scholarly journals Multiband transparency effect induced by toroidal excitation in a strongly coupled planar terahertz metamaterial

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angana Bhattacharya ◽  
Rakesh Sarkar ◽  
Naval K. Sharma ◽  
Bhairov K. Bhowmik ◽  
Amir Ahmad ◽  
...  
Keyword(s):  
Coupled Oscillators ◽  
Ring Resonator ◽  
Near Field ◽  
Split Ring Resonator ◽  
Split Ring ◽  
Strongly Coupled ◽  
Future Studies ◽  
High Q ◽  
Field Coupling ◽  
Sensing Applications

AbstractThe multiband transparency effect in terahertz (THz) domain has intrigued the scientific community due to its significance in developing THz multiband devices. In this article, we have proposed a planar metamaterial geometry comprised of a toroidal split ring resonator (TSRR) flanked by two asymmetric C resonators. The proposed geometry results in multi-band transparency windows in the THz region via strong near field coupling of the toroidal excitation with the dipolar C-resonators of the meta molecule. The geometry displays dominant toroidal excitation as demonstrated by a multipolar analysis of scattered radiation. High Q factor resonances of the metamaterial configuration is reported which can find significance in sensing applications. We report the frequency modulation of transparency windows by changing the separation between TSRR and the C resonators. The numerically simulated findings have been interpreted and validated using an equivalent theoretical model based upon three coupled oscillators system. Such modeling of toroidal resonances may be utilized in future studies on toroidal excitation based EIT responses in metamaterials. Our study has the potential to impact the development of terahertz photonic components useful in building next generation devices.

scholarly journals Coupling Schemes in Terahertz Planar Metamaterials

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Dibakar Roy Chowdhury ◽  
Ranjan Singh ◽  
Antoinette J. Taylor ◽  
Hou-Tong Chen ◽  
Weili Zhang ◽  
...  
Keyword(s):  
Resonance Line ◽  
Ring Resonator ◽  
Near Field ◽  
Split Ring Resonator ◽  
Higher Order ◽  
Ring Resonators ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Sensing Applications ◽  
Lattice Mode

We present a review of the different coupling schemes in a planar array of terahertz metamaterials. The gap-to-gap near-field capacitive coupling between split-ring resonators in a unit cell leads to either blue shift or red shift of the fundamental inductive-capacitive (LC) resonance, depending on the position of the split gap. The inductive coupling is enhanced by decreasing the inter resonator distance resulting in strong blue shifts of theLCresonance. We observe theLCresonance tuning only when the split-ring resonators are in close proximity of each other; otherwise, they appear to be uncoupled. Conversely, the higher-order resonances are sensitive to the smallest change in the inter particle distance or split-ring resonator orientation and undergo tremendous resonance line reshaping giving rise to a sharp subradiant resonance mode which produces hot spots useful for sensing applications. Most of the coupling schemes in a metamaterial are based on a near-field effect, though there also exists a mechanism to couple the resonators through the excitation of lowest-order lattice mode which facilitates the long-range radiative or diffractive coupling in the split-ring resonator plane leading to resonance line narrowing of the fundamental as well as the higher order resonance modes.

Near-field coupling and second-harmonic generation in split-ring resonator arrays

2012 ◽  
Author(s):  
Yevgen Grynko ◽  
Torsten Meier ◽  
Stefan Linden ◽  
Fabian B. P. Niesler ◽  
Martin Wegener ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Ring Resonator ◽  
Second Harmonic ◽  
Near Field ◽  
Split Ring Resonator ◽  
Split Ring ◽  
Field Coupling ◽  
Resonator Arrays

scholarly journals Efficient and Compact Near-Field Coupled Hybrid Antenna Using a Single Radiating Subwavelength Split-Ring Resonator

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 527
Author(s):  
Zinching Dang ◽  
Marco Rahm
Keyword(s):  
Resonance Frequency ◽  
Electromagnetic Waves ◽  
Ring Resonator ◽  
Near Field ◽  
Low Frequency ◽  
Split Ring Resonator ◽  
Dipole Antenna ◽  
Angular Width ◽  
Split Ring ◽  
Broadband Internet

Modern applications in the realms of wireless communication and mobile broadband Internet increase the demand for compact antennas with well defined directivity. Here, we present an approach for the design and implementation of hybrid antennas consisting of a classic feeding antenna that is near-field-coupled to a subwavelength resonator. In such a combined structure, the composite antenna always radiates at the resonance frequency of the subwavelength oscillator as well as at the resonance frequency of the feeding antenna. While the classic antenna serves as impedance-matched feeding element, the subwavelength resonator induces an additional resonance to the composite antenna. In general, these near-field coupled structures are known for decades and are lately published as near-field resonant parasitic antennas. We describe an antenna design consisting of a high-frequency electric dipole antenna at f d = 25 GHz that couples to a low-frequency subwavelength split-ring resonator, which emits electromagnetic waves at f SRR = 10.41 GHz. The radiating part of the antenna has a size of approximately 3.2 mm × 8 mm × 1 mm and thus is electrically small at this frequency with a product k · a = 0.5 . The input return loss of the antenna was moderate at − 18 dB and it radiated at a spectral bandwidth of 120 MHz. The measured main lobe of the antenna was observed at 60 ∘ with a − 3 dB angular width of 65 ∘ in the E-plane and at 130 ∘ with a − 3 dB angular width of 145 ∘ in the H-plane.

scholarly journals Near-field terahertz imaging of a discontinuity in split ring resonator array

2013 ◽  
Vol 41 ◽  
pp. 09006
Author(s):  
F. Blanchard ◽  
K. Ooi ◽  
T. Tanaka ◽  
A. Doi ◽  
K. Tanaka
Keyword(s):  
Ring Resonator ◽  
Near Field ◽  
Split Ring Resonator ◽  
Terahertz Imaging ◽  
Split Ring

scholarly journals A Novel Symmetrical Split Ring Resonator Based on Microstrip for Microwave Sensors

2016 ◽  
Vol 16 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Rammah A. Alahnomi ◽  
Z. Zakaria ◽  
E. Ruslan ◽  
Amyrul Azuan Mohd Bahar
Keyword(s):  
Insertion Loss ◽  
Ring Resonator ◽  
Performance Enhancement ◽  
Split Ring Resonator ◽  
Q Factor ◽  
Loose Coupling ◽  
Split Ring ◽  
Linear Coupling ◽  
High Q ◽  
Microwave Sensors

Abstract In this paper, novel symmetrical split ring resonator (SSRR) is proposed as a suitable component for performance enhancement of microwave sensors. SSRR has been employed for enhancing the insertion loss of the microwave sensors. Using the same device area, we can achieve a high Q-factor of 141.54 from the periphery enhancement using Quasi-linear coupling SSRR, whereas loose coupling SSRR can achieve a Q-factor of 33.98 only. Using Quasi-linear coupling SSRR, the Q-factor is enhanced 4.16 times the loose coupling SSRR using the same device area. After the optimization was made, the SSRR sensor with loose coupling scheme has achieved a very high Qfactor value around 407.34 while quasi-linear scheme has achieved high Q-factor value of 278.78 at the same operating frequency with smaller insertion loss. Spurious passbands at 1st, 2nd, 3rd, and 4th harmonics have been completely suppressed well above -20 dB rejection level without visible changes in the passband filter characteristics. The most significant of using SSRR is to be used for various industrial applications such as food industry, quality control, bio-sensing medicine and pharmacy. The simulation result that Quasi-linear coupling SSRR is a viable candidate for the performance enhancement of microwave sensors has been verified.

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