- Date: June 18, 2021
MERL Contacts: Mouhacine Benosman; Rui Ma
Research Areas: Electronic and Photonic Devices, Machine Learning, Signal Processing
Brief - During the 2021 International Microwave Symposium Week (June 20-25), Rui Ma will give an invited talk on MERL's recent power amplifiers research at an IMS Technical Workshop to be held on June 21st, titled "From Digital to Intelligent: Advancement of MISO Power Amplifiers by Machine Learning".
IMS is the annual flagship conference of IEEE MTT-S (Microwave Theory and Techniques Society) and the centerpiece of Microwave Week. It is the largest gathering of RF/Microwave professionals in the world and combines multiple technical conferences with the biggest commercial exhibitions for the microwave industry.
Mitsubishi Electric U.S. (MEUS) will also host an online interactive booth to showcase our latest high-frequency Semiconductor & Device products at IMS week.
More detailed information can be found at the Mitsubishi Electric booth.
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- Date: April 15, 2021
MERL Contacts: Mouhacine Benosman; Rui Ma; Koon Hoo Teo
Research Areas: Communications, Electronic and Photonic Devices, Machine Learning
Brief - The cover article in the April issue of Microwave Journal features MERL and MELCO's invited paper entitled "A New Frontier for Power Amplifiers Enabled by Machine Learning". Our recent research applying ML for optimizing operating conditions of advanced power amplifier designs is highlighted.
Since 1958, Microwave Journal has been the leading source for information about RF and Microwave technology, design techniques, news, events and educational information. Microwave Journal reaches 50,000 qualified readers monthly with a print magazine that has a global reach.
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- Date & Time: Tuesday, February 16, 2021; 11:00-12:00
Speaker: Prof. Pere Gilabert, Universitat Politecnica de Catalunya, Barcelona, Spain
MERL Host: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices, Machine Learning, Signal Processing
Brief - Digital predistortion (DPD) linearization is the most common and spread solution to cope with power amplifiers (PA) inherent linearity versus efficiency trade-off. The use of new radio 5G spectrally efficient signals with high peak-to-average power ratios (PAPR) occupying wider bandwidths only aggravates such compromise. When considering wide bandwidth signals, carrier aggregation or multi-band configurations in high efficient transmitter architectures, such as Doherty PAs, load-modulated balanced amplifiers, envelope tracking PAs or outphasing transmitters, the number of parameters required in the DPD model to compensate for both nonlinearities and memory effects can be unacceptably high. This has a negative impact in the DPD model extraction/adaptation, because it increases the computational complexity and drives to over-fitting and uncertainty.
This talk will discuss the use of machine learning techniques for DPD linearization. The use of artificial neural networks (ANNs) for adaptive DPD linearization and approaches to reduce the coefficients adaptation time will be discussed. In addition, an overview on several feature-extraction techniques used to reduce the number of parameters of the DPD linearization system as well as to ensure proper, well-conditioned estimation for related variables will be presented.
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- Date: October 13, 2020
Where: online
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices
Brief - MERL researcher Dr. Rui Ma is invited to give a talk on the latest insights on RF power Amplifier design, which is one of series invited courses organized by IEEE Boston Section.
Dr. Ma is addressing the advancement of digital radio transmitter based on enabling technology of GaN for next generation wireless communications.
This six week lecture series is intended to give a broad overview of state-of-the-art RF PA techniques with practical aspects for working professionals together with students for future RF PA designers, from fundamentals to applications. It begins with a review of RF power amplifier concepts then teaches handset PA design techniques, issues and solutions faced with designing RF PAs for mobile applications. It also discusses high efficiency amplifier structures with different classes of operation, and other architectures. A high linearity techniques lecture with behavioral modelling will follow. GaAs/GaN MMIC level millimeter-wave amplifier design tutorials and techniques will be lectured including foundry/technology selection, loadpull, loadline analysis and simulations with EDA tools. Lastly, digital perspective transmitters will be presented using GaN technology together with FPGA and ASICs.
