Compact and Highly Sensitive Bended Microwave Liquid Sensor Based on a Metamaterial Complementary Split-Ring Resonator

Round 1

Reviewer 1 Report

This paper provides a simulation-based parameter-adjusting design of a complementary split ring resonator for liquid sensing. Overall, the improvement is stated theoretically, and needs to be verified expeimentally, and the optimization might be efficient only for some limited design. Moreover, the results are all based on simulation, the theoretical origin is weakly presented. 

I think this work only made a design report that needs to be verified and is lack of theroretical deepth at this stage. I don't think this paper should be published at the current stage. More experimental data and theroretical analyses is needed.

Author Response

Responses to Editor and Reviewers

 

Dear Editor,

The authors would like to thank the Editor and the Reviewers for their precious time and valuable recommendations. We also greatly appreciate the reviewers’ constructive criticisms and appreciated comments and suggestions.

We have carefully addressed all the reviewers’ comments. A point-by-point response to reviewers’ comments and the corresponding changes and refinements made in the revised paper are denoted below.

The changes are highlighted in the new version.

 

Best regards,

 Dr. Issa Elfergani et al

 

 

Reviewer #1

 

Comments and Suggestions

This paper provides a simulation-based parameter-adjusting design of a complementary split ring resonator for liquid sensing. Overall, the improvement is stated theoretically, and needs to be verified expeimentally, and the optimization might be efficient only for some limited design. Moreover, the results are all based on simulation, the theoretical origin is weakly presented. 

I think this work only made a design report that needs to be verified and is lack of theroretical deepth at this stage. I don't think this paper should be published at the current stage. More experimental data and theroretical analyses is needed.

Response

We sincerely thank the reviewer for his constructive criticisms. We are grateful to the reviewer for his positive suggestion.

The present work is reinforced by experiments. A prototype of the flat structure is fabricated and experimental validation is added.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

thank you for this paper. I've read it with great interest.

Line 1) erase the word "too"

Line 132) please decribe the material caracteristics of "glass" used in your simulations

Figure 7b) indicate what is b/c/d/ sensors, either as a legend in the graph or in the figure text

Figure 8 a) and b) indicate what is the difference between staright line and dashed line as a legend in the graph or in the figure text

Line 144) I don't really understand this phrase because I don't see the superimposition.

Figures 8/10/12a) and 8/10/12b) What is straight line/dashed line difference? If it is the difference betwenne HFSS and CST simulations, how do you explain it ? Is it really interesting to show? Which one is closest to reality? After having made this test and presented it once, I would pick the best one and only use this every time for readability.

Lines 182 and 184) "kHz" not "KHz"

Lines 214 to 217) can you please elaborate on why the smaller tubes are better for extracting the imaginary part and the bigger tubes better for the real part?

Line 260) You wrote "The capillary glass test tube is filled with a mixture of and..." a mixture of what?

Line 265) I'm not sure to fully understand this sentence. Is there a difference between test tude and capillary tube or is it the same thing?

What is the bending radius of the CSRR substrate in Figs 8-12? Is this bending possible without delamination of the copper?

Is the glass tube wall always of the same thickness? Is this possible and do we find these tubes commercially?

References 8,9,10,11,12,18, 22, 24, 28, 34, 38 have no authors named, please correct.

This work is based on simulation only, even if the authors did check their results to an earlier publication that provides the test results (but no simulation results). They show HFSS and CST simulations for each setup in order to validate their results, at least one measurement of the parallel tube setup would have been interesting to see.

 

Author Response

Responses to Editor and Reviewers

 

Dear Editor,

The authors would like to thank the Editor and the Reviewers for their precious time and valuable recommendations. We also greatly appreciate the reviewers’ constructive criticisms and appreciated comments and suggestions.

We have carefully addressed all the reviewers’ comments. A point-by-point response to reviewers’ comments and the corresponding changes and refinements made in the revised paper are denoted below.

The changes are highlighted in the new version.

 

Best regards,

Dr. Issa Elfergani et al.

