Complementary Split Ring Resonator Research Articles

MCML-BF: A Metal-Column Embedded Microstrip Line Transmission Structure with Bias Feeders for Beam-Scanning Leakage Antenna Design

This article proposes a novel fixed-frequency beam scanning leakage antenna based on a liquid crystal metamaterial (LCM) and adopting a metal column embedded microstrip line (MCML) transmission structure. Based on the microstrip line (ML) transmission structure, it was observed that by adding two rows of metal columns in the dielectric substrate, electromagnetic waves can be more effectively transmitted to reduce dissipation, and attenuation loss can be lowered to improve energy radiation efficiency. This antenna couples TEM mode electromagnetic waves into free space by periodically arranging 72 complementary split ring resonators (CSRRs). The LC layer is encapsulated in the transmission medium between the ML and the metal grounding plate. The simulation results show that the antenna can achieve a 106° continuous beam turning from reverse −52° to forward 54° at a frequency of 38 GHz with the holographic principle. In practical applications, beam scanning is achieved by applying a DC bias voltage to the LC layer to adjust the LC dielectric constant. We designed a sector-blocking bias feeder structure to minimize the impact of RF signals on the DC source and avoid the effect of DC bias on antenna radiation. Further comparative experiments revealed that the bias feeder can significantly diminish the influence between the two sources, thereby reducing the impact of bias voltage introduced by LC layer feeding on antenna performance. Compared with existing approaches, the antenna array simultaneously combines the advantages of high frequency band, high gain, wide beam scanning range, and low loss.

Aging Characterization of Modified Insulating Paper Based on the Transmission Characteristics of Microstrip Resonant Sensors

In this paper, the aging characterization of a kind of insulating paper modified by magnetron sputtering MgO particles based on a microstrip resonant sensor was presented. Firstly, the modified insulating paper with 0, 15 and 30 min MgO particle sputtering times was prepared by a magnetron sputtering device. After that, the properties of the modified insulating paper with different sputtering times were analyzed through microscopic characterization, infrared spectrum, polymerization degree, dielectric constant, AC breakdown strength and thermal aging experiments. The results show that the dielectric constant of the modified insulating paper decreased obviously, the AC breakdown strength increased and the thermal aging resistance was better after 15 min of sputtering. The overall performance of the modified insulating paper after 30 min of sputtering is reduced due to excessive sputtering. In addition, microstrip resonant sensors are introduced to characterize the thermal aging degree of the modified insulating paper, and two microstrip resonant sensors are prepared: a complementary split ring resonator (CSRR) and an interdigital-capacitor-shaped defected ground structure resonator (IDCS-DGS). The resonance frequency deviation of the modified insulating paper samples after aging was measured by microstrip resonance sensors to show the influence of aging temperature on aging degree. The experimental results show that the test results of the microstrip resonance sensors are in good agreement with the traditional characterization methods and can characterize the various aging stages of the modified insulating paper to a certain extent, which proves the feasibility of the characterization method.

Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates With High Sensitivity

Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates With High Sensitivity

Trenched microwave resonator integrated with porous PDMS for detection and classification of VOCs with enhanced performance

Microwave resonators combined with polymer absorption layers are widely used in volatile organic compound (VOC) detection based on their variable resonant frequencies. However, the response time is limited due to the polymer’s slow volumetric absorption of VOC molecules. By constructing a porous structure in Polydimethylsiloxane (PDMS), resulting in reduced the response time to as short as 71.1%. To mitigate the sensitivity decline caused by the porous PDMS, a trenched-substrate complementary split-ring resonator (CSRR) is proposed for enhancing the interaction between the electromagnetic fields (EMFs) and the porous PDMS with VOCs. The removal of the substrate beneath CSRR’s sensing region enhances the effective EMF, increasing frequency and amplitude sensitivities up to 175.5% and 137.8%, respectively. Responses to four common VOCs by the sensor show a maximum sensitivity of 217 Hz/ppm and a minimum limit of detection of 295 ppm. Additionally, resonant parameters and extracted lumped parameters are utilized to establish two decision-tree-based VOC classification models, achieving high accuracies of 98.71% and 99.59%, respectively. And the latter one fully utilizing responses throughout the swept band, proves superior in identifying similar substances. This sensor technology helps promote the sensitive detection and accurate classification of diverse VOCs.

