What term refers to unpowered microchips that transmit encoded information through antennae?

The term that refers to unpowered microchips that transmit encoded information through antennae is Radio Frequency Identification (RFID). This technology relies on electromagnetic fields to automatically identify and track tags attached to objects. RFID technology consists of tags that contain an integrated circuit and an antenna, allowing them to communicate with an RFID reader.

RFID tags do not require a power source because they can harvest energy from the reader's signal to send information back. This is why they are termed "unpowered" microchips. The application of RFID technology is vast, ranging from inventory management to access control systems, enabling efficient tracking and data collection without the need for line-of-sight scanning.

Other terms like signal converters, data processors, and telemetry devices refer to different types of technologies and functions that do not specifically encapsulate the characteristics of unpowered microchips with antennae for data transmission.