2026-01-15 01:00:03
Peek inside the package of AMD’s or Nvidia’s most advanced AI products and you’ll find a familiar arrangement: The GPU is flanked on two sides by high-bandwidth memory (HBM), the most advanced memory chips available. These memory chips are placed as close as possible to the computing chips they serve in order to cut down on the biggest bottleneck in AI computing—the energy and delay in getting billions of bits per second from memory into logic. But what if you could bring computing and memory even closer together by stacking the HBM on top of the GPU?
Imec recently explored this scenario using advanced thermal simulations, and the answer—delivered in December at the 2025 IEEE International Electron Device Meeting (IEDM)—was a bit grim. 3D stacking doubles the operating temperature inside the GPU, rendering it inoperable. But the team, led by Imec’s James Myers, didn’t just give up. They identified several engineering optimizations that ultimately could whittle down the temperature difference to nearly zero.
Imec started with a thermal simulation of a GPU and four HBM dies as you’d find them today, inside what’s called a 2.5D package. That is, both the GPU and the HBM sit on substrate called an interposer, with minimal distance between them. The two types of chips are linked by thousands of micrometer-scale copper interconnects built into the interposer’s surface. In this configuration, the model GPU consumes 414 watts and reaches a peak temperature of just under 70 °C—typical for a processor. The memory chips consume an additional 40 W or so and get somewhat less hot. The heat is removed from the top of the package by the kind of liquid cooling that’s become common in new AI data centers.
“While this approach is currently used, it does not scale well for the future—especially as it blocks two sides of the GPU, limiting future GPU-to-GPU connections inside the package,” Yukai Chen, a senior researcher at Imec told engineers at IEDM. In contrast, “the 3D approach leads to higher bandwidth, lower latency… the most important improvement is the package footprint.”
Unfortunately, as Chen and his colleagues found, the most straightforward version of stacking, simply putting the HBM chips on top of the GPU and adding a block of blank silicon to fill in a gap at the center, shot temperatures in the GPU up to a scorching 140 °C—well past a typical GPU’s 80 °C limit.
The Imec team set about trying a number of technology and system optimizations aimed at lowering the temperature. The first thing they tried was to throw out a layer of silicon that was now redundant. To understand why, you have to first get a grip on what HBM really is.
This form of memory is a stack of as many as 12 high-density DRAM dies. Each has been thinned down to tens of micrometers and is shot through with vertical connections. These thinned dies are stacked one atop another and connected by tiny balls of solder, and this stack of memory is vertically connected to another piece of silicon, called the base die. The base die is a logic chip designed to multiplex the data—pack it into the limited number of wires that can fit across the millimeter-scale gap to the GPU.
But with the HBM now on top of the GPU, there’s no need for such a data pump. Bits can flow directly into the processor without regard for how many wires happen to fit along the side of the chip. Of course, this change means moving the memory control circuits from the base die into the GPU and therefore changing the processor’s floorplan, says Myers. But there should be ample room, he suggests, because the GPU will no longer need the circuits used to demultiplex incoming memory data.
Cutting out this middle-man of memory cooled things down by only a little less than 4 °C. But, importantly, it should massively boost the bandwidth between the memory and the processor, which is important for another optimization the team tried—slowing down the GPU.
That might seem contrary to the whole purpose of better AI computing, but in this case it’s an advantage. Large language models are what are called “memory bound” problems. That is, memory bandwidth is the main limiting factor. But Myers’ team estimated 3D stacking HBM on the GPU would boost bandwidth fourfold. With that added headroom, even slowing the GPU’s clock by 50 percent still leads to a performance win, while cooling everything down by more than 20 °C. In practice, the processor might not need to be slowed down quite that much. Increasing the clock frequency to 70 percent led to a GPU that was only 1.7 °C warmer, Myers says.
Another big drop in temperature came from making the HBM stack and the area around it more conductive. That included merging the four stacks into two wider stacks, thereby eliminating a heat-trapping region; thinning out the top—usually thicker—die of the stack; and filling in more of the space around the HBM with blank pieces of silicon to conduct more heat.