A compact, low‐loss, and wide passband ratio substrate integrated waveguide triplexer based on complementary split ring resonators for multiband applications

SummaryIn this paper, a design of a substrate‐integrated waveguide (SIW) triplexer with improved low‐loss performance, passband ratio, and compactness based on the complementary split ring resonator (CSRR) structure is presented. The proposed triplexer operates at three passbands of 6, 8, and 10 GHz that correspond to the passband ratios of 1.33 and 1.67. By appropriately designing square CSRRs on the surface of the SIW structure, the low‐loss and compact resonator filters below the cut‐off frequency of the SIW at each operation frequency can be realized. The wide passband ratio is obtainable by adjusting the dimensions of the T‐junction. The measured results show the minimum insertion losses of 1.5, 1.4, and 1.9 dB at 6, 8, and 10 GHz, respectively. In addition, the minimum measured return losses are −9.33, −11.3, and −12.4 dB at the corresponding three passbands. The measured isolation between output ports is better than −17 dB in the frequency range from 5 to 11 GHz. The measured results agree well with simulations which are conducted by the CST Microwave Studio simulator. The proposed triplexer is designed on a cost‐effective RO4003C substrate with a compact size of 35 25 mm2

A miniaturized and low-loss Q-band SIW bandpass filter based on evanescent-mode in wafer-level packaging process

This paper presents a miniaturized Q-band substrate integrated waveguide (SIW) bandpass filter (BPF) on a silicon-based wafer-level packaging (WLP) process. By incorporating capacitive quasi-coplanar waveguide (CPW) feeding structures and complementary split-ring resonators (CSRRs), the SIW operates in an evanescent-mode below the lower cutoff frequency and then achieves miniaturization. The efficient conversion of wave-modes, mutual excitation among multiple capacitive structures, and extremely short transmission paths, collectively resulting in the proposed BPF exhibiting low insertion loss. Furthermore, the area of fabricated filter has been reduced by 88.96 % compared to the requirement of the cutoff frequency. The measured results show that the minimum insertion loss is 1.24 dB, the return loss is better than 15 dB, and the 3 dB passband covers from 29.6 to 47.8 GHz (FBW is 47 %). These results indicate that, the proposed filter effectively solve the issues of large areas in SIW filters and high losses in silicon-based integrated or packaging processes.

Octagonal complementary split ring resonator on rectangular patch MIMO antenna for terahertz applications

A novel micro-sized inset-fed rectangular MIMO patch (IRMP) antenna with an octagonal complementary split ring resonator and defected ground structure is proposed for wide-band terahertz (THz) applications. The spatial and pattern diversity configurations consist of two identical radiating elements positioned adjacent to and orthogonal to each other. For both configurations, it exhibits an impedance bandwidth of 1.3 THz (S11 < −10 dB) spanning from 3.2 THz to 4.5 THz. The IRMP antenna has an isolation of S12 < −20 dB for both configurations. The overall dimensions of the two configurations are 200 × 400 × 20 µm3. The gain of the spatial diversity configuration is 8.9 dBi, 9.7 dBi, and 10.4 dBi. Similarly, the gain of pattern diversity configuration is 6.07 dBi, 7.54 dBi, and 10.2 dBi at 3.52 THz, 3.90 THz, and 4.26 THz, respectively. The MIMO performance parameters of both configurations are envelope correlation coefficient < 0.001, diversity gain > 9.995, channel capacity loss < 0.005 bits/sec/Hz, and mean effective gain between −6 dB and −8 dB within the band, which is acceptable.

