MTM-Inspired Graphene-Based THz MIMO Antenna Configurations Using Characteristic Mode Analysis for 6G/IoT Applications

Round 1

Reviewer 1 Report

Title is too long, It needs to be less than 15 words.

Authors need to be specific about 5G or 6G. They can not claim to accommodate both in single application. Anyone of these can be used at a time.

They can claim 6G application, but there is still no specific parameters are available for it.

In the same way they can claim 5G, but they need to make sure their antenna is satisfying the conditions set for 5G parameters.

Authors claim it as a MIMO antenna, however only two element patch array is discussed in the design and simulations. How it can be considered as a MIMO?

In Table 2, only one reference [42] cited from a credible source. All the references cited in the comparison Table should be latest and from the high impact journals.

The main challenge nowadays with Grahene is its fabrication and measurement. No information about it has been given in the manuscript.

Providing improved simulated results of Graphene based antenna at THz frequencies could be a good contribution. But it should be followed by how the authors plan to create such a small design physically. And how the real time measurements will be done.

Author Response

Dear Reviewer 

Thank you very much for these valuable comments that's will enrich our manuscript 

Author Response File: Author Response.pdf

Reviewer 2 Report

In this study, a graphene plasmonic two-port MIMO antenna based on a rectangular patch element is proposed for THz applications. Initially, the physical behavior of three 2x1 MIMO configurations was analyzed by characteristic mode theory (CMA) and current distributions analysis. In the ultimate 2x1 MIMO antenna design, a complementary dumbbell-shaped metamaterial structure is etched into the ground plane to block the coupling mode without any effect on the dominant mode. In the study, cross-comparative results obtained with commercial software are included. There are problems with the current organization and writing of the paper. The study needs to be reconsidered to increase its intelligibility and follow-up. It is not easy to follow the figures while reading the texts. Sometimes the figures are located a few pages away from the page where the text is located.

In the study, it was stated that the characteristic mode analysis was performed with the CST software. So, are the corresponding mathematical expressions (equations 2 and 3) necessary?

In section 2, 2.1 graphene conductivity and dispersion relations are given. What contribution does this section make to the study? Section 2 includes the definitions that are well-known. Also, while a tunability is mentioned here, it is not considered in the final design. In the conclusion section, 3.5 THz was taken into account.

In the ADS equivalent circuit model in Figure 4, each block must be associated with the graphene plasmonic patch antenna design, just like in Figure 20. Also, chemical potential / gate potential (Vg) can be included in the equivalent circuit model.

In Figure 8, which includes three different 2x1 MIMO antenna configurations, what is the distance between the plasmonic patch antenna elements? What does this distance correspond to electrically?

From the S-parameter results obtained for the three different 2x1 MIMO configurations examined; it is seen that the C-configuration has a lower coupling effect. Although these results show that the C-configuration is more suitable for 2x1 MIMO design, why were the CMA and current distribution analyzes in Chapter 3 needed? The results (Fig. 9) already show that the C-configuration is more suitable.

Dumbbell shaped MTM unit cell geometry should be given together with its dimensions. In addition, the effect of the relevant dimensions on the scattering performance should be examined and the critical design parameters should be defined.

Why did you choose a dumbbell shaped MTM design? In the literature, there are different geometries (such as SRR, CSRR) or different techniques to reduce coupling.

In Figure-14, the real and imaginary parts of the frequency-dependent structural parameters of the dumbbell shaped MTM structure should be given separately and re-examined.

Figure-15 should be visualized more clearly in 3D (a perspective view). (i.e., it must be shown that the dumbbell shaped MTM structure is in the ground plane.)

The paper should be carefully reviewed for grammatical, and typos. For example:

·         Page 14, line 475, "figure 18" should be written as "Figure 18", capitalized when citing figures in the text.

·         Page 15, line 517, “Figure21” should be written as “Figure 21”, There should be a space between the “figure” text and the “figure number”.

·         In Figure 22 the text "conclusion" is stuck in the image

The study is entirely based on simulation results (CST). In the paper, cross-comparison of these CST-based results is also performed with other software such as HFSS or ADS. By which software were the results in Figure 22 obtained? These results should be validated with another software (compare HFSS if obtained with CST).

If possible, it is useful to include fabrication results.

Finally, the recent literature should be thoroughly searched, and references should be updated by including it in the literature review section. I'm listing a few similar studies here.

·         Song, R.; Chen, X.; Jiang, S.; Hu, Z.; Liu, T.; Calatayud, D.G.; Mao, B.; He, D. A Graphene-Assembled Film Based MIMO Antenna Array with High Isolation for 5G Wireless Communication. Appl. Sci. 2021, 11, 2382. https://doi.org/10.3390/app11052382

·         Bekasiewicz, A., Koziel, S., Plotka, P., & Zwolski, K. (2021). EM-driven multi-objective optimization of a generic monopole antenna by means of a nested trust-region algorithm. Applied Sciences, 11(9), 3958.

·         Alharbi, A. G., & Sorathiya, V. (2022). Ultra-Wideband Graphene-Based Micro-Sized Circular Patch-Shaped Yagi-like MIMO Antenna for Terahertz Wireless Communication. Electronics, 11(9), 1305.

