Elliptical Resonator Research Articles

A Novel High Common‐Mode Suppression Balanced Bandpass Filter With Elliptical SIW Resonator

ABSTRACTA novel substrate integrated waveguide resonator, specifically an elliptical SIW resonator (ESIWR), is proposed in this research. Due to the incomplete symmetry of ESIWR, compared to circular SIW resonator (CSIWR), the natural resonance frequencies of the first degenerate modes TMC110 and TMS110 are different. Additionally, by incorporating C‐slotlines, the coupling between the two ESIWRs is enhanced. Moreover, transmission zeros are introduced through source‐load coupling to enhance frequency selectivity. Furthermore, the use of meandering technique reduces the resonant frequency and lowers the relative size λg by 12.1%. The simulation and measurement results are in good agreement, demonstrating the realization of three transmission zeros with out‐of‐band suppression levels of 56.5, 68.1, and 69.3 dB, respectively, indicating excellent out‐of‐band suppression performance. Additionally, the measured minimum common‐mode suppression within the passband exceeds 55.8 dB, metal perturbation columns loading desirable common‐mode suppression. Based on the simulation and measurement results, this novel filter is well‐suited for RF front‐end devices in complex electromagnetic environments.

Polarization-controlled Brillouin scattering in elliptical optophononic resonators.

The fast-growing development of optomechanical applications has motivated advancements in Brillouin scattering research. In particular, the study of high-frequency acoustic phonons at the nanoscale is interesting due to the large range of interactions with other excitations in matter. However, standard Brillouin spectroscopy schemes rely on fixed wavelength filtering, which limits their usefulness for the study of tunable optophononic resonators. It has been recently demonstrated that elliptical optophononic micropillar resonators induce different energy-dependent polarization states for the Brillouin and the elastic Rayleigh scattering and that a polarization filtering setup could be implemented to increase the contrast between the inelastic and elastic scattering of the light. An optimal filtering configuration can be reached when the polarization states of the laser and the Brillouin signal are orthogonal to each other. In this work, we theoretically investigate the parameters of such polarization-based filtering techniques to enhance the efficiency of Brillouin scattering detection. For the filtering optimization, we explore the initial wavelength and polarization state of the incident laser, as well as the ellipticity of the micropillars, and reach an almost optimal configuration for nearly background-free Brillouin detection. Our findings are one step forward in the efficient detection of Brillouin scattering in nanostructures for potential applications in fields such as optomechanics and quantum communication.

Elliptical micropillars for efficient generation and detection of coherent acoustic phonons

Coherent acoustic phonon generation and detection assisted by optical resonances are at the core of efficient optophononic transduction processes. However, when one is dealing with a single optical resonance, the optimum generation and detection conditions occur at different laser wavelengths, i.e., different detunings from the cavity mode. In this work, we theoretically propose and experimentally demonstrate the use of elliptical micropillars to reach these conditions simultaneously at a single wavelength. Elliptical micropillar optophononic resonators present two optical modes with orthogonal polarizations at different wavelengths. By using a cross-polarization-scheme pump-probe experiment, we exploit the mode splitting and couple the pump beam to one mode while the probe is detuned from the other mode. In this way, at a particular micropillar ellipticity, the phonon-generation and phonon-detection processes are both enhanced. We report an enhancement of the coherent-phonon-generation-detection process by a factor of approximately 3.1 when comparing the highest achievable signals from elliptical and circular micropillars. Our findings constitute a step forward in tailoring light-matter interaction for more-efficient ultrahigh-frequency optophononic devices. Published by the American Physical Society 2024

Enhancing connectivity/mobility in WBAN applications through detachable wearable multi-band MIMO antenna