Miniaturization of antenna using metamaterial loaded with CSRR for wireless applications

This paper proposes a compact decagon antenna for wireless applications based on inspired metamaterial (MTM) loaded with a modified complementary split ring resonator (CSRR). A MTM loaded with CSRR is used to achieve a size reduction of 50% when compared to a traditional antenna. The suggested decagon antenna's ground plane has been loaded with CSRR. The antenna was made on an FR4 substrate with a thickness of 1.6 mm and εr=4.4 and has a very small dimension of 0.288 λ_0x0.272 λ_0x0.013 λ_0 (where λ_0 represent center frequency at 2.4 GHz). The given antenna has a 90 MHz bandwidth (2.40-2.50 GHz) with a peak gain of 2.36 dB. The presented design is validated by showing simulated results of the S parameter, VSWR, gain, surface current, and radiation pattern. The proposed antenna is well suited for wireless applications.

All‐metal wide‐angle and polarization‐independent microwave metamaterial absorber

AbstractAn innovative all‐metal self‐support microwave metamaterial absorber (MMA) based on a continuous complementary split ring resonator (CSRR) array frequency selective surface (FSS) is constructed. The CSRR‐based FSS has a selected frequency of 23 GHz and is proved to be polarization insensitive. And the all‐metal MMA has the same response frequency as the FSS, showing convenience in the geometrical scaling process. Additionally, in both transverse electric and transverse magnetic modes, the all‐metal MMA shows stable response at oblique incidences with an incident angle as large as 50°. Along with lightweight, easy fabrication and high cost‐performance ratio, the new proposed all‐metal FSS‐based MMA has good potential to serve in many practical applications.

Meta-atom loaded circularly polarized triple band patch antenna for Wi-Fi, ISM and X-band communications

Microstrip antennas usually suffer from high losses, gain, and efficiency degradation. It is a challenging task to miniaturize the patch antenna without degrading the performance parameters. To mitigate the above problems, a microstrip patch antenna loaded with stubs and printed on the ground plane loaded with dumbbell meta-atom is presented in this paper. The proposed double dumbbell meta-atom consists of two complementary split ring resonator (CSRR) cells loaded with rectangular rings. This exhibits the Double Negative (DNG) characteristic at 2.45 GHz. The devised meta-atom possesses dimensions of 0.05λ x 0.03λ at lower giga-hertz range. The meta-atom is further analyzed in CST-Microwave Studio and the corresponding S-parameters are extracted in MATLAB using the Nicolson Ross Weir (NRW) method. The electrical model of the meta-atom is also analyzed using Agilent ADS simulator. Further, two models of the proposed antenna with FR-4 and RT/Duroid-5880 are designed and compared. The proposed patch antenna resonates at three different frequency bands i.e. 2.445 GHz with a 3-dB bandwidth of 110 MHz (2.4 GHz–2.51 GHz), at 5.85 GHz with a 3-dB bandwidth of 730 MHz (5.13 GHz–5.86 GHz), and at 8.83 GHz with a 3-dB bandwidth of 1.83 GHz (7.7 GHz–9.53 GHz). This exhibit peak gains of 2.75dBi, 3.53dBc and 4.36dBi with low cross polarization levels at the said frequencies of operation. Further, the antenna possesses circular polarization in the frequency band (5.15 GHz–5.63 GHz). This antenna is used for Wi-Fi, ISM and X-band communications. The designed prototype is fabricated and tested and bears resemblance to the simulated results.

