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TERAHERTZ BEAM SPLITTER BASED ON I-SHAPED METASURFACE
摘要： A linear polarization beam splitter operating in terahertz band is proposed and experimentally veri?ed in this paper. The unit cell of the beam splitter is composed of the top “I” type metal pattern, the middle dielectric layer, and the bottom metal layer. Each subarray structure of the device consists of four unit cells that rotate progressively at an angle of 45?. The horizontal and vertical sub-arrays form the gradient metasurface of 4 × 4. The incident linear polarized terahertz wave is re?ected by the device and divided into four beams with approximately equal power, while having di?erent propagating directions in the 0.18–0.30 THz band. The proposed terahertz beam splitter has the advantages of small size, low cost, and easy processing, and it can be applied to terahertz stealth and terahertz imaging.
关键词： terahertz,polarization,beam splitter,metasurface
更新于2025-09-23 15:21:01
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Terahertz refractive index sensor based on the guided resonance in a photonic crystal slab
摘要： The optical properties of a photonic crystals slab (PCS) are highly sensitive to environmental variation. PCS thus are an attractive platform for sensing application. We numerically demonstrate a terahertz refractive index sensor based on the guided resonance in a two-dimensional PCS. The PCS consists of a square lattice of air holes in a silicon slab fabricated on a quartz substrate. By varying each structural parameter systematically, we study the dependence of the resonance located around 0.508 THz on the structural parameters of PCS, and then optimize the structural parameters of PCS for a higher sensitivity. We apply the PCS sensor to detect the refractive index of analytes. The sensitivity of the sensor reaches 23.08 GHz/RIU for the resonance located around 0.508 THz. Our results provide insight into the future terahertz spectroscopy for sensing detection.
关键词： Terahertz,Sensor,Photonic crystals,Guided resonance
更新于2025-09-23 15:21:01
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[IEEE 2019 4th International Conference on Power and Renewable Energy (ICPRE) - Chengdu, China (2019.9.21-2019.9.23)] 2019 4th International Conference on Power and Renewable Energy (ICPRE) - Laser Beam Path Control Using a PSD Fuzzy Controller
摘要： We present novel waveguide packaging for sub-millimeter and terahertz-wave devices, which is suitable for large chip-width MMICs and doesn’t require any additional fabrication process. With full electromagnetic simulation, we analyze possible wave modes in a rectangular waveguide with thin E-plane slits formed for inserting large-width MMICs into the split waveguide block and show that parasitic modes can be well suppressed by lossy and high-dielectric material. For a 1.1-mm-wide test IC in the 260–320 GHz band, measured transition loss is around 1 dB with more than 60 dB inter-port isolation.
关键词： terahertz wave,waveguide package,Integrated E-plane probe
更新于2025-09-23 15:21:01
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Experimental Demonstration of 3.9 mm Range Resolution Enabled by Synthetic Linearly Chirped THz Photonic Pulses
摘要： We experimentally demonstrate ultrahigh range resolution based on photonically generated linear frequency modulated (LFM) terahertz (THz) pulses. By synthesizing dual-band pulses in 315-360 GHz, a THz LFM signal with 40 GHz bandwidth and a time-bandwidth product (TBWP) of 336 is achieved, which successfully enables a range resolution as high as 3.9 mm over more than 4 m in multi-target ranging.
关键词： photonic generation,range resolution,terahertz,LFM pulses,synthetic technique
更新于2025-09-23 15:21:01
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Dispersion Characteristics of Surface Plasmon Polaritons of Graphene Loaded Three Dimensional Dielectric Gratings
摘要： Graphene has been used widely in optical and electronic devices due to its extraordinary electromagnetic characteristics. Recent theories and experiments prove that (SPPS) and graphene support surface plasmon polariton transform it into Terahertz (THz) radiation. In this paper, a dispersion and electric amplitude equations of SPPS of graphene loaded on the three dimensional dielectric gratings excited by parallel moving electron beam are derived by solving the Maxwell’s equations. The numerical results show that the frequency of amplified electric amplitude are same as the frequency point where electron beam and dispersion curve meet, which demonstrate theoretical analysis are right. The influence of dielectric gratings width is considered. It is found that the cutoff frequency occurs and rises on the dispersion curve as the width narrowing. The working point frequency is also higher compared with infinite width dielectric gratings. The SPPS of graphene loaded the three dimensional dielectric gratings whose work point is under cutoff frequency can’t be excited, even though it can be tuned. The numerical results show the electric amplitude becomes greater with width increasing.