The connectivity and mobility of a miniaturized multi-band four-port textile leaky wave multiple-input multiple-output (MIMO) antenna designed on a layer of denim (εr = 1.6, tanδ = 0.006) is enhanced by integrating it with two detachable spiral buttons designed on circular PTFE substrate (εr = 2.1, tanδ = 0.001). The connectivity and mobility enhancement of the proposed antenna is evaluated in terms of radiation and diversity parameters. Nested hexagonal split rings behind the buttons, U-shaped slots on textiles, a comb-shaped neutralization network, and an aperture-coupled feed technique are utilized. The unique structure of the buttons on a rigid substrate and the leaky wave antenna on the textile and their integration, the periodic nested elliptical and circular split ring resonators (CSRRs) slots on the aperture coupled to ground, are to expand the connectivity and mobility of the proposed MIMO antenna by offering multiple bands, higher isolation, broadside radiation, and low specific absorption rate (SAR). The leaky wave and button antennas have dimensions of 40 × 30 × 1 mm3 and a diameter of only 13 mm, respectively. The operational bands are 0.86–2.75 GHz, 2.9–4.85 GHz, 5.75–6.15 GHz, and 8–9.85 GHz, covering the L, C, S, and X bands. Additionally, diversity performance is evaluated by defining the envelope correlation coefficient (ECC), diversity gain (DG), Channel Capacity Loss (CCL), and mean effective gain (MEG). The simulation and measurement findings are in good agreement. Following that, it offers a maximum gain of 8.25 dBi, low SAR (<0.05), an ECC below 0.05, DG above 9.85 dB, CCL< 0.25 bits/s/Hz, MEG <−3 dB, Circular polarization (CP), and strong isolation (>22 dB) between every two ports. These features make the proposed antenna an ideal option for MIMO communications and suitable for wireless local area network (WLAN) and fifth-generation (5G) communications.

Enhancing gain and isolation of a quad-element MIMO antenna array design for 5G sub-6 GHz applications assisted with characteristic mode analysis

This paper presents a novel quad-element array with multiple inputs and multiple outputs (MIMO) designed for 5th generation sub-6 GHz applications. The MIMO system achieves a wide impedance bandwidth, high gain, and high isolation among its components, representing significant advancements in sub-6 GHz antenna applications. The single element, an elliptical resonator with a circular slot, is fed by a 50 Ω microstrip feedline, achieves a broad characteristic bandwidth from 3.7 to 5.7 GHz with a resonant frequency of 4.33 GHz and a gain of 1.81 dBi. Characteristic Mode Analysis (CMA) was employed to elucidate the evolution phases of this design. The quad-element MIMO antenna array maintains a compact size and broadband characteristics by arranging mirrored elements on the same ground plane. Implemented on a cost-effective FR-4 substrate measuring 44 × 44 × 1.6 mm3, the recommended MIMO antenna array, enhanced with a partial ground plane and due to the introduction of a vertical strip, a high isolation of − 38.53 dB is achieved between MIMO components along with a realized gain of 3.01 dBi and a radiation efficiency of 71% in the 5G sub-6 GHz band. Noteworthy properties include high isolation, diversity gain (DG), and envelope correlation coefficient (ECC), verifying the appropriateness of the suggested MIMO scheme for 5G transmission and reception in sub-6 GHz applications.

Polarization-Selective Enhancement of Telecom Wavelength Quantum Dot Transitions in an Elliptical Bullseye Resonator.

Semiconductor quantum dots are promising candidates for the generation of nonclassical light. Coupling a quantum dot to a device capable of providing polarization-selective enhancement of optical transitions is highly beneficial for advanced functionalities, such as efficient resonant driving schemes or applications based on optical cyclicity. Here, we demonstrate broadband polarization-selective enhancement by coupling a quantum dot emitting in the telecom O-band to an elliptical bullseye resonator. We report bright single-photon emission with a degree of linear polarization of 96%, Purcell factor of 3.9 ± 0.6, and count rates up to 3 MHz. Furthermore, we present a measurement of two-photon interference without any external polarization filtering. Finally, we demonstrate compatibility with compact Stirling cryocoolers by operating the device at temperatures up to 40 K. These results represent an important step toward practical integration of optimal quantum dot photon sources in deployment-ready setups.

