Double Ring Resonator Research Articles

Plasma refractive index sensor based on MIM waveguide coupled with analogy T-shaped and double-ring resonators

Plasma refractive index sensor based on MIM waveguide coupled with analogy T-shaped and double-ring resonators

Temperature and refractive index sensor based on perfect absorber in InSb double rectangular ring resonator metamaterials

InSb is an important semiconductor material in the field of optoelectronic devices due to its high electron and hole mobility, low effective mass, and low energy gap at room temperature. In this paper, a thermally controlled dual-band terahertz metamaterial absorber with a patterned InSb film is designed and studied. The unit cell of the proposed metamaterial is composed of combined InSb double rectangular ring resonators (DRRR) adhered on a continuous gold layer and substrate. Finite-difference-time-domain (FDTD) simulation results demonstrate that the absorption peak can reach 98.95 %, and 99.45 % at 1.499 THz and 1.592 THz when the external environment temperature is 283 K. Electric field distribution and parameter sweep indicate the two absorption peaks result from the near-field coupled linear superposition between the big square and small square resonators. The proposed absorber not only has the features of wide incident-angle stability, but also polarization insensitivity. Besides, the proposed absorber shows temperature-tunable features due to the temperature-dependent variation of the permittivity of InSb material. The InSb pattern proposed in this paper provides an alternative method for designing of dual parameters sensor in the terahertz band, the proposed dual-band absorber can function as a temperature sensor with sensitivities of about 8.6 GHz/K and 12.8 GHz/K, respectively. The proposed dual-band absorber can also be used as a refractive index sensor with sensitivities of about 1.065 THz /RIU, and 0.499 THz /RIU, respectively. Therefore, the present work provides an effective method for implementing thermally and refractive index sensors in the terahertz range.

Design and development of graphene-based double split ring resonator metasurface biosensor using MgF2-gold materials for blood cancer detection

Design and development of graphene-based double split ring resonator metasurface biosensor using MgF2-gold materials for blood cancer detection

High-Q factor terahertz metamaterial sensor based on quasi-BIC

In this paper, we proposed a terahertz (THz) metamaterial sensor, which consists of an array with two mirrored double split ring resonators (DSRRs) in one unit cell deposited on a lossless polyimide substrate. The THz spectral response show that when the two DSRRs in one unit cell are mirror symmetric and center symmetric simultaneously, two types of symmetry-protected bound states in the continuum (BICs) can be generated with the incident polarization unchanged. When the gaps are on the short or long arms of DSRRs, different modes of BIC can be observed. By breaking the symmetry of the structure with the gaps deviating from the center line of the DSRRs, quasi-BICs can be achieved, which can provide high Q-factors for our designed THz metamaterial sensor. The performance of the sensor is also evaluated, which has the characteristics of high Q-factor, high sensitivity, and high linearity. The integration of quasi-BIC and THz sensing technology will help solve the problems faced in the design of ultra-high Q-factor THz sensors and further expand the applications of terahertz technology.

Compact design of circularly polarized microstrip patch antenna with double slip ring resonator for vehicle-to-vehicle communication

The paper mainly focuses on the compact design of circularly polarized microstrip patch antenna for vehicle-to-vehicle communication. The charging time of electric vehicle is longer waiting time than compared to traditional gasoline-based vehicles. The charging is done at the public charging stations. When the vehicles need charging while driving, they communicate with Dedicated Short Range Communications (DSRC) band to send the information to the nearest vehicles and receive information from the charging station. Moreover, DSRC band is used in many applications area such as Intelligent Transportation System (ITS), Electronic Toll Collection (ETC), Collision Avoidance, and connected vehicles. The research problem in this study is that when installing an antenna on a vehicle, it is important to have a compact size and achieve circular polarization. The research solution for the problem statement in this study is emphasized on 45? inclined slot and corner trimmed is added in rectangular patch to make the current part longer and the impedance matching better, and to get circular polarization. After that, Swiss roll structure CSRR is added in ground plane to improve bandwidth. Finally, outer SRR is added in the ground plane to improve S11. The proposed design has been validated for car-to-car (5.85-5.925 GHZ) communication.

