Electric-inductive-capacitive Research Articles

Unveiling photon–photon coupling induced transparency and absorption

Abstract This study presents the theoretical foundations of an analogous electromagnetically induced transparency (EIT) and absorption (EIA) which we are referring as coupling induced transparency (CIT) and absorption (CIA) respectively, along with an exploration of the transition between these phenomena. We provide a concise phenomenological description with analytical expressions for transmission spectra and dispersion elucidating how the interplay of coherent and dissipative interactions in a coupled system results in the emergence of level repulsion and attraction, corresponding to CIT and CIA, respectively. This theory comprehensively captures both the phenomena while modelling the microstripline loaded resonators and their couplings systematically. The model is validated through numerical simulations using a hybrid system comprising a split ring resonator (SRR) and electric inductive-capacitive (ELC) resonator in planar geometry. We analyse two cases while keeping ELC parameters constant; one involving a dynamic adjustment of the SRR size with a fixed split gap, and the other entailing a varying gap while maintaining a constant SRR size. Notably, in the first case, the dispersion profile of the transmission signal demonstrates level repulsion, while the second case results in level attraction, effectively showcasing CIT and CIA, respectively. These simulated findings not only align with the theoretical model but also underscore the versatility of our approach. Subsequently, we expand our model to a more general case, demonstrating that a controlled transition from CIT to CIA is achievable by manipulating the dissipation rate of individual modes within the hybrid system, leading to either coherent or dissipative interactions between the modes. The results provide a pathway for designing hybrid systems that can control the group velocity of light, offering potential applications in the fields of optical switching and quantum information technology.

Miniaturized bandpass metamaterials filters using hybrid plasmonic waveguide and defected surface structures

In this paper, we present a novel approach for designing single-/multiple-band bandpass filters (BPFs) using a hybrid metamaterials approach, incorporating substrate integrated waveguide (SIW), spoof surface plasmon polariton (SSPP), and defected surface structures (DSSs) technologies. The substrate-integrated plasmonic waveguide (SIPW) is constructed by embedding a hybrid dual SSPP into a three-layer SIW. The SIPW demonstrates a reduced phase velocity and a lowered lower cutoff frequency, extracted from the slow-wave dispersion relationship. Initially, the SIPW-based single-band metamaterial BPF demonstrates miniaturized size and broadened bandwidth. Furthermore, by loading a pair of complementary electric-inductive capacitive (ELC) resonators consisting of DSSs and adjusting their symmetry properties and geometric parameters, multiple BPFs from 1 to 3 are realized. To validate the proposed designs, three prototypes are fabricated and measured. The results demonstrate good filtering performances of proposed metamaterial BPFs, featuring high reflection loss (S11 < −10.5 dB) and a high level of out-of-band rejection exceeding 25 dB between multiple passbands.

Single-layer near-zero refractive index metamaterial lens based on non-complete periodic arrays.

In this study, an electric inductive-capacitive (ELC) resonator with a refractive index of around 0.08+i0.08 at 5.8 GHz serves as the unit cell. Based on the ELC unit cell, together with the electromagnetic wave (EMW) single knife-edge diffraction model, a near-zero refractive index metamaterial (NZIM) lens with a non-complete periodic array and small dimension of 0.8λ0 2 is proposed to weaken the blocking of feed source radiation, and bring more significant gain enhancement compared to that with a complete periodic array. To demonstrate the proposed lens performance, the lens-loaded antenna formed by the proposed NZIM lens and a rectangular microstrip patch antenna (MPA) operating at the center frequency of 5.8GHz is provided. The measured results show that the relative bandwidth (RBW) of the lens-loaded antenna is 9.83% (5.51-6.08 GHz), which is expanded by 3.6 times contrasted with that of MPA (2.75%). Moreover, the average and maximum gains enhancement of 4.77 dB and 6.88 dB are obtained. Due to improving the radiation characteristic, this work can be used to drive the application of MPAs in wireless communication systems.

