METHOD AND APPARATUS TO DETERMINE THE DIRECTION TO A TRANSPONDER IN A MODULATED BACKSCATTER COMMUNICATION SYSTEM

摘要

Methods and systems for determining the direction to a transponder are disclosed. The methods and systems include transmitting (R) a first signal to an area where communications with a transponder is desired; producing a second signal desired from the first signal; receiving the second signal via a first (R) and second antenna (B) forming a difference signal from the second signal received via the first and second antennas (201); forming a third signal by adding the second signal received via the first antenna and the second signal received via the third antenna; delaying the difference signal; and comparing a fist polarity of the delayed difference signal with a second polarity of the third signal (212).