ULTRA LOW FREQUENCY TAG AND SYSTEM

摘要

Active high frequency radio tags have two major disadvantages: First, since the power consumption of any solid state circuit is proportional to the operating speed, active LF1HF and UHF tags require large batteries with limited life (two to maximum five years) and as a result are bulky heavy devices; Second, they must use high speed semiconductor devices that have a major impact on the active tag costs as compared to other semiconductor processes that operate at lower frequencies. The present invention provides a method, system, and ultra low frequency (below 1 megahertz) tag for detection and tracking of animate and inanimate objects attached thereto, the aforesaid ULF tag comprising: a) a tag antenna (e.g. wound on a ferrite core)operable at a low radio frequency below 1 megahertz; b) a communication device operatively connected to the aforesaid tag antenna and operable to transmit data at the aforesaid low radio frequency; c) a clock device, such as a crystal with a natural frequency (with characteristic variations in phase or amplitude to enable discovery of tags within the field of a large loop antenna) operatively connected to the aforesaid communication device and operable to emit clock data to determine the aforesaid low radio frequency; and d) an energy storage device operable to activate the aforesaid communication device and the aforesaid clock device.