Article
Multidisciplinary Sciences
Rabi Shrestha, Hichem Guerboukha, Zhaoji Fang, Edward Knightly, Daniel M. Mittleman
Summary: As wireless communications move towards terahertz frequencies, new vulnerabilities are discovered. These vulnerabilities include high directional attacks, beat jamming, and asymmetric bit interference. The study reveals the distinct features of jamming at these high frequencies and quantifies the increasing susceptibility of broadband receivers to jamming.
NATURE COMMUNICATIONS
(2022)
Letter
Optics
Yasaman Ghasempour, Yasith Amarasinghe, Chia-Yi Yeh, Edward Knightly, Daniel M. Mittleman
Summary: This paper investigates the usage of reflected non-line-of-sight (NLOS) paths for communication in directional networks at frequencies above 100 GHz. The study explores how high-gain directional antennas bring new challenges and opportunities for exploiting NLOS paths, demonstrating that NLOS paths can offer higher data rates under certain circumstances, distinguishing THz wireless systems from those operating at lower frequencies.
Article
Optics
Kazutoshi Kato
Summary: Beam forming and beam steering are essential technologies for the practical application of high-frequency electromagnetic waves, while beam control technology using a phased array for terahertz waves above 100 GHz is necessary for achieving high-speed wireless communication. Adjusting the beam of terahertz waves improves not only the power efficiency but also the security of wireless transmission at the physical layer.
Article
Engineering, Electrical & Electronic
Kaile Li, Jianguo Yu
Summary: This tutorial introduces the key technologies and principles of ultrahigh speed and large capacity THz-wave signal transmission, including photonics-aided THz-wave generation technology, new progress in optical frequency combs and optical modulators, and the application of DSP technology for heterodyne detection and multidimensional multiplexing technology.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Geng-Bo Wu, Ka Fai Chan, Kam Man Shum, Chi Hou Chan
Summary: The incoming 5G and beyond 5G wireless communications offer unprecedented ultra-high-speed data transmission rates. This article presents novel discrete lens antenna designs to address the challenges of orbital angular momentum (OAM) applications in mmWave and THz bands, opening up possibilities for future high-speed wireless communications.
IEEE COMMUNICATIONS MAGAZINE
(2022)
Article
Engineering, Electrical & Electronic
Jintao Wang, Xiaohui Zhang, Xu Shi, Jian Song
Summary: In the new 5G era, millimeter wave communications can achieve huge data rate growth and wide bandwidth with a hybrid precoding architecture, effectively optimizing the system's spectral efficiency through the design of digital and analog precoders. The use of index modulation (IM) techniques can further improve spectral efficiency in mmWave systems. Simulation results demonstrate that IM-aided systems outperform traditional mmWave systems, making IM a promising technique for practical SE-driven mmWave systems.
IEEE COMMUNICATIONS MAGAZINE
(2021)
Article
Engineering, Electrical & Electronic
Nishant Singh, Guy Torfs, Joris Van Kerrebrouck, Christophe Caillaud, Piet Demeester, Xin Yin
Summary: The proposed analog radio-over-fiber photoreceiver based on a resonant narrowband transimpedance low noise amplifier (TILNA) is designed for low-cost and low-power remote radio heads in the unlicensed 60GHz band. This photoreceiver offers improved gain with resonant matching and has shown success in achieving high-speed data transmission over standard single-mode fiber.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Ke Guan, Juan Moreno, Bo Ai, Cesar Briso-Rodriguez, Bile Peng, Danping He, Andrej Hrovat, Zhangdui Zhong, Thomas Kuerner
Summary: This article focuses on developing realistic 5G mmWave channel models for high-speed trains, addressing the need for high-speed wireless connectivity with multiple GHz bandwidths. By defining reference scenarios to parameterize channel models for railway use at mmWave band, the accuracy of simulations reflecting the detailed influence of railway objects is validated. The future direction points towards terahertz (THz) communications powering the full version of smart rail mobility.
