Grounded L-Shaped Corner-Embraced Patch Array Polarization Conversion Metasurface Compatible with Multiband and Broadband Characteristics

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this article, the authors propose a grounded L-shaped corner-embraced patch array metasurface capable of achieving broadband linear-to-linear polarization conversion with high efficiency. The design integrates via grounding and multi-resonant patch coupling to extend the operational bandwidth, and both simulation and experimental results are presented for verification. In my opinion, this work is relevant to the microwave and metasurface communities and has potential applications in broadband polarization conversion and communication systems. However, before the paper can be recommended for publication in Micromachines, several important issues need to be carefully addressed:

1. The language used in several parts of the manuscript appears rather colloquial and informal for a scientific paper. The authors are advised to revise the manuscript carefully to improve the academic tone.
2. The parameter “t” in Table 1 was not clearly represented in Figure 1(b).
3. The boundary conditions applied in the simulations should be described in detail within the main text. In addition, the representation of the boundary conditions in Figure 2(a) seems potentially misleading and should be revised to reflect the actual simulation setup clearly.
4. It is recommended to mark or annotate the frequencies corresponding to the maximum values of the cross-polarized reflection coefficient in Figure 2(c).
5. The authors mention that the phase difference between Rxx and Rxy is approximately ±90°. Please clarify whether this phase relationship results from a dispersion-free polarization conversion mechanism, and if not, explain the underlying physical cause.
6. In the fifth paragraph of Section 2, the description of Figure 3 is unclear. The coordinate axes are missing in the figure, which reduces readability. Additionally, the angle between the surface current direction and the x-axis should be indicated as ±45° to accurately reflect the polarization rotation.
7. Since the authors discuss the formation of electric dipoles when analyzing the polarization conversion mechanism, it would be beneficial to include the corresponding electromagnetic field distributions (e.g., |E| and |H| maps) at the relevant resonance frequencies to support the theoretical explanation.
8. The authors describe the metasurface unit as being equivalent to four coupled LC resonators. Please clarify whether the resonant frequencies of these LC circuits correspond directly to the four frequency points showing the maximum cross-polarized reflection coefficients. In addition, the description of the equivalent circuit is currently qualitative. The authors are encouraged to include an explicit circuit diagram and parameter fitting results (L, C, coupling coefficients) to interpret the multi-resonant behavior better.
9. When calculating the polarization conversion ratio (PCR), should the absorption of the incident wave by the metasurface be considered? If absorption is neglected, please justify this assumption and estimate its potential impact on the accuracy of the PCR results.
10. Some seminal works are suggested to be added and discussed, e.g., doi.org/10.1038/srep08434, Science China Physics, Mechanics & Astronomy, 2015, 58(9): 594201, Science Advances, 2015, 1(9): e1500396, DOI: 10.29026/oes.2024.230052.
11. The text of the manuscript lacks a description of the contents of Table 2., Moreover, Table 2 includes only limited metrics. Please expand it to include relative bandwidth, average PCR, and angular stability, and cite more recent references (2023–2025) for fair comparison.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a metasurface for linear-to-linear polarization conversion with a conversion ratio exceeding 90% over multiple bands. The design is of interest; however, I cannot recommend it for publication before the following concerns are well addressed:
1. The authors state that adding rectangular patches enhances polarization conversion efficiency while reducing the unit-cell size. Please explain the underlying mechanism more clearly.
2. The phase difference between the incident and reflected waves shown in Fig. 2(c) is unnecessary and may be removed.
3. A clear deviation exists between simulation and measurement in Fig. 8(c). The explanation of fabrication tolerance is insufficient. Please analyze which parameters most likely cause this discrepancy.
4. The design performs linear polarization rotation. It should not be referred to as “linear-to-linear polarization conversion,” which is ambiguous. Actually, it is a linear polarization rotator.
5. In Table 2, reference [22] should be removed as its function differs from the proposed work. Instead, the authors are encouraged to discuss the beamforming metasurfaces (DOI: 10.1002/adom.201900791) and systematic design methods for polarization-controlling metasurfaces (DOI: 10.1109/IRMMW-THz50926.2021.9566980).
6. Please thoroughly proofread the manuscript. For example, the sentence beginning with “However, for stable operation…” appears twice and should be corrected.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In the paper 'Grounded L-shaped Corner Embraced Patch Array Polarization conversion Metasurface Compatible with Multi-band and Broadband Characteristics' the authors present their recent results about a linear-to-linear polarization conversion metasurface composed of a grounded array of L-shaped corner-embraced patches. The paper is overall well organized and the methodologies are well explained. I have few minor comments that may be consider before publication:

1. I think the authors should better explain why they study only 3 different unit cells (as reported in Fig.5);
2. It would be helpful if the authors could elaborate on the changes observed in the PCR spectrum for φ values greater than 30°, as this region appears not deeply discussed in the manuscript.
3. The authors are encouraged to identify at least one specific application where the proposed device could be effectively utilized.
4. The authors should provide more detail regarding the experimental setup and parameters.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I'm glad that the revised version has solved the reviewers' concerns and the manuscript quality has been greatly improved. I suggest it can be accepted now.