Title: RF Circuits and Systems for Next Generation Multiband and Multimode Communication
Speaker: Nathan Neihart, Associate Professor
Abstract: With mobile technology becoming almost ubiquitous and with the types of enriched features and services that are available to the end user, mobile devices are being required to support higher data rates. This has led to the independent development of several spectrally efficient communication standards such as long-term evolution (LTE) and wireless metropolitan area networks (WiMAX) which is rapidly increasing the amount of spectrum fragmentation and leading to an environment where systems must communicate in many different, non-contiguous frequency bands spread between 400 MHz and 6 GHz. Moreover, there is an ever increasing need for wireless users to roam across wide geographic areas and across many different networks furthering the problem of spectrum fragmentation. The current approach of using multiple, parallel RF front-ends to support the various frequency bands and communication standards is quickly becoming unsustainable as more standards are being developed. This presentation will focus on research being performed in the Wireless Systems Lab directed at the development of transceivers that can support multiple standards spread over a wide range of carrier frequencies that are more area efficient than current parallel-path approaches yet more flexible than current wideband approaches. We have developed techniques, utilizing integrated transformers, for realizing two-band-selectable low-noise amplifiers that requires minimal increases in area, power consumption, and noise figure compared to traditional single-band amplifiers. These techniques were then adapted to realize a highly reconfigurable low-noise amplifier which is capable of operating in narrowband, broad-band, or concurrent dual-band configurations. Finally, I will discuss ongoing work in the area of highly efficient, concurrent multi-band power amplifier design and present some early results.