Breakthroughs in Microwaves: Increasing Signal Strength in Swarms of Wireless Sensors-An Interview With Dr. Aydin Babakhani

This article is the first in the periodic Breakthroughs in Microwaves series. This series is intended to highlight recent accomplishments, especially to those new to the field, by researchers in microwave engineering that hold promise for long-term impact in the field. The articles are written after a conversation with the author so that background information can be provided to understand the breakthrough more fully. This first article looks at the pioneering work of Dr. Aydin Babakhani from UCLA in the USA. Dr. Babakhani's work is a novel application based on oscillator injection locking to synchronize, in the RF domain, the transmit frequency from individual sensors in a sensor swarm so that the individual sensors' signals constructively add at the receiver to increase the overall swarm signal level. The article reviews the loss issues in the system, both path loss for the transmit-receive path as well as for wireless power transfer. The article also provides background on RF integrated circuit transceiver circuits so that the reader can more fully understand the novelty of the RF phase synchronization technique. Finally, the article concludes with a short conversation with Dr. Babakhani that provides further insight into this pioneering technique.