EAGER: Phononic Amplification for Active Filtering at Radio Frequency

非技术：对无线通信系统的速度和可靠性的需求不断增长。因此，与十年前相比，解决此类系统的复杂性是一项艰巨得多的任务。例如，在最先进的智能手机中，有多个无线电同时工作。随着5G无线通信网络的到来，预计传输频率将超过10ghz。低噪声放大和特定频率的选择（滤波）是天线接收信号的关键过程。传统的无源声滤波器技术不能有效地满足这种复杂系统的需求，特别是在高频下。提出的工作研究一类新的设备，将提供同时低噪声放大和过滤射频（RF）信号。在单个芯片上集成多个射频前端的能力将为无线通信系统提供前所未有的可能性。单个设备可以彻底改变接收器前端架构，并为更复杂的无线电系统铺平道路。这种新型电子设备可以开辟一个新的研究和开发领域，具有巨大的商业应用潜力。技术方面：本项目的技术重点是进一步探索和增强机电谐振器件中的声子放大概念，以开发频率在GHz范围内的窄带有源滤波器。这种设备可以通过消除传统的半导体放大器并将放大转移到声学领域来显著简化和改进射频前端，在声学领域中频率选择同时进行。声子放大是基于微纳米级机械谐振腔中的载流子-声子相构干涉效应，在许多方面相当于激光和光学放大。从外部电源吸收能量，机械振动（声子）可以被放大，由于载流子-声子的相互作用。在电域中，结果是在机械结构的谐振频率周围的窄带宽内产生负等效电阻。负电阻与阻性负载相结合，可以充当放大器，从泵源吸收功率，并将放大的射频功率传递给负载。声子放大器提供的高选择性滤波可以显著降低RF模数转换器的动态范围要求，从而降低功耗。因此，声子放大器非常适合具有直接采样架构的现代射频收发器，其中射频信号在不进行下变频的情况下进行处理。为了满足线性度和功率处理要求，将设计和实现这种器件的二维机械耦合（电并联）阵列。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical:There is an ever-growing need for speed and reliability of wireless communication systems. Addressing the complexity of such systems is therefore a much more daunting task than it was a decade ago. For example, there are multiple radios operating at the same time in a state of the art smartphone. With the imminent advent of 5G wireless communication networks and beyond, transmission frequencies are expected to reach beyond 10 GHz. Low-noise amplification and selection of specific frequencies (filtering) are crucial processes on signals received from the antenna. Conventional passive acoustic filter technologies are not capable of efficiently addressing the needs of such complex systems, especially at high frequencies. The proposed work investigates a new class of devices that will provide simultaneous low-noise amplification and filtering of radio frequency (RF) signals. The ability to integrate multiple RF front-ends on a single chip will enable a host of unprecedented possibilities in wireless communication systems. Individual devices can revolutionize receiver front-end architectures and pave the way to more sophisticated radio systems. This new class of electronic devices can open up a new area of research and development with great potential for commercial applications.Technical:The technical focus of this project is to further explore and enhance the concept of phononic amplification in electromechanical resonant devices for development of narrow-band active filters with frequencies in the GHz range. Such devices can significantly simplify and improve RF front-ends by eliminating the conventional semiconductor amplifiers and moving the amplification into the acoustic domain, where frequency selection takes place simultaneously. Phononic amplification is based on carrier-phonon constructive interference effect in micro to nanoscale mechanical resonant cavities and is in many ways the acoustic equivalent of LASER and Optical Amplification. Absorbing power from an external electrical power source, mechanical vibrations (phonons) can be amplified due to carrier-phonon interactions. The result in the electrical domain is a negative electrical equivalent resistance within a narrow bandwidth around the resonance frequency of the mechanical structure. A negative resistance in combination with a resistive load can act as an amplifier absorbing power from the pump source and delivering amplified RF power to the load. Highly selective filtering provided by the phononic amplifiers can significantly relax the dynamic range requirement and therefore power consumption of RF analog to digital converters. Phononic amplifiers are therefore well suited for modern RF transceivers with direct sampling architectures, in which the RF signal is processed without being down-converted. To meet the linearity and power handling requirements, two-dimensional mechanically coupled (electrically parallel) arrays of such devices will be designed and implemented.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.