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[IEEE 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Padang, Indonesia (2019.7.22-2019.7.24)] 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Surface Current Analysis of THz Bowtie Antenna-coupled Microbolometer
摘要： Terahertz (THz) frequency band offers several advantages over microwave band such as larger bandwidth and radiation capability for various imaging applications. One of the important components is the THz detector applicable for room temperature use. For the lower THz frequency band, an antenna-coupled microbolometer is considered as the THz wave detector due to its compact structure and easy to fabricate. In this paper, we design and simulate the antenna-coupled microbolometer for 1 THz frequency band. Simulation is conducted by using CST Microwave Studio. A surface current analysis is performed to understand the effect of the increasing resistance of the microbolometer to the power efficiency performance. From the simulation results, the proposed design and analysis method reveals that power efficiency of the microbolometer can be increased by increasing the resistance of the microbolometer.
关键词： microbolometer,Terahertz,surface current
更新于2025-09-11 14:15:04
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Highly sensitive and tunable terahertz biosensor based on optical Tamm states in graphene-based Bragg reflector
摘要： A highly sensitive and tunable biosensor at terahertz (THz) frequencies is proposed by using a composite structure of graphene and one-dimensional photonic crystal. The theoretical analysis and simulation results show that the sensitivity and figure-of-merit of the biosensor can reach 517.9°/RIU and 1222.9RIU-1, respectively. The high sensitivity of the biosensor originates from the excitation of optical Tamm states caused by graphene-based distributed Bragg reflector. By varying the voltage on graphene, we can electrically control the sensitivity and figure-of-merit of the biosensor. Furthermore, we have shown that the biosensor has a wide range (1.40~1.70) for measuring the refractive index of the sensing medium. We believe the biosensor has a good application prospect in the field of biological detection.
关键词： figure-of-merit,terahertz biosensor,Bragg reflector,sensitivity,optical Tamm states,graphene
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE International Conference on Signals and Systems (ICSigSys) - Bandung, Indonesia (2019.7.16-2019.7.18)] 2019 IEEE International Conference on Signals and Systems (ICSigSys) - Study of Impedance Matching for Optimum Power Transfer in Terahertz Bow-tie Antenna-coupled Microbolometer
摘要： The demand for higher wireless communication speed and latency has been increasing over the past decade. As the LTE frequency has found its maturity in terms of bandwidth spectrum, exploration of new frequency bands is critical to addressing the capacity demand in the future. Terahertz (THz) technology is one of the promising solutions to provide higher bandwidth capacity, data rates and interference-free from other wireless legacy frequency spectrum for the next generation applications such as Internet of Things (IoT). However, the development of THz wave’s detector is still a challenging issue to the date due to its unique radiation characteristic between millimeter wave and infrared domains as well as its complexity issues in very small wavelength. A bolometer can be considered as THz signal detector by converting the received THz waves into heat and further transformed into electrical signals by the thermistor. In this research, we designed an antenna-coupled microbolometer as THz wave receiver. An analysis base on the dissipated energy of the bolometer is conducted to find the optimum energy absorption in which the impedance of the bolometer will be matched with the antenna. The simulation results show that an optimum matching condition can be obtained by considering maximum dissipated energy in higher bolometer resistance.
关键词： microbolometer,dissipated energy,Terahertz
更新于2025-09-11 14:15:04
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Terahertz Nonlinear Optics of Graphene: From Saturable Absorption to High‐Harmonics Generation
摘要： Graphene has long been predicted to show exceptional nonlinear optical properties, especially in the technologically important terahertz (THz) frequency range. Recent experiments have shown that this atomically thin material indeed exhibits possibly the largest nonlinear coefficients of any material known to date, paving the way for practical graphene-based applications in ultrafast (opto-)electronics operating at THz rates. Here the advances in the booming field of nonlinear THz optics of graphene are reported, and the state-of-the-art understanding of the nature of the nonlinear interaction of graphene with the THz fields based on the thermodynamic model of electron transport in graphene is described. A comparison between different mechanisms of nonlinear interaction of graphene with light fields in THz, infrared, and visible frequency ranges is also provided. Finally, the perspectives for the expected technological applications of graphene based on its extraordinary THz nonlinear properties are summarized. This report covers the evolution of the field of THz nonlinear optics of graphene from the very pioneering to the state-of-the-art works. It also serves as a concise overview of the current understanding of THz nonlinear optics of graphene and as a compact reference for researchers entering the field, as well as for the technology developers.