UWB TAPERED-SLOT PATCH ANTENNA WITH RECONFIGURABLE DUAL BAND-NOTCHES CHARACTERISTICS

An ultra-wideband patch antenna (UWB) that makes use of tapered slot technology is designed and analyzed in this article. Coplanar waveguide feeds the projected antenna. The presented antenna displayed superior UWB performances with -10 dB return-loss bandwidth, ranging from 1.9 to 12 GHz. The projected slot antenna has another benefit of minimizing the interference effect of the narrow band communications conducted by two notch bands operating at 3.3–3.8 GHz (WiMAX) and 5.1-6 GHz (WLAN and HIPERLAN/2), respectively. The Dual-Bands rejection is generated by etching out a complementary split ring resonator (CSRR) from the patch and placing a trapezoidal split ring resonator (TSRR). Adaptable single or dual-band rejection characteristics have been added to the behavior of the UWB antenna, by mounting electronic switching across SRR and CSRR. Furthermore, the presented UWB slot antenna is printed on an FR4-epoxy substrate (εr = 4.4) and it has an overall size of . 55x48x1.5 mm3

Dual-Notched UWB Orthogonal MIMO Antenna with Improved Gain Characteristics Using Frequency Selective Surfaces for Wireless Communication Applications

In this paper, a complementary split ring resonator (CSRR) loaded compact CPW-fed circular shaped monopole UWB antenna with dual band notch characteristics is designed on an FR-4 substrate. The propounded band-notched UWB antenna is integrated with two frequency selective surface layers referred as bandpass frequency selective surface (FSS-1) and reflector (FSS-2) to offer enhanced radiation performance. Bandpass FSS-1 enhances the gain of the antenna by improving directivity and reflector FSS-2 reflects back the backside radiation of the proposed antenna towards the forward direction thereby increasing gain and directivity of the proposed antenna. Furthermore, a two-element orthogonal MIMO antenna is proposed with improved gain using two FSS layers. The complete configuration of the proposed two-element MIMO antenna consists of CSRR-based radiating patches, monopole ground planes and two integrated FSS layers. The proposed MIMO antenna operates in UWB range from 3.46[Formula: see text]GHz to 16.02[Formula: see text]GHz with dual notches at 3.9[Formula: see text]GHz and 7.2[Formula: see text]GHz. Isolation between MIMO elements is greater than 23 dB. Both antennas are fabricated and investigated at 5.9[Formula: see text]GHz for vehicular communications. Maximum gain improvements of 8 dB and 6.4 dB are observed in case of the presented single element and MIMO antenna within the entire operating band due to the integration of dual FSS layers. The diversity performance of the suggested MIMO antenna is investigated by analyzing mean effective gain, envelope correlation coefficient, channel capacity loss and diversity gain parameters. The proposed MIMO antenna is a suitable candidate for vehicular and UWB wireless communication applications.

Development of CPW Fed Slot Antenna with CSRR for Biomedical Applications

This paper presents a complementary split-ring resonator (CSRR) loaded coplanar waveguide (CPW) fed with a circular shape, miniaturized diamond slot planar monopole antenna. The proposed antenna for healthcare monitoring biomedical applications uses the industrial medical and scientific band. The antenna design and development to implant the human phantom are proposed. The primary goal of this work is to continuously monitor the patient’s ability to detect abnormal conditions as soon as possible as a result of improvements in quality of life. In this case, an antenna design methodology must prioritize features such as miniaturization, increased gain and bandwidth, and biocompatibility. Simulated and measured antenna characteristics for biomedical applications are performed at ISM Band frequency.

Highly Sensitive Microwave Sensors Based on Open Complementary Square Split-Ring Resonator for Sensing Liquid Materials.

This paper presents high-sensitivity sensors based on an open complementary square split-ring resonator and a modified open complementary split-ring resonator operating at 4.5 GHz and 3.4 GHz, respectively. The sensors are designed for the detection of multiple liquid materials, including distilled water, methanol, and ethanol. The liquid under test is filled in a glass container loaded using a pipette. Compared to the conventional OCSSRR, the modified OCSSRR with multiple rings exhibits a higher frequency shift of 1200 MHz, 1270 MHz, and 1520 MHz for ethanol, methanol, and distilled water, respectively. The modified sensor also demonstrates a high sensitivity of 308 MHz/RIU for ethanol concentration which is the highest among the existing microwave sensors. The sensors in this manuscript are suitable for multiple liquid-material-sensing applications.

