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Richard Lai

Bio: Richard Lai is an academic researcher from Northrop Grumman Corporation. The author has contributed to research in topics: Amplifier & Monolithic microwave integrated circuit. The author has an hindex of 36, co-authored 255 publications receiving 5095 citations. Previous affiliations of Richard Lai include TRW Inc. & Grumman Aircraft Corporation.


Papers
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Journal ArticleDOI
TL;DR: In this article, the first terahertz integrated circuit amplifier based on 25-nm InP high electron mobility transistor (HEMT) process was demonstrated at 1 GHz with 9-dB measured gain at 1.5 GHz.
Abstract: We report the first ever terahertz monolithic integrated circuit amplifier based on 25-nm InP high electron mobility transistor (HEMT) process demonstrating amplification at 1 THz (1000 GHz) with 9-dB measured gain at 1 THz. This milestone was achieved with a 25-nm InP HEMT transistor, which exhibits 3.5-dB maximum available gain at 1 and 1.5 THz projected $f_{\mathrm {\mathbf {MAX}}}$ .

312 citations

Proceedings ArticleDOI
01 Dec 2007
TL;DR: In this article, the authors presented the latest advancements of sub 50 nm InGaAs/lnAIAS/lnP high electron mobility transistor (InP HEMT) devices that have achieved extrapolated Fmax above 1 THz.
Abstract: In this paper, we present the latest advancements of sub 50 nm InGaAs/lnAIAs/lnP high electron mobility transistor (InP HEMT) devices that have achieved extrapolated Fmax above 1 THz. This extrapolation is both based on unilateral gain (1.2 THz) and maximum stable gain/maximum available gain (1.1 THz) extrapolations, with an associated fT of 385 GHz. This extrapolation is validated by the demonstration of a 3-stage common source low noise MMIC amplifier which exhibits greater than 18 dB gain at 300 GHz and 15 dB gain at 340 GHz.

270 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a background describing THz monolithic integrated circuits using InP HEMT, which has been used to realize amplifiers, mixers, and multipliers operating at 670 GHz.
Abstract: In this paper, background describing THz monolithic integrated circuits using InP HEMT is presented. This three-terminal transistor technology has been used to realize amplifiers, mixers, and multipliers operating at 670 GHz. Transistor and processing technology, packaging technology, and circuit results at 670 GHz are described. The paper concludes with initial results from a 670-GHz InP HEMT receiver and trends for InP HEMT components.

197 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe a two-stage InP-based amplifier with a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry.
Abstract: This paper describes cryogenic broad-band amplifiers with very low power consumption and very low noise for the 4-8-GHz frequency range. At room temperature, the two-stage InP-based amplifier has a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry. When cooled to 15 K, an input noise temperature of 1.4 K is obtained at 5.7 mW per stage. At 0.51 mW per stage, the input noise increases to 2.4 K. The noise measurements have been repeated at different laboratories using different methods and are found consistent.

146 citations

Journal ArticleDOI
TL;DR: In this paper, a high fMAX InP HEMT transistors in a 5-stage coplanar waveguide integrated circuit were used for low noise amplification at 0.67 GHz.
Abstract: In this letter, low noise amplification at 0.67 THz is demonstrated for the first time. A packaged InP High Electron Mobility Transistor (HEMT) amplifier is reported to achieve a noise figure of 13 dB with an associated gain greater than 7 dB at 670 GHz using a high fMAX InP HEMT transistors in a 5 stage coplanar waveguide integrated circuit. A 10-stage version is also reported to reach a peak gain of 30 dB. These results indicate that InP HEMT integrated circuits can be useful at frequencies approaching a terahertz.

109 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of electronic devices based on two-dimensional materials, outlining their potential as a technological option beyond scaled complementary metal-oxide-semiconductor switches and the performance limits and advantages, when exploited for both digital and analog applications.
Abstract: The compelling demand for higher performance and lower power consumption in electronic systems is the main driving force of the electronics industry's quest for devices and/or architectures based on new materials. Here, we provide a review of electronic devices based on two-dimensional materials, outlining their potential as a technological option beyond scaled complementary metal-oxide-semiconductor switches. We focus on the performance limits and advantages of these materials and associated technologies, when exploited for both digital and analog applications, focusing on the main figures of merit needed to meet industry requirements. We also discuss the use of two-dimensional materials as an enabling factor for flexible electronics and provide our perspectives on future developments.

2,531 citations

Journal ArticleDOI
16 Jan 2008
TL;DR: The latest developments of the GaN HEMT technologies, including material growth, processing technologies, device epitaxial structures and MMIC designs, are reviewed to achieve the state-of-the-art microwave and millimeter-wave performance.
Abstract: The rapid development of the RF power electronics requires the introduction of wide bandgap material due to its potential in high output power density, high operation voltage and high input impedance GaN-based RF power devices have made substantial progresses in the last decade This paper attempts to review the latest developments of the GaN HEMT technologies, including material growth, processing technologies, device epitaxial structures and MMIC designs, to achieve the state-of-the-art microwave and millimeter-wave performance The reliability and manufacturing challenges are also discussed

1,503 citations

Journal ArticleDOI
TL;DR: The current progress of terahertz-wave technologies related to communications applications are examined and some issues that need to be considered for the future of THz communications are discussed.
Abstract: Recent changes in how people consume multimedia services are causing an explosive increase in mobile traffic. With more and more people using wireless networks, the demand for the ultra-fast wireless communications systems is increasing. To date, this demand has been accommodated with advanced modulation schemes and signal-processing technologies at microwave frequencies. However, without increasing the carrier frequencies for more spectral resources, it may be quite difficult to keep up with the needs of users. Although there are several alternative bands, recent advances in terahertz-wave (THz-wave) technologies have attracted attention due to the huge bandwidth of THz waves and its potential for use in wireless communications. The frequency band of 275 ~ 3000 GHz , which has not been allocated for specific uses yet, is especially of interest for future wireless systems with data rates of 10 Gb/s or higher. Although THz communications is still in a very early stage of development, there have been lots of reports that show its potential. In this review, we will examine the current progress of THz-wave technologies related to communications applications and discuss some issues that need to be considered for the future of THz communications.

1,072 citations

Journal ArticleDOI
TL;DR: In the past 20 years, impressive progress has been made both experimentally and theoretically in superconducting quantum circuits, which provide a platform for manipulating microwave photons as mentioned in this paper, and many higher-order effects, unusual and less familiar in traditional cavity quantum electrodynamics with natural atoms, have been experimentally observed.

909 citations

Journal ArticleDOI
Kinam Kim1, Jae-Young Choi1, Taek Kim1, Seong-Ho Cho1, Hyun-Jong Chung1 
17 Nov 2011-Nature
TL;DR: Graphene is unlikely to replace silicon completely, however, because of the poor on/off current ratio resulting from its zero bandgap, but it could be used to improve silicon-based devices, in particular in high-speed electronics and optical modulators.
Abstract: As silicon-based electronics approach the limit of improvements to performance and capacity through dimensional scaling, attention in the semiconductor field has turned to graphene, a single layer of carbon atoms arranged in a honeycomb lattice. Its high mobility of charge carriers (electrons and holes) could lead to its use in the next generation of high-performance devices. Graphene is unlikely to replace silicon completely, however, because of the poor on/off current ratio resulting from its zero bandgap. But it could be used to improve silicon-based devices, in particular in high-speed electronics and optical modulators.

707 citations