Efficiency Improvement for Chipless RFID Tag Design Using Frequency Placement and Taguchi-Based Initialized PSO
<p>Backscattering chipless RFID system.</p> "> Figure 2
<p>Principal of measuring RCS of the object.</p> "> Figure 3
<p>Example RCS response of tags with different numbers of resonant elements.</p> "> Figure 4
<p>Parameters related to frequency shift caused by the mutual coupling.</p> "> Figure 5
<p>Tag design process in the presence of mutual coupling: (<b>a</b>) traditional; (<b>b</b>) proposed.</p> "> Figure 6
<p>Chipless tag design using optimization algorithm.</p> "> Figure 7
<p>Simulated RCS response of the single-element tags and the tag combining all the elements.</p> "> Figure 8
<p>Tag combining all the 5 resonant elements without modification.</p> "> Figure 9
<p>Convergence process of the objective function for frequencies [6.7, 6.9, 7.1, 7.3, 7.5] (GHz).</p> "> Figure 10
<p>RCS response of tags designed for frequencies [6.7, 6.9, 7.1, 7.3, 7.5] (GHz).</p> "> Figure 11
<p>Convergence process of the objective function for frequencies [6.6, 6.8, 7.0, 7.2, 7.4] (GHz).</p> "> Figure 12
<p>RCS response of tags designed for frequencies [6.6, 6.8, 7.0, 7.2, 7.4] (GHz).</p> "> Figure 13
<p>Convergence process of the objective function for frequencies [6.6, 6.8, 6.9, 7.2, 7.4] (GHz).</p> "> Figure 14
<p>RCS response of tag designed for frequencies [6.6, 6.8, 6.9, 7.2, 7.4] (GHz).</p> "> Figure 15
<p>Fabricated tag prototypes.</p> "> Figure 16
<p>Tag RCS measurement system: (<b>a</b>) in ambient chamber with a designed tag; (<b>b</b>) in anechoic chamber with a designed tag; and (<b>c</b>) in anechoic chamber with a reference tag.</p> "> Figure 16 Cont.
<p>Tag RCS measurement system: (<b>a</b>) in ambient chamber with a designed tag; (<b>b</b>) in anechoic chamber with a designed tag; and (<b>c</b>) in anechoic chamber with a reference tag.</p> "> Figure 17
<p>Tags fabricated with parameter sets optimized for frequencies [6.7, 6.9, 7.1, 7.3, 7.5] (GHz) using (<b>a</b>) PSO only, and using (<b>b</b>) PSO with TM.</p> "> Figure 18
<p>Simulated and measured RCS response of the two tags designed for frequencies 6.7, 6.9, 7.1, 7.3, and 7.5 GHz, and a reference tag.</p> "> Figure 19
<p>Tags fabricated with parameter sets optimized for frequencies: (<b>a</b>) [6.6, 6.8, 7.0, 7.2, 7.4] (GHz), and (<b>b</b>) [6.6, 6.8, 6.9, 7.2, 7.4] (GHz).</p> "> Figure 20
<p>Simulated and measured RCS response of the two tags designed for frequencies [6.6, 6.8, 7.0, 7.2, 7.4] (GHz) and [6.6, 6.8, 6.9, 7.2, 7.4] (GHz).</p> ">
Abstract
:1. Introduction
- (i)
- The resonant frequencies corresponding to the elements can vary only within a limited frequency range when the tag adds or removes other resonant elements.
- (ii)
- The difference in terms of RCS amplitude at resonant and non-resonant frequencies must be large enough in order to make the minima distinguishable.
2. Proposed Approach
- Step 1: Select the backscattering tag type. Different tag structures with multiple resonant frequencies, small sizes, and low influence of mutual coupling have been introduced [27]. However, with the proposed design method, mutual coupling can easily be compensated; hence, the structure type can be freely specified by the user.