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- Date & Time: Tuesday, August 25, 2020; 11:00 AM
Speaker: Prof. James Hwang, Cornell University
MERL Host: Rui Ma
Research Areas: Applied Physics, Electronic and Photonic Devices
Brief 
Microwave is not just for cooking, smart cars, or mobile phones. We can take advantage of the wide electromagnetic spectrum to do wonderful things that are more vital to our lives. For example, microwave ablation of cancer tumor is already in wide use, and microwave remote monitoring of vital signs is becoming more important as the population ages. This talk will focus on a biomedical use of microwave at the single-cell level. At low power, microwave can readily penetrate a cell membrane to interrogate what is inside a cell, without cooking it or otherwise hurting it. It is currently the fastest, most compact, and least costly way to tell whether a cell is alive or dead. On the other hand, at higher power but lower frequency, the electromagnetic signal can interact strongly with the cell membrane to drill temporary holes of nanometer size. The nanopores allow drugs to diffuse into the cell and, based on the reaction of the cell, individualized medicine can be developed and drug development can be sped up in general. Conversely, the nanopores allow strands of DNA molecules to be pulled out of the cell without killing it, which can speed up genetic engineering. Lastly, by changing both the power and frequency of the signal, we can have either positive or negative dielectrophoresis effects, which we have used to coerce a live cell to the examination table of Dr. Microwave, then usher it out after examination. These interesting uses of microwave and the resulted fundamental knowledge about biological cells will be explored in the talk.
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- Date & Time: Tuesday, July 14, 2020; 11:00 AM
Speaker: Hanrui Wang, MIT
MERL Host: Rui Ma
Research Areas: Electronic and Photonic Devices, Machine Learning
Brief - Automatic transistor sizing is a challenging problem in circuit design due to the large design space, complex performance trade-offs, and fast technological advancements. Although there has been plenty of work on transistor sizing targeting on one circuit, limited research has been done on transferring the knowledge from one circuit to another to reduce the re-design overhead. In this work, we present GCN-RL Circuit Designer, leveraging reinforcement learning (RL) to transfer the knowledge between different technology nodes and topologies. Moreover, inspired by the simple fact that circuit is a graph, we learn on the circuit topology representation with graph convolutional neural networks (GCN). The GCN-RL agent extracts features of the topology graph whose vertices are transistors, edges are wires. Our learning-based optimization consistently achieves the highest Figures of Merit (FoM) on four different circuits compared with conventional black-box optimization methods (Bayesian Optimization, Evolutionary Algorithms), random search, and human expert designs. Experiments on transfer learning between five technology nodes and two circuit topologies demonstrate that RL with transfer learning can achieve much higher FoMs than methods without knowledge transfer. Our transferable optimization method makes transistor sizing and design porting more effective and efficient. The work is accepted to DAC 2020.
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- Date: July 14, 2020
Where: Tokyo, Japan
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices
Brief - Mitsubishi Electric Corporation announced today its developement of a new technology to realize a gallium nitride (GaN) power amplifier module for 5G base-stations that offers a combination of compact (6mm by 10mm) footprint and high power-efficiency, the latter exceeding an unprecedented rating of 43%.
MERL and Mitsubishi Electric researchers collaborated to develop high density mounting technology and matching circuit that uses a minimum number of chip components to achieve efficient, wide-band power amplification in the 3.4-3.8GHz bands used for 5G communication.
Please see the link below for the full Mitsubishi Electric press release text. Technical details of the new module will be presented at the IEEE International Microwave Symposium this coming August.
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- Date: December 13, 2019
Where: IEEE
MERL Contact: Rui Ma Brief - Dr. Rui Ma has been appointed as Associate Editor of IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology (IEEE J-ERM).
IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology, sponsored by IEEE Microwave Theory and Techniques Society (MTT-S), Antennas and Propagation Society (APS), Engineering in Medicine and Biology Society (EMBS) and Sensor Councils (with 26 IEEE member societies), encourages the submission of manuscripts with scopes in state-of-the-art research related to electromagnetics theory, RF and Microwave techniques and integration for medical and biological applications.
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- Date: December 9, 2019 - December 13, 2019
Where: Waikoloa, Hawaii, USA
MERL Contacts: Jianlin Guo; Kyeong Jin (K.J.) Kim; Toshiaki Koike-Akino; Rui Ma; Philip V. Orlik; Pu (Perry) Wang
Research Areas: Communications, Computer Vision, Machine Learning, Signal Processing, Information Security
Brief - MERL Signal Processing scientists and collaborators will be presenting 11 papers at the IEEE Global Communications Conference (GLOBECOM) 2019, which is being held in Waikoloa, Hawaii from December 9-13, 2019. Topics to be presented include recent advances in power amplifier, MIMO algorithms, WiFi sensing, video casting, visible light communications, user authentication, vehicular communications, secrecy, and relay systems, including sophisticated machine learning applications. A number of these papers are a result of successful collaboration between MERL and world-leading Universities including: Osaka University, University of New South Wales, Oxford University, Princeton University, South China University of Technology, Massachusetts Institute of Technology and Aalborg University.
