Terahertz Reflectarray with Enhanced Bandwidth

You, Xiaolong; Ako, Rajour Tanyi; Lee, Wendy S. L.; Low, Mei Xian; Bhaskaran, Madhu; Sriram, Sharath; Withayachumnankul, Withawat

doi:10.1002/adom.201900791

Cited by 24 publications

(10 citation statements)

References 40 publications

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“…Moreover, the reflection coefficient value is less than reported one in [10]. As it is stated in Table 5, the efficiency of the designed square and circular antennas are considerably more than corresponding values in [10,31,32]. Since the aperture sizes of proposed arrays are much smaller in comparison to mentioned works, the resulting gain values are reduced.…”

Section: -4 Discussionmentioning

confidence: 73%

Design and optimization of a wideband metasurface for utilization in a highly efficient terahertz reflectarray antenna

Sharifi¹,

Basiri²,

Zareian‐Jahromi³

2021

Preprint

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In this manuscript, two wideband single layer reflectarray antennas are designed utilizing an optimization-based metasurface in terahertz (THz) regime. It is demanded to design a metasurface with wide phase variation range in a broad frequency region of terahertz band. The proposed metasurface is designed based on Random Hill Climbing optimization algorithm whereas a multiobjective fitness function is defined to consider the desired characteristics. A provided link between Matlab and HFSS softwares is utilized to define and simulate various metasurfaces. The finalized cell has considerable wide phase variation (≥ 600˚) and notable bandwidth of 30.76% (1.1–1.5 THz) whereas the mean value of magnitude variation of reflection coefficient is -0.42dB. Two square and circular metasurfaces are designed based on the optimized cell and illuminated using a THz feeding horn antenna. The angles of incident and reflected waves are considered equal to zero. The simulation results confirm 3-dB gain bandwidths of 20.3% and 20.4% for square and circular reflectors, respectively. Moreover, the considerable efficiencies of 45.67% and 46.27% are achieved for square and circular arrays, consequently. The maximum gain of square array with 361 elements is 25.9dB whereas it is equal to 24.9dB for circular metasurface including 277 unit cells.

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Section: -4 Discussionmentioning

confidence: 73%

Design and optimization of a wideband metasurface for utilization in a highly efficient terahertz reflectarray antenna

Sharifi¹,

Basiri²,

Zareian‐Jahromi³

2021

Preprint

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“…Another demonstrated method of achieving tunable EIT response is through the photoexcitation of metamaterials by an optical pump beam [29,35,38]. The active EIT responses achieved in these systems can lead to the realization of different tunable practical metadevices [39][40][41] which in turn, can benefit the so called terahertz (THz) gap which is still suffering due to the lack of efficient functional devices [3,[42][43][44][45]. In particular, dynamically tunable slow light based on EIT in metamaterials could be utilized to develop tunable delay lines [29] and communication channels [21] at the THz band that can be advantageous for 6G communication systems.…”

Section: Introductionmentioning

confidence: 99%

Polarization-independent tunable terahertz slow light with electromagnetically induced transparency metasurface

et al. 2022

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Tunable slow light systems have gained much interests recently due to their efficient control of strong light-matter interactions as well as their huge potential for realizing tunable device applications. Here, a dynamically tunable polarization independent slow light system is experimentally demonstrated via electromagnetically induced transparency (EIT) in a terahertz (THz) metasurface constituted by plus and dimer-shaped resonators. Optical pump-power dependent THz transmissions through the metasurface samples are studied using the optical pump terahertz probe technique. Under various photoexcitations, the EIT spectra undergo significant modulations in terms of its resonance line shapes (amplitude and intensity contrast) leading to dynamic tailoring of the slow light characteristics. Group delay and delay bandwidth product (DBP) values are modulated from 0.915 ps to 0.42 ps and 0.059 to 0.025 as the pump fluence increases from 0 to 62.5 〖nJ cm〗^(-2). This results in tunable slow THz light with group velocities ranging from 2.18×〖10〗^5 〖m s〗^(-1) to 4.76×〖10〗^5 〖m s〗^(-1), almost 54% change in group velocity. The observed tuning is attributed to the photo-induced modifications of the optoelectronic properties of the substrate layer. The demonstrated slow light scheme can provide opportunities for realizing dynamically tunable slow light devices, delay lines, and other ultrafast devices for THz domain.

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“…This paper presents a novel method for arbitrarily manipulating the beam numbers, the TCs, the propagation directions, and the nondiffractive depths of quasi-nondiffractive THz OAM waves (QTOWs) via a single phase-engineered lens. Since metadevices designed by metallic resonators suffer from high ohmic losses in the THz regime, − all-dielectric lenses (ADLs) are employed in this design. On the basis of the proposed approach, two ADLs operating in the sub-THz regime are designed using the concepts of the optical conical lens and the multivorticity metasurface.…”

Section: Introductionmentioning

confidence: 99%

3D Printed Sub-Terahertz All-Dielectric Lens for Arbitrary Manipulation of Quasi-Nondiffractive Orbital Angular Momentum Waves

Yang

Deng

et al. 2021

ACS Appl. Mater. Interfaces

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Terahertz (THz) vortex waves carrying orbital angular momentum (OAM) hold great potential in dealing with the capacity crunch in wireless high-speed communication systems. Nevertheless, it is quite a challenge for the widespread applications of OAM in the THz regime due to the beam divergence and stringent alignment requirement. To address this issue, an all-dielectric lens (ADL) is proposed for the arbitrary manipulation of quasi-nondiffractive THz OAM waves (QTOWs). On the basis of the concept of the optical conical lens and the multivorticity metasurface, the beam number, the topological charge (TC), and the deflection angle as well as the nondiffractive depth of the generated THz OAM waves are controllable. For proof-of-concept, two ADLs are 3D printed to create single and dual deflected QTOWs, respectively. Remarkably, measured by a THz imaging camera, the desired QTOWs with high mode purity are observed in predesigned directions with a nondiffractive depth predefined theoretically. The proposed designs and experiments, for the first time, verified that the QTOWs could be achieved with a nondiffractive range of 55.58λ g (λ g = wavelength at 140 GHz) and large deflection angles of 30°and 45°.

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Terahertz Reflectarray with Enhanced Bandwidth

Cited by 24 publications

References 40 publications

Design and optimization of a wideband metasurface for utilization in a highly efficient terahertz reflectarray antenna

Design and optimization of a wideband metasurface for utilization in a highly efficient terahertz reflectarray antenna

Polarization-independent tunable terahertz slow light with electromagnetically induced transparency metasurface

3D Printed Sub-Terahertz All-Dielectric Lens for Arbitrary Manipulation of Quasi-Nondiffractive Orbital Angular Momentum Waves

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