In one embodiment the present invention includes a radio frequency identification (RFID) system with a shorting loop. The shorting loop at least partially surrounds the antenna. The shorting loop distorts the electromagnetic field generated by the antenna to improve the definition of the border of the read region of the antenna. In this manner, the RFID system provides more accurate discrimination between RFID tags inside the read region versus RFID tags outside the read region (i.e., improves the accuracy of determining that a particular RFID tag is inside the read region).