Dual-band dual-polarized sub-6 GHz phased array antenna with suppressed higher order modes

This manuscript proposes a dual-band dual-polarized 64-element phased array antenna (PAA) with suppressed higher order modes (HoMs). Each array element is a microstrip patch structure with complementary split ring resonator (CSRR) loading, allowing for simultaneous dual-band and dual-polarization performance at 3.45 GHz and 3.87 GHz. The proposed PAA exhibits impedance matching of ≤-20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le - 20$$\\end{document} dB at 3.45 GHz and 3.87 GHz while limiting the mutual coupling below -19\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$- 19$$\\end{document} dB between the adjacent elements at both the operating bands. The proposed design includes a plated through hole placed near the CSRR loading to suppress any higher-order modes (HOMs). Two antenna prototypes, without and with HOMs suppression techniques are fabricated and measured. In addition, we demonstrate the beam steering of the proposed PAA up to ±600\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm 60^0$$\\end{document} using an off-the-shelf 6-bit phase shifter module. The proposed 64 -element array achieves a gain of 23 dBi, and shows a minimal steering loss of ≃3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\simeq 3$$\\end{document} dB over the steering angle.

Enhanced accuracy and high sensitivity in dielectric characterization through a compact and miniaturized metamaterial inspired microwave sensor

This academic paper introduces a novel sensor known as the Planar Microstrip-based Triple Ring Bridge Complementary Split Ring Resonator (TRB-CSRR) sensor. The main objective of this sensor is to determine the permittivity and thickness of solid dielectric substances. The TRB-CSRR sensor is meticulously designed to resonate precisely at a frequency of 4.86 GHz, achieving a significant notch depth of −33.5 dB. This configuration displays an enhanced average relative sensitivity of 20.2%. The study undertakes numerical assessments across various scenarios, encompassing situations where the sensor interacts with diverse dielectric materials. These assessments yield insights into alterations in resonant frequencies. By meticulously refining the design, the sensor's capability to confine electric fields precisely at the resonant frequency is amplified, ultimately resulting in heightened sensitivity towards dielectric characteristics. The sensor's efficacy is tested using materials featuring relative permittivity values spanning from 1.006 to 12.9, while consistently adhering to dimensions of 5 mm×5 mm×1.6 mm. To validate the conceptual frame-work, a physical sensor is fabricated, and its response is gauged through the utilization of a vector network analyzer (VNA-AV3672D). Employing curve fitting methodologies, alterations in resonance frequencies due to interactions with the tested materials are presented, underscoring the impact of permittivity and thickness. The outcomes derived from simulations, empirical measurements, and calculations display a robust alignment.

Dual circular complementary split ring resonator based metamaterial sensor with high sensitivity and quality factor for textile material detection

In this paper, a novel metamaterial sensor with excellent sensitivity and quality factor for microwave sensing applications is presented. The designed metamaterial sensor is assembled on a 1.575 mm thickness of low-cost dielectric substrate material (Rogers RT5880), and the copper is used as a resonator. Computer Simulation Technology version 2019 (CST-2019) software is employed to design and analyze the proposed metamaterial sensor. In addition, the Advanced Design System version 2016 (ADS 2016) software is used to validate the CST simulated model. Subsequently, the simulated results were validated using laboratory measurements. The optimized cell is small; its dimension is 10 × 10 mm2, and the obtained resonances are 3.85 and 6.85 GHz with notches of −26.29 and −40.03 dB, respectively. The textile material is detected by the resonance frequency change, and this frequency is dependent on the material’s permittivity values. To test the developed sensor’s sensing capabilities, three types of textiles—wool, fleece, and denim—are used. The effective medium ratio, sensitivity, and Q-factor of the structure are evaluated, and the obtained values are 8.96, 14.57%, and 345, respectively. The sensor for detecting textile materials works in the S and C bands. The resonances are shifted 530 MHz between the air and wool, 420 MHz between the air and fleece, and 640 MHz between the air and denim. The simulated outcomes and laboratory results almost matched. The projected sensor can be employed in the apparel sector to identify textile materials because it is small, inexpensive, has a high quality factor, and has high sensitivity.

