Exploiting Surface Plasmon with Dielectric Coating in Copper Wires Waveguide for the Propagation of Terahertz Waves
, Fauziahanim Che Seman 1, Ahmed Jamal Abdullah Al-Gburi 2,*, Hamza Ahmad 3, Yee See Khee 1, Nurul Syafeeqa Binti Ishak 1, Thamer A. H. Alghamdi 4,5,* and Moath Alathbah 6
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper discusses the effect of dielectric coating in copper wires for plasmonic wave propagation near the THz regime. The biggest concern for this work is its novelty since the analysis is very trivial. Specifically,
1) The authors analyzed a specific setup (wire radius, type of dielectrics, etc.), and the conclusions are trivial. In particular, it has been concluded that the confinement is better with a dielectric coating leading to smaller attenuation. Nevertheless, this is a totally expected behavior, while it can be, also, evaluated theoretically by exploiting the symmetry.
2) The analysis is conducted via full-wave simulations to extract the attenuation coefficient. However, the calculation of the attenuation coefficient is not discussed at all. Moreover, a modal solver can be, optimally, utilized for this type of analysis, where the imaginary part of the effective index leads to the attenuation coefficient straightforwardly.
Finally, some additional remarks:
3) There are some acronyms that require explanation, e.g. FCC and DSL in the Introduction.
4) In line 139, a loss tangent is linked with parameter d. Is this correct?
5) In Figures 3 and 7, there is an axis on the right which is not linked to any value.
6) The results in Table 1 are not matching with the discussion in the manuscript. Moreover, it is not rational that the transmission coefficient is increased by 84% (referring to the text), while the attenuation is reduced by the same amount. Maybe, it is better to show the values of these parameters. The same stands for the 4 wires setup.
Comments on the Quality of English LanguageThe language manipulation is good.
Author Response
Dear Reviewer,
Please see the attached file, which contains the answers to your valuable comments. Thanks.
Best regards,
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authorscoatings-2609006
Review Report
The MS entitled “Exploiting Surface Plasmon with Dielectric Coating in Copper Wires Waveguide for the Propagation of Terahertz Waves” by Arslan Ahmed Sohoo and coworkers presents a numerical study using CST Microwave Studio of the electromagnetic (EM) propagation in two and four metallic copper wires with and without dielectric coatings and placed at different relative gap distances.
The MS is of interest and I recommend it for publication.
Nevertheless, authors should address the following issues before publication:
1 – Lines 52-53 (page #2). It is written “ … including transverse electric (TE) and transverse magnetic (TE) modes [5].” The second TE must be replaced by TM.
2 – Please, describe in detail the model used in simulations and add a new table containing the values of the parameters of all the materials used in the work.
3 – Authors state on page #2 (lines 88-90) that using SWWGs makes it difficult to couple the radiation to PCAs while TWWGs sources can be excited by a dipole source. Please, provide in the MS examples of available THz dipole sources.
Author Response
Dear Reviewer,
Please see the attached file, which contains the answers to your valuable comments. Thanks.
Best regards,
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsA very well presented paper.
Some points:
Sufficient detail regarding the simulation parameters needs to be provided for a reader to be able to replicate the simulation.
Thus, time step size, voxel size and total simulation time need to be provided.
Direction and polarisation of the incident radiation would also be desirable.
References relied upon for the properties of the copper wire and PTFE need to cited.
The length of the wire simulated at 20 mm is rather short, some estimation of the loses per unit length would be useful.
Author Response
Dear Reviewer,
Please see the attached file, which contains the answers to your valuable comments. Thanks.
Best regards,
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsAs the authors mentioned, high-data-rate telecommunication requires a high-frequency range, but unfortunately, it has a lot of loss as frequency increases and skin depth exponentially decays from the surface of materials. Therefore lossless transmission requires new materials and new methods.
The work is done well and the English also is nice. However, I have some comments as follows.
1. What is "FCC" in the Introduction part (line 42) - please describe it first. Is it "Federal Communications Commission"?
2. Similarly first introduce all abbreviations then use them through MS. For example DSL (Digital Subscriber Line) at the beginning of the 2nd page (line 51). Each sentence should be easily readable for the general reader.
3. Line 53: Transvers magnteic (TE) should be (TM)
4. The ref. [12] at Line 87 does not exist in the Ref. list. - please check and correct it.
5. Please give the Ref. for the CST Studio Suite - Line 124.
6. Fig 1.
- Fig 1d is squeezed - please make it circular.
- what is the dashed circular line for Fig. 1 b and d? Is it a simulation boundary?
7. Line 139 - what is the "d" before the "... loss tangent ..."?
8. Why chapters 3 and 4 are named as same? It is better to remove the title of Chapter 4 and continue with the "3.1. .... "
9. Also before going to "3.1." can you describe background properties for your simulations, i.e. how big is the background, and what are the boundary conditions: is it effect of field confinement due to the BC resolved?
10. Fig. 2. I think, it is better to use the same color for the S11 and S21 of the same d, but just use dashed lines for the S21. It will give more quick distinguishing of which is which.
- use the same color for different d for the next figures, too.
11. Fig 2 and 3.: What is the meaning of periodic picks at every 15 GHz (~2cm)???
12. Fig. 4.: Please use the better E-field profile by making it a "field at plane" - CST has this function. Also, put these two figures side by side in order to save space. - For what case is this figure: d=???
13. The sentence in Lines 233-236 is not understandable well. Because Fig. 2 and 3 are showing that S21 does not depend on Frequency, and as mentioned above, you did not explain the periodic behavior of the S11-parameter. As we know, different frequencies have different skin depths, and hence propagation also depends on frequency. But your explanation from Fig. 2 is not correct, because 220 GHz and 320 GHz (and 12 more points) cases behave similarly.
14. Similar comments for the 4-wire case.
Author Response
Dear Reviewer,
Please see the attached file, which contains the answers to your valuable comments. Thanks.
Best regards,
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe novelty of the paper is still in question since the analysis is trivial. As mentioned in the comments of the previous round, the modal solver is more appropriate for such an analysis; thus, the numerical results are not optimal from this point of view. There are various commercial solvers for modal analysis, while the following paper discusses this methodology:
Selleri, S., Vincetti, L., Cucinotta, A., & Zoboli, M. (2001). Complex FEM modal solver of optical waveguides with PML boundary conditions. Optical and Quantum Electronics, 33, 359-371.
Additionally, the attenuation constant methodology has many serious flaws. First of all, the dielectric losses contain the omega_c parameter, which is not presented (possibly the cut-off frequency) and not calculated. Moreover, the equation for conductor losses does not seem to be correct since both conductor and dielectric losses are considered in P_loss. As a consequence, the results are not reliable.
In summary, this paper is not recommended for publishing due to its limited novelty and the serious problems in methodology (both the selected type of solver and the attenuation constant calculation)
Comments on the Quality of English LanguageThe language manipulation is ok
Author Response
Dear Reviewer,
Please see the attached file, which contains the answers to your valuable comments. Thanks.
Best regards,
Author Response File: Author Response.pdf
