Patent ID: 8010067

Claim:
An RFID system configured to determine a location of an RFID tag in a retail environment, comprising a central transmitter for generating the RF signal for transmission to the RFID tag; a first transmission antenna coupled to the central transmitter via a first transmission medium; a second transmission antenna coupled to the central transmitter via a second transmission medium; wherein the first transmission medium and the second transmission medium are cables of different lengths; a first RF signal compensating circuit coupled between the central transmitter and the first transmission antenna that applies a first variable gain to the RF signal to compensate for attenuation of the RF signal caused by the first transmission medium; and a second RF signal compensating circuit coupled between the central transmitter and the second transmission antenna that applies a second variable gain to the RF signal to compensate for attenuation of the RF signal caused by the second transmission medium; the first and second RF signal compensating circuits causing the first and second transmission antennas to broadcast the RF signal with substantially a same signal strength, the first and second RF signal compensating circuits each comprising: an automatic gain control circuit for automatically adjusting a gain applied to the RF signal to maintain the same signal strength at the transmission antennas, the automatic gain control circuit comprising: a first static gain control circuit for applying a first predetermined static gain to the RF signal; a second static gain control circuit, in parallel with the first gain control circuit, for applying a second predetermined static gain to the RF signal; and a switch configured to manually select either the first static gain control circuit or the second static gain control circuit to apply the first or second predetermined static gain to the RF signal.