Switchable Filter with Four Operating Modes Implemented on a 50-Ohm Microstrip Line

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

To show the novelty of the manuscript, I suggest the author to improve the writing of the introduction.

1. Please introduce the structures of the reference structures to show the difference compared to the proposed structure.
2. Table I should be placed at the Section 4.
3. Please show the structure of Section 3.3.

Comments on the Quality of English Language

1. Please describe the multiband frequency range of the wireless communication and show that the designed filter can satisfy this demand.
2. In Table I, please add operation frequency range and the structure of the references and clarify why the designed filter by the authors can obtain small size. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I have reviewed the manuscript titled "Switchable Filter with Four Operating Modes Implemented on a 50-ohm Microstrip Line." The proposed design appears to be compact and practically applicable. The authors have also presented a comparison table that effectively demonstrates the superiority of the proposed filter. However, to further improve the quality and clarity of the manuscript, I recommend the following comments and suggestions:

1. Please rewrite the introduction to clearly explain the motivation behind designing a switchable filter with four operating modes using five PIN diodes. Provide context and supporting references to justify this design choice within the scope of modern communication needs.

2. The sentence in line 265, "On the other hand, when 68 and 90 nH are mixed, there is almost no electric field formed in the bias circuit," is confusing. Please revise this sentence for clarity and provide a more precise explanation of the physical mechanism or simulation result being discussed.

3. You state that the proposed design can be applied to next-generation communication systems such as 5G and IoT. However, the relevant frequency bands for these applications are only mentioned in the conclusion. Please also include a brief discussion of the specific frequency requirements for 5G and IoT systems at the end of the introduction section to strengthen the motivation and contextual relevance of the work.

4. I recommend reducing the overall similarity index below 10%. A check performed using CopyKiller shows the current similarity score is 11%. Lowering this will improve the originality and credibility of the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript presents a compact and versatile switchable filter implemented on a 50-ohm microstrip line, demonstrating four operating modes: two dual-band bandpass filters, one wideband bandpass filter, and an all-pass filter. Overall, the paper is logically structured and clearly communicates both conceptual rationale and detailed analyses.

The strengths include systematic parameter studies, clear explanations of operating principles, and comprehensive comparisons of measured results against simulations. The explicit comparison with prior works regarding bandwidth, insertion loss, diode count, and size highlights its practical advantages.

Very minor recommendations:

Expand briefly on the specific limitations of diode models or fabrication precision at high frequencies to enhance logical clarity around discrepancies between simulations and measurements.

Clarify figure legends, especially distinguishing dotted and solid lines, to improve reader comprehension, or maybe change the 2-d legend to a 1-d legend—for example, figure 1.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf