Orientation Insensitive Chip-less RFID Tag using Modified Concentric Rings

Frequency-coded Chip-less Radio Frequency Identification (RFID) tags are rapidly advancing and replacing conventional technologies like barcodes in the near future. Orientation Insensitivity is the look-out feature of the Chip-less RFID which has so many applications in Manufacturing and Retail applications. The compactness and non-Line of Sight (LOS) are the extraordinary features that make RFID a competitor for the current tracking and identification technologies. The designs that are orientation insensitive in nature can be read from any orientation. The orientation insensitive feature can be used as an attribute to suppress the background reflections in the RFID domain. The designs that are presented in this paper are orientation insensitive and can be used in applications where the reading capability is not compromised by the angle or orientation of the tag with respect to the reader. The design is based on concentric flower-shaped rings. The compact design can encode four bits in the Frequency Shift Coding (FSC) technique. The dimension of the designed tag is 12 mm $\times 12$ mm $\times 1.585$ mm as length, width, and thickness of the substrate respectively. The design is placed on an FR-4 epoxy substrate which has a dielectric constant ($\varepsilon_{r}$) of 4.2 and a loss tangent (tan $\delta$) of 0.02. The design is simulated in a 3D electromagnetic (EM) field simulator.