With all of that, the stack now operated at about 88 °C. One final optimization brought things back to near 70 °C. Generally, some 95 percent of a chip’s heat is removed from the top of the package, where in this case water carries the heat away. But adding similar cooling to the underside as well drove the stacked chips down a final 17 °C.
Although the research presented at IEDM shows it might be possible, HBM-on-GPU isn’t necessarily the best choice, Myers says. “We are simulating other system configurations to help build confidence that this is or isn’t the best choice,” he says. “GPU-on-HBM is of interest to some in industry,” because it puts the GPU closer to the cooling. But it would likely be a more complex design, because the GPU’s power and data would have to flow vertically through the HBM to reach it.
2026-01-15 00:00:04
Wearable displays are catching up with phones and smart watches. For decades, engineers have sought OLEDs that can bend, twist, and stretch while maintaining bright and stable light. These displays could be integrated into a new class of devices—woven into clothing fabric, for example, to show real-time information, like a runner’s speed or heart rate, without breaking or dimming.
But engineers have always encountered a trade-off: the more you stretch these materials, the dimmer they become. Now, a group co-led by Yury Gogotsi, a materials scientist at Drexel University in Philadelphia, has found a way around the problem by employing a special class of materials called MXenes—which Gogotsi helped discover—that maintain brightness while being significantly stretched.
The team developed an OLED that can stretch to twice its original size while keeping a steady glow. It also converts electricity into light more efficiently than any stretchable OLED before it, reaching a record 17 percent external quantum efficiency—a measure of how efficiently a device turns electricity into light.
Gogotsi didn’t have much experience with OLEDs when, about five years ago, he teamed up with Tae-Woo Lee, a materials scientist at Seoul National University, to develop better flexible OLEDs, driven by the ever-increasing use of flexible electronics like foldable phones.
Traditionally, the displays are built from multiple stacked layers. At the base, a cathode supplies electrons that enter the adjacent organic layers, which are designed to conduct this charge efficiently. As the electrons move through these layers, they meet positive charge injected by an indium tin oxide (ITO) film. The moment these charges combine, the organic material releases energy as light, creating the illuminated pixels that make up the image. The entire structure is sealed with a glass layer on top.
The ITO film—adhered to the glass—serves as the anode, allowing current to pass through the organic layers without blocking the generated light. “But it’s brittle. It’s ceramic, basically,” so it works well for flat surfaces, but can’t be bent, Gogotsi explains. There have been attempts to engineer flexible OLEDs many times before, but they failed to meaningfully overcome both flexibility and brightness limitations.
Gogotsi’s students started by creating a transparent, conducting film out of a MXene, a type of ultra-thin and flexible material with metal-like conductivity. The material is unique in its inherent ability to bend because it’s made from many two-dimensional sheets that can slide relative to each other without breaking. The film—only 10 nanometers thick—“appeared to be this perfect replacement for ITO,” Gogotsi says.
Through experimentation, Gogotsi and Lee’s shared team found that a mix of the MXene and silver nanowire would actually stretch the most while maintaining stability. “We were able to double the size, achieving 200 percent stretching without losing performance,” Gogotsi says.
The new material can also be twisted without losing its glow.Source image: Huanyu Zhou, Hyun-Wook Kim, et al.
And the new MXene film was not only more flexible than ITO, but also increased brightness by almost an order of magnitude by making the contact between the topmost light-emitting organic layer and the film more efficient.
Unlike ITO, the surface of MXenes can be chemically adjusted to make it easier for electrons to move from the electrode into the light-emitting layer. This more efficient electron flow significantly increases the brightness of the display, as evidenced by an external quantum efficiency of 17 percent, which the group claims is a record for stretchable OLEDs.
“Achieving those numbers in intrinsically stretchable OLEDs under substantial stretching is quite significant,” says Seunghyup Yoo, who runs the Integrated Organic Electronics Laboratory at South Korea’s KAIST. An external quantum efficiency of 20 percent is an important benchmark for this kind of device because it is the upper limit of efficiency dictated by the physical properties of light generation, Yoo explains.
