Real time RFID location system

Indoor locating problem is the subject which has been generally studied in last years. While in outdoors positioning from satellite is common, due to the reflections of the signal in the interior, positioning is difficult. Although human and goods tracking is solved by different methods in interior space, position determination comes into prominence with RFID which has low cost, high reliability and least-location position error. With real time positioning and tracking systems using passive RFID technology, it can be used for many applications in hospital and in industry such as determining the position of patient, inventory, equipment, personal, products, materials, monitoring and protection. The most critical and innovative aspect of this work is the antenna assembly. In previous studies, the half-power beam width (HPBW) of the patch antenna was 65-70 degrees in one element; In this study, HPBW antenna design below 45 degrees was achieved in one element. This designed antenna has four replicates and is arranged in a metal profile on the vertical axis in different directions. The multiplexer circuit is designed for switching antennas quickly and with little loss. The reason why a series of antennas with phase shifter are not used in the study; loss of phase shifting circuits and antenna gain is reduced. Since the losses in the multiplexer circuit are minimal, it does not affect the antenna gain. The device is intended to function as a kind of radar. In fact, this system has been proposed inspired by follow-up radars. The other purpose in considering the antenna in this way; both to scan more areas and to increase accuracy. In this study, high gain, narrow width antenna and low loss switching circuit are designed at UHF band frequency (865-867 MHz). Designs were made in CST Studio Suite designed program. A beam-controlled structure that can adapt itself according to the different classifications of the interior space will be tried to be developed.