Spherical antenna pattern(s) from antenna(s) arranged in a two- dimensional plane for use in RFID tags and labels

摘要

The present invention introduces an RFID system that comprises a two- dimensional antenna configuration having a dipole in combination with a loop antenna or a second dipole with their dipole axes at approximately a 90 angle to one another. The pattern of two dipole antennas combined with the pattern of a single loop antenna, allows the sequential combination of the patterns to represent a nearly spherical antenna pattern in three dimensions, while the antennas reside in a two- dimensional plane. The presence of multiple antennas also allows for a method to switch among the multiple antennas to find the antenna or combination of antennas that create(s) the strongest RF communication link thereby enabling more efficient transmitted power or more directional reception coverage. Improving efficiency can be further improved by taking this concept one step further by adding multiple antennas into the interrogator unit. Now the possibility exists whereby the best RF communication possible can be established between the interrogator and transceiver units by switching to the best antenna combination that would most efficiently pass an RF signal between the interrogator and the transceiver before and after which any of the antennas are now free to be used for trickle charging the chargeable battery cell(s) that reside in the transceiver unit.