To increase illumination, the researchers went beyond working with MXene. Lee’s group developed two additional organic layers to add into the middle of their OLED—one that directs positive charges to the light-emitting layer, ensuring that electricity is used more efficiently, and one that recycles wasted energy that would normally be lost, boosting overall brightness.
Together, the MXene layer and two organic layers allow for a notably bright and stable OLED, even when stretched. Gogotsi thinks the subsequent OLED is “very successful” because it combines both brightness and stretchability, while, historically, engineers have only been able to achieve one or the other.
“The performance that they are able to achieve in this work is an important advancement,” says Sihong Wang, a molecular engineer at the University of Chicago who also develops stretchable OLED materials. Wang also notes that the 200 percent stretchability that Gogotsi’s group attained is beyond robust for wearable applications.
A stretchable OLED that maintains its brightness has uses in many settings, including industrial environments, robotics, wearable clothing and devices, and communications, Gogotsi says, although he’s most excited about its adoption in health-monitoring devices. He sees a near future in which displays for diagnostics and treatment become embedded in clothing or “epidermal electronics,” comparing their function to smart watches.
Before these displays can come to market, however, stability issues inherent to all stretchable OLEDs need to be solved, Wang says. Current materials are not able to sustain light emissions for long enough to serve customers in the ways they require.
Finding housings to protect them is also a problem. “You need a stretchable encapsulation material that can protect the central device without allowing oxygen and moisture to permeate,” Wang says.
Yoo agrees: He says it’s a tough problem to solve because the best protective layers are rigid and not very stretchable. He notes yet another challenge in the way of commercialization, which is “developing stretchable displays that do not exhibit image distortion.”
Regardless, Gogotsi is excited about the future of stretchable OLEDs. “We started with computers occupying the room, then moved to our desktops, then to laptops, then we got smartphones and iPads, but still we carry stuff with us,” he says. “Flexible displays can be on the sleeve of your jacket. They can be rolled into a tube or folded and put in your pocket. They can be everywhere.”
2026-01-14 03:00:03
The IEEE Board of Directors has received petition intentions from IEEE Senior Member Gerardo Barbosa and IEEE Life Senior Member Timothy T. Lee as candidates for 2027 IEEE president-elect. The petitioners are listed in alphabetical order and indicate no preference.
The winner of this year’s election will serve as IEEE president in 2028. For more information about the petitioners and Board-nominated candidates, visit ieee.org/pe27. You can sign their petitions at ieee.org/petition.
Signatures for IEEE president-elect candidate petitions are due 10 April at 12:00 p.m. EST/16:00 p.m. UTC.
Gerardo Sosa
Barbosa is an expert in information technology management and technology commercialization, with a career spanning innovation, entrepreneurship,and an international perspective. He began his career designing radio-frequency identification systems for real-time asset tracking and inventory management. In 2014 he founded CLOUDCOM, a software company that develops enterprise software to improve businesses’ billing and logistics operations, and serves as its CEO.
Barbosa’s IEEE journey began in 2009 at the IEEE Monterrey (Mexico) Section, where he served as chair and treasurer. He led grassroots initiatives with students and young professionals. His leadership positions in IEEE Region 9 include technical activities chair and treasurer.
As the 2019—2020 vice chair and 2021—2023 treasurer of IEEE Member and Geographic Activities, Barbosa became recognized as a trusted, data-driven, and collaborative leader.
He has been a member of the IEEE Finance Committee since 2021 and is now its chair due to his role as IEEE treasurer on the IEEE Board of Directors. He is deeply committed to the responsible stewardship of IEEE’s global resources, ensuring long-term financial sustainability in service of IEEE’s mission.
Nikon/CES
Lee is a Technical Fellow at Boeing in Southern California with expertise in microelectronics and advanced 2.5D and 3D chip packaging for AI workloads, 5G, and SATCOM systems for aerospace platforms. He leads R&D projects, including work funded by the Defense Advanced Research Projects Agency. He previously held leadership roles at MACOM Technology Solutions and COMSAT Laboratories.
Lee was the 2015 president of the IEEE Microwave Theory and Technology Society. He has served on the IEEE Board of Directors as 2025 IEEE-USA president and 2021–2022 IEEE Region 6 director. He has also been a member of several IEEE committees including Future Directions, Industry Engagement, and New Initiatives.
