Design of High-Precision Terahertz Filter Based on Directional Optimization Correction Method
Round 1
Reviewer 1 Report
Three 340 GHz terahertz filters with a bandwidth of 20 GHz are designed and fabricated . Here are my comments
1- The introduction section should be improved and new references should be added.
2- Filter syntheses should be added first and the design procedures.
3- Fig.2 d, Fig.3, and Fig.7 please change the color of the S11 simulated and measured
4- Please check the caption of Fig.3
5- Please change all S11, and S21 to S11, and S21 in the text and all figures.
6- New references from 2022-2023 should be added.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
By studying the THz bandpass filter's coupling window structure, resonator structure, and asymmetry parameters, this work proposes the DOC technique. The DOC technique allows for rapid correction of the center frequency and bandwidth defects of terahertz filters by modifying the coupling window length and resonator width.
1- Related work section needs to be expanded.
2- Please add a figure to compare your simulation results with Table 1. Comparisons with Other Previous Works.
3- Please add a section on how will this work help the practical applications such as 5G and beyond communication, imaging etc. and add practical usage cases.
4- Why authors selected 340GHz? 240GHz to 300Ghz has better frequency response for communication perspectives.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
1. What is the definition of GOC? I feel that the GOC method used in this manuscript is to manually introduce a design offset to compensate the discrepancy of the result between the first experiment and the simulation. While this method may be effective practically, we do not know the physics of the mismatch between the first simulation and experiment.
2. After reading the manuscript, I am still not clear about the definition of DOC. I feel that what the authors did in the DOC method is to find a physical parameter (d/t) that only affects one output (center frequency/bandwidth) but not others. The authors do not explain the physics why a certain output is only affected by a certain parameter. And the authors found the d/t parameters by a brute-force approach (searching almost all the physical parameters of the filter). I don’t see much originality in this method.
3. Following the previous point, it is not clear to me how the authors determine the simulation goal in Fig. 7(b). With that being said, I cannot understand the logic why the simulation and measurement results can match in Fig. 7(c).
4. Why do they use this type of terahertz filter? How does it compare with other type of filters? Why do they choose a 7-order filter?
5. What is the fabrication accuracy of CNC? For some parameters (e.g., L1), the numerical accuracy is 0.0001 mm. Can CNC provide such fabrication accuracy? If not, how does it affect the measurement result?
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
1. What are the main questions that remain to be addressed by the authors of the article?
There are no MAIN questions opened because the proposed work is, in my opinion, complete and solid.
2. What specific improvements should the authors consider regarding the methodology?
For a better understanding of the material, I would suggest the Authors would address the following MINOR points:
A. In which programming language the DOC method has been implemented? Which is the order of magnitude of the CPU time and memory used for the problems dealt? The Authors are invited to add a few comments to the text.
B. What is the impact of the mechanical tolerances due to the manufacturing of the filter on the accuracy of the proposed approach? The Authors are invited to add few comments in the text
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors replied to all comments.
Reviewer 2 Report
This reviewer is satisfied with current version of this manuscript.
Reviewer 3 Report
Thanks for the revised manuscript. The scientific logic is much better. I recommend publication in the current form.