 

 

 

Reviewer #2

We sincerely thank the reviewer for the constructive criticisms and we also appreciate his insightful comments on revising the paper.

 

Comments and Suggestions

Line 1) erase the word "too"

the word "too" is erased

Line 132) please decribe the material caracteristics of "glass" used in your simulations

Properties of glass : 75 mm-long with an outer radius of 0.75 mm and an inner radius of 0.5 mm  with    a relative permittivity  =  5.5. they are added in the reviewed version.

Figure 7b) indicate what is b/c/d/ sensors, either as a legend in the graph or in the figure text

Figure 7b) became Figure 8b) and updated with corrected legend

Figure 8 a) and b) indicate what is the difference between staright line and dashed line as a legend in the graph or in the figure text

Dashed and solid lines are identified in all Figures. dashed : CST, solid : HFSS

Line 144) I don't really understand this phrase because I don't see the super imposition.

We updated with

On the other hand, the resonant frequency and quality factor patterns are nearly overlapping with a shift of less than 5 MHz.

Figures 8/10/12a) and 8/10/12b) What is straight line/dashed line difference?

Figures’ legends are updated.

If it is the difference betwenne HFSS and CST simulations, how do you explain it ?

HFSS and CST are two different simulation software. HFSS is based on Finite Element Method (FEM), while CST is based on Finite Integration Technique (FIT). Different methods yield to different results; this is very logical. Despite that, they both gave almost the same results : in our study, the maximum relative error between the two results does not exceed 5%. So both software are reliable.

Is it really interesting to show?

Yes, we think it is quite interesting, so that we could validate our results twice, since experimentation is not easy to get for all cases.

Which one is closest to reality? After having made this test and presented it once, I would pick the best one and only use this every time for readability.

Both are close to reality : (a relative error of 5%, between the two results, is insignificant). On the other hand, we cannot decide which one is the best. We used them to validate our results since we could not validate with measurements for all designs.

Lines 182 and 184) "kHz" not "KHz"

Corrected

Lines 214 to 217) can you please elaborate on why the smaller tubes are better for extracting the imaginary part and the bigger tubes better for the real part?

Justification is added.

The following changes are inserted in the text and a reference is added [47] for more details.

“According to Table 3, the accuracy and reliability of the proposed device is improved through 5 measurements for different tube radii. For instance, tubes with r=0.75 and 1.5mm have higher Q-factors are mainly used to extract the imaginary part (e’’). Tubes with larger radius (r=3.75 and 5mm) have a sensitivity range frequency of 400MHz, hence, they are advantageously used for the permittivity real part (e’) extraction, since e’ and e’’ are directly related to Δfr and to Q-factor, respectively [45].”

[45]. Li, D., Free, C. E., Pitt, K. E., & Barnwell, P. G. (2001). A simple method for accurate loss tangent measurement of dielectrics using a microwave resonant cavity. IEEE microwave and wireless components letters, 11(3), 118-120.

Line 260) You wrote "The capillary glass test tube is filled with a mixture of and..." a mixture of what?

Corrected

“The capillary glass test tube is filled with a water-ethanol mixture”

Line 265) I'm not sure to fully understand this sentence. Is there a difference between test tube and capillary tube or is it the same thing?

They are the same, however, small-radius tubes are generally qualified as capillary.

What is the bending radius of the CSRR substrate in Figs 8-12? Is this bending possible without delamination of the copper?

The bending radius in these figures is taken to be R=5mm as an inferior limit. Smaller radii may alter the structure itself and are not practically possible.

 

We updated the text with : 

“It can be seen that the frequency interval between the upper (100% water) and lower (0% water) water concentrations increases with the decrease in the bending radius for 10mm, 7mm and the minimum possible value 5mm, beyond that, the structure is no longer practically feasible due to the structure deformation, consequently the sensitivity increases and reaches its maximum.”

Is the glass tube wall always of the same thickness? Is this possible and do we find these tubes commercially?