High-efficiency electromagnetic energy harvesting using double-elliptical metasurface resonators.

This study introduces a metasurface (MS) based electrically small resonator for ambient electromagnetic (EM) energy harvesting. It is an array of novel resonators comprising double-elliptical cylinders. The harvester's input impedance is designed to match free space, allowing incident EM power to be efficiently absorbed and then maximally channelled to a single load through optimally positioned vias. Unlike the previous research works where each array resonator was connected to a single load, in this work, the received power by all array resonators is channelled to a single load maximizing the power efficiency. The performance of the MS unit cell, when treated as an infinite structure, is examined concerning its absorption and harvesting efficiency. The numerical results demonstrate that the MS unit cell can absorb EM power, with near-perfect absorption of 90% in the frequency range of 5.14 GHz to 5.5 GHz under normal incidence and with a fractional bandwidth of 21%. The MS unit cell also achieves higher harvesting efficiency at various incident angles up to 60o. The design and analysis of an array of 4x4 double elliptical cylinder MS resonators integrated with a corporate feed network are also presented. The corporate feed network connects all the array elements to a single load, maximizing harvesting efficiency. The simulation and measurement results reveal an overall radiation to AC efficiency of about 90%, making it a prime candidate for energy harvesting applications.

Systematic Analysis of Rotated Dual-Split Elliptical SRR with Band-Stop Characteristics

In this research article, a novel double-split elliptical split ring resonator (DS-ESRR) is proposed to achieve frequency-notching behavior of ultrawideband filtenna, where the semimajor and minor axes of the ellipse are taken as a bivariate random variable and expressed in Ramanujan’s correction coefficient so that more degree of freedom is available for choosing degenerated impedance and thus for variable frequency-notching applications. To verify this hypothetical method, finite sets of variables for DS-ESRR are presented in this proposed work, and a mathematical expression is formulated to estimate the resonant frequency of the DS-ESRR, such that for practical applications, frequency-notching parameters can be easily estimated accurately rather than previously used SRR like circular or square-shaped geometry. DS-ESRR is deployed at the back of a CPW-fed ultrawideband antenna for notching filter application, and the computed data is compared with the eigen mode simulation results which reveal good agreement with each other.

Double elliptical resonator based quad-band incident angle and polarization angle insensitive metamaterial absorber for wireless applications

In this article, a double elliptical split ring resonator-based quad band metamaterial absorber (MMA) is demonstrated for applications in the microwave range. The resonator is made up of four squares outside split rings and two elliptical split rings positioned in the middle of the structure. The resonating patch is placed over an FR-4 dielectric layer with a thickness of 1.6 mm. The unit cell has an electrical size of 0.103λ0 × 0.103λ0, where λ0 is the wavelength determined at 2.576 GHz. The MMA shows maximum absorption of 99.83% at 2.576 GHz, 99.98% at 5.648 GHz, 99.56% at 8.32 GHz, and 99.15% at 13.456 GHz with TE mode. For TM mode, at 2.576 GHz, 5.632 GHz, 8.304 GHz, and 13.44 GHz, corresponding absorptions are 99.21%, 99.67%, 99.5%, and 99%, respectively. The MMA is polarisation and incidence angle (0° to 90°) insensitivity for both TM and TE modes. The unit cell provides single negative characteristics including an EMR (effective medium ratio) of 9.71 and a Q factor (quality factor) over 25. The proposed MMA provides high harvesting efficiencies of 92.87%, 76.9%, 94.12%, and 90.97% for frequencies of 2.57 GHz, 5.64 GHz, 8.32 GHz, and 13.45 GHz, correspondingly. The equivalent circuit is modeled to understand the resonance behavior of the MMA and the circuit parameters are determined and validated using Advanced Design Systems (ADS) software. The performance of the MMA is examined using the prototype of the array of the unit cells in an experimental setup. The experimental outcome provides a close similarity with simulation outcomes indicating the good performance of the MMA. The metamaterial absorber's high performance makes it suitable for many applications, such as RF energy harvesting applications, image technologies, stealth technologies, and radar systems as well as minimizing electromagnetic interference in satellites.