- Step 2: Select the encoding resonant frequency set . These frequencies depend primarily on the operating range of the reader antenna and the size limit of the tag. In addition, it is necessary to select a data encoding method that uses these frequencies. Many data encoding methods for chipless RFID tags have been reported, of which the basic method is OOK (On–Off Keying), where each resonant frequency corresponds to a binary bit. The data bit has a logic value of “1” when the corresponding resonant element exists and has a logic value of “0” in the opposite case. In this method, as the number of resonant elements on the tag increases, the physical distance between them decreases and the difference in the encoded resonant frequencies also diminishes. This also increases the influence of mutual coupling between the elements, leading to encoded data corruption. Recently, the Frequency Shift Coding (FSC) method has allowed us to limit the increase in the number of resonant elements. In this method, the parameters of each element are adjusted to resonate at a specific frequency among a predefined set of encoded resonant frequencies. For this reason, the frequency combinations from frequency set can be realized with a small number of resonant elements on the tag.
- Step 3: Determine the threshold parameters and to evaluate the quality of the design parameter sets after obtaining the RCS response, as shown in Figure 4. Increasing the number of encoding frequencies in in the working range makes smaller, and it is more difficult to find design parameters. To overcome this problem, a robust optimization method is required, as discussed in Section 2. The value of depends on the accuracy of the measurement system, ability of the resonant structure to backscatter electromagnetic signals, tag material, and quality requirements imposed on the RCS signals.
- Step 4: From the set of frequencies, the apply the FSC method to specify the frequency combinations, noting that each frequency corresponds to a resonant element on the tag. Theoretically, each resonant element can be treated as an antenna; therefore, the design parameters of the magnetic part can be calculated according to antenna theory. However, the antenna model of the chipless RFID tag resonator element does not have a fixed waveguide port, and the computation of the design parameters is approximate. This discrepancy requires calibration and is handled optimally in subsequent steps.
- Step 5: Design and simulate the RCS response of the tag using specialized software such as CST Microwave Studio 2024, HFSS 2023 R2, or FEKO 2022. The resonant frequencies under the influence of mutual coupling and must be ascertained for use in Step 6.
- Step 6: Evaluate the level of deviation of the values and and compare with the threshold in Step 3. If the level of deviation satisfies the specified requirements, the design parameters of the tag are obtained, and the design process is completed (Step 8). Otherwise, this deviation is taken as the input for the optimization algorithm to propose another set of design parameters.
- Step 7: Deploy the optimization algorithm for the design parameters. This algorithm is based on the deviation to propose new sets of design parameters, which are then re-evaluated according to Step 5 until a satisfactory result is achieved.
