The reading region of ultra high frequency radio-frequency identification(UHF RFID) system is affected by polarization mismatch,reader antenna height,coherent interference and so on.Based on the principles of RFID technology and ray-tracing method,a complete propagation model in real environments is derived.Utilizing recognition rate of target region(RRTR),a method of evalualing the performances of a system is presented.In order to obtain the maximization of RRTR,two solutions including tag diversity and ph...