MRI: Acquisition of a 4-40 GHz VNA-Based Material and Channel Sounder for Wireless Communications and Radar Research

Lafayette College, Easton PA

Investigators

Abstract

Abstract Nontechnical Current wireless systems, such as WiFi and 4G cellular networks, operate at microwave frequencies below 6 GHz. Since transfer speeds in this limited spectrum are typically only 10s of megabits-per-second, an important aim of 5G is the development of gigabit-per-second wireless networks providing speeds more similar to wired networks. Recently, intense research has demonstrated that gigabit wireless is possible by exploiting millimeter-wave bands at 60 GHz and above, yet at those frequencies signal losses from obstacles are prohibitive and the cost of semiconductor devices is currently high. This project proposes acquisition of a channel measurement instrument allowing detailed study of the 10-40 GHz frequency range (the Ku-Ka bands), likely providing the needed bandwidth increase for gigabit wireless, but without some drawbacks present above 60 GHz. To date, the Ku-Ka bands have received little attention, and detailed information on signal transmission in the presence of common building materials in Ku-Ka is not openly available. Measurements performed with the proposed instrumentation will correct this situation, resulting in an open database of building materials for the Ku-Ka bands. This database is expected to have immense value to industry and academia in the assessment and planning of wireless networks operating in the 10-40 GHz range, supporting the development of practical gigabit wireless networks and devices. The instrument will also support new experiments in multiple-antenna communications, radar, and remote sensing. The instrument will find extensive use in undergraduate teaching and research, exposing approximately 80 students per year to state-of-the-art equipment and techniques. Availability of the instrumentation to other institutions within the Lehigh Valley at no cost will provide opportunities for new collaborative research. Technical To support detailed characterization of the Ku-Ka bands for 5G networks and beyond, this project proposes the acquisition of a 4-40 GHz channel sounder consisting of a high dynamic range vector network analyzer, where two of the ports may be optically remoted up to 150m. Further, switches at the ports accommodate up to 8 antennas per port for multiple-input multiple-output (MIMO) propagation studies. This instrumentation enables a comprehensive database of building material properties, such as permittivity, conductivity, and rough surface and random volume parameters, to be developed for the Ku-Ka bands, which is expected to be extremely important for wireless networks in 5G and beyond. In-situ measurement of building materials at several sites on and off campus will allow the database to include not only mean values, but also statistical variation of properties. Employing the extracted properties in detailed ray-tracing simulations will reveal which bands are most suitable as a replacement for currently used wireless bands, and will allow the true necessity and/or benefits of beamforming, MIMO transmission, and massive MIMO to be quantified. The capability of the system to support direct MIMO measurement of 8x8 channels at up to four nodes will allow the underlying accuracy of the extracted material properties to be assessed. Given the flexibility of the system, new experimentation in MIMO communications, MIMO radar, and sensing from unmanned aircraft systems (UAS) will help advance the state-of-the-art in those areas.