A New Design Paradigm for Switch-Mode Power Amplifiers Supporting Concurrent Multi-Band Wireless Communication

2010年，全球手机用户总数突破50亿大关，截至2013年，全球手机年销量达到18亿部。随着移动技术变得几乎无处不在，以及终端用户可以使用的丰富功能和服务类型，移动设备被要求支持更高的数据速率。不幸的是，这种对更高数据速率的需求导致系统现在需要支持在0.4 GHz和6 GHz之间扩展的许多不同的、不连续的频段中的通信。目前的解决方案包括使用多个并行的单频功率放大器，导致现代蜂窝电话具有多达10个独立的功率放大器。最终，这个问题将导致移动设备变得更笨重、更昂贵，并且无法支持关键的新多频段技术。问题的根源在于，传统上，单个功率放大器只能支持单个频段。研究人员试图通过并行多频段功率放大器的设计来解决这个问题，但这些系统的性能显著下降，这在很大程度上是传统设计理论无法解释的。这项研究将对并行多频段功率放大器的设计权衡和一套新的设计技术提供详细的理解。拟议的研究将为射频(RF)设计者提供一套新的工具，使他们能够应对下一代无线系统设计带来的挑战。此外，该项目还将提供提高整体电源效率的方法，从而延长多频段系统的电池寿命。此外，该项目将通过研究、通过增加本科生和研究生STEM项目中的女性和少数民族人数以及通过演讲和合作支持当地行业来加强美国收发信机行业。现代功率放大器设计面临两条战线：并行多频段通信正在成为现实，无线设备必须支持各种不同的通信标准。这导致发射机必须支持在0.4到6 GHz之间的许多不同频段上的通信。目前并行使用多个单频功率放大器的方法正变得不可持续，下一代无线设备将需要新技术。一种有前景的技术是使用并行多频带功率放大器，其中单个功率单元/匹配网络能够支持多个同时信号。遗憾的是，目前还没有现有的理论框架来描述并发多频段功率的最大效率、输出功率、稳定性或线性度。这种基础知识的持续缺乏将从根本上限制这项新技术满足未来无线设备需求的潜力。这项建议将为此类功率放大器的分析和实际实施制定一个理论框架和一套实用指导方针。总而言之，这些结果将为射频设计者提供一套新的工具，他们可以利用这些工具来减少现代设备中当前的功率放大器数量，并促进在已经指定的通信频段内提高数据速率和效率的新技术。这反过来将导致更有效地利用可用的频谱，而不会出现与动态频谱接入等技术相关的复杂监管障碍。这项工作的更广泛影响在于多频段功率放大器能够降低下一代收发器的总体成本，同时产生更灵活和更强大的移动设备。

The total number of worldwide cell phone users surpassed the 5 billion mark in 2010 and annual global sales of cellular telephones is reaching 1.8 billion units, as of 2013. 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. Unfortunately, this need for higher data rates is resulting in systems that are now required to support communication in many different, non-contiguous frequency bands spread between 0.4 and 6 GHz. The current solution consists of using multiple, parallel, single-band power amplifiers resulting in modern cellular telephones having upwards of ten separate power amplifiers. Ultimately, this problem will result in mobile devices becoming bulkier, more expensive, and unable to support key new multi-band technologies. The root problem is that, conventionally, a single power amplifier can support only a single band. Researchers have tried to address this problem through the design of concurrent multi-band power amplifiers, but, these systems suffered significant drops in performance that were largely unexplainable using conventional design theories. This research will provide a detailed understanding of the design trade-offs in concurrent multi-band power amplifiers and a new set of design techniques. The proposed research will give radio frequency (RF) designers a new set of tools enabling them to address the challenges posed by next generation wireless system design. In addition, this project will provide methods for increasing overall power efficiency and thereby increasing battery life in multi-band systems. Moreover, this project will strengthen the U.S. transceiver industry through research, through bolstering the number of women and minorities in undergraduate and graduate STEM programs, and through supporting local industry with presentations and collaborations.Modern power amplifier design is besieged on two fronts: concurrent multi-band communication is becoming a reality and wireless devices must support a variety of different communication standards. This is leading to transmitters that must support communication over many different frequency bands spread between 0.4 and 6 GHz. The current approach of using multiple, single-band power amplifiers in parallel is becoming unsustainable and new technology is going to be required for next generation wireless devices. One promising technique is the use of concurrent multi-band power amplifiers wherein a single power cell/matching network is capable of supporting multiple, simultaneous signals. Unfortunately, there is currently no existing theoretical framework to describe the maximum efficiency, output power, stability, or linearity of concurrent multi-band power. The continued lack of such basic knowledge will fundamentally limit the potential of this new technology to address the needs of future wireless devices. This proposal will develop both a theoretical framework and a set of practical guidelines for the analysis and physical implementation of such power amplifiers. Together, these results will give RF designers a new set of tools with which they can reduce the current number of power amplifiers in modern devices, and facilitate new techniques for improving data rates and efficiency in already-designated communication bands. This, in turn, will result in a more efficient use of the available spectrum without the complicated regulatory hurdles associated with techniques such as dynamic spectrum access. The broader impact of this work lies in the ability of multi-band power amplifiers to reduce the overall cost of next generation transceivers while yielding a more flexible and robust mobile device.