Power strength or Received Signal Strength Indicator (RSSI), a primary technique used in Real Time Location Systems (RTLS), is analyzed in this paper for RFID tracking applications. Critical issues are studied and hardware novelties are introduced in order to improve its performance. The main novelty is the accomplishment of an RFID RTLS through a mesh of individual active radiofrequency (RF) barriers composed by active emitter and receiver nodes/tags that cover only small individual areas. The result is a Sensor Area Network (SAN) that offers some advantages over classical tracking systems, which are based on Wireless Sensor Networks (WSN), especially in the multipath impairment mitigation, such as a controlled power emission, and the chance to warrant privacy regarding the exchange of RFID information. Experimental measurements were done to estimate the influence of the transmitted signal type and the receiver end architecture in the detection of the RF barrier presence. The parameterization of the coverage area of a SAN cell in terms of power is derived for both free-space and log-distance propagation models. The Kalman filtering technique is introduced as a valid tool to severely mitigate the multipath propagation effects that can affect the accurate operation of the proposed SAN for indoor operation conditions. Outcomes show a promising performance for this wireless network design, which has not received enough attention in literature.