A Novel Approach to Reach Impedance Matching in Wireless Power Transfer Systems

Round  1

Reviewer 1 Report

The paper is clear and pretty well written. The topic is very interesting.
On the other hand, some parts are too much descriptive and very few rigorous.
In the following, my comments to address before acceptance:

_ Section "1. Introduction"

The introduction is really clear and all the objectives well stated.
On the other hand some recent technology developments are missing such as:

_ metamaterials [From metamaterials to metadevices, Nature Materials, 11,917–924, 2012]
_ nanoparticles [Metamaterial resonator arrays for organic and inorganic compound sensing, Photonics, Devices, and Systems V 8306, 83060I, 2011]
_ near-zero-index materials [Near-zero refractive index photonics, Nature Photonics, 11, 149–158, 2017]
_ plasmons [Spectral Green's function for SPR meta-structures, Materials Science Forum 792, 2014]
_ graphene [Broadband, electrically tunable third-harmonic generation in graphene, Nature Nanotechnology 13, 583–588, 2018]

It would be beneficial if authors can expand and explain such techniques and make a comparison among theirs and the above suggested works: pro/cons should be highlighted.

_ Section "2. Circuit Theory Analyzing"

The related method is very well detailed. On the other hand, the method proposed is similar to the approach used in [Metasurfaces for Advanced Sensing and Diagnostics, Sensors 2019, 19(2), 355, 2019]. Therefore:

1.1) Explain in details what are the advantages/disadvantages and similarities/differences of your method compared to the above-mentioned.

1.2) A comparison in terms of transmission coefficient (Fig.10) obtained from the analytical model above mentioned and your model, it would be beneficial for the reader and  a good proof-of-concept to confirm the reliability of your approach.

_ Section "3. Calculating couple coils parameters"

1) A deeper study of the unit-cell (Fig.4) is needed.
1.1) Authors should write some lines in this paragraph to explain why they chose to use the proposed structure
1.2) Explore the capability of the shape and compare yours with the ones contained in the above-mentioned work.
What are the advantages/disadvantages?

_ Section "4. Experimental results"

1) The detail of measurements is not properly introduced. How the results in Fig.10 have been measured?

2) Authors should refer to the following additional phenomena such as: electric currents, surface waves and magnetic currents.
How such phenomena affect the structure functionality and in particular its dielectric properties?

_ Section "4. Discussion"

1) The paper lack in further application examples. Besides the glucose application. Take into consideration the following:medical diagnostics, telemedicine, refractive index measurements, nano-therapy and antennas.
I would suggest to consider such applications and explaining how you can use your device for them.
Please highlight what's new in yours.

_ Section "5. Conclusions"

1) No limitations of the proposed method have been highlighted.

2) No future improvements/works have been discussed.

Author Response

Dear Reviewer,

    This letter of response accompanies the revision of the manuscript ID. applsci-443932: “A Novel Approach to Reach Impedance Matching in Wireless Power Transfer System,” being considered for publication in Applied Sciences. We are thankful for the valuable and constructive comments from the reviewers. In order to further improve the quality of our manuscript prior to publication, we have carefully addressed the comments and included the details in this letter. All the changes are highlighted in the attached manuscript.

Best regards,

Xiong Tao (first author)

Minghai Liu (corresponding author)

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript claims a new method for increasing the efficiency of wireless power transfer (WPT) systems. However, it suffers from some flaws.

The theoretical frameworks presented in section 2 and 3 are rudimentary and do not seem right.

A definition of S-parameters should be added and steps to derive the s-parameters should be provide.

Reference list should be expanded and the following papers

W. Chen, H. Li and W. Lu, "Decoupling design of multi-coil wireless power transfer system with metal insulator," 2017 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW), Chongqing, 2017, pp. 30-33.
doi: 10.1109/WoW.2017.7959360

T. Arakawa et al., "Optimizing Wireless Power Transfer From Multiple Transmit Coils," in IEEE Access, vol. 6, pp. 23828-23838, 2018.
doi: 10.1109/ACCESS.2018.2825290

Author Response

Dear Reviewer,

    This letter of response accompanies the revision of the manuscript ID. applsci-443932: “A Novel Approach to Reach Impedance Matching in Wireless Power Transfer System,” being considered for publication in Applied Sciences. We are thankful for the valuable and constructive comments from the reviewers. In order to further improve the quality of our manuscript prior to publication, we have carefully addressed the comments and included the details in this letter. All the changes are highlighted in the attached manuscript.

Best regards,

Xiong Tao (first author)

Minghai Liu (corresponding author)

Author Response File: Author Response.docx

Round  2

Reviewer 2 Report

The author's did not provide the requested definitions and derivations. From my point of view, the paper is incomplete and needs imrovement.

Author Response

Dear Reviewer,
Thanks for your hard work on reviewing this paper.
For the specific reply to your suggestions, please refer to the file "Respond reviewer 2-2- MDPI.docx".

Best regards,
Xiong Tao (first author)
Minghai Liu (corresponding author)

Author Response File: Author Response.docx