A new SOI sensor design for detecting cancer using hybrid waveguide with higher sensitivity than both strip and slot waveguides

A new highly accurate optical biomedical sensor is proposed for cancer detection characterized by high sensitivity, small footprint, low cost, and low limit of detection. The sensor is based on double-ring resonators made of silicon on insulator. The type of the waveguide is critical in determining the sensor performance. To compromise the advantages and disadvantages of strip and slot waveguides, a mixed design of both has been introduced in literature at the expense of increased footprint compared to traditional sensors. Indeed, almost 27-fold footprint increase is required to improve the sensitivity by only one third of that of slot waveguide’s sensitivity. In this paper, we introduce a new design that keeps the same footprint of traditional sensors, while achieving high sensitivity. This sensitivity depends on the resonance wavelength shift due to different refractive indices of the biosample. It has the value 109.8 nm/RIU compared to 55.57 nm/RIU and 129.621 nm/RIU for strip and slot waveguides, respectively. The hybrid waveguide quality factor is 537.7 while the quality factors of the strip and the slot waveguides are 627.99 and 380.76, respectively. In addition, the new design achieves the minimum limit of detection (0.0255) when compared to that of traditional designs. Furthermore, a new method of detection is proposed with the same design, providing a higher sensitivity over both traditional waveguide types with a value of 15.3, compared to 13.2 and 11.5 for strip and slot waveguides, respectively. In this method, the sensitivity relies on various values of output transmitted light at the same wavelength due to altering the biocell refractive index. The biosensor output equation is developed. In addition, the relationship between the supermodes and the sensitivity is determined at variance conditions. It is found that there is an inverse relation between them.

Tunable asymmetric square split ring resonator based triple band metamaterial absorber for wireless communication system

This article presents a triple band square split ring with double circular split ring resonator incident angle-insensitive perfect metamaterial absorber. The MMA unit cell was manufactured using a FR4 substrate that had dimensions of 8 mm by 8 mm. With the flexibility of on-design adjusting of the highest absorption frequencies, the suggested MA displays peak absorption of 99.67 %, 99.85 %, and 99.97 % at 2.52 GHz, 6.99 GHz, and 9.28 GHz, correspondingly. The tuning metallic two circular split rings and square split ring resonator provide the possibility of frequency modification throughout three distinct frequency ranges: the first frequency range extends from 2.45 GHz to 2.53 GHz, the second frequency range extends from 6.91 GHz to 7 GHz, and the third frequency range extends from 8.85 GHz to 10.32 GHz. Furthermore, the suggested MA displays near-zero absorption at an oblique incidence angle of up to 45° for both the TE as well as TM modes. The unit cell demonstrates single negative properties, such as an effective medium ratio (EMR) of 14.88 and a quality factor (Q factor) that is more than 30 for both the TM mode as well as the TE mode. An equivalent circuit successfully demonstrated its performance capability, which indicated that it would create an MMA of good quality when using ADS software. A comparison between the measured results of the suggested MMA and the simulated one reveals that there is a significant amount of a similarity between both of them. Because of its easy design within small dimension, wide angular stability, strong absorption, good EMR, and flexibility to frequency tuning is suitable for a wide range of wireless communication system, especially satellite applications like electromagnetic interference reduction, radar systems, imaging, and stealth technology.

Packet Header Recognition Utilizing an All-Optical Reservoir Based on Reinforcement-Learning- Optimized Double-Ring Resonators

Packet Header Recognition Utilizing an All-Optical Reservoir Based on Reinforcement-Learning- Optimized Double-Ring Resonators

Highly sensitive DS-CSRR based microwave sensor for permittivity measurement of liquids

In this work, a low-cost double split complementary split ring resonator (CSRR) microwave sensor has been designed and fabricated on an FR4 substrate for permittivity characterization of liquids. This modified CSRR structure is proposed to make use of the benefits of the dielectric resonator technique compared to other types of microwave methods. The resonator structure comprises two slits in each of the rings normal to each other while maintaining one slit in each ring along the feed line for maximum excitation of the resonator. The resonator with substrate dimensions of acts like an inductance-capacitance-resistance (LCR) circuit and operates at of the industrial scientific and medical band. Eleven different liquid samples (each with of volume) covering a wide permittivity range of have been used to measure the transmission coefficient using vector network analyzer. In comparison with many recently reported works, the sensitivity of the sensor is found to be higher with average and normalized sensitivity of permittivity and respectively. Fit equations are developed for both real and imaginary parts of permittivity, and using the fit equations the permittivity of three unknown samples are determined with less than error. The sensor adopts a unique orientation of the slits to enhance the E-field intensity for better interaction of the samples with the sensor. A compact form factor, low production cost, future integration possibilities, and high sensitivity are the distinct highlights of the sensor. The sensor promises to be a potential candidate for situations that demands low-cost and highly accurate measurements and may be a good alternative to commercial sensors for dielectric characterization, concentration analysis, and impurity measurement of liquids.

