An RFID detection system for determining the location of tagged items within an interrogation zone. The system includes one or more printed circuit boards coupled to each other and placed within a region of the interrogation zone. Each printed circuit board contains an antenna array having one or more antennas where each antenna detects the presence of one or more tagged items within a specific read zone in the region. The printed circuit board also contains a multiplexer coupled to the antenna array, where the antenna array and the multiplexer are provided on a substrate. Upon an interrogation request from an RFID reader, a specific antenna can be activated and selected by the multiplexer and tagged items within the antenna's read zone are interrogated. RF signals containing RF identification information are then transmitted back to the RFID reader where a host computer interprets the signals and determines the location of the identified tagged items.