3. Sample Design Case Studies
3.1. Tag Design for Frequency Combination [6.7, 6.9, 7.1, 7.3, 7.5] (GHz)
3.2. Tag Design for Frequency Combination [6.6, 6.8, 7.0, 7.2, 7.4] (GHz)
3.3. Tag Design for Frequency Combination [6.6, 6.8, 6.9, 7.2, 7.4] (GHz)
4. Experimental Results
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Herrojo, C.; Paredes, F.; Mata-Contreras, J.; Martín, F. Chipless-RFID: A Review and Recent Developments. Sensors 2019, 19, 3385. [Google Scholar] [CrossRef] [PubMed]
- Sharma, V.; Hashmi, M. Advances in the Design Techniques and Applications of Chipless RFIDs. IEEE Access 2021, 9, 79264–79277. [Google Scholar] [CrossRef]
- Brinker, K.R.; Zoughi, R. A Review of Chipless RFID Measurement Methods, Response Detection Approaches, and Decoding Techniques. IEEE Open J. Instrum. Meas. 2022, 1, 1–31. [Google Scholar] [CrossRef]
- Vena, A.; Perret, E.; Tedjini, S. Chipless RFID Based on RF Encoding Particle: Realization, Coding and Reading System; ISTE Press-Elsevier: Amsterdam, The Netherlands, 2016. [Google Scholar]
- Martinez, M.; Gu, Y.; Van der Weide, D. Fully Printable, Folded, High Frequency Chipless RFID Tag for Surgical Tracking and Detection. IEEE Radio Wirel. Symp. RWS 2020, 2020, 130–133. [Google Scholar] [CrossRef]
- Borgese, M.; Genovesi, S.; Manara, G.; Costa, F. Radar Cross Section of Chipless RFID Tags and BER Performance. IEEE Trans. Antennas Propag. 2021, 69, 2877–2886. [Google Scholar] [CrossRef]
- Preradovic, S.; Karmakar, N.C. Design of fully printable planar chipless RFID transponder with 35-bit data capacity. In Proceedings of the 2009 European Microwave Conference (EuMC), Rome, Italy, 29 September–1 October 2009; pp. 013–016. [Google Scholar] [CrossRef]
- Svanda, M.; Polivka, M.; Havlicek, J.; Machac, J.; Werner, D.H. Platform tolerant, high encoding capacity dipole array-plate chipless RFID tags. IEEE Access 2019, 7, 138707–138720. [Google Scholar] [CrossRef]
- Abdulkawi, W.M.; Sheta, A.F.A. K-state resonators for high-coding-capacity chipless RFID applications. IEEE Access 2019, 7, 185868–185878. [Google Scholar] [CrossRef]
- Abdulkawi, W.M.; Nizam-Uddin, N.; Sheta, A.F.A.; Elshafiey, I.; Al-Shaalan, A.M. Towards an efficient chipless rfid system for modern applications in iot networks. Appl. Sci. 2021, 11, 8948. [Google Scholar] [CrossRef]
- Ashraf, M.A.; Alshoudokhi, Y.A.; Behairy, H.M.; Alshareef, M.R.; Alshebeili, S.A.; Issa, K.; Fathallah, H. Design and analysis of multi-resonators loaded broadband antipodal tapered slot antenna for chipless RFID applications. IEEE Access 2017, 5, 25798–25807. [Google Scholar] [CrossRef]
- Babaeian, F.; Forouzandeh, M.; Karmakar, N. Solving a chipless RFID inverse problem based on tag range estimation. IET Microw. Antennas Propag. 2020, 14, 1361–1370. [Google Scholar] [CrossRef]
- Aliasgari, J.; Karmakar, N.C. Mathematical model of chipless RFID tags for detection improvement. IEEE Trans. Microw. Theory Tech. 2020, 68, 4103–4115. [Google Scholar] [CrossRef]
- Rance, O.; Perret, E.; Siragusa, R.; Lemai, P. RCS Synthesis for Chipless RFID: Theory and Design, 1st ed.; ISTE Press-Elsevier: Amsterdam, The Netherlands, 2017. [Google Scholar]
- Svanda, M.; Polivka, M.; Havlicek, J.; Machac, J. Chipless RFID tag with an improved magnitude and robustness of RCS response. Microw. Opt. Technol. Lett. 2017, 59, 488–492. [Google Scholar] [CrossRef]