A tri-band monopole antenna loaded with circular electric–inductive–capacitive metamaterial resonator for wireless application

The triband circular electric–inductive–capacitive (ELC)-based monopole antenna for wireless application is proposed. The proposed structure has a closed ring resonator and an ELC metamaterial resonator, which are connected by a small metal stub. ELC, with its unique negative permeability property, modifies the current direction and creates a new resonance that results in multiband characteristics for the proposed antenna. The fabrication of the proposed antenna is done on an FR4 substrate having the dimension 32 × 36 × 1.6 mm3. The measured results show multiband characteristics at 2.23 GHz, 2.56 GHz, and 4.29 GHz with return loss equal to − 34.21 dB, − 25.83 dB, and − 35.89 dB, respectively. The simulated resonant frequency of the proposed circular ELC is validated with quasi-static analysis, and it could be observed that the simulated and quasi-static analysis results comply with each other. Also, the negative permeability and new resonance of the proposed circular ELC metamaterial resonator are verified using the parameter extraction method. The measured and simulated radiation pattern also displays an excellent uniformity between them. The small size, ease in design, minimal return loss, multiband characteristics, and a considerable gain are the significant features of the proposed work.

Broadband µ-negative antenna using ELC unit cell

A broadband printed monopole antenna is designed by using ELC (Electric Inductive–Capacitive) based metamaterial element for WLAN applications. The proposed antenna comprises single ring hexagon loaded with ELC metamaterial for broadband radiation. ELC is designed with a square loop nested inside the ring hexagon structure which is coupled by the small metal stub. By introducing ELC, it significantly improves the impedance bandwidth of the antenna due to unique EM wave property. The band characteristics of the ELC and its metamaterial property (negative permeability) are explained through waveguide setup method. The designed antenna involves with dimensions 30 × 30 × 0.8 mm3 and fabricated on a low-cost Flame Retardant-4 substrate having εr = 4.4 and tanδ = 0.02. It yields an impedance bandwidth of 2600 MHz (2.61–5.21 GHz) with a dual resonance of 3.21 GHz and 4.89 GHz, which is usable for WiMAX, C-band and WLAN applications. The measured far-filed pattern exhibits a stable pattern. The proposed antenna has many benefits, such as comprising compact size, simple structure, lower S11 (dB) and capable of broadband characteristics.

A Comprehensive Review of Metasurface Structures Suitable for RF Energy Harvesting

Energy harvesting (EH) or scavenging is recognized as harvesting energy from ambient energy sources in the surrounding environment. This paper reports a literature review on radio frequency (RF) EH using different metasurface/metamaterial structures based on split-ring resonators (SRRs), electric inductive–capacitive (ELC) resonators, square-patch unit cells, square-ring unit cells, etc. The essential parameters in rectifying antenna (rectenna) design are included, such as receiving antenna efficiency, conversion efficiency, dimensions, supporting substrate properties, frequency band, and overall performance, etc. It is noted that rectenna design using conventional antennas such as microstrip antennas, monopole antennas, slot antennas, dielectric resonator antennas, etc. suffers from low power conversion efficiency with larger size. To overcome the above-mentioned constraints and enhance the conversion efficiency with smaller size, metasurface/metamaterial structures are used as EH collectors. An introduction to EH is discussed, followed by an overview of energy sources in the ambient environment. Several hypothetical and experimental studies on metasurface-based EH systems are summarized.

Pattern and frequency reconfigurable antenna with diode loaded ELC resonator

AbstractIn this work, a new compact, low profile, frequency, and end-fire pattern reconfigurable antenna is presented. The proposed antenna consists of four parasitic elements and an electric-inductive-capacitive (ELC) resonator enclosed with a closed ring resonator (CRR). The reconfigurability in the proposed antenna is achieved with the help of five PIN diodes (D1–D5) embedded on the top surface of the substrate. The diode (D1) is implanted between ELC and CRR resonators for frequency reconfigurability. The other four diodes (D2–D5) are implanted between the ground plane and four parasitic elements to control the electrical length of the ground plane to achieve pattern diversity. The ground plane and parasitic elements steer the primary omni-directional beam to bi-directional and uni-directional end-fire radiation at multiple frequencies. The proposed antenna exhibits multiband operation and end-fire pattern diversity depending upon the different states of PIN diodes. The overall size of the proposed antenna is 0.20λ0× 0.17λ0× 0.009λ0, where λ0 is calculated at the lowest resonance frequency. The impedance bandwidth of the antenna ranges from 1.45 to 26.22%, while peak gain varies from 0.86 to 3.86 dBi depending upon the state of operation. The measured results are in agreement with the simulated results, which confirm the frequency and pattern diversity performance of the antenna. The proposed antenna can be used in back-to-back repeater systems.