His vision is to deliver societal value through trust, integrity, ownership, innovation, and customer focus, while strengthening the IEEE member experience. Lee also wants to work to prepare members for AI-enabled work in the future.
He earned bachelor’s and master’s degrees in electrical engineering from MIT and a master’s degree in systems architecting and engineering from the University of Southern California in Los Angeles.
2026-01-13 22:00:02
In 2018, Justin Kropp was working on a transmission circuit in Southern California when disaster struck. Grid operators had earlier shut down the 115-kilovolt circuit, but six high-voltage lines that shared the corridor were still operating, and some of their power snuck onto the deenergized wires he was working on. That rogue current shot to the ground through Kropp’s body and his elevated work platform, killing the 32-year-old father of two.
“It went in both of his hands and came out his stomach, where he was leaning against the platform rail,” says Justin’s father, Barry Kropp, who is himself a retired line worker. “Justin got hung up on the wire. When they finally got him on the ground, it was too late.”
Budapest-based Electrostatics makes conductive suits that protect line workers from unexpected current. Electrostatics
Justin’s accident was caused by induction: a hazard that occurs when an electric or magnetic field causes current to flow through equipment whose intended power supply has been cut off. Safety practices seek to prevent such induction shocks by grounding all conductive objects in a work zone, giving electricity alternative paths. But accidents happen. In Justin’s case, his platform unexpectedly swung into the line before it could be grounded.
Adding a layer of defense against induction injuries is the motivation behind Budapest-based Electrostatics’ specialized conductive jumpsuits, which are designed to protect against burns, cardiac fibrillation, and other ills. “If my boy had been wearing one, I know he’d be alive today,” says the elder Kropp, who purchased a line-worker safety training business after Justin’s death. The Mesa, Ariz.–based company, Electrical Safety Consulting International (ESCI), now distributes those suits.
Conductive socks that are connected to the trousers complete the protective suit. BME HVL
Eduardo Ramirez Bettoni, one of the developers of the suits, dug into induction risk after a series of major accidents in the United States in 2017 and 2018, including Justin Kropp’s. At the time, he was principal engineer for transmission and substation standards at Minneapolis-based Xcel Energy. In talking to Xcel line workers and fellow safety engineers, he sensed that the accident cluster might be the tip of an iceberg. And when he and two industry colleagues scoured data from the U.S. Bureau of Labor Statistics, they found 81 induction accidents between 1985 and 2021 and 60 deaths, which they documented in a 2022 report.
“Unfortunately, it is really common. I would say there are hundreds of induction contacts every year in the United States alone,” says Ramirez Bettoni, who is now technical director of R&D for the Houston-based power-distribution equipment firm Powell Industries. He bets that such “contacts”—exposures to dangerous levels of induction—are increasing as grid operators boost grid capacity by squeezing additional circuits into transmission corridors.
Electrostatics’ suits are an enhancement of the standard protective gear that line workers wear when their tasks involve working close to or even touching energized live lines, or “bare-hands” work. Both are interwoven with conductive materials such as stainless steel threads, which form a Faraday cage that shields the wearer against the lines’ electric fields. But the standard suits have limited capacity to shunt current because usually they don’t need to. Like a bird on a wire, bare-hands workers are electrically floating, rather than grounded, so current largely bypasses them via the line itself.
Backed by a US $250,000 investment from Xcel in 2019, Electrostatics adapted its standard suits by adding low-resistance conductive straps that pass current around a worker’s body. “When I’m touching a conductor with one hand and the other hand is grounded, the current will flow through the straps to get out,” says Bálint Németh, Electrostatics’ CEO and director of the High Voltage Laboratory at Budapest University of Technology and Economics.
A strapping system links all the elements of the suit—the jacket, trousers, gloves, and socks—and guides current through a controlled path outside the body. BME HVL
The company began selling the suits in 2023, and they have since been adopted by over a dozen transmission operators in the United States and Europe, as well as other countries including Canada, Indonesia, and Turkey. They cost about $5,200 in the United States.
