Considering High-Performance Near-Field Reader Antennas: Comparisons of Proposed Antenna Layouts for Ultrahigh-Frequency Near-Field Radio-Frequency Identification

Abstract

An overview of the state-of-the-art of the antennas for ultra high frequency (UHF) near-field (NF) radio frequency identification (RFID) readers is presented. The specific requirements, design considerations, and design guidelines are addressed. Major types of designs reported in the scientific literature are illustrated and discussed.

A UHF RFID Tag Embeddable in Small Metal Cavities

“…As a conclusion of this numerical analysis, it is apparent that a trade-off is needed among cavity size and depth, and epoxy resin thickness. It is worth noting that in some applications a long read range is not required, while a reliable tag detection in a well-defined area should be guaranteed [10], [25]. In particular, in the application scenario considered in this paper, a read range larger than 60cm can be enough to detect small/medium size manufactured metal components moving on a conveyor belt.…”

Near Field UHF RFID Reader Antenna based on Composite Right/Left Handed Structure Compatible with Configurable Reading

“…The current vanishes and changes direction along the loop inducing a weak and inhomogeneous magnetic field and thus a reduced reading volume [2]. Two families of antennas are used to solve this problem [3]: segmented resonant loops and nonresonant antennas (TWA). The first solution is to segment the loop antenna to obtain an almost constant current [2].…”

Detection of UHF RFID Tags in Metallic Guided Structures

“…proximity identification and payments) and they are based on inductive coupling between two coils. On the other hand, UHF RFID systems are used for both near-field [2], [3] and far-field applications such as localization [4], sensing and Item Level Tagging (ILT) applications.…”

“…In a number of scientific contributions, research is devoted to theoretically model the RFID signal propagation, aiming at predicting the tag detection by means of numerical results [5]. However, it is worth mentioning that, in some specific scenarios such as near-field systems, the ray model [2] typically used for long-range UHF RFID systems can not be applied, since the main requirements are not satisfied. Thus, more accurate models have been studied [5]- [7].…”