Biomedical electronic devices for sensing physiological parameters are gaining popularity. With the miniaturization of electronics, wearable devices come equipped with sensors for vital sign monitoring such as ECG, heart rate, body temperature, sleep pattern, etc. However, the sensing capability of wearable devices is limited to parameters accessible outside the body. Biomedical devices placed directly inside the body are more helpful and promising in monitoring physiological parameters. These devices can also help treat disorders and restore the functionality of damaged organs.

The primary challenge associated with in-body devices is limited physical access. For proper operation, the device must be programmable, able to transmit signals, and powered appropriately. Battery-powered devices are unattractive due to their larger overall size, bio-incompatibility issues, and the need for frequent surgeries for battery replacement and charging.