Electrostatics’ suits had to meet a crucial design threshold: keeping body exposure below the 6-milliampere “let-go” threshold, beyond which electrocuted workers become unable to remove themselves from a circuit. “If you lose control of your muscles, you’re going to hold onto the conductor until you pass out or possibly die,” says Ramirez Bettoni.
The gear, which includes the suit, gloves, and socks, protects against 100 amperes for 10 seconds and 50 A for 30 seconds. It also has insulation to protect against heat created by high current and flame retardants to protect against electric arcs.
Kropp, Németh, and Ramirez Bettoni are hoping that developing industry standards for induction safety gear, including ones published in October, will broaden their use. Meanwhile, the recently enacted Justin Kropp Safety Act in California, for which the elder Kropp lobbied, mandates automated defibrillators at power-line work sites.
This article was updated on 14 January 2026.
2026-01-12 22:00:02
On a blustery November day, a Cessna turboprop flew over Pennsylvania at 5,000 meters, in crosswinds of up to 70 knots—nearly as fast as the little plane was flying. But the bumpy conditions didn’t thwart its mission: to wirelessly beam power down to receivers on the ground as it flew by.
The test flight marked the first time power has been beamed from a moving aircraft. It was conducted by the Ashburn, Va.-based startup Overview Energy, which emerged from stealth mode in December by announcing the feat.
But the greater purpose of the flight was to demonstrate the feasibility of a much grander ambition: to beam power from space to Earth. Overview plans to launch satellites into geosynchronous orbit (GEO) to collect unfiltered solar energy where the sun never sets and then beam this abundance back to humanity. The solar energy would be transferred as near-infrared waves and received by existing solar panels on the ground.
The far-flung strategy, known as space-based solar power, has become the subject of both daydreaming and serious research over the past decade. Caltech’s Space Solar Power Project launched a demonstration mission in 2023 that transferred power in space using microwaves. And terrestrial power beaming is coming along too. The U.S. Defense Advanced Research Projects Agency (DARPA) in July 2025 set a new record for wirelessly transmitting power: 800 watts over 8.6 kilometers for 30 seconds using a laser beam.
But until November, no one had actively beamed power from a moving platform to a ground receiver.
Overview’s test transferred only a sprinkling of power, but it did it with the same components and techniques that the company plans to send to space. “Not only is it the first optical power beaming from a moving platform at any substantial range or power,” says Overview CEO Marc Berte, “but also it’s the first time anyone’s really done a power beaming thing where it’s all of the functional pieces all working together. It’s the same methodology and function that we will take to space and scale up in the long term.”
The approach was compelling enough that power-beaming expert Paul Jaffe left his job as a program manager at DARPA to join the company as head of systems engineering. Prior to DARPA, Jaffe spent three decades with the U.S. Naval Research Laboratory.
“This actually sounds like it could work.” –Paul Jaffe
It was hearing Berte explain Overview’s plan at a conference that helped to convince Jaffe to take a chance on the startup. “This actually sounds like it could work,” Jaffe remembers thinking at the time. “It really seems like it gets around a lot of the showstoppers for a lot of the other concepts. I remember coming home and telling my wife that I almost felt like the problem had been solved. So I thought: Should [I] do something which is almost unheard of—to leave in the middle of being a DARPA program manager—to try to do something else?”
For Jaffe, the most compelling reason was in Overview’s solution for space-based solar’s power-density problem. A beam with low power density is safer because it’s not blasting too much concentrated energy onto a single spot on the Earth’s surface, but it’s less efficient for the task of delivering usable solar energy. A higher-density beam does the job better, but then the researchers must engineer some way to maintain safety.
Startup Overview Energy demonstrates how space-based solar power could be beamed to Earth from satellites. Overview Energy
Many researchers have settled on microwaves as their beam of choice for wireless power. But, in addition to the safety concerns about shooting such intense waves at the Earth, Jaffe says there’s another problem: Microwaves are part of what he calls the “beachfront property” of the electromagnetic spectrum—a range from 2 to 20 gigahertz that is set aside for many other applications, such as 5G cellular networks.