IEEE INTELLIGENT TRANSPORTATION SYSTEMS MAGAZINE
(2021)
Article
Engineering, Electrical & Electronic
Nishant Singh, Guy Torfs, Joris Van Kerrebrouck, Reinier Broucke, Piet Demeester, Xin Yin
Summary: This article presents an all-silicon analog radio-over-fiber transmitter chipset for narrowband operation in the unlicensed 60 GHz V-band. The chipset consists of a low-noise high-speed quadrature driver RFIC and an EAM based single-sideband I/Q modulator PIC. The RFIC includes a low-noise input stage, gain stages, a hybrid coupler, and two output stages, while the PIC consists of parallel electro-absorption modulators and thermo-optic phase shifters. Optical back-to-back experiments were successfully conducted using various QAM signals, demonstrating a sideband suppression ratio of 25 dB, a chipset size of 1.1 mm², and a power consumption of 45 mW.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Computer Science, Hardware & Architecture
Peilan Wang, Jun Fang, Weizheng Zhang, Zhi Chen, Hongbin Li, Wei Zhang
Summary: Reconfigurable intelligent surface (RIS) is a promising paradigm for future cellular networks, addressing blockage issues in mmWave or terahertz communications. However, the deployment of RIS complicates system architecture and poses challenges for beam training (BT)/beam alignment (BA).
IEEE WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Zu-Kai Weng, Atsushi Kanno, Pham Tien Dat, Keizo Inagaki, Kosuke Tanabe, Eisaku Sasaki, Thomas Kurner, Bo Kum Jung, Tetsuya Kawanishi
Summary: This paper introduced a link budget evaluation for fixed wireless links under extreme weather conditions, focusing on high temperature, violent rain, and strong winds. A theoretical model was proposed to evaluate attenuation by wind effect, and the results confirmed heavy rain as a dominant factor in attenuation. Additionally, antenna gain degradation due to wind effect was found considerable for high frequency wireless links.
Article
Engineering, Electrical & Electronic
Lipeng Zhu, Jun Zhang, Zhenyu Xiao, Xiang-Gen Xia, Rui Zhang
Summary: This paper proposes the use of multiple unmanned aerial vehicle (UAV) base stations to serve ground users in the millimeter-wave frequency bands. It formulates a problem to optimize UAV positioning, user clustering, and hybrid analog-digital beamforming for maximizing user achievable sum rate. A suboptimal solution is developed using alternating optimization, successive convex optimization, and combinatorial optimization. The proposed algorithm outperforms benchmark schemes and closely approaches the performance bound of fully-digital beamforming.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Xiaodan Pang, Oskars Ozolins, Shi Jia, Lu Zhang, Richard Schatz, Aleksejs Udalcovs, Vjaceslavs Bobrovs, Hao Hu, Toshio Morioka, Yan-Ting Sun, Jiajia Chen, Sebastian Lourdudoss, Leif Oxenlowe, Sergei Popov, Xianbin Yu
Summary: Since one and half centuries ago, radio and optics have been separate electromagnetic spectrum regions for data transmission, but now the boundaries between them are becoming blurred and intercrossed. Optical technologies are expanding into infrared regions, while radio technologies strive for higher frequencies to gain broader bandwidth. Technological breakthroughs in photonics-assisted free-space transmission have been witnessed in recent years.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Abdelrahman Taha, Qi Qu, Sam Alex, Ping Wang, William L. Abbott, Ahmed Alkhateeb
Summary: In this paper, a novel solution for constructing AR/VR depth map using mmWave MIMO communication transceivers is proposed. Motivated by the deployment of advanced mmWave communication systems in future AR/VR devices and the interesting propagation characteristics of mmWave signals, a comprehensive framework for constructing accurate and high-resolution depth maps using mmWave systems is developed. The proposed solution demonstrates promising gains in building accurate depth maps compared to RGB-based approaches in several important use cases.
Article
Computer Science, Hardware & Architecture
Akram Shafie, Nan Yang, Chong Han, Josep Miquel Jornet, Markku Juntti, Thomas Kuerner
Summary: This article delves into key areas for developing end-to-end THzCom systems, focusing on physical, link, and network layers. It discusses the areas of THz spectrum management, THz antennas, and beamforming, as well as the integration of other 6G-enabling technologies for THzCom. The challenges imposed by the unique properties of the THz band are identified, and main advancements and perspective research directions in each area are outlined to stimulate future research efforts for realizing THzCom in 6G and beyond wireless networks.
