Wireless technology has traditionally used radio waves to transmit and receive data. High data rate demands driven by mobile communications are being addressed by emerging wireless communication systems operating at new frequency bands. A large frequency spectrum is available at terahertz (THz) frequencies, also known as mm-wave. However, mm-wave systems face challenges such as reduction in signal strength with distance or blockage and reflection of signals. These challenges drive the development of new antennas and devices that can maximize the signal strength with high efficiency and rapidly adapt their operation. This project focuses on an innovative microfluidic based approach to enable such mm-wave antennas and devices with reduced cost and enhanced efficiency. These novel devices will be enabled by integrated compact actuation mechanisms. Advances from this project can immediately benefit wireless communication as well as emerging mm-wave applications such as identification tags and smart appliances. The interdisciplinary nature of the program is expected to offer unique training and research opportunities for graduate and undergraduate students. The PIs will develop new curriculum content that focuses on problems faced by engineers working on interdisciplinary projects. The project also plans to expand research opportunities for high-school students and students from underrepresented minorities.
Microfluidic reconfiguration techniques have drawn interest to address efficiency, tunability, and power handling issues of reconfigurable radio-frequency (RF) devices. Unfortunately, the majority of the proposed devices cannot operate in mm-wave bands due to the challenges in manufacturing, RF modeling, and utilization of liquid metals exhibiting lower conductivities and oxidization issues. This project focuses on a more recent microfluidic reconfiguration technique that is suitable for mm-wave band operation due to its reliance on selectively metallized plates (SMPs) repositionable within microfluidic channels. The major goal is to integrate novel actuation mechanisms with the SMP based microfluidic devices and enable their practical operation in mm-wave frequencies to achieve superior performances in efficiency, tunability, and power handling. Two distinct actuation mechanisms based on piezoelectric disks and electrowetting (EW) will be investigated to allow discovery of a broad range of capabilities. Through refinement of fabrication methods, flow characterizations, and RF design; the piezoelectric actuation will be optimized to achieve maximum RF reconfiguration speed. EW-based actuation will create a microfluidic linear stepper motor for addressing the high precision motion requirements. The trade-offs in plate alignment accuracy, selection of liquids, device geometry and RF performance will be investigated to establish the fundamental design and fabrication guidelines. In the RF design domain, the project will introduce novel capabilities by modeling the motion-dependent RF parasitics of SMPs. The proposed actuation and modeling methods are applicable for a large class of mm-wave devices. This three-year program is particularly tailored for addressing the challenging needs imposed by the mm-wave beam-steering antenna arrays. The program aims to investigate novel switches, phase shifters, and beamforming networks by addressing their design (i.e. RF parasitics modeling, size reduction, high efficiency, power handling) and actuation aspects (integration, resilience to vibration and impact, lifetime, speed).
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.
