Inductive generation of arbitrary waveforms for electrical stimulation using implantable microcoils

Inductive coupling is widely used for powering biomedical implants, but is inadequate when transmitting low-frequency waveforms. We demonstrate that with amplitude modulation, specific waveforms can be transmitted via integrated receiving coils and passive demodulators. An ‘inlaid electroplating’ process with through-wafer plating is used to reduce internal resistance of microcoils and provide more flexibility for microcoil integration with electronics. Further utilizing link resonance specific to receiving microcoils, selective waveform transmission is demonstrated with a frequency-multiplexing input. Combining two microcoils with switching transistors, biphasic pulses are produced at the output, which has potential application for biomedical electrical stimulation.