- Le, C.C.; Dao, T.K.; Pham, N.Y.; Nguyen, T.H. Encoding Capacity Enhancement for Chipless RFID Tag Using Resonant Frequency Placement. IEEE Access 2023, 11, 117907–117919. [Google Scholar] [CrossRef]
- Wmylkiwskyj, W. Theory of Mutual Coupling Among Minimum-Scattering Antennas. IEEE Trans. Antennas Propag. 1970, 18, 204–216. [Google Scholar] [CrossRef]
- Mazzarella, G.; Panariello, G. On the Evaluation of Mutual Coupling Between Slots. IEEE Trans. Antennas Propag. 1987, 35, 1289–1293. [Google Scholar] [CrossRef]
- Kakatkar, S.S.; Ray, K.P. Evaluation of mutual coupling between slots from dipole expressions. Progress Electromagn. Res. M 2009, 9, 123–138. [Google Scholar] [CrossRef]
- Kennedy, J.; Eberhart, R. Particle swarm optimization. In Proceedings of the ICNN’95—International Conference on Neural Networks, Perth, WA, Australia, 27 November–1 December 1995; pp. 1942–1948. [Google Scholar] [CrossRef]
- Taguchi, G.; Chowdhury, S.; Wu, Y. Taguchi’s Quality Engineering Handbook; Talylor Francis Group: Abingdon, UK, 2007; pp. 1–1662. [Google Scholar] [CrossRef]
- Sharma, V.; Malhotra, S.; Hashmi, M. Slot Resonator Based Novel Orientation Independent Chipless RFID Tag Configurations. IEEE Sens. J. 2019, 19, 5153–5160. [Google Scholar] [CrossRef]
- Polivka, M.; Havlicek, J.; Svanda, M.; MacHac, J. Improvement in Robustness and Recognizability of RCS Response of U-Shaped Strip-Based Chipless RFID Tags. IEEE Antennas Wirel. Propag. Lett. 2016, 15, 2000–2003. [Google Scholar] [CrossRef]
- Machac, J.; Polivka, M.; Svanda, M.; Havlicek, J. Reducing mutual coupling in chipless RFID tags composed of U-folded dipole scatterers. Microw. Opt. Technol. Lett. 2016, 58, 2723–2725. [Google Scholar] [CrossRef]
- Chen, Y.S.; Jiang, T.Y.; Lai, F.P. Automatic Topology Generation of 21 Bit Chipless Radio Frequency Identification Tags Using a Noniterative Technique. IEEE Antennas Wirel. Propag. Lett. 2019, 18, 293–297. [Google Scholar] [CrossRef]
- Javed, N.; Azam, M.A.; Amin, Y. Chipless RFID Multisensor for Temperature Sensing and Crack Monitoring in an IoT Environment. IEEE Sens. Lett. 2021, 5, 1–4. [Google Scholar] [CrossRef]
- Islam, M.A.; Karmakar, N.C. A novel compact printable dual-polarized chipless RFID system. IEEE Trans. Microw. Theory Tech. 2012, 60, 2142–2151. [Google Scholar] [CrossRef]
- Goldberg, D.E.; Holland, J.H. Genetic Algorithms and Machine Learning. In Advanced Course on Artificial Intelligence; Springer: Berlin/Heidelberg, Germany, 1988; Volume 3. [Google Scholar] [CrossRef]
- Dorigo, M.; Maniezzo, V.; Colorni, A. Ant system: Optimization by a colony of cooperating agents. IEEE Trans. Syst. Man Cybern. Part B Cybern. 1996, 26, 29–41. [Google Scholar] [CrossRef] [PubMed]
- Shami, T.M.; El-Saleh, A.A.; Alswaitti, M.; Al-Tashi, Q.; Summakieh, M.A.; Mirjalili, S. Particle Swarm Optimization: A Comprehensive Survey. IEEE Access 2022, 10, 10031–10061. [Google Scholar] [CrossRef]
- Pérez, J.R.; Basterrechea, J. Comparison of different heuristic optimization methods for near-field antenna measurements. IEEE Trans. Antennas Propag. 2007, 55, 549–555. [Google Scholar] [CrossRef]
- Hedayat, A.S.; Sloane, N.J.A.; Stufken, J. Orthogonal Arrays; Springer Series in Statistics; Springer: New York, NY, USA, 1999. [Google Scholar] [CrossRef]