Article
Physics, Applied
Hiroshi Ito, Norihiko Shibata, Tadao Nagatsuma, Tadao Ishibashi
Summary: We have developed a novel terahertz-wave detector on a SiC platform using an InP/InGaAs FMB diode. The detector exhibits a low noise equivalent power and has successfully integrated a waveguide coupler and filters.
APPLIED PHYSICS EXPRESS
(2022)
Article
Optics
Ratmalgre Koala, Kei Iyoda, Weijie Gao, Yuji Matsuura, Masayuki Fujita, Tadao Nagatsuma
Summary: Existing interconnects suffer from high losses and low data throughput, while emerging data-intensive technologies require low-loss, short-range interconnects. In this study, we developed an efficient 22-Gbit/s terahertz fiber link using a tapered silicon interface as a coupler between the dielectric waveguide and hollow core fiber. By investigating the optical properties of hollow-core fibers with core diameters of 0.7 mm and 1 mm, we achieved a coupling efficiency of -60% and a 3-dB bandwidth of 150 GHz in the 0.3-THz band over a 10 cm fiber.
Article
Engineering, Electrical & Electronic
Julian Webber, Takumi Yamamoto, Naoki Nishigami, Yosuke Nishida, Masayuki Fujita, Tadao Nagatsuma
Summary: The paper presents an experiment on wireless communication in the terahertz band using a resonant tunneling diode receiver (Rx) and uni-travelling carrier photodiode transmitter. The use of intermediate-frequency-based transmission enables a low-complexity envelope-detection type Rx architecture for complex-modulated signals. Data rates of 60 and 68 Gbit/s are achieved for quadrature phase shift keying modulation and 16-level quadrature amplitude modulation respectively, with forward error correction enabling data recovery.
ELECTRONICS LETTERS
(2023)
Article
Optics
Brendan M. M. Heffernan, Yuma Kawamoto, Keisuke Maekawa, James Greenberg, Rubab Amin, Takashi Hori, Tatsuya Tanigawa, Tadao Nagatsuma, Antoine Rolland
Summary: Future wireless communication infrastructure will depend on terahertz systems to meet the increasing demand for high-bandwidth, ultra-fast wireless data transfer. To achieve this, compact, low-power, and low noise terahertz radiation sources are being developed. One promising approach is combining photonic-integrated optical frequency combs with fast photodiodes for difference frequency generation in the THz. In this experiment, wireless communication was demonstrated using a 300 GHz carrier wave generated by photomixing of two optical tones from diode lasers injection locked to a dissipative Kerr soliton frequency microcomb. Transfer rates of 80 Gbps were achieved using homodyne detection, and 60 Gbps were transmitted simultaneously for both data and clock signals in a dual-path wireless link. This experimental demonstration paves the way for low-noise and integrated photonic millimeter-wave transceivers for future wireless communication systems.
Article
Engineering, Electrical & Electronic
Ratmalgre Koala, Kei Iyoda, Masayuki Fujita, Tadao Nagatsuma
Summary: The authors investigated the transmission performance of orthogonal polarization fundamental modes in a dielectric silicon terahertz waveguide for doubling the data rate. The maximum data rate under on-off keying modulation at 0.3-THz band with practical error-free condition (bit-error rate < 10(-11)) is comparable for both polarizations, reaching 20 Gbit/s.
ELECTRONICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Li Yi, Yihan Li, Tadao Nagatsuma
Summary: This article provides an overview of recent progress in photonic radar systems, focusing on hardware components, imaging technology, and radar imaging applications in the millimeter wave to terahertz frequency bands. The potential for high-resolution imaging techniques enabled by photonic radar systems is also discussed.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Editorial Material
Engineering, Electrical & Electronic
Guillermo Carpintero, Elliott Brown, Tadao Nagatsuma, Pham Tien Dat, Lute Maleki, Daniel Yap, Andreas Stohr
Summary: This Special Issue of the IEEE/OSA Journal of Selected Topics in Quantum Electronics on Terahertz Photonics provides an overview of the latest developments in the field, covering a wide range from 100 GHz to 10 THz. Terahertz Photonics has played a leading role in accessing the Terahertz range, enabling important demonstrations in areas such as broadband communications, spectroscopy, and imaging through innovative THz sources and detectors.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Akihiko Hirata, Tubasa Saijo, Yuma Kawamoto, Tadao Nagatsuma, Issei Watanabe, Norihiko Sekine, Akifumi Kasamatsu
Summary: This study experimentally evaluated the transmission characteristics of a 120-GHz-band close-proximity wireless link using split-ring resonator (SRR) millimeter-wave absorber integrated on planar slot antennas. The results showed that the integration of the absorber reduced signal fluctuations and enabled successful transmission of high-speed data over the wireless link.