Yes, all used test tubes have the same thickness; a prototype is fabricated using a Creality Ender 3 Pro 3D printer with a 0.2 mm nozzle and PLA filament.

We updated the revised version with :

“The glass capillary tube was easily produced with Creality Ender 3 Pro 3D printer using 0.2 mm nozzle and PLA filament. It is used in the case of the flat structure measurements. This kind of capillary tubes is commonly used in clinical and laboratory settings. It is 75 mm-long with an outer radius of 0.75 mm and an inner radius of 0.5 mm with a relative permittivity of 5.5. After the confirmation on the microwave sensing application potential through the numerical computations, the microwave sensor model has been fabricated on 0.75mm thick Roger RO3035 substrate with Eleven Lab PCB prototyping system as shown in Fig.5.”

   References 8,9,10,11,12,18, 22, 24, 28, 34, 38 have no authors named, please correct.

All references are Corrected

This work is based on simulation only, even if the authors did check their results to an earlier publication that provides the test results (but no simulation results). They show HFSS and CST simulations for each setup in order to validate their results, at least one measurement of the parallel tube setup would have been interesting to see.

Thanks for this suggestion.

experimental validation is added for the flat structure.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have presented the design and analysis of a Bended liquid sensor based CSRR particles. The bending-based structure demonstrated an improvement of the sensor design, while the sensitivity and Q-factor depend on the radius of the liquid tube used for the test.
A good agreement is seen between results of performed simulations. However, there is no experimental validation.
The organization of the paper is not very well and need to review to help readers understanding this work. 
The are some to long sentences, line 158 as an example
Line 158 ‘radii’ and line 261 ‘tube of and’, to be corrected.
I think there is no need to study the effect of the tube radius on the sensor performances, for several radius values. Two radius values are enough to understand the behavior and male conclusions. 
Experimental results are required in order to validate simulations, at least for the flat sensor design.

Author Response

Responses to Editor and Reviewers

 

Dear Editor,

The authors would like to thank the Editor and the Reviewers for their precious time and valuable recommendations. We also greatly appreciate the reviewers’ constructive criticisms and appreciated comments and suggestions.

We have carefully addressed all the reviewers’ comments. A point-by-point response to reviewers’ comments and the corresponding changes and refinements made in the revised paper are denoted below.

The changes are highlighted in the new version.

 

Best regards,

Dr. Issa Elfergani et al.

 

 

 

Reviewer #3

 

The authors sincerely thank the reviewer for the constructive criticisms and we also appreciate his insightful comments on revising the paper.

 

Comments and Suggestions

The authors have presented the design and analysis of a Bended liquid sensor based CSRR particles. The bending-based structure demonstrated an improvement of the sensor design, while the sensitivity and Q-factor depend on the radius of the liquid tube used for the test.
A good agreement is seen between results of performed simulations. However, there is no experimental validation.

The organization of the paper is not very well and need to review to help readers understanding this work. 

The organization of the paper is modified, some results presentations are modified, placement of some figures are changed, and an experimental validation is added.

They are some to long sentences, line 158 as an example.

Thanks for the remark

The manuscript is reread for style and English improvement. Modification are highlighted in the text.

Line 158 ‘radii’ and line 261 ‘tube of and’, to be corrected.

By radii, we mean the plural of radius.
‘tube of and’ : Corrected :

“The capillary glass test tube is filled with a water-ethanol mixture”

 

I think there is no need to study the effect of the tube radius on the sensor performances, for several radius values. Two radius values are enough to understand the behavior and male conclusions. 

Thanks for the remark. The number of figures (results) is really large. Thus, we have reduced the subfigures of Figs. 9 - 13 by 50%.

However, for the use of several tube radii, we think that it is very important to consider a sufficient number of cases to multiply the effectiveness and the accuracy of the relative permittivity extraction.

Experimental results are required in order to validate simulations, at least for the flat sensor design.

Thanks

The flat sensor design is realized and measurements are performed.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The paper has been reviewed and answers provided. Good job , Thanks