关键词： terahertz,high-harmonics generation,nonlinear optics,thermodynamic model,graphene
更新于2025-09-11 14:15:04
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Handbook of Graphene || Graphene Terahertz Leaky‐Wave Antennas
摘要： In this chapter, we focus on the recent developments made in the context of graphene THz antennas, especially those exploiting the graphene field effect to reconfigure their radiating features. To this purpose, we first review the electronic properties of graphene in the THz range from both a physical and an engineering perspective. This will serve us to analyze the application of graphene in THz antenna systems on a rigorous theoretical basis. A bird’s eye view on the various graphene antennas proposed so far will allow the reader to recognize the benefits and drawbacks of using graphene in place of other materials, as well as to understand the different possible mechanisms of radiation. In this respect, specific attention is devoted to graphene antennas based on either plasmonic or nonplasmonic waves discussing the inherent differences and the relevant radiating properties. Specifically, the accurate design of graphene nonplasmonic leaky-wave antennas is addressed to introduce the reader to a systematic and convenient approach for the design of graphene THz leaky-wave antennas. Finally, the technological constraints dictated by both THz technology and graphene synthesis are thoroughly discussed to highlight the true perspectives of this surprising material in the context of THz antennas.
关键词： antennas,tunable devices,terahertz radiation,Graphene,leaky waves,plasmonics
更新于2025-09-11 14:15:04
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Handbook of Graphene || Modelling of Graphene Nanoribbons Antenna Based on MoM‐GEC Method to Enhance Nanocommunications in Terahertz Range
摘要： In this chapter, we present an electromagnetic modelling formulation of graphene nanoribbon antenna based on moments method combined to the generalized equivalent circuit method (MoM-GEC). The electrical properties of graphene are introduced in the mathematical formulation via a quantum mechanical conductivity deduced from the Kubo formalism. The antenna structure is shielded in a rectangular waveguide with electric boundary walls. Next, the global antenna structure is modelled by an electric equivalent circuit to investigate the antenna parameters. It is proved that, graphene nanoribbon-based antenna presents similar performances as well as conventional one, hence allowing to work at terahertz frequencies range. The high input impedance of a single graphene nanoribbon antenna causes an impedance mismatch problem, which requires the use of an antenna array. So, the coupling phenomena have been well studied in order to optimize the antenna response. Obtained numerical results show that the antenna resonant frequency is very sensitive to the variation of the graphene chemical potential. This leads to a reconfigurable antenna by a simple control of bias voltage. On the other hand, it is showed that, at terahertz frequencies, graphene nanoribbon antenna array allows to enhance the far field communication for short distances, which is beneficial for nanocommunications.
关键词： antenna array,nanocommunications,dynamic conductivity,terahertz range,nanoantenna,MoM-GEC method,Graphene nanoribbon
更新于2025-09-11 14:15:04
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Handbook of Graphene || Graphene‐Based Plasmonic Components for THz Applications: Planar Ring Array Devices
摘要： In this chapter, we present graphene-based planar components for THz applications. Firstly, the symmetry properties of the array are analyzed by using group-theoretical methods. Then numerical simulations of several components are discussed. The first component can operate as an electromagnetic filter. It is a planar array based on graphene elements. A unit cell of the array consists of two graphene rings arranged coaxially on the opposite sides of a dielectric substrate. The rings coupled electromagnetically possess dipole resonances of plasmonic modes. We show that the frequency position of the transmission peak can be varied in a wide range by the graphene chemical potential. Another example is a new electromagnetic tunable multifunctional component. The structure consists of a square array of graphene elements placed on both sides of a thin dielectric. Changing the graphene chemical potential electrostatically, the central frequencies of the pass-band and stop-band filter can be dislocated. This corresponds to a dynamic control of the filter. A combination of a high peak and a deep valley in the transmission response allows one to create a switch and a modulator in two separated frequency bands.
