A Design for a Wide-Band Antenna Pair Applied for Mobile Terminals at the Sub-6 GHz Band
Round 1
Reviewer 1 Report
The authors have presented “A Design of Ultra-wide Band Planar Antenna Applied for Mobile MIMO System at Sub-6 GHz Band”.I have some concerns about the article
The authors may change the title without the “Ultra-wide Band” term. Because, usually it is used for 3.1 GHz to 10.6 GHz after the FCC unlicensed spectrum allocation in 2002, even though the definition given earlier as more than 500 MHz may be considered.
In my point of view, the authors could consider a multiband antenna instead of an Ultra-wide Band.
Why the simulation results are not matching in Figure 10 with any of the other figures such as Figure 7 and Figure 5?
The authors have not provided the measured radiation behavior of the proposed antenna
The standard operating frequency is chosen -10dB for impedance bandwidth. The authors may explain on which standard the authors have chosen an operating frequency band less than -6dB. Also, the isolation is usually considered less than -15 dB. Why it is chosen less than -13 dB?
There is no continuity from the second paragraph to the third paragraph in the introduction
The authors could provide the advantage of the proposed antenna with the existing antenna by comparing it with recent literature
The loss tangent of 0.0009 of FR-4 is not available commercially. How the authors obtained this material
As it looks like the vertical and horizontal substrates are looking different in the fabricated antenna. What is the supporting substrate the authors have used? And what is the effect of this on the performance
The transmission coefficient almost approaching -10dB in the operating band shown in Figure 10, but the authors have claimed it is -13 dB. How can the authors justify this?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors demonstrated the Design of Ultra-wide Band Planar Antenna Applied for Mobile MIMO System at Sub-6 GHz Band. The concept is exciting, and the simulation results are reasonably good, showing strong reconfigurability. I have the following suggestions before accepting it for publication.
Introduction
A total of 20 references are not enough; the authors must explain some metamaterial structures for sub-6 GHz, such as FSS [1] and EBG [2].
Please see these articles, which may add value to the introduction.
[1] A Wideband High-Gain Microstrip Array Antenna Integrated with Frequency-Selective Surface for Sub-6 GHz 5G Applications. Micromachines 2022, 13, 1215. https://doi.org/10.3390/mi13081215.
[2]Mutual Coupling Effect and Reduction Method with Modified Electromagnetic Band Gap in UWB MIMO Antenna. Appl. Sci. 2022, 12, 12358. https://doi.org/10.3390/app122312358.
4. Performance of Eight-port MIMO
The authors are required to measure the envelope correlation coefficient (ECC). Simulated results are not enough?
-At the end of the paper, I want to see a comparison table with the proposed state of artworks of literature. The comparison information in the table should be as follows:
1- Frequency band.
2- Bandwidth (%).
3- Sizes.
4- Gain (dBi).
5- ECC.
6. Isolation.
7. Radiation efficiency.
8. Number of elements.
That's all for me at this moment! The authors are required to revise the comments above carefully. Thanks
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Authors have presented a design of ultra-wide band planar antenna applied for mobile MIMO system at Sub-6 GHz band. The work is interesting, well presented and is supported with simulated and experimental results. Following comment will be helpful to further improve the manuscript.
Add a comment in abstract to highlight that MIMO performance has been investigated through ECC. This could be added after sentence “In addition, the performance of the antenna system under single handheld conditions is also discussed.” “ECC comment………..”
If possible, adding more MIMO performance parameters will enhance the significance of presented work. i.e., Channel Capacity Loss (CCL), Diversity Gain (DG), Mean Effective Gain (MEG). For details see following articles.
https://www.mdpi.com/2079-9292/10/4/405
https://www.mdpi.com/2079-9292/11/15/2450
https://www.mdpi.com/2079-9292/11/6/962
https://www.mdpi.com/1424-8220/21/24/8350
Scale values in Figures 4, 8 and 11 are too small and font size may be increased for better readability.
To demonstrate the significance of presented work, add a comparison table to compare presented work against the exiting literature.
Overall, the work is interesting and useful.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors responded to my comments
Author Response
Dear Reviewer 1，
Thank you for taking the time to review this manuscript and for your valuable suggestions concerning our manuscript (applsci-2105751).
Thanks again!
Authors
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors have revised the given comments successfully, and I believe the article is ready now to be published in a reputational journal like Applied Sciences. However, there are still typos and spacing errors that need to be carefully checked.
Best regards,
Author Response
Dear Reviewer 2，
Thank you for taking the time to review this manuscript and for your valuable suggestions concerning our manuscript (applsci-2105751).
Based on your suggestions, the manuscript has been revised. The size of the Figure 4 and 8 are increased. And some typos and spacing errors were corrected.
Thanks again!
We would like to thank you for following us resubmit a revised manuscript and we highly appreciate your time and consideration.
Authors
Author Response File: Author Response.pdf
