Abstract: A medical pill intended for human or animal consumption includes an RF ID tag in or on the pill. The tag will respond to a nearby reader, the tag itself being without a battery or other constant power supply, capturing power from the reader's transmitted signal and storing a portion of that power in a power supply. An antenna for the RF ID tag may be integral with the tag or it may be transferred to the pill using conductive materials in the pill's coating, filler or binding agents, embedded within the pill, or printed onto the pill. If separate from the tag the antenna is electromagnetically coupled to the tag which has a small onboard antenna. The RF ID tag of each pill has data that are transmitted when the tag is interrogated by a signal from a reader. Incorporation of an ingestable ID tag is possible because of the tag's very small size compatible with ingestion and because the tag can contain an antenna within the pill that allows the tag to be read at a substantial distance.

Abstract: An electronic identification tag, usually in very small size, responds to a reader with an identification code unique to the object to which the tag is attached. The stand-alone device responds to a reader signal by storing energy received from the signal, then using the stored energy to generate another signal that is encoded with identification information. In operation, a reader generates RF energy which can reach a multiplicity of such tags over a distance of several meters. The system minimizes power requirements for the tag by minimizing intelligence in the IC. Use of a transmit frequency which is different from the reader's power frequency reduces interference between the power pulse and information pulse, eliminates the need for filters and enables the multiplied clock reference frequency as the transmit carrier frequency.