Quad-Band Metamaterial Perfect Absorber with High Shielding Effectiveness Using Double X-Shaped Ring Resonator.

This study assesses quad-band metamaterial perfect absorbers (MPAs) based on a double X-shaped ring resonator for electromagnetic interference (EMI) shielding applications. EMI shielding applications are primarily concerned with the shielding effectiveness values where the resonance is uniformly or non-sequentially modulated depending on the reflection and absorption behaviour. The proposed unit cell consists of double X-shaped ring resonators, a dielectric substrate of Rogers RT5870 with 1.575 mm thickness, a sensing layer, and a copper ground layer. The presented MPA yielded maximum absorptions of 99.9%, 99.9%, 99.9%, and 99.8% at 4.87 GHz, 7.49 GHz, 11.78 GHz, and 13.09 GHz resonance frequencies for the transverse electric (TE) and transverse magnetic (TM) modes at a normal polarisation angle. When the electromagnetic (EM) field with the surface current flow was investigated, the mechanisms of quad-band perfect absorption were revealed. Moreover, the theoretical analysis indicated that the MPA provides a shielding effectiveness of more than 45 dB across all bands in both TE and TM modes. An analogous circuit demonstrated that it could yield superior MPAs using the ADS software. Based on the findings, the suggested MPA is anticipated to be valuable for EMI shielding purposes.

Double slot micro ring resonators with inner wall angular gratings as ultra-sensitive biochemical sensors.

We simulate and demonstrate experimentally an inner-wall grating double slot micro ring resonator (IG-DSMRR) with a center slot ring radius of only 6.72 µm based on the silicon-on-insulator platform. This novel photonic-integrated sensor for optical label-free biochemical analysis boosts the measured refractive index (RI) sensitivity in glucose solutions to 563 nm/RIU with the limit of detection value being 3.7 × 10-6 RIU (refractive index units). The concentration sensitivity for sodium chloride solutions can reach 981 pm/%, with a minimum concentration detection limit of 0.02%. Using the combination of DSMRR and IG, the detection range is enlarged significantly to 72.62 nm, three times the free spectral range of conventional slot micro ring resonators. The measured Q-factor is 1.6 × 104, and the straight strip and double slot waveguide transmission losses are 0.9 dB/cm and 20.2 dB/cm, respectively. This IG-DSMRR combines the advantages of a micro ring resonator, slot waveguide, and angular grating and is highly desirable for biochemical sensing in liquids and gases offering an ultra-high sensitivity and ultra-large measurement range. This is the first report of a fabricated and measured double-slot micro ring resonator with an inner sidewall grating structure.

Near-Field Wireless Sensing of Plastics and Papers Using Frugal Peel-Off Passive Tag

This article presents a novel frugal approach of testing plastics and papers using a near-field microwave sensing technique with a peel-off tag. The proposed sensing technique involves two electrical entities: the sensor, which may be regarded as a reader, and a disposable tag. The reader is a modified design of a gap-coupled microstrip line (GCML) sensor, while the passive tag is a standard double-ring complementary split-ring resonator (CSRR) engraved on a commercially available copper foil using laser printing techniques. A detailed numerical study is presented for the engineered sensing methodology, showing the effect of the sample height, sensing distance, bending angle, and inclination. Empirical formulas associated with the dielectric properties of the sample under test are also given. The errors associated with a possible air gap between the peel-off tag and the sample, as well as the relative positioning of the tag and the reader, are analyzed while also considering the bending of the tag. Finally, the sensor is fabricated on a 1.5-mm-thick Rogers RT5880 laminate, and several standard samples are prepared to experimentally check the validity of the approach. The sensor provides a transmission bandwidth (BW) of 1.9 GHz with a typical insertion loss (IL) of 1 dB and a reflection loss of 20 dB. The tag engraved on the frugal peel-off copper foil is used for sensing various dielectric materials by placing it on planar and curved surfaces. The simulation and measured results are found to be in close agreement. The proposed scheme is found to be reliable and cost-effective also for the testing of microwave substrates. It provides robust results for the wireless sensing of objects located within a range of 10 mm from the reader.