Design a Wilkinson power divider with improved passband and rejection band

ABSTRACT In this paper, a Wilkinson power divider based on a new harmonic suppressor structure is proposed with suppressed harmonics and improved operating band parameters. The proposed suppressor structure consists of three resonators. The first resonator is an elliptic rectangular shaped resonator with a short base line and two slots. These slots decrease the resonant frequency location, without changing the dimensions of the resonator. This mode has been fully analysed by investigating the effect of surface current density. The second resonator is an elliptic resonator with a long base length to suppress the second harmonic. The third resonator is a rectangular suppressor to suppress higher order harmonics. The proposed power divider is fabricated and measured. The operating frequency of this power divider is 1.26 GHz, the return loss is 31.5 dB and the insertion loss is 3.1 dB. The operating bandwidth is from 0.99 to 1.4 GHz with a return loss better than 15 dB which shows the fractional bandwidth of FBW = 34%. The second to sixth harmonics have suppression level better than 50 dB, and for higher harmonics up to the 14th harmonic, they have suppression level better than 25 dB.

Metamaterial graphene sensors for the detection of two food additives.

Food safety is an important consideration for the food industry and for daily life, and food additives are essential in the modern food industry. Graphene-based metamaterial sensors are of great value and have potential applications in the detection of food additives, due to their ultra-sensitivity. This paper proposes a metasurface sensor consisting of graphene and dual elliptical ring resonators (Gr-DERRs) sensor for the detection of two common food additives. The limit of detection (LOD) for Sudan I solution is 581.43 fg/ml and, for taurine, 52.86 fg/ml. This ultra-sensitive detection is achieved by exploiting the unique electromagnetic properties of electromagnetically induced transparency (EIT) resonance, together with the Fermi energy level of graphene moving to the Dirac point, resulting in a dramatic change in the dielectric environment. The Gr-DERRs sensor has brings significant improvement in the detection of food additives with detection limits reduced to the femtogram level.

High-performance plasmonic band-pass / band-stop / cut-off filter using elliptical and rectangular ring resonators

A plasmonic filter including Metal-Insulator-Metal waveguides (MIM) with an elliptical ring resonator is proposed. Using the Finite Difference Time Domain (FDTD) method, we analyze the amount of transmittance in the structure. The results show the creation of five resonance modes with narrow FWHM and suitable transmittance at the resonance points of the spectrum. The resonance wavelength and transmittance at the resonance points are tuned by changing the device geometry. In this structure, preventing the transmittance of the spectrum creates a band-gap between the wavelengths 919 nm–1388 nm, which by changing the size of the structure, the band-gap width changes. This filter also cuts off the transmission of wavelengths greater than 1707 nm. By adding a rectangular ring resonator outside the elliptical ring resonator, the performance of the device was improved and the transmittance included very narrow resonance modes. Due to the number of resonance modes and their narrow FWHM, the introduced structures can be used as devices for filtering several wavelengths, which significantly reduces costs and enhances economic efficiency for the production of plasmonic band-pass filters. Also, this structure can be used as band-stop and cut-off filters. This multiplicity of functions makes it cost-effective to use the proposed device for making integrated optics devices.

A UWB bandpass filter based on elliptical open stub-loaded resonator and dumbbell-sided cross-circle DGS

An Ultra-wideband (UWB) bandpass filter (BPF) based on an elliptical open stub-loaded resonator (EOSLR) and dumbbell-sided cross-circle (DSCC) defected ground structure (DGS) is proposed in this paper. The measured results show that the 3 dB bandwidth of the filter is 3.49 ∼ 11.04 GHz, the skirt factor (S.F) is 0.844, the upper stopband rejection is greater than 20 d B at 11.70 ∼ 26.80 GHz, and the stopband width is 15.1 GHz. The proposed filter has the advantages of high selectivity and extremely broad upper stopband and it can be applied in UWB Wireless communication system.