关键词： filter,surface plasmon polariton,terahertz,Graphene
更新于2025-09-11 14:15:04
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Handbook of Graphene || Graphene Plasmonic: Switching Applications
摘要： This chapter focuses on the graphene plasmonic-based optical switching devices operating in the infrared to terahertz spectrum. Graphene plasmonic due to high strong light–matter interaction and nanoscale size has received significant attention in recent years, as they have found an important role in many areas of optical science and engineering by offering schemes to control electromagnetic fields. Another area of science that has been under the spotlight for the last few years relates to graphene plasmonic metasurface, which is formed of graphene layer packed into a structure. This material exhibits exceptional electronic and optical properties, intriguing many research groups across the world including us. However, our interest is specifically in studying the interaction between electromagnetic waves with surface modes of graphene in multilayer configuration (such as Otto configuration) and switching applications that might follow. In this chapter, relying on theoretical models and numerical simulations, we show that by designing and manipulating optical and electrical properties of graphene such as chemical potential, temperature, scattering rate, as well as incident beam characteristics such as beam width, one can have the structures based on graphene as a good platform for not only infrared optical switching devices but also terahertz switching devices.
关键词： Otto configuration,Graphene plasmonic,graphene conductivity,optical switches,terahertz,metasurface
更新于2025-09-11 14:15:04
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A mixture of vortex terahertz radiation generation in inhomogeneous plasma by considering pump depletion
摘要： An attempt to extend helical terahertz radiation generation based on pump depletion is presented here. By considering an upward plasma density ramp, such a reasonable extension is examined to improve the results. It is claimed that the output terahertz energy is saturated which is attributed to laser pump divergence. The saturation effect is enhanced by considering suitable laser and plasma parameters. The adjustable slope of the density ramp is an important parameter for tuning terahertz generation efficiency, which is restricted to the up and down limit. For the resonant excitation of terahertz radiation, the ripple wave number is suitably chosen to satisfy the phase matching condition. Furthermore, as plasma frequency increases and approaches beat frequency, terahertz generation efficiency increases. Various laser and plasma parameters are employed and we report an efficiency of the order of 5×10?3 for the current scheme.
关键词： Laguerre–Gaussian beam,plasma density ramp,pump depletion,terahertz radiation generation,cross-focusing
更新于2025-09-11 14:15:04
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Compact silicon-micromachined wideband 220-330 GHz turnstile orthomode transducer
摘要： This paper reports on a turnstile-junction orthomode transducer (OMT) implemented by silicon micromachining in the 220 – 330 GHz band. Turnstile OMTs are very wideband and allow for co-planar ports, but require accurate and complex geometries which makes their fabrication challenging at higher frequencies. The compact 10 x10 x0.9 mm3 OMT-chip presented in this paper is the first micromachined full-band OMT in any frequency range, and only the second turnstile OMT implemented above 110 GHz. The measured insertion loss (0.3 dB average, 0.6 dB worst-case) and the cross-polarization (60 dB average, 30 dB worst-case) over the whole waveguide band represent the best performance of any wideband OMT, regardless of design or fabrication technology, in the 220 – 330 GHz band. The return loss with 22 dB average (16 dB worst-case) is comparable or better than previous work. The paper discusses design considerations and compromises of this complex 9 layer silicon micromachined device, including the influence of sidewall slopes, underetching, and post-bonding misalignment between the chips. It is shown that for a device which is very sensitive to geometrical variations, such as a turnstile OMT, it is necessary to anticipate and compensate for any fabrication imperfections in the design to achieve high RF performance.
关键词： terahertz,mmW,DRIE,orthomode transducer,turnstile,silicon micromachining,THz,millimeter wave,MEMS,OMT
更新于2025-09-11 14:15:04