Abstract: According to several embodiments of the invention, a radio frequency identification (RFID) interrogator utilizing a circuit to remove unwanted distortion from a received signal is described. The interrogator transmits a transmitted signal continuously, while receiving a received signal from a radio frequency identification (RFID) tags. The circuit samples the transmitted signal, and removes the unwanted distortion created by the transmitted signal from the received signal.

Abstract: According to an embodiment of the invention, a patch antenna includes a patch coupled to a ground plane. The ground plane includes a first and second strip line. When the first strip line is activated, the antenna generates a signal having a first polarization, and when the second strip line is activated, the antenna generates a second polarization. The first polarization may be a horizontal polarization, and the second polarization may be a vertical polarization. The antenna may be incorporated into a radio frequency identification (RFID) interrogator, which may be used to read RFID tags attached to individual items.