High Performance Optically-Controlled RF Switches with Ferroelectric Latching for Advanced Reconfigurable mmW-THz Circuits

The project will investigate and develop a novel millimeter-wave to terahertz (mmW-THz) wideband RF switching technology using lightwave control and the unique properties of ferroelectric materials to deliver superior performance. The switches resulting from this project will enable the development of a novel class of more advanced tunable or reconfigurable circuits and components required in the next generation mmW-THz sensing, imaging and communication systems.

This is an important technological area with a wide range of applications that will generate significant benefits to society. For example, switch-based reconfigurable mmW-THz filters may enable spectroscopic sensing and imaging for substance or material identification and detection, advanced chemical and biological sensing, disease or cancer diagnostics, and defense and security screening.

In addition, adaptive mmW-THz communication networks employing switch-based beam-steering or beam-forming phased-array antenna systems and tunable filters may have profound impact on future 6G or beyond cellular networks, the internet-of-things, chip-to-chip ultra-high-speed interconnections, 4K TV signal broadcasting, multimeda downloading, and secure military and defense communication links. The project also provides significant educational opportunities for students.

The graduate students working on this project will be immersed in an interdisciplinary research including semiconductor physics, electromagnetic wave propagation, advanced THz system design and characterization from single device to circuit and system levels. Undergraduate students, including those from underrepresented groups, will be involved through summer research program or honors thesis research and mentored by the principal investigators.

Finally, this project will also promote science and engineering education among local middle schools and high schools through NSF Research Experience for Teachers (RET) program with lab tours and hands-on STEM activities.

The objective of this project is to develop and demonstrate a novel mmW-THz wideband switching technology based on optical-modulation of free carriers in semiconductors (e.g., silicon, germanium, etc.) using novel device and circuit architectures to deliver superior switching performance and enhanced functionality. The combination of mmW-THz device design with optical control of photo-induced carriers in semiconductors, including the use of non-contact capacitively coupled structures to enhance carrier modulation, is central to the advancement of device performance beyond the current state of the art.

In addition, switching/latching using ferroelectric material hafnium zirconium oxide (HZO) will be integrated into the optically modulated switches, providing the first demonstration of non-volatile mmW-THz switch state retention as well as low power consumption. Furthermore, the new switches can exploit spatial optical modulation using computer-programmed light patterns, making them suitable for large-scale array applications.

This research will lead to optically controlled wideband mmW-THz switches that are compact, offer low power consumption, and are easy to fabricate and integrate into circuits and systems, while simultaneously providing performance superior to conventional semiconductor switches, emerging phase-change material (PCM) counterparts, and some micro-electromechanical system (MEMS) switches. The new switches will be employed to experimentally demonstrate mmW-THz tunable and reconfigurable prototypes including reconfigurable filters based on waveguide platforms and switch-based beam-steering or beam-forming antennas.

By using the RF switching technology developed in this project, more advanced tunable or reconfigurable mmW-THz circuits and components required in the next generation sensing, imaging and communication systems can be realized.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.