BAE Systems and Purdue University recently published a groundbreaking study on tunable radio‑frequency (RF) filters in the journal Nature. For more than 150 years, Nature has published pivotal breakthroughs, including articles on the structure of DNA, gravitational waves, the Higgs boson, and the genetic editing tool CRISPR. This new article marks the first time RF filters have been the primary focus of a paper in the journal, underscoring the high‑impact nature of this research.
"This achievement represents a major milestone in our research and development efforts," said Connor Devitt, a doctoral researcher at Purdue University and lead author of the paper. "Our work on tunable RF filters has the potential to revolutionize wireless communication systems, and we look forward to exploring its possibilities."
At BAE Systems, the company’s FAST Labs™ research and development organization is at the forefront of advanced technology solutions. We push the boundaries of microelectronics and electronic warfare to enhance mission‑critical capabilities. We sat down with Dr. Bill Zivasatienraj to discuss the newly published research, tunable RF filters, and explore the implications for the defense community.
Can you tell us a little about your role?
Bill: I’m a senior principal scientist within BAE Systems' FAST Labs research, development, and production organization, where we drive emerging technologies that shape the future of microelectronics. Working with the Microelectronics Science & Technology team, I help close the gap between cutting‑edge science and the threats that jeopardize our warfighters. My focus is on device physics across a broad range of functional materials—including gallium nitride, gallium arsenide, silicon carbide, yttrium iron garnet, lithium tantalate, and lead zirconium titanate. I collaborate with government agencies, universities, and small businesses to unlock new applications and disruptive performance.
You co‑authored the paper in Nature on tunable RF Filters. How would you explain it to a non‑technical audience?
Bill: Imagine you're listening to your favorite radio station. It is surrounded by dozens of other stations, each with a different frequency. Engineers use filters to block unwanted signals and allow only the desired signal to pass through. Our research developed a tiny, highly selective filter that uses spin waves—tiny magnetic vibrations—in YIG (yttrium iron garnet).
By carefully shaping the YIG material, we created a filter that can tune across a wide range of frequencies, while maintaining low signal loss and strong performance. The filters also have a wide bandwidth, which allows them to handle large amounts of data.
Could you discuss the publication in more detail—who else was involved, and why it matters?
Bill: This paper is the culmination of a five‑year collaboration between BAE Systems and Purdue University. While tunable YIG filters have existed in past high‑end systems, they were typically narrow‑band, bulky, and power‑hungry—limitations that constrain their use in miniaturized platforms. By integrating advanced materials, precise fabrication and novel circuit design, we’ve achieved a chip‑scale filter with a wide bandwidth that can tune from 7 GHz to 21 GHz. These are key bands of the spectrum for 5G/6G communications as well as for military purposes. This technology can replace multiple separate filters in compact systems, dramatically reducing size, weight, and power requirements. That’s a game changer for both commercial and defense applications.
Why is this technology important for the defense community?
Bill: Modern warfare involves adversaries using jamming and spoofing to disrupt signals and obscure situational awareness. Robust, high‑performance filters enable us to reject those interferers and recover valuable signals faster and more accurately. They also safeguard critical systems by keeping them operating strictly within designated frequency bands, thereby enhancing reliability. In an era where electronic warfare and signal intelligence are pivotal, these filters give our warfighters a decisive edge.
What’s next for YIG filters?
Bill: Our research has matured spin‑wave filters to the point where existing platforms can readily adopt the technology. The next milestone is to refine the manufacturing processes and integrate this innovation into the supply chain for operational systems. Beyond filtering, YIG possesses a wealth of other capabilities, such as tunable GHz‑frequency oscillators and sensors, that we are excited to explore. YIG is a key to a broader portfolio of high‑performance, low‑profile RF solutions that will serve our defense customers.
About Bill:
Dr. Bill Zivasatienraj works in the Microelectronics Product Line at BAE Systems FAST Labs. He received his Ph.D. in electrical engineering from Georgia Tech, with a minor in materials science engineering. At BAE Systems, Bill works as a materials and semiconductor physics subject matter expert and has led multiple efforts on RF microelectronics, device-level thermal management, wide-bandgap semiconductors, spin-wave technology, non-volatile memory, neuromorphic computing hardware, and ferroelectrics.
Acknowledgement:
The authors would like to thank Dr. Ben Griffin, Dr. Todd Bauer, and Dr. Zack Fishman for their insights on the topic, and support from the DARPA COFFEE program (contract no. HR001122C00860). The views, opinions, and/or findings expressed in this Q&A are those of the authors and are not official views or policies of the Department of War or the U.S. Government.