Near-field wireless magnetic link for an ingestible cattle health monitoring pill

Cattle health assessment is receiving increased attention due to threats that disease and bioterrorism pose to producer profits and to the safety of the food supply. Ingestible pill technology offers a promising means to obtain these physiologic data, since a bovine reticulum is an environment sheltered from outside elements that offers direct access to feed intake and heart/lung data. Traditional radio-frequency links are inappropriate for this application, as water absorption severely limits transmission ranges through tissue. This paper presents the initial design of a communications link that utilizes magnetic induction for signal transport and should be well-suited for a tissue medium. The link consists of a transmitter/receiver pair that employs loop antennae frequency matched at 125 kHz. Optimization of the link design offers the potential to achieve transmission distances of several feet through tissue.