AI slashes cost and time for chip design, but that is not all

Professor Kaushik Sengupta, left, and first author Emir Ali Karahan, a gradate student in electrical and computer engineering. Photos by Tori Repp/Fotobuddy

“We are coming up with structures that are complex and look random shaped and when connected with circuits, they create previously unachievable performance. Humans cannot really understand them, but they can work better,” said Sengupta, a professor of electrical and computer engineering and co-director of NextG, Princeton’s industry partnership program to develop next-generation communications.

These circuits can be engineered toward more energy efficient operation or to make them operable across an enormous frequency range that is not currently possible. Furthermore, the method synthesizes inherently complex structures in minutes, while conventional algorithms may take weeks. In some cases, the new methodology can create structures that are impossible to synthesize with current techniques.

An enlarged image of the chip’s circuitry in Sengupta’s lab at Princeton.

Uday Khankhoje, a co-author and associate professor of electrical engineering at IIT Madras, said the new technique not only delivers efficiency but promises to unlock new approaches to design challenges that have been beyond the capability of engineers.

“This work presents a compelling vision of the future,” he said. “AI powers not just the acceleration of time-consuming electromagnetic simulations, but also enables exploration into a hitherto unexplored design space and delivers stunning high-performance devices that run counter to the usual rules of thumb and human intuition.”

Wireless chips are a combination of standard electronic circuits like those in computer chips and electromagnetic structures including antennas, resonators, signal splitters, combiners and others. These combinations of elements are put together in every circuit block, carefully handcrafted and co-designed to operate optimally. This method is then scaled to other circuits, sub-systems and systems, making the design process extremely complex and time consuming, particularly for modern, high-performance chips behind applications like wireless communication, autonomous driving, radar and gesture recognition.

“Classical designs, carefully, put these circuits and electromagnetic elements together, piece by piece, so that the signal flows in the way we want it to flow in the chip. By changing those structures, we incorporate new properties,” Sengupta said. “Before, we had a finite way of doing this, but now the options are much larger.”

An enlarged image of the chip’s circuitry shows unusual patterns.

It can be hard to comprehend the vastness of a wireless chip’s design space. The circuitry in an advanced chip is so small, and the geometry so detailed, that the number of possible configurations for a chip exceeds the number of atoms in the universe, Sengupta said. There is no way for a person to understand that level of complexity, so human designers don’t try. They build chips from the bottom up, adding components as needed and adjusting the design as they build.

The AI approaches the challenge from a different perspective, Sengupta said. It views the chip as a single artifact. This can lead to strange, but effective arrangements. He said humans play a critical role in the AI system, in part because that AI can make faulty arrangements as well as efficient ones. It is possible for AI to hallucinate elements that don’t work, at least for now. This requires some level of human oversight.

“There are pitfalls that still require human designers to correct,” Sengupta said. “The point is not to replace human designers with tools. The point is to enhance productivity with new tools. The human mind is best utilized to create or invent new things, and the more mundane, utilitarian work can be offloaded to these tools.”

The researchers have used AI to discover and design complex electromagnetic structures that are co-designed with circuits to create broadband amplifiers. Sengupta said future research will involve linking multiple structures and designing entire wireless chips with the AI system.

“Now that this has shown promise, there is a larger effort to think about more complicated systems and designs,” he said. “This is just the tip of the iceberg in terms of what the future holds for the field.”

The article, “Deep-learning Enabled Generalized Inverse Design of Multi-Port Radio-frequency and Sub-Terahertz Passives and Integrated Circuits,” was published Dec. 30, 2024, in the journal Nature Communications. Besides Sengupta, authors included Emir Ali Karahan, the lead author and a graduate student at Princeton; Zheng Liu, Zijian Shao and Jonathan Zhou of Princeton; and Aggraj Gupta and Uday Khankhoje of the Indian Institute of Technology Madras. Support for the research was provided in part by the Air Force Office of Scientific Research, the Office of Naval Research, Princeton Research Computing and the M. S. Chadha Center for Global India at Princeton University.