Compact Metallic RFID Tag Antennas With a Loop-Fed Method

Passive UHF RFID Tags with Specific Printed Antennas for Dielectric and Metallic Objects Applications

“…; and b) a performance as good as other tags presented in the literature. Indicatively in [19] tags of size 105 mm  60 mm  0.76 mm exhibit reading distance of 7.3 m, in [36] tags of size 111.13 mm  23.56 mm have the reading distance of 5 m, in [37] reading distance of 8.9 m is obtained with tags of size 72.1 mm  25.5 mm  3.2 mm and in [38] tags with size 88 mm  25 mm  3.5 mm have reading distance of 5 m.…”

“…In the case of the RFID tag, this proximity is the maximum possible as the tag is attached to the object. In the literature, various configurations of antennas destined for metallic hosts have been proposed as, inverted-F type [30], antennas modeled by loop and open and shorted printed strip lines [31], bow-tie patches connected through metallic pins to the back plane [32] or bowtie slot type combined with Artificial Magnetic Conductor (AMC) [33], meander-type [34] or metamaterial structured antennas [35], patches, inset fed by open stub printed line at which the IC is mounted [36], patch antenna with proximity-coupled feed with line shorted at its end [37] and coupled shorted patches fed by printed loop for the IC hosting [38]. The microstrip type is superior to the printed type due to the fact the effectiveness of the printed models are strongly reduced when they are positioned very close to metallic surfaces and moreover large shifting of their resonance frequency occurs.…”

S-Parameter Method and Its Application for Antenna Measurements

“…For example, an asymmetric antenna was measured by using the S-parameter method and accurate results were shown for a wide range of bandwidths in [17]. An offset fed dipole antenna [18], RFID tags with asymmetric configurations [10], [12], [13], [18], and an antenna on a small housing [19] were also measured successfully by using the S-parameter method.…”

A Slim Wideband and Conformal Uhf Rfid Tag Antenna Based on U-Shaped Slots for Metallic Objects

“…Besides, some requirements in commercially should be taken into account in design process, such as the size of the antenna, sensitive read range, manufacturing cost, and impedance matching [8,9]. Based on the above considerations, several designs have been developed [10][11][12][13][14]. However, the size of the tag antenna in these designs is not small or thin enough, e.g., 118×43×1.5 mm 3 in [10].…”

“…A circular shape tag with highpermittivity ceramic (BaTiO 3 ) structure has been proposed in [11], and its diameter and thickness are 27.5 mm and 2.75 mm, respectively. Another 80 × 25 × 3.5 mm 3 metal tag is designed in [12] and consists of an additional loop feed. Ref.…”