Article
Engineering, Electrical & Electronic
Yasushi Koyama, Yuki Kitazawa, Koji Yukimasa, Tatsuro Uchida, Takeshi Yoshioka, Kokichi Fujimoto, Takahiro Sato, Jun Iba, Katsuhito Sakurai, Takeshi Ichikawa
Summary: This study proposes a compact, high-power, and high-directivity terahertz source based on an active antenna array. The use of coherent oscillation and spatial power combining improves radiation power and directivity. The source's performance and feasibility were verified through measurements and the suppression of parasitic oscillation using a bias stabilization circuit.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Tomoki Hiraoka, Takashi Arikawa, Hiroaki Yasuda, Yuta Inose, Norihiko Sekine, Iwao Hosako, Hiroshi Ito, Koichiro Tanaka
Summary: The study focused on the injection-locking properties of a resonant-tunneling-diode terahertz oscillator in the small-signal injection regime, showing that injection locking significantly reduced the emission spectrum linewidth. Experimental results indicated that the locking range was proportional to the injection amplitude, and an increase in injection amplitude led to a decrease in noise component and increase in injection-locked component.
Review
Chemistry, Multidisciplinary
Jue Wang, Mira Naftaly, Edward Wasige
Summary: This paper introduces the applications of terahertz (THz) imaging in the industrial sector and the room temperature THz transceiver technology using resonant tunneling diode (RTD) devices, which provides an effective approach to achieve compact, low-cost THz imaging systems.
APPLIED SCIENCES-BASEL
(2022)
Article
Physics, Applied
Shuya Iwamatsu, Yosuke Nishida, Masayuki Fujita, Tadao Nagatsuma
Summary: This study proposes integrating two resonant tunneling diode (RTD) oscillators within a single slot-ring antenna, achieving mutual-coupling and radiation simultaneously through an innate phase-locking mechanism. Experimental results show that this double-RTD device exhibits higher output power and excellent performance at 354 GHz.
APPLIED PHYSICS EXPRESS
(2021)
Review
Chemistry, Analytical
Masahiro Asada, Safumi Suzuki
Summary: This paper reviews recent progress in resonant-tunneling diode (RTD) terahertz (THz) oscillators, which are compact semiconductor THz sources, including principles and characteristics of oscillation, studies addressing high-frequency and high output power, a structure which can easily be fabricated, frequency tuning, spectral narrowing, different polarizations, and select applications. Fundamental oscillation up to 1.98 THz and output power of 0.7 mW at 1 THz by a large-scale array have been reported, with structures integrated with cylindrical and rectangular cavities proposed for high-frequency and high output power. Wide electrical tuning of 400-900 GHz has been demonstrated using oscillators integrated with varactor diodes and their arrays. A line width as narrow as 1 Hz has been obtained for spectral narrowing through use of a phase-locked loop system with a frequency-tunable oscillator. Basic research for various applications of RTD oscillators has been carried out, with discussion of recent results related to imaging, spectroscopy, high-capacity wireless communication, and radar systems.
Review
Engineering, Electrical & Electronic
Davide Cimbri, Jue Wang, Abdullah Al-Khalidi, Edward Wasige
Summary: This article provides an overview of the application and key performance of resonant tunneling diode (RTD) technology in the field of terahertz wireless communications, and proposes possible directions for future technological development.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Applied
Kota Endo, Masashi Sekiya, Jaeyoung Kim, Kento Sato, Takehito Suzuki
Summary: The study demonstrates that a collimating metalens made with our original metasurface can significantly enhance the directivity of terahertz waves when mounted on a resonant tunneling diode, making it suitable for emerging industries such as 6G communications.
APPLIED PHYSICS EXPRESS
(2021)
Article
Engineering, Electrical & Electronic
Feifan Han, Kazunori Kobayashi, Safumi Suzuki, Hiroki Tanaka, Hidenari Fujikata, Masahiro Asada
Summary: This paper theoretically presents a terahertz oscillator utilizing a RTD and a rectangular cavity to radiate high output power through impedance matching with MIM capacitors. Simulation results demonstrate that high output power up to 5 mW can be achieved by using a long cavity.
IEICE TRANSACTIONS ON ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Yusei Suzuki, Ta Van Mai, Xiongbin Yu, Safumi Suzuki, Masahiro Asada
Summary: This study successfully demonstrated the phase control of an injection-locked RTD oscillator, with the use of a developed device package and a heterodyne detection system, achieving accurate phase control in the injection-locking state.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Mingxiang Stephen Li, Ta Van Mai, Christophe Fumeaux, Safumi Suzuki, Withawat Withayachumnankul
Summary: A slot-based RTD structure is proposed to simplify the fabrication process, but it causes an unexpected large tilt angle in the main lobe of its radiation pattern. To solve this issue, a series-fed patch array design is introduced and it directs leakage surface waves to the broadside direction. The simulation and experimental results demonstrate improved radiation performance and potential for future array-level designs and flat lens systems.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Zoltan Jehn, Michael Feiginov
Summary: As a proof of principle, the operation of traveling-wave resonant-tunneling-diodes (RTDs) oscillators has been experimentally demonstrated in the frequency range of 100-400 GHz. A theoretical model has been developed to describe a realistic coupled system, consisting of a traveling-wave RTD and a patch antenna, which depicts the mixed resonance and mode characteristics of both subsystems. The model and experimental results are in agreement. It has also been shown that some oscillators can switch between different resonant modes of the system with a change in bias, offering an extended frequency control for RTD oscillators.
IEEE TRANSACTIONS ON NANOTECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yucheng Liu, Weihao Liu, Qika Jia, Baogen Sun, Jun Chen
Summary: This article introduces an enhanced TLD boosted by resonant cavities, which significantly increases the quality factor of the resonant modes and enhances the output power by more than an order of magnitude. Furthermore, by changing the shape of the cavity, the operation modes and frequency of the TLD can be adjusted, allowing for efficient operation with high-order modes and increasing the output frequency without increasing machining difficulty, which is beneficial for developing high-power and high-frequency free-electron THz sources.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Optics
Liu Jun, Song Rui-Liang, Liu Ning, Liang Shi-Xiong
Summary: This study designs and realizes an oscillator above 1THz using an InP-based resonant tunneling diode (RTD) and an on-chip antenna with a Si-lens. The RTD model is built and studied using Silvaco software. The effects of doping concentration, barrier layer thickness, space layer, and well layer on the DC characteristics of the device have been analyzed. The experimental results show that the oscillator achieves high RF output power and oscillation frequency at an operation frequency above 1THz.
JOURNAL OF INFRARED AND MILLIMETER WAVES
(2022)
Article
Engineering, Electrical & Electronic
Zoltan Jehn
Summary: This work focuses on the theoretical shapes of cavities for RTD lumped-element oscillators, aiming to achieve the highest operational frequency. By employing functional variation principles and the EFIE method, simple design parameters were derived for smaller cavities, and the maximum achievable frequency was calculated using these new cavities.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2022)
Article
Chemistry, Multidisciplinary
Florian Rothmayr, Edgar David Guarin Castro, Fabian Hartmann, Georg Knebl, Anne Schade, Sven Hoefling, Johannes Koeth, Andreas Pfenning, Lukas Worschech, Victor Lopez-Richard
Summary: Resonant tunneling diode photodetectors show promise for mid-infrared sensing at room temperature due to their simple design. We fabricated devices with GalnAsSb absorbers and achieved significant electrical responsivity. This paper provides a comprehensive theoretical analysis of the sensor's functionality and performance, including the effects of photogenerated carriers on electrostatic modulation and the control of sensing abilities.
