Design of an Analog RFID-Based Tag Antenna with Opened Circuited L-Shaped Stubs for Applications in Localization

Abstract

This paper presents a new analog design for a radio-frequency identification (RFID) tag antenna with a long-read range oriented to localization applications. The actual work focuses on the analog input characterization of antenna impedance by studying the capacitive effect, created by the gaps, and the effect of the introduced opened circuited L-shaped stubs, on the RFID tag characteristics. Numerical and measured results confirm that proposed tag antenna performances are significantly improved by introducing gaps and stub structures and after optimizing their dimensions, such as length and width. The introduced stubs with optimum dimensions provide good impedance matching, and improved return loss values. Furthermore, two operating frequency bands have been created when the antenna is excited by a 50 Ω port: a low-frequency band around 837 MHz and a higher one around 927 MHz. These results have been validated by measured ones. The proposed RFID antenna is mainly composed of three split rectangular resonators (SRR) where introduced structures concern only the larger SRR. The optimized antenna has an area of 76 × 24.6 mm2 and is printed on the Taconic RF-60A substrate with a dielectric constant of 6.12, a thickness of 1.6 mm, and a loss tangent of 0.025. Simulation results show interesting communication performances, of the proposed tag antenna, with a return loss of −22.3 dB around 916 MHz and a long-read range up to 25 m when it is fed by an industrial Mping M730 chip with a power sensitivity of −24 dB and an output impedance Zchip = 16 − j194 (Ω) at 916 MHz

The Influence of Textile Substrates on the Performance of Textronic RFID Transponders

“…These parameters, although important, are not of key importance in the case of multichannel/broadband textile antennas dedicated to classic radio communication systems with an impedance of 50 Ω [ 6 , 7 ]. The problem is much more important in the case of RFID systems of the UHF band (operating frequency f 0 = 860–960 MHz) [ 8 , 9 ]. The input impedance of RF front-ends in RFID chips changes during the operation of the transponders, depending on the strength of the electromagnetic field or computing tasks performed in a digital circuit, and is affected by many factors, such as tag orientation, distance from antenna of read/write device (RWD), proximity of other objects or obstacles, interferences by other electromagnetic fields, etc.…”

Frequency Switchable Global RFID Tag Antennae with Metal Compatibility for Worldwide Vehicle Transportation

“…A microchip is attached to the tag antenna which is used to store the information about the tag. Generally, the tag is placed on the object, and the reader antenna needs to detect and locate the tag [2]. The impedance of the microchip is complex, and therefore impedance matching between the antenna and integrated chip to design tag antennae is very challenging.…”

“…Above all, by applying the meandering technique on the dipole antennae, the total antenna dimension can be reduced. The association with metal plates degrades its performance in terms of radiation patterns [2]. Artificial Magnetic Conductor below the antenna structure is a well-known method to shield the antenna from the effect of the metal surface [12,13].…”

Near Field Sensing Applications with Tunable Beam Millimeter Wave Antenna Sensors in an All-in-One Chip Design

“…Wireless sensors are differentiated into active and passive wireless sensors. Applications of passive wireless sensors include passive radar [1][2][3][4][5], liquid sensing [6][7][8], spatial positioning [9][10][11][12][13], RFID [14][15][16][17][18][19][20][21], and blood glucose determination [22,23].…”