The US Army Research Laboratory and the University of Michigan have released a paper demonstrating a technique for shrinking antennas used for robot control — without, they claim, sacrificing performance.
“Conventional impedance matching techniques with passive components — such as resistors, inductors and capacitors — have a fundamental limit, known as the Chu-Wheeler limit, which defines a bound for the maximum achievable bandwidth-efficiency product for a given antenna size," explains Army researcher Dr. Fikadu Dagefu of the teams' work. "In general, low-frequency antennas are physically large, or their miniaturized counterparts have very limited bandwidth and efficiency, resulting in higher power requirement."
The solution: A modular active circuit applied to a highly-miniaturised and efficient antenna, which the researchers claim is capable of overcoming the Chu-Wheeler performance limit. "This miniature, actively matched antenna," Dr. Juhon Choi says, "enables the integration of power-efficient, low-frequency radio systems on compact mobile agents such as unmanned ground and aerial vehicles."
"We integrated the developed antenna on small, unmanned ground vehicles and demonstrated reliable, real-time digital video streaming between UGVs [Uncrewed Ground Vehicles], which has not been done before with such compact low-frequency radio systems," adds Dr. Dagefu. "By exploiting this technology, the robotic agents could coordinate and form teams, enabling unique capabilities such as distributed on-demand beam-forming for directional and secure battlefield networking."
“This technology is ripe for future development and transition to our various partners within the Army. We are optimistic that with the integration of aspects of our heterogeneous networking research, this technology will further develop and will be integrated into future Army communications systems."
The paper has been published under closed-access terms in the journal IEEE Transactions on Antennas and Propagation.