis, where an individual unit cell integrates a balancing SRR and CLS pair, which makes the antenna radiation omnidirectional over the operating frequencies. The electrical dimensions of this proposed antenna are 0.28λ × 0.20λ × 0.016λ, measured at the lowest operating frequency of 2.97 GHz as the operating bandwidth of this is in between 2.97–15 GHz (134.82% bandwidth), with stable directional radiation pattern. SP8T 8 port switch is used to enable the eight receiver antennas to sequentially send a 3–8.0 GHz microwave signal to capture the backscattered signal by MATLAB software. A low-cost realistic homogeneous breast phantom with tumor material is developed and measured to test the capability of the imaging system to detect the breast tumors. A post-processing delay-multiply-and-sum (DMAS) algorithm is used to process the recorded backscatter signal to get an image of the breast phantom, and to accurately identify the existence and located area of multiple breast tumor tissues.

Differential Sensors Using Microstrip Lines Loaded With Two Split-Ring Resonators

This paper presents a microwave sensor using a pair of split-ring resonators (SRRs). The sensor is designed by loading a microstrip transmission line by two identical SRRs on its sides. Differential permittivity sensing is performed by loading the SRRs with dielectric samples. One transmission notch is observed for the identical loads, whereas the non-identical samples produce two split notches. The sensor’s operating principle is described through a circuit model analysis. A prototype of the designed sensor is fabricated and experimentally validated for verifying the differential sensing concept. The developed device can be used to compare or differentially characterize solid dielectric samples improving the robustness to environmental factors producing cross-sensitivity or miscalibration.