In order to decrease the cost of RFID ( Radio Frequency Identification Devices) tags,a printable compact chipless tag on the basis of I-shaped slot resonators is proposed.By adding or removing the I-shaped slots of different length and width on conductive materials to perform information coding,different coded tags are obtained.Then,tag information is acquired from the radar cross-section ( RCS) of tags.Finally,the chipless tags of twelvebit code capacity are achieved on a 37.0 mm × 20.5 mm F4BM-1 /2 substrate.Simulation and experimental results demonstrate that ( 1) every slot resonator has its corresponding resonant frequency; ( 2) adjusting the length of slots can change the resonant frequency by a large margin,while adjusting the width can change it slightly; and ( 3) decreasing the space of adjacent slots or the width of slots can greatly improve coding capacity.