A W-Band Active Phased Array Miniaturized Scan-SAR with High Resolution on Multi-Rotor UAVs
Round 1
Reviewer 1 Report
After carefully reading the manuscript, I found that similar work has already been published and the objectives of this experiment have been investigated in various studies. The manuscript is well written, although the introduction does not explicitly elaborate novelty of this work. The figures are not presented in way to convince the readers for the achieved results.
Therefore in my opinion this article cannot be published in its current state. My suggestions for the improvement are as follows.
1. The introductory part must be improved, so that a clear picture of the originality can be realized.
2. Figure captions must describe all the essential details including symbols.
3. Recheck all the figures and the units along the axes.
4. The details of electronic components employed for the device must be mentioned.
5. What is the reason for choosing a tetrahedral corner reflector?
6. Why the figure 21 is included?
7. If the mathematical model has been previously published elsewhere by the authors, reduce the number of equations.
8. Include better results to justify the achieved resolution of 4.4cm. I am not convinced with whatever has been tried to prove it.
9. Reduce the number of figures by removing minor results. Include images of several targets near by in the field of view and then explain appropriately so that the readers can be convinced.
Author Response
Thank you for your review. We have answered all the concerns carefully. Our response can be found at the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and suggestions can be found at the attachment.
Comments for author File: Comments.pdf
Author Response
Thank you for your review. We have answered all the concerns carefully. Our response can be found at the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The core idea of this paper seems to be the construction of a drone SAR system capable of wide swath measurement. In Ch.2 ~ Ch.3, the main points of this paper are revealed, and also it looks convincing. However, I want to ask a few questions from a different perspective.
First, wide swath imaging and scanning are different. As far as I understand, the wide swath referred to in this paper is merging three images. However, the image splicing results (Fig. 21) can not be treated as one wide swath image. Therefore, if there is a misunderstanding, you need to solve it or please give me more explanation.
Second, the reason that the necessity of HRWS occurs in spaceborne SAR is deeply related to the height of the platform. The satellite has a problem with deciding PRF because of RASR and AASR. But, in the drone system, we don’t have those problems. So, you should explain the necessity of HRWS in the drone SAR in this respect of view.
Third, you should check your typing errors. For example, there is no ‘e’ in Table1 when you wanted to say Max imaging range, or there is no Figure 11. I would not write all errors because those things are not the main point of revision. Additionally, it may look better if there is a colorbar in Fig .8.
Author Response
Thank you for your review. We have answered all the concerns carefully. Our response can be found at the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
After reading the revised manuscript, I recommend this work for publication. However minor spell check is required along with correction in Fig.4 and Fig.6 labels along the x-axis.
The correction should be as Time (µs) .
Author Response
I have corrected it in Fig.4 and Fig.6. Thank you.
Reviewer 2 Report
All the concerns have been answered. I think researchers in the area would be interested to hear this newest progress of W-band mini-SAR in combination with a phased array. No comments.
Author Response
Thank you for reviewing.
Reviewer 3 Report
The main problem of the previous manuscript was the word 'HRWS'.
If the intended purpose of your research was SCAN SAR for the wide swath, the rest of the articles look reasonable.
Author Response
Thank you for reviewing.
