Compact Printable Chipless RFID Systems

Two novel compact printable chipless RFID systems are presented, which are: 1) a dual-polarized (DP) system and 2) an orientation insensitive (OI) system. Chipless tags for both the DP and OI systems consist of horizontally (H) and vertically (V) polarized “I” shaped slot resonators of different lengths, which create frequency signatures in the backscattered signal. Here, different V-H slots are used in the DP tag to double the encoding capacity within a fixed bandwidth and same V-H slots are used in the OI tag to achieve orientation insensitivity. Next, for reading these DP and OI tags, a low-profile low-cost wideband DP aperture coupled microstrip patch antenna (ACMPA) with high port-to-port isolation is developed as well. A reader with DP transmission and reception is capable of reading both the DP and OI tags. These single-sided compact tags are directly printable using conductive ink. Here, DP tags with double data capacity are suitable for fixed orientation applications demanding high data capacity, whereas OI tags are suitable for low data capacity applications requiring orientation insensitivity. Moreover, the developed commercially suitable DP ACMPA can also be used universally for reading all other frequency-domain-based tags.