Wireless technologies are poised to revolutionize all aspects of human life through enabling the infrastructures of a modern society, including intelligent transportation systems, internet of things, smart manufacturing, and connected healthcare. To enable such a revolution, there is a pressing need for tremendous enhancement of the scarce radio spectrum resources and their use efficiency. The effective access to radio spectrum is crucial for a diverse span of social needs ranging from national security and public safety to transportation, broadcasting and commercial services and plays a decisive role in continuous economic growth.
The wireless access to radio spectrum resources is currently limited by the available signal processing hardware that are only efficient in the lower end of the spectrum; hence, forcing current wireless systems such as smart phones, tablets and global positioning systems (GPS) to operate in a very limited frequency range (i.e. over ~0.3-6 GHz). Such a small frequency range is already overcrowded and cannot accommodate new wireless users or amenities that require ultra-fast data communication. Furthermore, available hardware are fundamentally incapable of simultaneous data transmission and reception in the same frequency band and at the same time. Therefore, current wireless systems are forced to occupy separate bands for data transmission and reception; hence, cutting the efficiency of the spectrum use in half.
The proposed research targets surpassing the fundamental limitations of current integrated signal processors through development of a transformative nano-acoustic technology in single crystal germanium (Ge) that 1) operates efficiently over the entire super- and extremely-high-frequency regimes (i.e. 3-300 GHz), and 2) enables simultaneous data transmission and reception in the same frequency band and at the same time, through fundamentally different operation physics; hence, doubling the spectrum use efficiency. Research shall consist of (1) investigation of nano-acoustic waveguides in semiconductors, with a focus on single crystal Ge, for wideband signal processing beyond the ultra-high-frequency regime (>UHF: 0.3-3GHz); (2) exploration of the physics/science of active electronic amplification of elastic signals through the acoustoelectric effects in piezoelectric-semiconductor nano-acoustic waveguides; (3) design and demonstration of low-loss and wideband signal processors beyond the UHF; and (4) engineering of chip-scale nonreciprocal signal processors, with a focus on isolators and circulators. Integrated with the research, this project targets the enrichment of social knowledge on novel nano-electro-mechanical systems and their indispensable role in everyday life through educational kits and high-school curriculum, and enhancement of diversity in interdisciplinary Science, Technology, Engineering and Math (iSTEM) research and careers through involvement of female and minority students.