Investigation of High-Q Lithium Niobate-Based Double Ring Resonator Used in RF Signal Modulation

In recent years, millimeter-wave communication has played a crucial role in satellite communication, 5G, and even 6G applications. The millimeter-wave electro-optic modulator is capable of receiving and processing millimeter-wave signals effectively. However, the large attenuation of millimeter waves in the air remains a primary limiting factor for their future applications. Therefore, finding a waveguide structure with a high quality factor (Q-factor) is critical for millimeter-wave electro-optic modulators. This manuscript presents the demonstration of a double ring modulator made of lithium niobate with the specific goal of modulating an RF signal at approximately 35 GHz. By optimizing the microring structure, the double ring resonator with high Q-factor is studied to obtain high sensitivity modulation of the RF signal. This manuscript employs the transfer matrix method to investigate the operational principles of the double ring structure and conducts simulations to explore the influence of structural parameters on its performance. Through a comparison with the traditional single ring structure, it is observed that the Q-factor of the double ring modulator can reach 7.05 × 108, which is two orders of magnitude greater than that of the single ring structure. Meanwhile, the electro-optical tunability of the double ring modulator is 6 pm/V with a bandwidth of 2.4 pm, which only needs 0.4 V driving voltage. The high Q double ring structure proposed in this study has potential applications not only in the field of communication but also as a promising candidate for a variety of chemical and biomedical sensing applications.

Microstrip Sensor Based on Ring Resonator Coupled with Double Square Split Ring Resonator for Solid Material Permittivity Characterization

This paper analyzes a microwave resonator sensor based on a square split-ring resonator operating at 5.122 GHz for permittivity characterization of a material under test (MUT). A single-ring square resonator edge (S-SRR) is coupled with several double-split square ring resonators to form the structure (D-SRR). The function of the S-SRR is to generate a resonant at the center frequency, whereas D-SRRs function as sensors, with their resonant frequency being very sensitive to changes in the MUT’s permittivity. In a traditional S-SRR, a gap emerges between the ring and the feed line to improve the Q-factor, but the loss increases as a result of the mismatched coupling of the feed lines. To provide adequate matching, the microstrip feed line is directly connected to the single-ring resonator in this article. The S-SRR’s operation switches from passband to stopband by generating edge coupling with dual D-SRRs located vertically on both sides of the S-SRR. The proposed sensor was designed, fabricated, and tested to effectively identify the dielectric properties of three MUTs (Taconic-TLY5, Rogers 4003C, and FR4) by measuring the microwave sensor’s resonant frequency. When the MUT is applied to the structure, the measured findings indicate a change in resonance frequency. The primary constraint of the sensor is that it can only be modeled for materials with a permittivity ranging from 1.0 to 5.0. The proposed sensors’ acceptable performance was achieved through simulation and measurement in this paper. Although the simulated and measured resonance frequencies have shifted, mathematical models have been developed to minimize the difference and obtain greater accuracy with a sensitivity of 3.27. Hence, resonance sensors offer a mechanism for characterizing the dielectric characteristics of varied permittivity of solid materials.

Broad band solar cell absorber based on double-ring coupled disk resonator structure: from visible to mid infrared

In this paper, a broad band absorber based on a double-ring coupled disk resonator periodic structure, which can work in the visible and mid infrared range, is proposed and investigated. Results show the absorbance is large than 92.4% in the range of 300 nm–4096 nm, and the average absorption is about 97.4% from the visible to mid-infrared bands. Besides, the proposed absorber is wide angle acceptance, background refractive index (RI), and polarization state insensitive. The absorption mechanisms are analyzed and found that it mainly originated from the dielectric lossy property in short-wavelength and gap plasmonic resonances in long-wavelength. It is believed the proposed absorber can find potential applications in the fields of solar cell devices, thermal emitters, and plasmonic imaging.

Design of a metamaterial chipless RFID sensor tag for high temperature

A high temperature sensor based on a metamaterial is proposed as a chipless radio frequency identification sensor tag that can measure temperature wirelessly. The metamaterial, based on a double circular split ring resonator (SRR), is highly frequency selective and has negative permittivity. The double circular SRR is fabricated on the alumina ceramic substrate, which acted as the temperature sensing material. The permittivity of the material varies with the temperature parameter, resulting in a shift of backscattered resonant frequency of the sensor tag. Simulations verify the feasibility of this sensor tag in the microwave band under electromagnetic stimuli. When the temperature increases from 200 to 1000 °C, the resonant frequency monotone decreases from 6.64 to 6.26 GHz with an average sensitivity of 0.475 MHz/°C. The sensor tag has features such as high temperature, being wireless, passive, of comparatively low-cost, and miniature, with diversified application potential, allowing it to compete with other sophisticated temperature devices in terms of performance.