“The fact is,” Jaffe says, “if you somehow magically had a fully operational solar power satellite that used microwave power transmission in orbit today—and a multi-kilometer-scale microwave power satellite receiver on the ground magically in place today—you could not turn it on because the spectrum is not allocated to do this kind of transmission.”
Instead, Overview plans to use less-dense, wide-field infrared waves. Existing utility-scale solar farms would be able to receive the beamed energy just like they receive the sun’s energy during daylight hours. So “your receivers are already built,” Berte says. The next major step is a prototype demonstrator for low Earth orbit, after which he hopes to have GEO satellites beaming megawatts of power by 2030 and gigawatts by later that decade.
Plenty of doubts about the feasibility of space-based power abound. It is an exotic technology with much left to prove, including the ability to survive orbital debris and the exorbitant cost of launching the power stations. (Overview’s satellite will be built on Earth in a folded configuration, and it will unfold after it’s brought to orbit, according to the company.)
“Getting down the cost per unit mass for launch is a big deal,” Jaffe says. “Then, it just becomes a question of increasing the specific power. A lot of the technologies we’re working on at Overview are squarely focused on that.”
2026-01-11 22:00:02
For decades, scientists have observed the cosmos with radio antennas to visualize the dark, distant regions of the universe. This includes the gas and dust of the interstellar medium, planet-forming disks, and objects that cannot be observed in visible light. In this field, the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile stands out as one of the world’s most powerful radio telescopes. Using its 66 parabolic antennas, ALMA observes the millimeter and submillimeter radiation emitted by cold molecular clouds from which new stars are born.
Each antenna is equipped with high-frequency receivers for 10 wavelength ranges, 35 to 50 gigahertz and 787 to 950 GHz, collectively known as Band 1. Thanks to the Fraunhofer Institute for Applied Solid State Physics (IAF) and the Max Planck Institute for Radio Astronomy, ALMA has received an upgrade with the addition of 145 new low-noise amplifiers (LNAs). These amplifiers are part of the facilities’ Band 2 coverage, ranging from 67 to 116 GHz on the electromagnetic spectrum. This additional coverage will allow researchers to study and gain a better understanding of the universe.
In particular, they hope to gain new insights into the “cold interstellar medium”: The dust, gas, radiation, and magnetic fields from which stars are born. In addition, scientists will be able to study planet-forming disks in better detail. Last, but certainly not least, they will be able to study complex organic molecules in nearby galaxies, which are considered precursors to the building blocks of life. In short, these studies will allow astronomers and cosmologists to witness how stars and planetary systems form and evolve, and how the presence of organic molecules can lead to the emergence of life.
Each LNA includes a series of monolithic microwave integrated circuits (MMICs) developed by Fraunhofer IAF using the semiconducting material indium gallium arsenide. MMICs are based on metamorphic high-electron-mobility transistor technology, a method for creating advanced transistors that are flexible and allow for optimized performance in high-frequency receivers. The addition of LNAs equipped with these circuits will amplify low-noise signals and minimize background noise, dramatically increasing the sensitivity of ALMA’s receivers.
Fabian Thome, head of the subproject at Fraunhofer IAF, explained in an IAF press release:
“The performance of receivers depends largely on the performance of the first high-frequency amplifiers installed in them. Our technology is characterized by an average noise temperature of 22 K, which is unmatched worldwide.” With the new LNAs, signals can be amplified more than 300-fold in the first step. “This enables the ALMA receivers to measure millimeter and submillimeter radiation from the depths of the universe much more precisely and obtain better data. We are incredibly proud that our LNA technology is helping us to better understand the origins of stars and entire galaxies.”
Both Fraunhofer IAF and the Max Planck Institute for Radio Astronomy were commissioned by the European Southern Observatory to provide the amplifiers. While Fraunhofer IAF was responsible for designing, manufacturing, and testing the MMICs at room temperature, Max Planck was tasked with assembling and qualifying the LNA modules, then testing them in cryogenic conditions. “This is a wonderful recognition of our fantastic collaboration with Fraunhofer IAF, which shows that our amplifiers are not only ‘made in Germany’ but also the best in the world,” said Michael Kramer, executive director at the Max Planck Institute for Radio Astronomy.