Flexible ultra-wideband antenna incorporated with metamaterial structures: multiple notches for chipless RFID application

A coplanar waveguide (CPW) ultra-wideband (UWB) antenna incorporated with metamaterial—split ring resonator structure—that operates from 3.0 to 12.0 GHz is proposed for chipless RFID tag. The 30 mm × 40 mm flexible chipless RFID tag is designed on the fleece substrate (er = 1.35, thickness = 1 mm and tan \( \delta \) = 0.025). A six-slotted modified complementary split ring resonator (MCSRR) is introduced into the ultra-wideband antenna to produce multiple band notches at 3.0, 4.0, 5.0, 6.0 and 7.0 GHz. The frequency shifting technique is introduced for designing a high-capacity chipless RFID tag with compact size. Each MCSRR is able to code in four different allocations (00, 01, 10 and 11). To achieve encoding of 10-bits data (10,234 number), six MCSRRs are proposed with three-slotted MCSRR in the radiator and three-slotted MCSRR in the ground plane.