Design and performances improvement of an UWB antenna with DGS structure using a grey wolf optimization algorithm

In this article, we propose the design of a rectangular-shaped patch antenna suitable for ultra-wideband (UWB) applications and short and long–range Millimeter-Wave Communications. We begin with the design of a high-gain UWB rectangular patch antenna featuring a partial ground plane and operating within the 3.1–10.6 GHz bandwidth. Complementary Split Ring Resonators (CSRRs) are integrated on both sides of the structure to meet desired specifications. The resulting UWB antenna boasts an extended frequency bandwidth, covering 2.38–22.5 GHz (twice that of the original antenna), with a peak gain of 6.5 dBi and an 88% radiation efficiency. The grey wolf optimization technique (GWO) determines optimal structural dimensions. Validation of the antenna's performance is demonstrated through the strong agreement between measurement and simulation.

A Ka-band one-dimensional beam scanning leaky-wave antenna based on liquid crystal

Fixed frequency beam-scanning leaky-wave antennas have been a focus of attention for many scholars in recent years, and numerous related results have been obtained. However, these antennas suffer from several issues such as small beam-scanning range, low gain, and unsatisfactory impedance matching. To address these problems, this paper proposes a microstrip line (ML) antenna unit based on liquid crystal (LC) materials etched Complementary Split Ring Resonator (CSRR). In a first-of-its-kind approach, the substrate integrated waveguide (SIW) structure and the ML transmission structure are combined to present the SIW-ML transmission structure. The antenna operates in the Ka-band with excellent resonance characteristics at 34.7 GHz, and the S11 parameters are below − 13 dB in the frequency range of 30–40 GHz, indicating outstanding impedance matching. By arranging 56 antenna units, a periodic leaky-wave antenna is created, enabling fixed-frequency beam-scanning at 34.7 GHz. Experimental results show that the antenna can achieve scanning of angles between − 53° and + 60° with a gain of up to 12.63 dB. Once single-beam scanning is achieved, a method combining LC and discrete amplitude weighting technique, as well as multi-beam theory, is proposed for multi-beam study. Experimental results reveal that the designed 56-unit beam-scanning antenna can effectively realize beam scanning in two directions.

A hybrid energy supply system based on metamaterial antenna integrated solar cells for IoT nodes

In this paper, a hybrid energy supply system based on solar cells integrated metamaterial (MTM) antenna is presented for use in Internet of Things (IoT) nodes. The work develops an energy supply system having dimensions of 40×40 mm2, that is qualified for storing and releasing energy. To realize miniaturization technique and gain enhancing, the design of antenna employs complementary split-ring resonator (CSRR) and a 4×1 array. Meanwhile, this work is miniaturized by integrating solar cells on the substrate. The result is a very compact integrated antenna with overall dimensions of 82.5×33 mm2 and the ability to harvest radio frequency (RF) energy and solar energy, which covers frequency band from 5.2 to 6.2 GHz. Different antenna structures were built to analyze S11 spectra, voltage standing wave ratio (VSWR), radiation patterns and surface current distribution, respectively. For further verification, the design was fabricated and compared to the simulated one. Moreover, practical experiments were conducted with four kinds of environment setup. The fabricated antenna provides maximum voltage of 1.63 V, indicating a good applicability to RF energy harvesting. The energy supply system provides a stable output voltage with 2.9 V in different conditions. The results highlight the feasibility of energy supply system in energy harvesting and powering for various IoT nodes.