Nanoscale plasmonic combinational logic circuits based on an elliptical resonator.

The half-adder (HA) and half-subtractor (HS) plasmonic combinational logic circuits are explained using a finite element method with a COMSOL software package. The combinational circuits are created using insulator-metal-insulator technology with nanoscale plasmonic structures. In order to achieve an excellent transmission value, the phase angle of optical waves and the position of the control and input ports are the more crucial elements. In this design, the nanoscale combinational circuits are realized at a 35% transmission threshold to distinguish between the logic "0" and logic "1" stand on the interference between the input and control ports with 540n m×250n m dimensions and an 850nm resonant wavelength. The modulation depth, contrast ratio, and insertion loss have 97.38%, and 11.84 and 3.3dB for the HA, and they have 92.38%, and 7.12 and -1.41d B for the HS, respectively.

Nanoscale plasmonic logic gates design by using an elliptical resonator.

This study implemented AND, NAND, OR, XOR, NOR, XNOR, and NOT plasmonic logic gates using the finite element method. The all-optical nanoscale logic gates were designed using a single structure based on the technology of insulator-metal-insulator nanoscale plasmonic waveguides. The phase of optical waves and the position of the control and input ports are the most important factors for attaining the optimal transmission value based on interference between the input and control ports. The transmission threshold is 35%, and 850 nm is the operating wavelength. This design creates nanoscale logic gates with a structure dimension of 250nm×250nm. The transmission threshold, modulation depth, contrast ratio, and insertion loss criteria were proposed to evaluate the efficacy of the all-optical gates.

Detection of viral and bacterial diseases using 2D photonic crystal-based elliptical ring resonator sensor

Our proposed work analyzes and models the photonic crystal (PhC)-based elliptical ring resonator for detecting viral and bacterial infections. Optical sensors show extreme results as sensing devices. So, they are broadly accepted in the medical field for the rapid and effective diagnosis of diseases. Optical biosensors are designed to detect cancer, malaria, typhoid, tuberculosis, etc. The principle behind the working of optical biosensors is a shift in the peak resonance wavelength corresponding to the small changes in the refractive index values. Due to the rapid mutation and replication of viral pathogens in the human cell nucleus, there is high demand for sensors that provide accurate results for viral and bacterial diseases in seconds. Hence, optical biosensors can give results in a short amount of time with a high sensitivity. The proposed sensor achieved a high sensitivity of 881.25 nm / RIU for tuberculosis and 555.55 nm / RIU for hepatitis B. The quality factor and figure of merit is also calculated, and their values come out to be 624.37 and 346.38, respectively, in the case of typhoid and Bacillus cereus. The platform used for simulating the analytes is the finite-difference time-domain.

A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces

We present strong enhancement of third harmonic generation in an amorphous silicon metasurface consisting of elliptical nano resonators. We show that this enhancement originates from a new type of multi-mode Fano mechanism. These ‘Super-Fano’ resonances are investigated numerically in great detail using full-wave simulations. The theoretically predicted behavior of the metasurface is experimentally verified by linear and nonlinear transmission spectroscopy. Moreover, quantitative nonlinear measurements are performed, in which an absolute conversion efficiency as high as ηmax ≈ 2.8 × 10−7 a peak power intensity of 1.2 GW cm−2 is found. Compared to an unpatterned silicon film of the same thickness amplification factors of up to ~900 are demonstrated. Our results pave the way to exploiting a strong Fano-type multi-mode coupling in metasurfaces for high THG in potential applications.

