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Electronic components join forces to take up 10 times less space on computer chips

Electronic filters are essential to the inner workings of our phones and other wireless devices. They eliminate or enhance specific input signals to achieve the desired output signals. They are essential, but take up space on the chips that researchers are on a constant quest to make smaller. A new study demonstrates the successful integration of the individual elements that make up electronic filters onto a single component, significantly reducing the amount of space taken up by the device.

Researchers at the University of Illinois, Urbana-Champaign have ditched the conventional 2D on-chip lumped or distributed filter network design — composed of separate inductors and capacitors — for a single, space-saving 3D rolled membrane that contains both independently designed elements.

The results of the study, led by electrical and computer engineering professor Xiuling Li, are published in the journal Advanced Functional Materials.

“With the success that our team has had on rolled inductors and capacitors, it makes sense to take advantage of the 2D to 3D self-assembly nature of this fabrication process to integrate these different components onto a single self-rolling and space-saving device,” Li said.

In the lab, the team uses a specialized etching and lithography process to pattern 2D circuitry onto very thin membranes. In the circuit, they join the capacitors and inductors together and with ground or signal lines, all in a single plane. The multilayer membrane can then be rolled into a thin tube and placed onto a chip, the researchers said.

“The patterns, or masks, we use to form the circuitry on the 2D membrane layers can be tuned to achieve whatever kind of electrical interactions we need for a particular device,” said graduate student and co-author Mark Kraman. “Experimenting with different filter designs is relatively simple using this technique because we only need to modify that mask structure when we want to make changes.”

The team tested the performance of the rolled components and found that under the current design, the filters were suitable for applications in the 1-10 gigahertz frequency range, the researchers said. While the designs are targeted for use in radio frequency communications systems, the team posits that other frequencies, including in the megahertz range, are also possible based on their ability to achieve high power inductors in past research.

“We worked with several simple filter designs, but theoretically we can make any filter network combination using the same process steps,” said graduate student and lead author Mike Yang. “We took what was already out there to provide a new, easier platform to lump these components together closer than ever.”

“Our way of integrating inductors and capacitors monolithically could bring passive electronic circuit integration to a whole new level,” Li said. “There is practically no limit to the complexity or configuration of circuits that can be made in this manner, all with one mask set.”

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Materials provided by University of Illinois at Urbana-Champaign, News Bureau. Original written by Lois Yoksoulian. Note: Content may be edited for style and length.

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Boost soybean yields by adapting photosynthesis to fleeting shadows, according to model

Komorebi is a Japanese word that describes how light filters through leaves — creating shifting, dappled “sunflecks” that illustrate plants’ ever-changing light environment. Crops harness light energy to fix carbon dioxide into food via photosynthesis. In a special issue of Plant Journal, a team from the University of Illinois reports a new mathematical computer model that is used to understand how much yield is lost as soybean crops grapple with minute-by-minute light fluctuations on cloudy and sunny days.

“Soybean is the fourth most important crop in terms of overall production, but it is the top source of vegetable protein globally,” said Yu Wang, a postdoctoral researcher at Illinois, who led this work for Realizing Increased Photosynthetic Efficiency (RIPE). “We found that soybean plants may lose as much as 13 percent of their productivity because they cannot adjust quickly enough to the changes in light intensity that are standard in any crop field. It may not sound like much, but in terms of the global yield — this is massive.”

RIPE is an international research project that aims to improve photosynthesis to equip farmers worldwide with higher-yielding crops needed to ensure everyone has enough food to lead a healthy, productive life. RIPE is sponsored by the Bill & Melinda Gates Foundation, the U.S. Foundation for Food and Agriculture Research (FFAR), and the U.K. Government’s Department for International Development (DFID).

Past models have only examined hour-by-hour changes in light intensity. For this study, the team created a dynamic computational ray-tracing model that was able to predict light levels to the millimeter across every leaf for every minute of the day in a flowering soybean crop. The model also takes into account two critical factors: photoprotection and Rubisco activase.

Photoprotection protects plants from sun damage. Triggered by high light levels, this process dissipates excess light energy safely as heat. But, when light levels drop, it can take minutes to hours for photoprotection to relax, or stop — costing the plant potential yield. The team evaluated 41 varieties of soybean to find out the fastest, slowest, and average rate from induction to the relaxation of photoprotection. Less than 30 minutes is considered “short-term,” and anything longer is “long-term” photoprotection.

Using this new model, the team simulated a sunny and cloudy day in Champaign, Illinois. On the sunny day, long-term photoprotection was the most significant limitation of photosynthesis. On the cloudy day, photosynthesis was the most limited by short-term photoprotection and Rubisco activase, which is a helper enzyme — triggered by light — that turns on Rubisco to fix carbon into sugar.

The RIPE project has already begun to address photoprotection limitations in soybean and other crops, including cassava, cowpea, and rice. In 2016, the team published a study in Science where they increased the levels of three proteins involved in photoprotection to boost the productivity of a model crop by 14-20 percent. In addition, the RIPE team from the Lancaster Environment Centre at Lancaster University is seeking better forms of Rubisco activase in soybean and cowpea. The RIPE project and its sponsors are committed to ensuring Global Access and making these technologies available to the farmers who need them the most.

“Models like these are critical to uncovering barriers — and solutions — to attain this crop’s full potential,” said RIPE Director Stephen Long, Ikenberry Endowed University Chair Plant Biology and Crop Sciences at Illinois’ Carl R. Woese Institute for Genomic Biology. “We’ve already begun to address these bottlenecks and seen significant gains, but this study shows us that there is still room for improvement.”

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Sunscreens release metals and nutrients into seawater

Beachgoers are becoming increasingly aware of the potentially harmful effects UV filters from sunscreens can have on coral and other marine organisms when the protective lotions wash off their bodies into the ocean. Now, researchers have studied how sunscreens release different compounds — trace metals and inorganic nutrients — into Mediterranean seawater, with unknown effects on marine ecology. They report their results in ACS’ journal Environmental Science & Technology.

Millions of people are hitting the beach slathered in sunscreen this summer. Some might choose “coral-safe” sunscreens that lack oxybenzone and octinoxate, the two substances most widely linked to coral reef damage. However, scientists don’t yet know what effects other trace compounds in sunscreens might have on marine ecosystems. As a first step, researcher Araceli Rodríguez-Romero and colleagues wanted to determine how quickly sunscreen releases trace metals and nutrients into seawater, and how sunscreen from beachgoers’ bodies could impact the overall levels of the compounds in coastal waters.

The researchers added a commercial, titanium-dioxide-containing sunscreen to samples of Mediterranean seawater and observed how droplets of the lotions released various metals and nutrients into the water. Some compounds entered the seawater more quickly after UV treatment, which simulated sun exposure. Aluminum, silica and phosphorus had the highest release rates under both light and dark conditions. The team used these data to develop a model that predicts the release of compounds from sunscreen under different conditions. Then, they used the model to estimate that, on a typical summer day at the beach, beachgoers could increase the concentration of aluminum in coastal waters by 4% and of titanium by almost 20%. More research is needed to determine how these metals and nutrients, which are normally present at very low amounts in seawater, could be affecting marine ecosystems, the researchers say.

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Materials provided by American Chemical Society. Note: Content may be edited for style and length.

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IEEE Spectrum

Simulation-Driven Optimization of 5G RF MEMS Filters

Efficiently design RF MEMS acoustic resonator-based filters, reducing cost, risk and time