·         Das, P., Singh, A. K., & Mandal, K. (2022). Metamaterial loaded highly isolated tunable polarisation diversity MIMO antennas for THz applications. Optical and Quantum Electronics, 54(4), 1-19.

 

Author Response

Dear Reviewer,

Thank you very much for these good comments 

best regards 

Author Response File: Author Response.pdf

Reviewer 3 Report

Prototype realization would have been a huge plus point.

 

Author Response

Dear Reviewer,

Thank you very much for this revision it is very good.

best regards

sherif

Author Response File: Author Response.docx

Reviewer 4 Report

The presented study is of the interest of the readers and can be considered to publish but after following minor revisions

1. The title: "MTM-Inspired Graphene-Based THz MIMO Antenna with Reduced Coupling and Characteristic Mode Analysis for 5G/6G and IoT Applications" looks to me a sentence. Please modify to present the contribution of the study more clearly.

2. The abstract is generally in good shape and represent compactly the intending meaning. However, at the start one or two sentences are given on the importance or significance of the field.

3. Introduction is generally presented well but it is in much better shape if segmented into subsections, like. 1. Introduction, 1,1 State of the art on Related literature, 1.2 Problem Statement with justification 1.3 Innovative contributions, 1.4 Organization.

4. Literature review section of the introduction is week and suggested to provided a table on the existing relevant studies with necessary explanations.

5. Methodology is presented well but the mathematical expression presented are not given with sufficient elaborative details.

6. Results section and analysis is provided in appropriate manner and suggested to add more interpretations of each graphical and numerical illustrations.

7. Limitations and scope of the work in future should be added in the conclusion section.

 

Author Response

Dear Reviewer, 

I need to thank you very much for this valuable comment. it will give a high value to our manuscript

Best regards

sherif

Author Response File: Author Response.pdf

Reviewer 5 Report

In the introduction text, there is no interesting explanation of Graphene's previous and different works that is attractive to the reader. Please add the following articles:

1. Razaq, A .; Bibi, F .; Zheng, X .; Papadakis, R .; Jafri, S.H.M .; Li, H. Review on Graphene-, Graphene Oxide-, Reduced Graphene Oxide-Based Flexible Composites: From Fabrication to Applications. Materials 2022, 15, 1012. 

2. A.G. Olabi, Mohammad Ali Abdelkareem, Tabbi Wilberforce, Enas Taha Sayed, Application of graphene in energy storage device - A review Renewable and Sustainable Energy Reviews, Volume 135,2021,110026, 

3.. H. Zhang, D. Yang, A. Lau, T. Ma, H. Lin, B. Jia, Hybridized graphene for supercapacitors: beyond the limitation of pure graphene, Small 17 (12) (2021) 2007311.

4. Beiranvand, B .; Sobolev, A.S. A Proposal for a Multi-Functional Tunable Dual-Band Plasmonic Absorber Consisting of a Periodic Array of Elliptical Grooves. J. Opt. 2020, 22, 105005.

5. Beiranvand, B.; Sobolev, A.S.; Sheikhaleh, A. A Proposal for a Dual-Band Tunable Plasmonic Absorber Using Concentric-Rings Resonators and Mono-Layer Graphene. Optik 2020, 223, 165587.

6. Purwidyantri, A.; Domingues, T.; Borme, J.; Guerreiro, J.R.; Ipatov, A.; Abreu, C.M.; Martins, M.; Alpuim, P.; Prado, M. Influence of the Electrolyte Salt Concentration on DNA Detection with Graphene Transistors. Biosensors 2021, 11, 24.

7. Chenkang Rui, Cheng Shao, Jiaxu Liu, Aqing Chen, Kaigui Zhu, Qingyi Shao, Transport properties of B/P doped graphene nanoribbon field-effect transistor, Materials Science in Semiconductor Processing, Volume 130, 2021,105826

 

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From line 69 to the end of the introduction, it should be separated from the introduction and added to the next section.

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You did not mention the antenna impedance matching and the graphene effect at all.

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What is the effect of antenna dimensions with and without graphene on S parameters?

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Author Response

Dear Reviewer,

I need to thank you very much for your time and your valuable comments that will modify our manuscript to be better

Best regards

sherif

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

When the previous and revised versions of the paper are evaluated together, it is seen that the authors make the corrections requested by the referees and show the necessary sensitivity in the writing of the paper and improving the figures in line with the comments. In the revised version of the paper, almost all the comments have been considered and addressed by the authors.

The response to reviewers file is well-prepared. The changes made by the authors in line with the opinions/suggestions/evaluations of the referees can be tracked. The existing organization and spelling problems in the previous version of the article have been fixed. In the revised version, the clarity and follow-up of the study have been increased. In addition, the article has been carefully reviewed for grammatical and typos.

This revision is sufficient and it is possible to evaluate the paper for publication in its current version.

Reviewer 4 Report

Revised manuscript improve and recommended for publication

Reviewer 5 Report

All changes are added. I accept this manuscript as paper.