GLOBECOM is one of the IEEE Communications Society’s two flagship conferences dedicated to driving innovation in nearly every aspect of communications. Each year, more than 3000 scientific researchers and their management submit proposals for program sessions to be held at the annual conference. Themed “Revolutionizing Communications,” GLOBECOM2019 will feature a comprehensive high-quality technical program including 13 symposia and a variety of tutorials and workshops to share visions and ideas, obtain updates on latest technologies and expand professional and social networking.
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- Date: October 1, 2019
MERL Contact: Rui Ma Brief - Rui Ma has been invited to join the editorial team of IEEE Transactions on Microwave Theory and Techniques as an Associate Editor.
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- Date: January 16, 2019
Awarded to: Daniel Dinis
MERL Contact: Rui Ma
Research Areas: Communications, Signal Processing
Brief - Former MERL intern Daniel Dinis from University of Aveiro (UA), Portugal has received the 2018 IBM Scientific Award with Honorable Mention referring to the contributions on "Real-time Tunable Delta-sigma modulators for All-Digital RF Transmitters" in his Ph.D. study.
The award-winning work includes research conducted under the supervision of Arnaldo Oliveira and José Neto Vieira, professors from the Department of Electronics and Information Technology (DETI) of the UA, as well as contributions made during Daniel's 7 month internship in 2017 at MERL.
The ceremony for the presentation of the 28th IBM Scientific Prize took on January 16th, at the Noble Hall of the Superior Technical Institute. It was chaired by Marcelo Rebelo de Sousa, President of the Portuguese Republic.
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- Date: January 10, 2019
Where: Tokyo, Japan
MERL Contacts: Mouhacine Benosman; Rui Ma; Philip V. Orlik; Koon Hoo Teo
Research Areas: Communications, Electronic and Photonic Devices, Machine Learning, Signal Processing
Brief - Mitsubishi Electric Corporation announced today its development of the world's first ultra-wideband digitally controlled gallium nitride (GaN) amplifier, which is compatible with a world-leading range of sub-6GHz bands focused on fifth-generation (5G) mobile communication systems. With a power efficiency rating of above 40%, the amplifier is expected to contribute to large-capacity communication and reduce the power consumption of mobile base stations.
MERL and Mitsubishi Electric researchers collaborated to develop digital control methods for amplifiers achieving high-efficiency of 40% and above, with 110% of the fractional bandwidth over frequency range 1.4-4.8 GHz. The digital control signals are designed using a learning-function based on Maisart®.
Please see the link below for the full Mitsubishi Electric press release text.
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- Date: June 13, 2018
Where: Philadelphia, PA
MERL Contacts: Rui Ma; Philip V. Orlik
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - Invited by IEEE MTT-S (Microwave Theory and Techniques Society), Researcher Dr. Rui Ma attended and presented MERL's cutting edge technology demonstration on real-time of multi-band All-Digital Transmitter at 5G Interactive Theater, which was held during IMS2018 in Philadelphia, PA on June 13th 2018. All-digital transmitter (ADT) is envisioned as a key enabling technology for next generation software defined radio.
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- Date: February 14, 2018
Where: Tokyo, Japan
MERL Contacts: Mouhacine Benosman; Rui Ma; Philip V. Orlik; Koon Hoo Teo
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - MERL machine learning power amplifier and all-digital transmitter technologies that enable future intelligent wireless communications were reported at a recent press release event in Tokyo. Please see the link below for the full Mitsubishi Electric press release text.
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- Date: June 5, 2017
Where: Honolulu, HI
MERL Contacts: Rui Ma; Philip V. Orlik; Koon Hoo Teo
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - MERL researcher Dr. Rui Ma, is organizing a Workshop in collaboration with Dr. SungWon Chung of the University of Southern California (USC) on advanced digital transmitters. This workshop overviews recent advances in digital-intensive wireless transmitter R&D for both base-stations and mobile devices. The focus will be on the digital signal processing techniques and related digital-intensive transmitter circuits and architectures for advanced modulation, linearization, spur cancellation, high efficiency encoding, and parallel processing. This workshop takes place on Monday, June 5th 2017 at International Microwave Week, in Honolulu, HI. In total, 8 technical presentations from world leading research groups will be given.
