Wireless Power Transmission System for High-Throughput Behavioral Studies on Small Freely Moving Animal Subjects

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Project Summary In behavioral neuroscience experiments on small freely moving animals, such as rodents, wireless cage systems have been widely used to enable wireless and battery-free operation of wearable/implantable devices (WIDs) attached to or implanted in the animal body. Typically, the neuroscience experiments need to run for extended periods in large enough subject populations to enhance the quality and statistical validity of the experiment results. Researchers need to transfer animals from their homecage to the experimental arena, one at a time, and return the animals back to the homecage and eventually to the animal facility after the experiments. This procedure is quite labor-intensive and inefficient for researchers, stressful for the animals, and costly. We have developed a rack-mountable wireless cage system, called EHC system. The EHC system is a resonance-based multi-coil inductive link system built around a standard-sized rodent homecage. Simultaneously operating multiple EHC systems can increase the data throughput in each experiment section. However, the challenge to do this is the severe cross-couplings among adjacent EHC systems, which would shift the system operating parameters, particularly the transmitter resonance frequency, and deteriorate the power transfer efficiency of the inductive link. The inductive link even enters the frequency-splitting zone when adjacent homecages are placed closer than a certain threshold. And the splitted resonance frequency cannot be converged by tuning the resonance capacitance. To address this challenge, we propose a multi-EHC system to empower the simultaneous operation of an array of EHC units placed right next to each other in the standard rack by adding resonant reactive shielding coils in between the adjacent EHC units and implementing triple-loop auto-tuning in each EHC unit for high throughput experiments. The shielding coil will reduce the undesired mutual coupling between adjacent EHC units to a certain threshold that the triple-loop auto-tuning technique can adjust each EHC unit at its optimal wireless power transmission condition on a continuous basis and over an extended period with minimal operator involvement.