Inverse Design of Broadband Artificial Magnetic Conductor Metasurface for Radar Cross Section Reduction Using Simulated Annealing
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper attempts to optimize certain geometrical parameters using simulated annealing.
1) The system model does not fit the solution.
Upon inspecting Figure 3, the authors refer to the Metropolis criterion. However, simulated annealing does not inherently require Monte Carlo sampling, making the Metropolis criterion irrelevant in this context. What kind of data is being sampled, and from which distribution? The proposed model in (1)–(4) appears to be deterministic.
It is recommended to include a dedicated section on "Parameter Optimization" that thoroughly explains the entire optimization process. This section should introduce a probabilistic system model (which is currently missing), clearly define the parameters, specify the function being optimized (by simulated annealing), and describe the solution approach.
Another concern is the computational complexity, which is known to be extremely high for simulated annealing and should be explicitly discussed.
2) The results have not been compared with any state-of-the-art solutions.
Without a comparison, it is unclear how well the proposed framework performs relative to existing methods. A quantitative evaluation against relevant benchmarks should be included.
3) What are the limitations of the proposed approach?
The manuscript does not discuss potential drawbacks or constraints of the method. Addressing these aspects would improve the clarity and completeness of the study.
These open issues require a substantial revision and a complete redesign of the paper.
Author Response
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Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper presents a design method for metasuface unit cells with reduced the radar cross-section. The following concerns need to be addressed.
1. In line 29 of page 1, unnecessary spaces between letters need to be removed.
2. It would be good to summarize the organization of the paper at the end of Section 1.
3. In line 95 of page 2, “n” is missing in “As shown”.
4. Table 2 spans two pages, degrading the readability.
5. The subfigure numberings are missing in Figs. 11, 12, 13.
6. A figure of merit can be defined for comprehensive comparison in Table 2.
7. The measured results deviate much from the simulated results in Fig. 8, which needs to be justified.
8. The resolutions of the figures need to be enhanced.
9. How will the results be for the sets of parameters other than those in Table 1?
10. The notations need to be consistent throughout the paper. For example, some of them alternate between uppercased or lowercased.
11. The algorithmic details regarding Fig. 3 must be added.
12. Fig. 3 does not follow the convention of drawing a flowchart. The branching conditions are not illustrated rigorously.
13. The prior designs need to be reviewed in more detail so that they can be contrasted to the proposed one.
14. Simulated annealing (SA) has been widely used in various applications. In this regard, employing the SA itself cannot be considered as a novel contribution.
15. The details of configuring the SA must be described in detail.
16. The computational complexity overhead resulting from employing SA needs to be justified.
17. What does lg mean in (3) and (4)?
Author Response
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Reviewer 3 Report
Comments and Suggestions for AuthorsIn this study, the authors present a novel design methodology for unit cells in chessboard metasurfaces to reduce the radar cross-section (RCS) for linearly polarized waves. The design employs rotational symmetry and incorporates ten continuous parameters to define the metasurface units, enabling the creation of flexible 2D structures. The geometrical parameters of the two units are then optimized using a simulated annealing (SA) algorithm to achieve a low RCS chessboard metasurface. Following optimization, the properties of the metasurface were experimentally verified.
Major issues:
1) Recently, global optimization algorithms such as genetic algorithm and particle swarm optimization (PSO) algorithm have been used to optimize the RCS reduction performance of metasurfaces. However, it is well known that these optimization algorithms are time-consuming and increase the complexity of the design. The authors have employed simulated annealing, which is also a global optimization algorithm, but without justifying this choice. What kind of advantage has simulated annealing compared with genetic or swarm optimization? Is it less time-consuming? To this aim, the authors should report the CPU time involved in designing the metasurface unit cell.
2) The overall computational process depicted in Figure 3 must be better described. The revised version of their work must provide a pseudocode of the proposed design approach. How have they interfaced the Python code with CST? Although this operation cannot be described in detail, some indications must be provided.
3) The measured and numerical results of monostatic and bistatic RCS reported in Figures 8 and 9 are quite different. The authors attributed this discrepancy to the fabrication process of the proposed cell pair, which involves several rectangles with a width of 0.1 mm. To improve the simulation predictions, this issue must be taken into account. Otherwise, the simulation approach proposed by the authors results in inaccurate results, whether compared to other design approaches proposed in the literature. How do the authors intend to overcome this issue?
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for Authorsthe authors did a good job
Comments on the Quality of English Languageminor issues
Author Response
We sincerely appreciate your positive feedback. It is very encouraging to know our work has met with your approval. Thank you for taking the time to review our paper and for offering your support. We value your comments and look forward to further improving our research.
Reviewer 2 Report
Comments and Suggestions for AuthorsMost concerns have been addressed. The sentences that summarize the paper organization can be a single paragraph. Why not use “log_10” rather than “lg”?
Author Response
Thank you for your suggestion regarding the summary of the paper’s organization. We have combined these sentences into a single paragraph, and replaced "lg" with "log₁₀" for greater rigor in our notation
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors have answered all my questions. However, there are some minor issues that the authors must fix.
Minor:
The caption of Figure 4 “(a)Reflection Phase of Unit Cell (b)Phase Difference of Two Cells” should be rewritten as “(a) Reflection phase of the unit cell. (b) The phase difference between two cells.”
The caption of Figure 5 “Top View of Proposed Chessboard Metasurface: (a) Illustration (b) Fabrication” should be rewritten as “Figure 5. Top View of Proposed Chessboard Metasurface: (a) Design Layout (b) Physical Layout”
The caption of Figure 6 “Surface current distribution of upper layer and ground layer at 5.77, 10.94, 16.7 GHz. (a)-(c) upper layed. (d)-(f) ground layer” should be rewritten as “Figure 6. Surface current distribution of upper and ground layers at 5.77, 10.94, and 16.7 GHz. (a)-(c) upper layer. (d)-(f) ground layer”
The caption of Figure 7 “(a)Block diagram of measurement (b)Measurement Enviroment” should be rewritten as “(a) Measurement system schematic (b) Measuring system equipment.”
The caption of Figure 8: “Monostatic Results of Simulate and Measurement.” should be rewritten as “Simulated and Measured Monostatic RCS.”
Comments on the Quality of English LanguageThe English language needs some improvements.
Author Response
Thank you for your feedback regarding the figure captions. We have updated them as suggested. We greatly appreciate your attention to detail