- Xie, K.; Xue, Y. A 12 bits chipless RFID tag based on ‘I-shaped’ slot resonators. In Proceedings of the 2017 6th International Conference on Computer Science and Network Technology (ICCSNT), Dalian, China, 21–22 October 2017; pp. 320–324. [Google Scholar] [CrossRef]
- Noor, T.; Habib, A.; Amin, Y.; Loo, J.; Tenhunen, H. High-density chipless RFID tag for temperature sensing. Electron. Lett. 2016, 52, 620–622. [Google Scholar] [CrossRef]
- Vena, A.; Perret, E.; Tedjini, S. A fully printable Chipless RFID tag with detuning correction technique. IEEE Microw. Wirel. Compon. Lett. 2012, 22, 209–211. [Google Scholar] [CrossRef]
- Ferro, V.; Rebello, P.; Quadros, M.; Staehler, W. L-Shaped Chipless Tag Design Analysis and Optimization for Fully Inkjet Printing. In Proceedings of the 2019 IEEE International Conference on RFID (RFID), Phoenix, AZ, USA, 2–4 April 2019; pp. 1–8. [Google Scholar] [CrossRef]
- Issa, K.; Alshoudokhi, Y.A.; Ashraf, M.A.; AlShareef, M.R.; Behairy, H.M.; Alshebeili, S.; Fathallah, H. A High-Density L-Shaped Backscattering Chipless Tag for RFID Bistatic Systems. Int. J. Antennas Propag. 2018, 2018, 1542520. [Google Scholar] [CrossRef]
- Abdulkawi, W.M.; Sheta, A.F.A.; Issa, K.; Alshebeili, S.A. Compact Printable Inverted-M Shaped Chipless RFID Tag Using Dual-Polarized Excitation. Electronics 2019, 8, 580. [Google Scholar] [CrossRef]
- Rather, N.; Buckley, J.; O’Flynn, B.; Pigeon, M. A Novel RCS based CRFID Tag Design. In Proceedings of the 2022 16th European Conference on Antennas and Propagation (EuCAP), Madrid, Spain, 27 March–1 April 2022. [Google Scholar] [CrossRef]
- Ni, Y.Z.; Huang, X.D.; Lv, Y.P.; Cheng, C.H. Hybrid coding chipless tag based on impedance loading. IET Microw. Antennas Propag. 2017, 11, 1325–1331. [Google Scholar] [CrossRef]
- Dissanayake, T.; Esselle, K.P. Prediction of the notch frequency of slot loaded printed UWB antennas. IEEE Trans. Antennas Propag. 2007, 55, 3320–3325. [Google Scholar] [CrossRef]
Element Number | Original Frequency (GHz) | Shifted Frequency (GHz) | Frequency Deviation (GHz) | Element Number | Original Frequency (GHz) | Shifted Frequency (GHz) | Frequency Deviation (GHz) |
---|---|---|---|---|---|---|---|
1 | 4.01 | 3.71 | −0.30 | 11 | 4.67 | 4.54 | −0.13 |
2 | 4.07 | 4.04 | −0.03 | 12 | 4.71 | 4.60 | −0.11 |
3 | 4.11 | 4.11 | 0.00 | 13 | 4.71 | 4.65 | −0.06 |
4 | 4.19 | 4.17 | −0.02 | 14 | 4.74 | 4.70 | −0.04 |
5 | 4.26 | 4.22 | −0.04 | 15 | 4.76 | 4.77 | 0.01 |
6 | 4.34 | 4.28 | −0.06 | 16 | 4.76 | 4.82 | 0.06 |
7 | 4.42 | 4.33 | −0.09 | 17 | 4.79 | 4.89 | 0.10 |
8 | 4.50 | 4.38 | −0.12 | 18 | 4.80 | 4.94 | 0.14 |
9 | 4.55 | 4.44 | −0.11 | 19 | 4.86 | 5.02 | 0.16 |
10 | 4.61 | 4.48 | −0.13 | 20 | 4.92 | 6.00 | 1.08 |
Resonant frequency (GHz) | |||||
6.7 | 6.9 | 7.1 | 7.3 | 7.5 | |
Element length (mm) | |||||
19.96 | 19.31 | 18.71 | 18.12 | 17.57 |
−0.28 | −0.42 | −0.31 | −0.34 | −0.45 | 0.48 | −0.81 | −1.15 | −1.20 |
−0.25 | −0.28 | −0.28 | −0.24 | −0.18 | −0.34 | −1.06 | −1.05 | 1.11 |
0.16 | −0.01 | −0.11 | −0.72 | −0.68 | 1.07 | −0.18 | −0.61 | −0.46 |
−0.14 | −0.35 | −0.58 | −0.35 | −0.04 | 0.20 | −0.84 | −1.06 | −1.17 |
−0.35 | −1.10 | −0.03 | −0.42 | −0.35 | 0.07 | −0.96 | −1.07 | −0.95 |
−0.28 | −0.49 | −0.41 | −0.25 | −0.03 | 1.03 | −1.25 | −1.23 | −1.04 |
