Defected Ground Structure With Half-Wavelength Spiral Resonator of Ultrawide Band Chipless RFID Tag

In this paper, a 2-bit unit chipless radio frequency identification (RFID) tag architecture is proposed through using both the defected ground structure (DGS) and the halfwavelength spiral resonator together. This tag structure with the size of 60 × 40 mm
²
consists of integrated microstrip with spiral DGS as well as λ/2 spiral resonators to realize compact 4-bit design without enlarging the tag size, and these spiral resonators can provide transmission zeros. Through combining the narrow band frequency modulated continuous wave radar, this proposed structure can offer the target location as well. Furthermore, the gap distance effect and the spiral dimension for the provided chipless RFID tag structure are analyzed and explained, and the three experimental results show excellent agreements with the theoretical analysis.