Improved design of CELC meta-resonators for bandwidth improvement and miniaturization of patch antenna

For metamaterial resonators, the essential figure of merit is its effective medium ratio (EMR), which is defined as the ratio of the resonant wavelength and lattice constant. In this paper, an altered topology of the electric-inductive–capacitive (ELC) metamaterial with an improved EMR is proposed. The proposed structure shrinks the electrical footprint of the conventional ELC resonator by accommodating additional inductance by meandering the arms of the resonator and fitting interdigital capacitors in the capacitive gap. The metamaterial properties of the proposed structure are investigated by parameter extraction, and analytical formulations are carried out for finding its resonant frequency. The proposed metamaterial structure is employed for performance enhancement and miniaturization of a standard patch antenna. A 3 × 4 array of the modified complementary resonators is etched in the ground plane of a patch antenna. A significant 293% improvement in bandwidth, with a miniaturization factor (unloaded frequency/loaded frequency) of 1.33 is achieved. The entire antenna resides in a small area of 37.5 mm × 37.5 mm. The design is substantiated both by simulation and experimental results, which complement each other. The presented design can be used for Mobile WiMAX (2.5–2.69 GHz) applications.

Dual-band monopole antenna loaded with ELC metamaterial resonator for WiMAX and WLAN applications

In this paper, a miniaturized ELC (Electric-inductive-capacitive) based dual-band antenna is proposed for WiMAX and WLAN Applications. The designed antenna consists of a ring monopole antenna coupled with ELC resonator and partial rectangular ground plane, which is fed by 50Ω microstrip transmission line. ELC metamaterial modifies the current direction and yields dual-band characteristics. The band characteristics of the ELC metamaterial element are explained in detail. The proposed antenna with a compact size of 30 $$\times$$ 30 $$\times$$ 0.8 mm3 is fabricated on a FR-4 substrate of thickness of 0.8 mm, with relative dielectric constant $${{\mathbf{\varepsilon }}_{\mathbf{r}}}$$ = 4.4 and loss tangent $$\tan \varvec{\delta}$$ = 0.002. The experimental results cover the bandwidth of 500 MHz (3.57–4.04 GHz) and 860 MHz (4.73–5.59 GHz) with a resonance frequency of 3.74 and 5.1 GHz, respectively, which is suitable for WiMAX and WLAN applications.

An Improvement Approach for Wide-Angle Impedance Matching Using ELC Metasurface Slabs for SIW Slot Array Antennas

The effects of mutual coupling in beam scanning arrays increase degradation in gain as the beam is scanned off the broadside. A simple and effective approach for a deployed SIW slot array antenna through the use of artificially structured materials is proposed to improve its performance of wide-angle scanning in the E-plane. Metasurface slabs of one-tenth wavelength electric-inductive-capacitive (ELC) resonators are vertically placed halfway between the adjacent waveguides without changing the antenna structure to realize wide-angle impedance matching (WAIM). The ELC metasurface is designed to operate at a linear region rather than at a resonance region to use its transmission property for greatly weakening mutual couplings. Inserting metasurface slabs between two adjacent waveguides to reduce the mutual coupling can achieve impedance matching at large scan angles. A 10 × 10 SIW slot array operating at X-band is modelled and simulated to study how the vertically placed ELC metasurface slabs over the antenna affect the array’s beam scanning performance. The simulated results show that the scan range of the antenna is extended from −50° to 50° to −70° to 70° under the criteria that radiating efficiency is greater than 80%.

Mutual coupling reduction in planar antenna by graphene metasurface for THz application

This paper presents an effective approach to mitigate mutual coupling between two densely packed planar antenna operating at the lower THz frequency band by incorporating a graphene-based metasurface. The graphene metasurface has been designed using Electric inductive capacitive (ELC) resonator on the both sides of a silicon substrate. The metasurface is designed to provide band stop functionality in the operating bandwidth of the antenna. Here, surface impedance model of the graphene is used for analysing the metasurface layer. Throughout the operating band of the antenna, coupling suppression of 8–12 dB is obtained with element separation of less than . Thus, this proposed approach can be utilized to mitigate mutual coupling between antennas in THz application.

ELC metamaterial based CPW‐fed printed dual‐band antenna

ABSTRACTThis letter presents metamaterial (MTM) based dual band antenna. Two resonances are obtained by making use of square ELC (Electric‐inductive‐capacitive) resonator and CR (Closed Ring) resonator. This research evolves an antenna having dimension only of 21 × 30 × 1.6 mm3 which operates at two bands from 3.28 GHz to 4.52 GHz and from 5.20 GHz to 5.87 GHz. This antenna can be useful for WiMAX and WLAN transceiver at 3.5 GHz and 5 GHz band respectively. It can also be used in RFID applications at 3.9 GHz band. This paper includes the parametric investigations as well as measurement details. Simulation and measurement data have shown good equivalence which emphasis the practicability of the proposed antenna. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:304–307, 2017

Miniaturized power limiter metasurface based on Fano-type resonance and Babinet principle.

