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Toshikazu Mukai

Bio: Toshikazu Mukai is an academic researcher from Rohm. The author has contributed to research in topics: Resonant-tunneling diode & Terahertz radiation. The author has an hindex of 11, co-authored 38 publications receiving 374 citations.

Papers
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Journal ArticleDOI
TL;DR: An error-free wireless transmission of a 9 Gbit/s on–off keying modulated signal as well as a 4 k video signal is demonstrated using resonant tunnelling diodes as active elements in both the transmitter and the receiver.
Abstract: An error-free wireless transmission of a 9 Gbit/s on–off keying modulated signal as well as a 4 k video signal is demonstrated using resonant tunnelling diodes as active elements in both the transmitter and the receiver. The employed system and the modulation scheme enabling the high data rate are discussed.

70 citations

Journal ArticleDOI
TL;DR: In this article, a feasibility study of a terahertz imaging system with resonant tunneling diodes (RTDs) that oscillate at 0.30 THz was performed.
Abstract: We report a feasibility study of a terahertz imaging system with resonant tunneling diodes (RTDs) that oscillate at 0.30 THz. A pair of RTDs acted as an emitter and a detector in the system. Terahertz reflection images of opaque samples were acquired with our RTD imaging system. A spatial resolution of 1 mm, which is equal to the wavelength of the RTD emitter, was achieved. The signal-to-noise ratio (SNR) of the reflection image was improved by 6 dB by using polarization optics that reduced interference effects. Additionally, the coherence of the RTD enabled a depth resolution of less than 3 µm to be achieved by an interferometric technique. Thus, RTDs are an attractive candidate for use in small THz imaging systems.

66 citations

Journal ArticleDOI
TL;DR: In this article, circuit models of transmission line elements and of a terahertz resonant tunneling diode (RTD) have been developed for a reliable design of RTD-based oscillator and detector circuits.
Abstract: Circuit models of transmission line elements and of a terahertz resonant tunneling diode (RTD) have been developed. The models allow for a reliable design of RTD-based oscillator and detector circuits. The transmission line elements have been modeled based on electromagnetic field simulations and dc measurements. Their accuracy has been verified through S-parameter measurements. The RTD has been modeled on the basis of dc and S-parameter measurements. The models have been used for the circuit design. A new circuit has been developed that can provide a load impedance that allows for high-output-power oscillators and high-sensitivity detectors. The circuit has been manufactured and measured as an oscillator and as a detector at frequencies around 300 GHz. An excellent agreement between measurement and simulation has been obtained, proving the accuracy of the developed models.

42 citations

Proceedings Article
01 Dec 2011
TL;DR: In this paper, the use of a resonant tunneling diode (RTD) as a detector in terahertz wireless communications systems was proposed, which is expected to provide about 30dB increase in the sensitivity due to its strong nonlinearity.
Abstract: We propose the use of a resonant tunneling diode (RTD) as a detector in terahertz wireless communications systems. Comparing to the conventional Schottky-barrier diode detector, the RTD is expected to provide about 30-dB increase in the sensitivity due to its strong nonlinearity. We have experimentally demonstrated an error-free wireless transmission at a bit rate of 2 Gbit/s using the RTD at 300 GHz.

37 citations

Journal ArticleDOI
TL;DR: In this paper, a dual-pass high current density resonant tunneling diode (RTD) for terahertz wave applications is presented, which reduces the overall fabrication complexity and improves the reproducibility for creating low resistance ohmic contacts.
Abstract: We report on a dual-pass high current density resonant tunneling diode (RTD) for terahertz wave applications. This technique reduces the overall fabrication complexity and improves the reproducibility for creating low resistance ohmic contacts. With our dual-pass technique, we demonstrate accurate control over the final device area by measuring the RTD current–voltage characteristic during the fabrication process and guiding the emitter current through the full RTD structure with a second contact electrode on the collector side. We go on to show how we may extract important information about the RTD performance using this method.

30 citations


Cited by
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01 Jan 2016
TL;DR: The electronic transport in mesoscopic systems is universally compatible with any devices to read, and is available in the book collection an online access to it is set as public so you can get it instantly.
Abstract: Thank you very much for reading electronic transport in mesoscopic systems. Maybe you have knowledge that, people have look numerous times for their favorite readings like this electronic transport in mesoscopic systems, but end up in harmful downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they juggled with some harmful bugs inside their computer. electronic transport in mesoscopic systems is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the electronic transport in mesoscopic systems is universally compatible with any devices to read.

1,220 citations

01 Jan 2017
TL;DR: The 2017 roadmap of terahertz frequency electromagnetic radiation (100 GHz-30 THz) as mentioned in this paper provides a snapshot of the present state of THz science and technology in 2017, and provides an opinion on the challenges and opportunities that the future holds.
Abstract: Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.

690 citations

Patent
11 Feb 2014
TL;DR: In this paper, the first and second conductor layers are formed on a main surface of a base layer, and a tapered slot is formed between the first-and second-conductive layers.
Abstract: First and second conductor layers are formed on a main surface of a base layer. A tapered slot is formed between the first and second conductive layers. A first slit is formed at the first conductor layer, and a second slit is formed at the second conductor layer. Thus, the first conductor layer is divided into a first device connection portion and a first antenna portion, and the second conductor layer is divided into a second device connection portion and a second antenna portion. A semiconductor device is connected to the first and second device connection portions.

154 citations

Journal ArticleDOI
06 Feb 2018
TL;DR: The underlying principles of wavefront engineering include array antenna theory and diffraction optics, which are drawn from the neighboring microwave and optical regimes, respectively, which provides a useful foundation for investigations into beam control in the terahertz range.
Abstract: The terahertz range possesses significant untapped potential for applications including high-volume wireless communications, noninvasive medical imaging, sensing, and safe security screening However, due to the unique characteristics and constraints of terahertz waves, the vast majority of these applications are entirely dependent upon the availability of beam control techniques Thus, the development of advanced terahertz-range beam control techniques yields a range of useful and unparalleled applications This article provides an overview and tutorial on terahertz beam control The underlying principles of wavefront engineering include array antenna theory and diffraction optics, which are drawn from the neighboring microwave and optical regimes, respectively As both principles are applicable across the electromagnetic spectrum, they are reconciled in this overview This provides a useful foundation for investigations into beam control in the terahertz range, which lies between microwaves and infrared

134 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the structure needed to achieve high output power in resonant tunneling diode (RTD) oscillators in the terahertz range.
Abstract: We report the theoretical and experimental results of an examination of the structure needed to achieve high output power in resonant tunneling diode (RTD) oscillators in the terahertz range. An offset-fed slot antenna and antenna width adjustments were employed in a single oscillator to increase the output power by increasing the radiation conductance and impedance matching. A high output power oscillation (~400 μW) at 530-590 GHz was obtained by RTDs with a large negative deferential conductance (NDC) region and offset-fed slot antennas. The maximization of the output power that was obtained by adjusting the antenna width was attributed to the impedance matching between the RTD and antenna. An output power of >;1 mW is theoretically expected in an oscillator that combines an RTD with a large NDC region, offset-fed slot antenna, and antenna width adjustment. In an array configuration, oscillators with an offset structure were employed for array elements and connected together with the metal-insulator-metal stub structure. A single peak was observed in the oscillation spectrum, and combined output powers of 610, 270, and 180 μW at 620, 770, and 810 GHz were obtained in a two-element array.

131 citations