CAREER: RF Co-Designated Fully-Directional Antenna Interfaces for Dynamic and Efficient Spectrum Access

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Wireless communication systems are increasingly covering every facet of our lives, including their use in mobile phones, healthcare delivery, autonomous driving, and space exploration. While wireless technologies are significantly changing the way our society is exploiting them for public safety and economic growth, they have resulted in an extremely congested radio spectrum. To address this challenge, innovative spectrum sharing solutions targeting new allocations at millimeter-wave frequencies (30-100 GHz), full-duplex spectrum usage and operation in under-utilized or unlicensed frequency bands are currently being considered. While the use of higher frequencies promises wider bandwidths and higher data-rates, these frequencies are not suitable for long-range communications and require expensive radio frequency (RF) hardware solutions. The main goal of this research is to address the nation's needs for spectrum sustainability, ubiquitous connectivity and increased national security for frequencies lower than 6 GHz, where the spectrum is more congested. In particular, this career development project will focus on RF co-designed fully-directional antenna interfaces that pave the way to efficient spectrum sharing through: i) full-duplex operation, ii) dynamic access of under-utilized and unlicensed frequency bands and iii) suppression of interference. The proposed research promises revolutionary improvements in spectrum sharing and allows for new capabilities in areas in which high-performance and high-density wireless technologies are of paramount importance, including next generation cellular communications, internet of things, and public safety. The program's broader educational goals include training of undergraduate and graduate students in areas related to next-generation RF systems, enhancing the Electrical Engineering (EE) curriculum at the University of Colorado Boulder with new class modules and a new class on tunable filter design techniques. The outreach activities will focus on broadening the participation of students in EE and promote higher education to traditionally under-represented populations including community-college students, veterans and women. The major objective of this proposal is to investigate and establish the theoretical foundations for highly-miniaturized and highly-reconfigurable RF front-ends through a new RF front-end design and integration concept based on RF co-designed fully-directional antenna interfaces that are in-field programmable and enable dynamic and efficient spectrum access. In particular, the proposed research will set the basic foundations for: i) fully-directional filter synthesis and design methods, ii) RF components with collocated signal processing capabilities and iii) multi-level transfer function tunability of the RF front-end chain. A specific focus of the research will be to understand the fundamental limits of spatio-temporal modulation and non-reciprocal filter design and determine trade-offs for various high-impact applications ranging for cellular to military and space communication systems. Tuning methods that facilitate multiple levels of transfer function reconfigurability will be developed, and their effectiveness in terms of efficient spectrum access will be studied. Furthermore, the trade-offs of size and performance of RF co-designed antenna interfaces will be systematically investigated. The proposed techniques will transform the way full-duplex radios are implemented and operated in spectrally-congested environments and will pave the way to generalized RF front-ends with multi-functional and multi-standard capabilities. 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.