Dr. Ma will present a talk titled, "Advanced Power Encoding and Non-Contiguous Multi-Band Digital Transmitter Architectures".
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- Date: January 12, 2017
Where: Tokyo, Japan
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices
Brief - Mitsubishi Electric Corporation and Mitsubishi Electric Research Laboratories (MERL) announced today the development of an ultra-wideband gallium nitride (GaN) Doherty power amplifier for next generation base stations that is compatible with a world-leading range (company estimate) of frequency bands above 3GHz to cover an operating bandwidth of 600MHz. The technology is expected to help reduce the size and energy consumption of next generation wireless base stations.
Please see the link below for the full Mitsubishi Electric press release text.
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- Date: October 11, 2016
Where: MIT Lincoln Laboratory
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - Dr. Rui Ma was invited to give a talk on Modern Topics in Power Amplifier, which was IEEE Chapter course organized by IEEE Boston Section.
This five week lecture series intended to give a tutorial overview of the latest developments in power amplifier technology. It began with a review of RF power amplifier concepts then teaches the modern MMIC design flow process. Efficiency, and linearization techniques were discussed in the following weeks. The course was concluded with a hands on demonstration and exercise.
Dr. Ma was addressing the advancement of Digital Transmitter as a enabling technology for next generation wireless communications.
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- Date & Time: Friday, September 23, 2016; 12:00 PM- 1:00 PM
Speaker: Dr. Earl McCune, Eridan Communications
MERL Host: Rui Ma
Research Areas: Communications, Signal Processing
Brief 
To maximize the operating energy efficiency of any wireless communication link requires a global optimization not only across the entire block diagram, but also including the selected signal modulation and aspects of the link operating protocol. Achieving this global optimization is first examined for the transmitter, receiver, and baseband circuitry. Then the important aspects of signal modulation necessary to access these circuit optimizations, with examples, are presented, followed by the correspondingly important protocol aspects needed. A metric called modulation-available energy efficiency (MAEE) compares proposed signals for compatibility with high energy efficiency objectives.
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- Date: May 1, 2016
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - EC researcher Dr. Rui Ma is recently elected to serve on IEEE Microwave Theory and Techniques Society(MTT-S) Technical Committee (TC-20) on Wireless Communications.
The MTT-20 committee is responsible for all technical activities related to wireless communications for the Microwave Theory and Techniques Society. This includes, Internet of Things (IoTs), Next-Generation/5G communications, Machine-to-Machine Communications, Emergency Communications, Satellite Communications, Internet of Space, Space Communications and all aspects related to architecture and system level theoretical and practical issues.
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- Date: June 1, 2015
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices, Signal Processing
Brief - Rui Ma has been elected as Vice Chair of the IEEE Boston Section Microwave Theory and Techniques Society (MTT-S) Chapter.
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- Date: July 1, 2014
Where: IEEE International Wireless Symposium (IWS)
MERL Contact: Rui Ma Brief - Rui Ma has joined the Technical Program Committee for the 2015 IEEE International Wireless Symposium and will act as Sub-committee Chair for power amplifier design and organize a workshop on GaN.
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- Date: June 12, 2014
Where: IEEE Microwave Theory & Techniques Society
MERL Contact: Rui Ma Brief - Rui Ma has been accepted as a member of the Steering Committee of the IEEE
Microwave Theory & Techniques Society (Boston Section).
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- Date: June 2, 2013
Where: IEEE International Microwave Symposium (IMS)
MERL Contact: Rui Ma
Research Areas: Communications, Electronic and Photonic Devices
Brief - The paper "A 40-dBm High Voltage Broadband GaN Class-J Power Amplifier for PoE Micro-Basestations" by Ma, R., Goswami, S., Yamanaka, K., Komatsuzaki, Y. and Ohta, A. was presented at the IEEE International Microwave Symposium (IMS).
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- Date: May 26, 2013
Where: International Symposium on Power Semiconductor Devices and ICs (ISPSD)
MERL Contacts: Rui Ma; Koon Hoo Teo
Research Areas: Applied Physics, Electronic and Photonic Devices
Brief - The paper "Design of Enhancement Mode Single-gate and Double-gate Multi-channel GaN HEMT with Vertical Polarity Inversion Heterostructure" by Feng, P., Teo, K.H., Oishi, T., Yamanaka, K. and Ma, R. was presented at the International Symposium on Power Semiconductor Devices and ICs (ISPSD).
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