Flexible Transmit Beampattern Design via Waveform Diversity

发射波束图设计在许多应用中是至关重要的，包括国防和国土安全应用以及生物医学应用。传统的阵列方法要求所有天线发射相同的波形，并且调整每个天线输出的功率和相位以实现期望的发射波束图。然而，在许多实际系统中，天线的输出功率是受约束的，并且仅调整每个天线输出的相位在发射波束图设计中构成显著的限制。具体来说，研究人员利用波形多样性，即，由分布式传感器系统中的不同传感器提供的多样性传输不同但相关或不相关的波形，以实现灵活的传输波束图案设计。波形多样性提供了一个新的范例，灵活的波束方向图设计，因为显着增加的自由度。调查人员重点关注以下三个应用领域：1）通过有效的定向能量系统使肩射导弹失效，从而改善了对客机的保护，2）通过在基本功率约束下使用超声阵列提供足够大的焦点，从而增强了乳腺癌治疗，以及3）通过引入作为现有系统的可行替代方案，分布式传感器网络，每个传感器输出功率有限，以确保鲸鱼和其他海洋生物的安全。工作水平声明在建议的支持水平上，PI和Co-PI将尽一切努力满足项目的原始范围和工作水平。

Transmit beampattern design is critically important in many applications including defense and homeland security applications as well as biomedical applications. Traditional array approaches require all antennas to transmit the same waveform and the power and phase of each antenna output are adjusted to achieve a desired transmit beampattern. However, in many practical systems, the antenna output powers are constrained, and adjusting only the phase of each antenna output poses significant limitations in transmit beampattern designs.This research addresses the underlying transmit beampattern design technical issues associated with the current limitations. Specifically, the investigators exploit waveform diversity, i.e., the diversity offered by different sensors in a distributed-sensor system transmitting different but correlated or uncorrelated waveforms, to achieve flexible transmit beampattern designs. Waveform diversity offers a new paradigm for flexible beampattern design because of significantly increased degrees of freedom. The investigators focus on the following three application areas: 1) improved passenger aircraft protections by rending shoulder-launched guided missiles ineffective via effective directed energy systems, 2) enhanced breast cancer therapies by providing a sufficiently large focal spot using an ultrasound array under elemental power constraints, and 3) making the ocean quieter by introducing, as viable alternatives to existing systems, distributed sensor networks with each sensor output power limited to ensure the safety ofthe whales and other ocean creatures.Level of Effort StatementAt the recommended level of support, the PI and Co-PIs will make every attempt to meet the original scope and level of effort of the project.