TST, Vol. 3, No. 2, PP. 55-65
Challenges for Ultrahigh-Speed Wireless Communications Using Terahertz Waves
Tadao Nagatsuma1,2 Ho-Jin Song2, and Yuichi Kado2
1Graduate School of Engineering Science, Osaka University
1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
Email: nagatuma@ee.es.osaka-u.ac.jp
2NTT Microsystem Integration Laboratories, NTT Corporation
3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan
Abstract: Demand is increasing for higher data rate in wireless communications in order to keep up with the remarkable speed-up of fiber-optic networks such as Ethernet LANs. One of the most direct and easiest ways to achieve a higher data rate of 10-100 Gbit/s is to increase carrier frequencies to terahertz regions of from 100 GHz to 500 GHz. This paper will review our recent challenges for high-speed wireless communications technologies using terahertz electro-magnetic waves.
Keywords: wireless communications, Terahertz, photodiode, giga-bit
doi: 10.11906/TST.055-065.2010.06.05
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TST, Vol. 3, No. 2, PP. 66-73
A Numerical Investigation of Metamaterial Antireflection Coatings
Hou-Tong Chen*, Jiangfeng Zhou, John F. O’Hara, and Antoinette J. Taylor
MPA-CINT, MS K771, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
* Email: chenht@lanl.gov
Abstract: Electromagnetic metamaterials have emerged as a new class of effective media where exotic properties are determined from structural geometry and dimensions of the basic building blocks, or meta-atoms. Through such a bottom-up approach, metamaterials have found applications in the construction of terahertz functional devices and components with unprecedented performance. In this paper, we numerically investigate planar metamaterials that function as antireflection coatings for dielectric surfaces, suppressing the reflection and enhancing the transmission. We show in detail how the metamaterial structures and losses affect the antireflection performance. We also show the angular dependence of metamaterial antireflection for both transverse electric and transverse magnetic polarizations, which reveals a tunable Brewster’s angle behavior.
Keywords: metamaterials, antireflection coatings, Terahertz, simulations
doi: 10.11906/TST.066-073.2010.06.06
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TST, Vol. 3, No. 2, PP. 74-84
Far-field predictions of metamaterials from two-dimensional near-field measurement system
Hui Feng Ma, Tie Jun Cui*, Xin Mi Yang, Wei Xiang Jiang, and Qiang Cheng
State Key Laboratory of Millimeter Waves and Institute of Target
Characteristics and Identification, Southeast University, Nanjing 210096, P. R. China
* Email: hfma@emfield.org and tjcui@seu.edu.cn
Abstract: In this paper, the near-to-far field transformation is proposed to predict the far fields of metamaterials from the near-field measureddata, which can be achieved by two-dimensional (2D) near-field microwave scanning apparatus (2D mapper). The 2D mapper is a near-field scanning system, from which the far-field data cannot be obtained directly. The near-to-far field transformation method has been studied to predict the far fields from the known near-field information, which will make the 2D mapper more efficient in the measurement of metamaterials. The correctness and feasibility of the proposed transformation are verified by both numerical simulations and experiments.
Keywords: Metamaterials, near-field scanning system, far-field prediction
doi: 10.11906/TST.074-084.2010.06.07
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TST, Vol. 3, No. 2, PP. 85-91
THz Transmission Properties of Metallic Slit Array
Guozhong Zhao
Department of Physics, Capital Normal University, Beijing 100048, China
Beijing Key Lab for Terahertz Spectroscopy and Imaging
Key Lab of Terahertz Optoelectronics, Ministry of Education, China
No. 105 of XiSanHuan Bei Lu, Haidian District, Beijing 100048, China
Email: guozhong-zhao@mail.cnu.edu.cn
Abstract: Terahertz (THz) transmission spectrum of metallic slit array is studied by means of terahertz time-domain spectroscopy. Frequency-selective THz transmission of metallic slit array is shown experimentally and analyzed by numerical simulation. The results illustrate that the obvious transmission enhancement occur with the narrowing of slits. The terahertz transmission peak has a blue shift until the peak disappear when the slit width becomes larger. The transmission enhancement of metallic slit array strongly depends on the polarization of terahertz radiation. For the metallic fractal structures of slit array, the multiband including the pass band and stop band exists and their frequencies of transmission peaks are determined by the length of first-level of fractal line. The electric field distribution on the metallic fractal array of square hole shows that THz field is localized on the boundary of metallic hole. It implied that THz transmission properties of metallic mesh structure are domain by the interaction between the photon and boundary plasma of metallic slits.
Keywords: THz, function materials, devices, metallic slit, array
doi: 10.11906/TST.085-091.2010.06.08
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TST, Vol. 3, No. 2, PP. 92-96
Monte Carlo simulation and material growth of resonant-phonon assisted terahertz quantum cascade lasers
Yingjun Han, H. Li, Z. Y. Tan, X. G. Guo and J. C. Cao*
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, P. R. China
*Email: jccao@mail.sim.ac.cn
Abstract: An ensemble Monte Carlo method is employed to evaluate the performance of resonant-phonon terahertz quantum cascade lasers. Based on our simulation, a device structure is designed to avoid the strong absorption of atmosphere. The material growth, structural analyses and optical characteristics of the laser are present. Using gold-gold waveguide layers, we demonstrate a device lasing at 3.4 THz, which is just located at a low-loss stage of the atmosphere.
Keywords: Terahertz, Quantum Cascade Laser, Monte Carlo
doi: 10.11906/TST.092-096.2010.06.09
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