Low Sidelobe Series-Fed Patch Planar Array with AMC Structure to Suppress Parasitic Radiation
Round 1
Reviewer 1 Report
The authors propose a low SLL planar antenna array based on linear series-fed patch sub-arrays. The paper is well-written and there are both simulated and measured results. The performance of the array in terms of SLL, gain and impedance matching is satisfactory.
The only change that must be made in this paper to be suitable for publication is in the introduction and conclusions section. In both sections it should be made crystal-clear where the novelty on this paper is. Is this a completely new design? Does it improve upon a certain geometry proposed in a certain paper? Please clarify this in both sections.
Author Response
Response Reviewer: 1：
Comments and Suggestions for Authors：
The authors propose a low SLL planar antenna array based on linear series-fed patch sub-arrays. The paper is well-written and there are both simulated and measured results. The performance of the array in terms of SLL, gain and impedance matching is satisfactory.
The only change that must be made in this paper to be suitable for publication is in the introduction and conclusions section. In both sections it should be made crystal-clear where the novelty on this paper is. Is this a completely new design? Does it improve upon a certain geometry proposed in a certain paper? Please clarify this in both sections.
Response: Thanks for the comment. We rewrote the introduction and conclusion sections. In these two sections, the main contributions of this work are illustrated. The revised contents are marked in yellow.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Author
This manuscript describes a design of low side lobe series-fed antenna array for automotive radar application. It shows the antenna array design and proposes using a type of artificial magnetic conductor to suppress the parasitic radiation from the signal feeding line. Regarding to the content, I do have the following comments:
1. The manuscript should be better organized to highlight its major contribution. The techniques mentioned in this work, series fed antenna array, artificial magnetic conductor, etc., are all well developed. To my understanding, the key point or maybe the most innovative point is parasitic radiation suppression by AMC. It would be better if the author could concentrate on this part, including comprehensive analysis of the theory of proposed AMC structure, its equivalent circuit, and design paradigm. The rest of the parts, such as low side lobe series fed antenna array, optimization with HFSS and matlab, are pretty mature methods. The author may want to emphasize what is new here.
2. In the introduction, the author seems to made some questionable statement. Page 2. Line 52, the author believe the multilayer PCB technique used in [16] is high cost, but in fact, it is a cost effective way of integrating the whole radar system and massive production cost can be very low. Page 2, line 65, the author says [22] suffers from parasitic radiation from its signal distribution network. However, the original article believes the undesired radiation pattern is mainly due to fabrication error. In fact, in this manuscript, the author should also consider the fabrication precision issue and ensure the parasitic radiation claim is solid.
3. This work compares metallic shielding box with the proposed AMC. But proper shielding box typical can fully eliminate the “unwanted radiation”. The author should ensure the metallic shielding is properly designed.
4. Fig. 6 should include field plot with and without the bandstop structure.
5. Overall, the language is verbose. For example, there are too much “however” in the introduction. The author may want to improve the writing and make sure the content is precise and concise.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Authors in this work present the process of designing a low sidelobe series-fed parch planar array for automobile radar system. The planar array consists of six identical linear series fed patch subarrays, a series fed grounded coplanar waveguide power divider and an inverted microstrip gap waveguide to stop the parasitic radiation. The idea of the work, already partially published by the authors, is interesting to be seen as the whole process of such an antenna system design starting from the patch sub-array, adding the power divider, and lastly solving the parasitic radiation problem.
I have two basic problems with it is the way it is presented in the paper. Authors seem to divide unevenly their focus on random parts on the optimization of the subarray and the parasitic radiation problem. My basic comment to them is start from the top, first stating their goals and then provide details for their every step. This is done ok for the subarray (with the exception of my comments), but for example the whole section for the power divider is missing. This further highlight that the inverted microstrip gap waveguide part is basically an iteration of [27]. Overall, since the work in total is a total of many already published techniques and ideas, I would expect the paper to be presented in a step-by-step manner and be clear in every detail in order to add to the methodological aspect of it.
Secondly, there is the issue of using text from uncited sources. Rephrase the text radically and cite the source.
For example lines 33-37 are from (uncited) :
J. R. Pimentel, "Data heterogeneity, characterization, and integration in the context of autonomous vehicles," IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017, pp. 4571-4576, doi: 10.1109/IECON.2017.8216787.
There is a 28% similarity in turnitin. This must be radically reduced.
More comments:
-Line 14 correct «diver» to «divider»
-Line 92-93 “The center‐to‐center spacing between the adjacent patches is about one λg”. At this point the approximation “about one λg” should be clarified. Overall, this sentence is problematic since it tries to define the structure without stating that the structure will be optimized right after in the text. I advise to rewrite it carefully for clarity. Table 1 should be included at this point as its results are relevant to this section. Also, I advise to use consistently the term “sub-array” everywhere in the text for the linear series‐fed patch array and the term “array” for the whole planar array for clarity.
-Authors should provide the value of λg for 79GHz.
-Line 93-94 “To achieve low SLL, the array are set up the unequal element spacing and tapered width” sentence should be clarified.
-Provide specifics for the optimization method. E.g. population size? Any other settings?
- Line 116 w1-w2 should be w1-w5 if I understand correctly what the authors did.
-Line 102 flowchart should be one word.
- Line 120 the objective function is not stated elsewhere so I do not understand the “can be rewritten expression”. Moreover, and more importantly authors should elaborate why they selected this specific fitness function.
- No details are provided for the power divider. Why the selected power ratios? How was it developed? Some kind of optimization took place?
-Line 166 it seems odd authors used CST studio just for the dispersion curve while working in HFSS for the rest of the work.
-Line 182,216 correct to far-field
-Line 205 rephrase “realizes a good performance in interesting frequency band” along the lines of “achieves good performance in the frequency band of interest”.
-Line 213 delete a at “…., a small manufacturing…”
-Line 253 “The bed of nails does not exist the troubling cavity resonance modes appearing in package of microstrip circuits with common metal box.” Rephrase for clarity.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
The revised version shows great improvement. One minor problem is :
page 8, line 227, it should be the "wave" not the "field" cannot propagate in the gap.
Reviewer 3 Report
I would like to thank the authors for addressing my comments.