In this work, we present a miniaturize power limiter, a device with size smaller than that required by the working frequency, made of coupled self-complementary electric inductive-capacitive (CELC) resonator and original electric inductive-capacitive (ELC) structure. We also make use of Babinet principle to ensure both CELC and ELC are resonating at the same frequency. The CELC structure is loaded with a Schottky diode to achieve the effect of a nonlinear power limiter. The constructive interference of CELC and ELC structure produces a new Fano-type resonance peak at a lower frequency. The Fano peak is sharp and able to concentrate electric field at a region between the inner and outer metallic patch of the metastructure, hence enhancing the nonlinear properties of the loaded diode. The Fano peak enhances the maximum isolation of the power limiter due to the local field enhancement at where the diode is loaded. Numerical simulation and experiment are conducted in the S-band frequency to verify the power limiting effect of the device designed and to discuss the formation of Fano peak. The power limiter designed has a maximum isolation of 8.4 dB and a 3-dB isolation bandwidth of 6%.

A BROADBAND FLEXIBLE METAMATERIAL ABSORBER BASED ON DOUBLE RESONANCE

We present a broadband microwave metamaterial (MM) absorber, the unit cell of which consists of a lumped-resistor-loaded electric-inductive-capacitive (ELC) resonator and a cut-wire on the same side of a ∞exible polyimide substrate. In contrast to the common MM absorber, the metallic pattern layer of the proposed structure is placed parallel to the direction of propagation of the incident wave in order to reduce the radar cross-section (RCS) at frequencies other than the targeted frequency bands. Our experiments show that the proposed absorber exhibits a peak absorption rate of 92% and 93% at 8.6GHz and 13.4GHz, respectively, and 88% of the full-width at half-maximum (FWHM) bandwidth is achieved.

Resonant mode behavior of lumped-resistor-loaded electric-inductive-capacitive resonator and its absorber application

This paper presents investigations into the resonant mode behavior of a lumped-resistor-loaded electric-inductive-capacitive (ELC) resonator, which is illuminated with a parallel polarization external electromagnetic wave. An ELC resonator exhibits a negative effective permittivity for both parallel and perpendicular polarizations. In contrast to a common ELC resonator, the lumped-resistor-loaded ELC resonator exhibits a switchable resonant mode behavior, thereby revealing a negative effective permeability. In addition, this resonator exhibits a low quality factor owing to the loaded lumped resistors. A metamaterial absorber, which consists of a lumped-resistor-loaded ELC resonator and a cut-wire strip, is designed to confirm the effectiveness of the resonator.

Near-field interactions in electric inductive–capacitive resonators for metamaterials

Near-field interactions in an array of electric inductive–capacitive (ELC) resonators are investigated analytically, numerically and experimentally. The measurement and simulation results show that inter-cell coupling plays an important role in determining the response of metamaterials. A quasistatic dipole–dipole interaction model, together with a Lagrangian formalism, quantitatively explains the interplay between the electric and magnetic couplings in the resonator array. Depending on the alignment of the resonators, the couplings can cause resonance shifting and/or splitting. The knowledge obtained from this study is crucial in designing metamaterials with ELC resonators.

Analytically describing the temperature-dependent constitutive parameters of an electromagnetic metamaterial

Analogous to mechanical systems, modeling the electromagnetic (EM) performance of large and complex metamaterial structures requires the use of effective-medium/constitutive properties. Constitutive properties are critical for efficiently bridging the gap between subwavelength geometry and performance at the mesoscale. In this article, the temperature-dependent effective medium properties for a metamaterial electric-inductive-capacitive (ELC) resonator are described analytically. ELC structures are commonly used in metamaterial designs to provide a tailored electric response to EM waves. An equivalent circuit model, coupled with analytic expressions for the capacitances, inductance, and resistance of the ELC resonator, is utilized to describe how thermally induced mechanical strain and changes in material properties manifest as temperature-dependent permittivity and permeability curves for the metamaterial. The resulting analytic expressions account for the effects of spatial dispersion and losses. This article also details how the process may be expanded to similarly describe the temperature-dependent constitutive properties of metamaterial magnetic resonators.

Design of Wideband Compact Electric-Inductive-Capacitive (ELC) Inclusions for Metamaterials

Design of Wideband Compact Electric-Inductive-Capacitive (ELC) Inclusions for Metamaterials