−0.21 | −0.24 | −0.18 | −0.30 | −0.51 | −0.11 | −0.94 | 0.19 | −0.94 |
−0.25 | −0.75 | −0.88 | −0.63 | −0.86 | 1.49 | −1.25 | −1.25 | −1.23 |
−0.24 | −0.12 | −0.94 | 0.13 | −0.26 | −0.10 | −0.75 | −0.68 | −1.13 |
−0.52 | −0.39 | −0.44 | −0.26 | 0.00 | −0.45 | −0.63 | −0.63 | −0.56 |
Desired resonant frequency (GHz) | |||||
6.7 | 6.9 | 7.1 | 7.3 | 7.5 | |
Achieved frequency (GHz) | |||||
| 6.72 | 6.90 | 7.05 | 7.25 | 7.53 |
| 6.70 | 6.90 | 7.05 | 7.27 | 7.55 |
Element length adjustment (mm) | |||||
| −0.82 | −1.20 | −1.20 | 0.24 | 0.28 |
| −0.68 | −1.195 | −1.195 | −0.38 | 0.99 |
Element length (mm) | |||||
| 19.14 | 18.11 | 17.52 | 18.36 | 17.85 |
| 19.28 | 18.11 | 17.52 | 17.74 | 18.56 |
Element distance adjustment (mm) | |||||
| −1.25 | −1.25 | −1.02 | −1.25 | |
| −0.98 | −1.25 | −0.62 | −1.25 | |
Element distance (mm) | |||||
| 0.75 | 0.75 | 0.98 | 0.75 | |
| 1.02 | 0.75 | 1.38 | 0.75 |
Desired resonant frequency (GHz) | |||||
6.6 | 6.8 | 7.0 | 7.2 | 7.4 | |
Achieved frequency (GHz) | |||||
| 6.59 | 6.77 | 6.98 | 7.13 | 7.47 |
| 6.57 | 6.81 | 6.97 | 7.17 | 7.45 |
Element length adjustment (mm) | |||||
| −0.84 | −1.24 | −1.18 | −0.75 | 1.24 |
| −0.78 | −0.62 | −1.24 | −0.35 | 0.57 |
Element length (mm) | |||||
| 19.48 | 18.39 | 17.84 | 17.66 | 19.08 |
| 19.54 | 19.01 | 17.78 | 18.06 | 18.41 |
Element distance adjustment (mm) | |||||
| −1.25 | −1.25 | −1.25 | −1.25 | |
| −1.00 | −0.95 | −0.64 | −1.07 | |
Element distance (mm) | |||||
| 0.75 | 0.75 | 0.75 | 0.75 | |
| 1 | 1.05 | 1.36 | 0.93 |
Resonant frequency (GHz) | |||||
6.6 | 6.8 | 6.9 | 7.2 | 7.4 | |
Element length adjustment (mm) | |||||
−1.15 | −1 | −1.24 | 1.24 | −0.18 | |
Element length (mm) | |||||
19.17 | 18.63 | 18.07 | 19.65 | 17.66 | |
Element spacing adjustment (mm) | |||||
−0.35 | −0.86 | −0.73 | −1.25 | ||
Element spacing (mm) | |||||
1.65 | 1.14 | 1.27 | 0.75 |
Desired resonant frequency (GHz) | |||||
6.7 | 6.9 | 7.1 | 7.3 | 7.5 | |
Measured frequency with PSO alone (GHz) in ambient chamber | |||||
6.72 | 6.90 | 7.06 | 7.25 | 7.53 | |
Measured frequency with PSO and TM (GHz) in ambient chamber | |||||
6.71 | 6.90 | 7.05 | 7.27 | 7.51 | |
Measured frequency with PSO and TM (GHz) in anechoic chamber | |||||
6.70 | 6.90 | 7.05 | 7.27 | 7.52 |
[6.6, 6.8, 7.0, 7.2, 7.4] (GHz) tag | Desired frequency (GHz) | |||||
6.6 | 6.8 | 7.0 | 7.2 | 7.4 | ||
Measured frequency (GHz) | ||||||
6.57 | 6.79 | 6.96 | 7.17 | 7.42 | ||
[6.6, 6.8, 6.9, 7.2, 7.4] (GHz) tag | Desired frequency (GHz) | |||||
6.6 | 6.8 | 6.9 | 7.2 | 7.4 | ||
Measured frequency (GHz) | ||||||
6.56 | 6.80 | 6.92 | 7.19 | 7.43 |
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Le, C.-C.; Dao, T.-K.; Pham, N.-Y.; Nguyen, T.-H. Efficiency Improvement for Chipless RFID Tag Design Using Frequency Placement and Taguchi-Based Initialized PSO. Sensors 2024, 24, 4435. https://doi.org/10.3390/s24144435
Le C-C, Dao T-K, Pham N-Y, Nguyen T-H. Efficiency Improvement for Chipless RFID Tag Design Using Frequency Placement and Taguchi-Based Initialized PSO. Sensors. 2024; 24(14):4435. https://doi.org/10.3390/s24144435
Chicago/Turabian StyleLe, Cong-Cuong, Trung-Kien Dao, Ngoc-Yen Pham, and Thanh-Huong Nguyen. 2024. "Efficiency Improvement for Chipless RFID Tag Design Using Frequency Placement and Taguchi-Based Initialized PSO" Sensors 24, no. 14: 4435. https://doi.org/10.3390/s24144435