Compact Size of an Interdigital Band-Pass Filter with Flexible Bandwidth and Low Insertion-Loss Using a Folded Spiral and Stepped Impedance Resonant Structure

Round 1

Reviewer 1 Report

Review of the manuscript electronics-1336201 “Compact size of the UWB interdigital band-pass filter using a folded spiral and stepped impedance resonant structure” by Ki-cheol Yoon and Kwang Gi Kim.

 

This is a promising paper about the study of a proposal of a new compact ultrawide band interdigital band-pass filter, compact size, using a folded spiral and stepped impedance resonant structure, that affords low insertion loss and excellent group delay. This is what can be seen by reading the title and abstract. The reader thinks that they will read the proposal in detail throughout the structure of the article.

Before reviewing the manuscript, I need to ask what kind of work is being proposed. Assuming this is an article-type paper, I have a series of comments.

The manuscript is too heavy to read and understand on a first reading. The mathematical formalism is not well explained and there is some mess regarding equations and images.

The article must have the theme well introduced so that the main idea is well understood and must be contrasted with what already exists in a clear way for the reader. This also applies to the discussion section. In the discussion, Table 2 is not self-explanatory, referring to the bibliography, making it difficult for the reader to immediately understand, which can be resolved by placing the designation instead of the reference.

Figure schemes are very confusing, with low resolution and no explanation in the legends. The graphs of the results do not have an explanation (in the text and in the caption), nor is it explained what was done in a clear and evident way.

The manufacturing process of the proposed filter is not explained. Privacy issues and ethical restrictions cannot be invoked in order not to explain an unprecedented contribution to Science. Even if there are issues of professional secrecy the idea can be explained so that it can be replicated. Publishing an article protects someone from appropriating new ideas. However, you cannot explain something new without an "explanation" of what you are doing.

Still on the applicability of the study, the introduction mentions "The rapidly increasing demand for big data processing fueled by 5G mobile 31 communications and Industry 4.0 has necessitated ultrawide band (UWB : 3.1 GHz to 32 10.6 GHz) bandpass filters (BPFs) for reliable transmission of voice and video data [1, 2]". However, this subject is not further developed or discussed. It would be interesting to improve this part.

Thus, the article can be accepted if it is restructured and the whole process becomes clear. Science must be replicable!

Author Response

Thank you very much for pointing out. We did our best to reflect and correct your comments. There are some flaws in English sentences. Before publishing, we will check the English sentences as a whole. Thank you.

This study is an improved filter of the existing interdigital bandpass filter. The filter features a 2/8-fold reduction in size and low insertion-loss. The biggest advantage is that you can secure up to 80%-180% of the bandwidth through the variable of k-factor (lt change in structure) in the formula. Therefore, we have reflected the above content in the paper.

Please refer to the attached file for detailed answers.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, authors propose a new UWB filter using folded microstrip lines to downsize a filter. The analytical method is presented to design the proposed filter. To validate the filter, simulation and measured results are presented. However, the target frequency band of the proposed filter is not for UWB filter. As authors mentioned in introduction, UWB filters cover the frequency band between 3.1 GHz and 10.6 GHz. Moreover, we can not ensure that the proposed technique in this paper are valid in the UWB band since the folded technique results in parasitic coupling between lines. So, the reviewer thinks that  the paper title and introduction are not appropriate. The reviewer suggests the comments as follows.

[1] Please modify the paper title and introduction considering the target band of the proposed filter.

[2] It would be better if the limitation of the proposed filter were presented.

Author Response

In this paper, authors propose a new UWB filter using folded microstrip lines to downsize a filter. The analytical method is presented to design the proposed filter. To validate the filter, simulation and measured results are presented. However, the target frequency band of the proposed filter is not for UWB filter. As authors mentioned in introduction, UWB filters cover the frequency band between 3.1 GHz and 10.6 GHz. Moreover, we can not ensure that the proposed technique in this paper are valid in the UWB band since the folded technique results in parasitic coupling between lines. So, the reviewer thinks that  the paper title and introduction are not appropriate. The reviewer suggests the comments as follows.

Answer

Thank you very much for pointing out. We did our best to reflect and correct your comments. There are some flaws in English sentences. Before publishing, we will check the English sentences as a whole. Thank you.

The introduction has been completely revised. Thank you very much for the point.

[1] Please modify the paper title and introduction considering the target band of the proposed filter.

Answer

I have edited the title and introduction. thank you.

[2] It would be better if the limitation of the proposed filter were presented.

Answer

Limitations are reflected in the manuscript lines 172-182 (sky), 262-269 (yellow).

Author Response File: Author Response.pdf

Reviewer 3 Report

Is [15]-[22], [15-22]?

Please describe how have results from Fig. 5 been obtained. If analytically it would be very interesting to use a numerical simulator to compare obtained results.

In fig. 7 when talking about simulation results. Are you using a commercial or homemade simulation software? In any case please describe it clearly.

Please describe also if you have used a VNA and its working conditions.

Are there other works to be included in Table 4 working at similar frequencies? What have you selected 800 MHz as operating frequency?

Author Response

Thank you very much for pointing out. We did our best to reflect and correct your comments. There are some flaws in English sentences. Before publishing, we will check the English sentences as a whole. Thank you.

Please refer to the attached file for detailed answers.

 

Is [15]-[22], [15-22]? [15]-[22], [15-22]?

Answer

[15]-[22] is correct. [15]-[22] was used.

Please describe how have results from Fig. 5 been obtained. If analytically it would be very interesting to use a numerical simulator to compare obtained results.

Answer

Rather than comparing the results with other results, it seems more correct to explain the result of changing the bandwidth by adjusting the k value in the formula. So it is detailed in lines 172-182 (sky), 192-197 (sky). Thank you.

In fig. 7 when talking about simulation results. Are you using a commercial or homemade simulation software? In any case please describe it clearly.

Answer

Updated details on lines 151-258 (yellow).

Please describe also if you have used a VNA and its working conditions.

Answer

Is used VNA. Updated details on lines 151-258 (yellow).

Are there other works to be included in Table 4 working at similar frequencies? What have you selected 800 MHz as operating frequency?

Answer

Most of the frequencies are used for LTE, so they are similar frequencies (in each country) and usually include frequency bands. See lines 287-292 (yellow) in Manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Review of the manuscript electronics-1336201 “Compact size of the UWB interdigital band-pass filter using a folded spiral and stepped impedance resonant structure” by Ki-cheol Yoon and Kwang Gi Kim.

The suggestions made in the previous review were fully answered. The proposed changes were made by the authors. The article has quality for publication.

Author Response

The suggestions made in the previous review were fully answered. The proposed changes were made by the authors. The article has quality for publication.

Answer

Thank you for your good comments. Thank you very much again.

Author Response File: Author Response.pdf

Reviewer 2 Report

Thank you for considering the reviewer's comments.

I have one comments for improving the paper.

Please improve the quality of Fig. 6(a).

Your work is not clearly seen in the figure.

 

Author Response

I have one comments for improving the paper. Please improve the quality of Fig. 6(a).

Your work is not clearly seen in the figure.

Answer

I revised the Fig. 6 (a). Please refer to Fig. 6 of my manuscript.

Thank you for your good advice. Thank you very much again.

Author Response File: Author Response.pdf