IEICE TRANSACTIONS ON ELECTRONICS
(2023)
Article
Optics
Daniel Headland, Masayuki Fujita, Guillermo Carpintero, Tadao Nagatsuma, Withawat Withayachumnankul
Summary: The absence of a suitable standard device platform for terahertz waves is hindering the widespread adoption and exploitation of terahertz technology. However, establishing a common platform using substrateless all-silicon microstructures can consolidate design efforts and move beyond disconnected efforts. The all-silicon microstructures offer low loss, compactness, designability, physical rigidity, ease of manufacture, and versatility in integrating various functional devices and systems.
Proceedings Paper
Engineering, Electrical & Electronic
Keisuke Maekawa, Yuma Kawamoto, Tomoya Nakashita, Toki Yoshioka, Takashi Hori, Brendan M. Heffernan, James Greenberg, Rubab Amin, Tatsuya Tanigawa, Antoine Rolland, Tadao Nagatsuma
Summary: We propose a THz wireless link using photonics-based signal generators with ultralow amplitude- and phase-noise Brillouin laser sources for the transmitter and receiver. Furthermore, we demonstrate the successful transmission of over-100-Gbit/s signals at 300 GHz with on-line signal processing.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Mohamed Shehata, Ke Wang, Julian Webber, Masayuki Fujita, Tadao Nagatsuma, Withawat Withayachumnankul
Summary: We propose and experimentally demonstrate a Nyquist pulse that significantly improves the error rate of a 311 GHz photonic-terahertz communications system compared to a normalized timing-jitter of 22.5% and 1.44 Gbit/s bit rate.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Article
Engineering, Electrical & Electronic
Sumer Makhlouf, Oleg Cojocari, Martin Hofmann, Tadao Nagatsuma, Sascha Preu, Nils Weimann, Heinz-Wilhelm Huebers, Andreas Stoehr
Summary: This manuscript reports on the latest achievements in terahertz sources and receivers, providing a comprehensive overview of their working principles and applications in THz systems.
IEEE JOURNAL OF MICROWAVES
(2023)
Article
Engineering, Electrical & Electronic
Hiroshi Ito, Yuma Kawamoto, Takahiro Ohara, Tadao Nagatsuma, Tadao Ishibashi
Summary: In this study, a terahertz-wave balanced mixer was developed on a SiC substrate using epi-layer-transferred InP/InGaAs Fermi-level managed barrier diodes. The mixer exhibited a wide intermediate frequency bandwidth and high inter-port isolations. It also achieved a low noise equivalent power at high local-oscillator power.
IEICE ELECTRONICS EXPRESS
(2023)
Article
Engineering, Electrical & Electronic
Daniel Jonathan Headland, Yosuke Nishida, Xiongbin Yu, Masayuki Fujita, Tadao Nagatsuma
Summary: This study presents an effective method for connecting a terahertz oscillator chip with a broadband all-intrinsic-silicon dielectric waveguide through backside coupling. By using resonant tunneling diodes as compact electronic terahertz oscillators, terahertz waves from 270 GHz to 404 GHz were successfully observed.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yuma Kawamoto, Toki Yoshioka, Norihiko Shibata, Daniel Headland, Masayuki Fujita, Ryo Koma, Ryo Igarashi, Kazutaka Hara, Jun-ichi Kani, Tadao Nagatsuma
Summary: This paper proposes a novel silicon diplexer for frequency-division multiplexing in the 300 GHz band. The integrated filters in the diplexer can suppress crosstalk and provide high isolation, making it highly beneficial for terahertz-range wireless communications applications. The diplexer has been successfully used in a simultaneous error-free wireless transmission of 300 GHz and 335 GHz channels at a data rate of 36 Gbit/s.
2022 ASIA-PACIFIC MICROWAVE CONFERENCE (APMC)
(2022)