Techniques described herein address these and other issues by providing an architecture of antennas capable of generating a relatively even H-field without exceeding exposure limits, while solving communication issues at the same time. More specifically techniques described herein are directed toward the use of multiple antennas that enable an interrogator device of a biological measurement and stimulation system to power different groups of medical implants at different times by creating fields in different regions of the brain. By doing this, the interrogator device can independently power and/or communicate with groups of medical implants in these different regions and create more evenly-distributed fields while doing so.