Compact Metal-Mountable Uhf Rfid Tag Antenna With Two Large C-Shaped Slots for on-the-Fly Tuning

Abstract

A compact folded-patch UHF RFID tag antenna (30 mm × 30 mm × 3 mm or 0.0912λ × 0.0912λ × 0.009λ) is proposed for metallic surface applications. Two large C-shaped slots, which can be easily tuned by adjusting their lengths, are incorporated into the folded-patch for providing tuning mechanisms that can be employed in the production line for tuning the tag resonant frequency on the fly. The slots are tactfully embedded into the patch structure so that they occupy no footprint. The slots are large enough so that their lengths can be easily adjusted by employing a penknife and some copper tapes. This provides an impromptu tuning mechanism so that the tag resonant frequency can be easily corrected in the production line. With reference to the effective isotropic radiated power of 4 W, the proposed tag antenna can be read from 10 m on metal. The read range is found to be able to go beyond 5.5 m when the tag is placed on a dielectric with permittivity ranging from 1 to 12.

A Compact Folded RFID Tag Antenna with Nested Deformable Rings for Two-side Anti-metal Application

“…Compared with the antennas described in [22] and [23], the proposed tag antenna has a smaller volume. Compared with the antenna described in [25], the proposed tag antenna has a low profile. The most important thing is that the antenna designed in this paper can achieve two-side anti-metal performance.…”

“…Some special structures have also been used to design various on-metal tag antennas, such as complementary split ring resonator (CSRR) [17], double loop structure [18], and half-wavelength slot resonator [19]. Furthermore, several folded patch antennas [20][21][22][23][24][25] have been used for designing the anti-metal tags, which not only simplifies the fabrication complexity, but also increases the flexibility of antenna tuning. The antenna performance can be optimized by simply adjusting structures, such as radiating patches, shorting stubs, shorting walls, and grounds.…”