A MIMO Radar Signal Processing Algorithm for Identifying Chipless RFID Tags

Abstract

In this paper, the multiple-input, multiple-output (MIMO) radar signal processing algorithm is efficiently employed as an anticollision methodology for the identification of multiple chipless radio-frequency identification (RFID) tags. Tag-identifying methods for conventional chipped RFID tags rely mostly on the processing capabilities of application-specific integrated circuits (ASICs). In cases where more than one chipless tag exists in the same area, traditional methods are not sufficient to successfully read and distinguish the IDs, while the direction of each chipless tag can be obtained by applying MIMO technology to the backscattering signal. In order to read the IDs of the tags, beamforming is used to change the main beam direction of the antenna array and to receive the tag backscattered signal. On this basis, the RCS of the tags can be retrieved, and associated IDs can be identified. In the simulation, two tags with different IDs were placed away from each other. The IDs of the tags were successfully identified using the presented algorithm. The simulation result shows that tags with a distance of 0.88 m in azimuth can be read by a MIMO reader with eight antennas from 3 m away.

Frequency Domain Acoustic-Based Subharmonic Tags for Far-Field Identification

“…Nevertheless, as experimentally demonstrated in [41], such a strict resolution can be achieved by relying on bulk acoustic wave (BAW) resonators exploiting quasi thickness-extensional (TE) modes of vibration [42], like the Two-Dimensional-Mode-Resonators (2DMRs [41], [43], [44] ) or the Two-Dimensional-Resonant-Rods (2DRRs [45]) demonstrated by our group. In fact, even though these devices are not usable to build delay elements for TDR-based PTs due to their modal characteristics inhibiting the lateral propagation (8) f8 f16 fa (16) f24 f25 fa (24) C2 L2…”

“…Output Antenna f9 fa (8) f8 f16 fa (16) f24 f25 fa (24) Z out (a) (9) fa (8) fa (32) fa (16) fa (17) fa (24) fa (25) fa (1) Z out (3) fa (1) fa (2) fa (32) fa (4) Z out (c) b) and (c), respectively. Also, the simulated P out vs. f out trends relative to the SubHTs in (a), (b) and (c) and for f out values equal to half of the chirp interrogation signal's frequency (varying from 800 MHz to 816 MHz with 500 kHz steps) is also shown.…”

“…Nevertheless, the EDC and the interrogation range of the existing TDR-based ACO PTs is limited by transduction and acoustic propagation losses, which significantly increase as larger tag areas are employed to accommodate a higher number of identification bits [11]. In order to increase the maximum achievable EDC, PTs based on frequency-domain-reflectometry (FDR) have been reported [8], [14]. FDR-based PTs rely on chirped interrogation signals and encode their UID code directly into the spectrum of their backscattered signal.…”

An Innovative Method Based on Wavelet Analysis for Chipless RFID Tag Detection

“…Time-domain separation methods mainly refer to spatial filtering methods. The MIMO beamforming algorithm and TRM algorithm have been used for multitag detection in the literature [8,9]. The ISAR algorithm is also used in the literature [10] to improve the reading stability of moving chipless RFID tags.…”