Transmission-type coding metasurface with ultra-broadband polarization conversion

The advent of coding metasurfaces (MSs) has established a bond between electromagnetic scattering and digital control. Given that most of the current coding MSs are based on reflection-type, we investigate a novel transmission-type MS that can achieve ultra-wideband and efficient polarization conversion. A new double diagonal split ring resonator structure is designed to mainly constitute the unit. The 1-bit and 2-bit coding arrays are constructed using the proposed polarization rotation mechanism of the MS unit combined with the dimensional transformation to achieve beam focusing, beam deflection, and beam splitting. Finally, the broadband focusing characteristic of the coding MS is also demonstrated. Numerical simulation results demonstrate that the transmission coefficient of the proposed MS is above 90% in the frequency range of 0.4 to 2 THz, with a relative bandwidth of 133.3%. Asymmetric transmission phenomenon is observed in the range of 0.4 to 2 THz, with coefficients remaining above 80% in all ranges.The proposed coding MS can be used in terahertz polarization converters and unidirectional transmission devices due to its superior polarization conversion performance.

Broadband high-sensitivity acoustic sensing based on Brillouin random fiber laser

In this study, a broadband high-sensitivity fiber-optic acoustic sensor with simple structure and low cost based on Brillouin random fiber laser (BRFL) is proposed and demonstrated theoretically and experimentally. A double coupler fiber ring resonator (DCFRR) in the BRFL, which filters out redundant random modes and ensures high-quality lasing output, is utilized as the sensing element for acoustic sensing thanks to the high sensitivity of the transmission spectrum of the DCFRR to its cavity length variations induced by acoustic perturbations. The resultant shift in the transmission spectrum of the DCFRR by the external acoustic vibrations modulates the gain available inside the BRFL cavity and transfers the resonant random mode, leading to directly modulated lasing intensity output from the BRFL and thus the feasibility for acoustic signal recovery. The experimental results demonstrate the broadband frequency response and high sensitivity feature of the proposed BRFL-based acoustic sensor, which is able to detect acoustic signals in both low-frequency (2 Hz ∼ 500 Hz) and high-frequency (0.5 kHz ∼ 200 kHz) regions with high signal-to-noise ratio beyond 10 dB. In addition, the structural flexibility of the proposed sensor enables remote acoustic sensing, making it an ideal candidate for acoustic applications in harsh environments.

Compact and Highly Sensitive Refractive Index Sensor Based on Embedded Double-Ring Resonator Using Vernier Effect

A compact and highly sensitive liquid refractive index (RI) sensor using Vernier effect achieved with embedded double-ring resonator is proposed and demonstrated. Unlike these conventional sensors using cascaded double-ring resonators to achieve Vernier effect, in our proposed embedded double-ring sensor (EDRS) the sensing ring is embedded on the reference ring, which makes the sensor more compact while achieving high sensitivity. Our typical fabricated EDRS with polymer material, which has a footprint of 1500 μm × 850 μm, achieves the RI sensitivity as high as 7390 nm/RIU in aqueous medium, which is in excellent agreement with the theoretical one.

Reconfigurable Split Ring Resonators by MEMS-Driven Geometrical Tuning.

A novel approach for dynamic microwave modulation is proposed in the form of reconfigurable resonant circuits. This result is obtained through the monolithic integration of double split ring resonators (DSRRs) with microelectromechanical actuators (MEMS) for geometrical tuning. Two configurations were analyzed to achieve a controlled deformation of the DSRRs' metamaterial geometry by mutual rotation or extrusion along the azimuthal direction of the two constituent rings. Then, the transfer function was numerically simulated for a reconfigurable MEMS-DSRR hybrid architecture where the DSRR is embedded onto a realistic piezo actuator chip. In this case, a 370 MHz resonance frequency shift was obtained under of a 170 µm extrusion driven by a DC voltage. These characteristics in combination with a high Q factor and dimensions compatible with standard CMOS manufacturing techniques provide a step forward for the production of devices with applications in multiband telecommunications and wireless power transfer and in the IoT field.