Reconfigurability analysis of an all‐dielectric thermal microfluidic‐based metasurface

AbstractMetasurface tuning is performed using different ways for a wide range of applications. This study presents the design of a thermally‐tuned all‐dielectric reconfigurable metasurface. A microfluidic channel, filled with different concentrations of tellurium–selenium (Te‐Se) alloy, is added on the top of the elliptical dielectric resonator (EDR) unit cell of the considered metasurface. The electrical properties of used semiconductor alloy are varied in the range of 400 to 700°C (steps size of 100°C). The impact of thermal tuning on the reflection and transmission characteristics of the designed metasurface is analyzed in the frequency range of 20–30 GHz using COMSOL Multiphysics. Obtained results demonstrated that the realized metasurface exhibits reconfigurable behavior in terms of variations in the reflection and transmission characteristics with a change in either temperature or concentrations of selenium and tellurium. The wider bands with high reflection and low transmission frequency bands are obtained with lower concentrations of selenium and tellurium for all operating temperatures.

Double elliptical resonator based quadruple band metamaterial absorber for EMI shielding applications in microwave regime

A quadruple band wide angle polarization insensitivity metamaterial absorber based on double elliptical resonator structure for electromagnetic interference (EMI) shielding applications in microwave regime has been considered in this paper. The proposed metamaterial absorber (MA) unit cell comprises of a top metallic resonating patch and a ground copper, both of which are separated by an inexpensive FR-4 substrate with a thickness of 0.0185λ and an electrical size of 0.138λ, at lowest resonance frequency. The proposed MA demonstrates the peak absorption of 97 %, 99.9 %, 99.9 % and 99.6 % at 3.46 GHz, 6.44 GHz, 7.89 GHz and 12.44 GHz, respectively for transverse-electric (TE) mode at normal incidence. The quadruple band absorption mechanism has been understood by the analysis of electromagnetic field with surface current distribution. In addition, the designed MA also exhibits near unity absorption for a polarization and oblique incident angle up to 60° for TE mode. The proposed MA offers greater than 35 dB shielding effectiveness in all bands under both simulated and measured environment. The designed MA has been fabricated and measured to validate the simulation results. The agreement between the measured and simulated results allow for EMI shielding applications in microwave regime.

Development of a continuous operation hop-kiln with power supply

Introduction.Hop production in the Russian Federation averages 116 thousand tons from 54 thousand hectares. The HS-400 hop-kiln used in the hop drying process line is energy-intensive. The concept of hop growing development in the Chuvash Republic for 2020–2025, approved by the decree of the Cabinet of Ministers of the Chuvash Republic (dated 20.08.2020 No. 738-r), provides for the development of up to 45–50 hectares of new areas for hop, at the rate of 15–17 hectares per one hop-kiln HS-400. To expand the production of hop, it is necessary to effectively master innovative technologies and installations for drying freshly harvested hop that are not inferior in technical and economic parameters of foreign analogues. The development of a hop-kiln that provides dehydration and disinfection of freshly harvested hop, pre-servs consumer properties with reduced operating costs, is currently relevant.Methodology.The electrophysical parameters of hop cones (according to the Rogov method) were analyzed depending on the frequency of the electromagnetic field, humidity and temperature, heat and mass transfer processes during the supply of convective heat to the volumetric resonator of the microwave installation were theoretically investigated, and the effective technological parameters of the hop-kiln were determined. Studies of the electromagnetic field strength, current density, and intrinsic Q-factor of resonators were carried out in the CST Studio Suite 2017 three-dimensional computer modeling program and its CST Microwave Studio subprogram.Results.A multi-resonator hop-kiln with an energy supply in an electromagnetic field has been developed. The proposed hop-kiln contains resonators sequentially arranged in a horizontal plane with curved surfaces, docked through ceramic biconvex perforated plates. The design and technological scheme of the hop-kiln has been developed. The intrinsic Q-factor of elliptical toroidal resonator is 14600, of triangular prismatic resonator — in the range of 9000–1200, depending on the degree of concavity of the upper face. The calculation of the installation productivity amounts to 180–200 kg/h with a power of 15.66 kW, which made it possible to determine energy costs — to 0.1 kWh/kg.