关键词： Terahertz Radiation,Graphene,Electron Beam,Dielectric Gratings,Surface Plasmon Polariton
更新于2025-09-23 15:21:01
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Radar cross-section of pedestrians in the low-THz band
摘要： Low-terahertz (THz) (above 150?GHz) radar sensing is one of the promising technologies to provide safe navigation for autonomous cars due to its expected high-resolution imaging capability. It is anticipated that for robust operation at high levels of autonomy the sensor suite should provide a fusion of video and radar data and its efficiency depends on radar ability to deliver a resolution high enough to be compatible with that of the optical image. Performance of low-THz radar, capable to deliver required resolution, is considered in this study, with the focus on reflectivities of pedestrians at frequencies within the low-THz region – 150 and 300?GHz. Backscatter returns are collected in a controlled environment at a number of frequency bands and at different aspect angles. Measurement methodology is presented and several indicators of reflectivities are calculated. Results are compared with values of radar cross-section reported for current automotive frequency standards 24 and 77?GHz. The effect of clothing on reflectivities is also considered in this study.
关键词： autonomous cars,Low-terahertz radar,automotive sensing,pedestrian detection,radar cross-section
更新于2025-09-23 15:21:01
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Visual Measurement of Terahertz Power Based on Graphene and Cholesteric Liquid Crystal Microcapsule
摘要： We demonstrate a new method to detect terahertz (THz) power by combining cholesteric liquid crystal microcapsule (CLCM) with three-dimensional porous grapheme (3DPG). The power of the THz radiation is measured using the hue image which is digitalized from the color change of a CLCM. Based on the the rmochromic property of CLCM and the high absorption of 3DPG over 97% in the frequency range of 0.32 THz a quantitative visualization of the THz intensity up to 2.7×103 mW/cm2 is presented and the minimal detectable THz power is only 0.009 mW. The THz power meter is cost-e?ective, portable, and high e?cient, which can be used in many applications such as THz imaging, inspection and sensing.
关键词： visualization,graphene,cholesteric liquid crystal microcapsule,terahertz power
更新于2025-09-23 15:21:01
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The coherent THz Smith-Purcell radiation from a three-dimensional open holes array structure
摘要： Coherent Smith-Purcell radiation from multiple electron beam excitation in a three-dimensional open holes array structure has been proposed. The electron beam passes through the holes, which can be coupled with each other to enhance surface wave fields, so that the multiple electron beam injection can interact with the surface wave field efficiently. And the Smith-Purcell radiation will be enhanced due to an increasement in dipole oscillations occurring when the electrons pass through the holes. Therefore, a high beam-wave interaction efficiency is yielded and very strong coherent terahertz radiation can be generated. This multi-beam system is expected to provide a favorable way to excite the coherent Smith-Purcell radiation, which would be used to generate terahertz radiation.
关键词： terahertz radiation,open holes array structure,Smith-Purcell radiation,electron beam
更新于2025-09-23 15:21:01
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[IEEE 2019 12th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - London, United Kingdom (2019.8.20-2019.8.22)] 2019 12th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Design of a 110GHz GaN Schottky Diode Frequency Tripler
摘要： In this paper, a 110GHz GaN Schottky diode frequency tripler is presented. The GaN Schottky diodes and the whole circuit are on Rogers/RT5880 and the thickness is 0.127m. The circuit design, simulation and optimization of the frequency tripler are carried out by using HFSS and ADS. The simulation result shows the efficiency of the tripler can achieve at least 7% in 110GHz and the outpower can achieve 100mW.
关键词： Schottky diode,terahertz tripler,GaN
更新于2025-09-23 15:21:01
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Secrecy rate optimization for intelligent reflecting surface aided multi-input-single-output terahertz communication
摘要： Intelligent reflecting surface (IRS) is an emerging paradigm to enhance terahertz (THz) communications with low hardware costs and reduced power consumptions. In this work, we study an IRS-aided THz multi-input-single-output secure communication system, where a base station (BS) transmits confidential signals to a single-antenna user with the presence of a single-antenna eavesdropper. We seek to maximize the secrecy rate by designing the discrete phase-shifts at the IRS and the precoder at the BS, which is an intractable nonconvex optimization problem. To solve it, we propose to iteratively design the above two matrix variables. Specifically, with a given phase-shift matrix, we can obtain the optimal precoder by the Rayleigh-Ritz theorem. And with a given precoder matrix, we propose a cross-entropy-based algorithm to obtain the optimal phase-shift matrix. Numerical results demonstrate that our proposed solution is able to improve the secrecy rate than that of the case without IRS.
关键词： intelligent reflecting surface,terahertz communication,secrecy rate
更新于2025-09-23 15:21:01