Highly Efficient GaN Doherty Power Amplifier for N78 Sub-6 GHz Band 5G Applications

Round 1

Reviewer 1 Report

1) There is excessive repetition of certain descriptions without necessity:

For example:

L202-L203, L208-L209, "a drain bias of 28 V";

Repetition of formulas (10) and (11);

L260-L269, similar content mentioned earlier;

L153-L158 and L280-L285, as well as repetition of formulas (12) and (13);

L613-L619, similar content mentioned earlier.

 

2) There is an overabundance of basic formulas and figures:

For example:

Formula (2);

Formula (5), which is also incorrect;

Figure 3.

 

3) In Figure 2, why is ηaux not equal to 0 at the boundary between the Low power region and Medium power region?

 

4) Numerous writing errors have appeared due to lack of rigor:

For example:

L157-L158, ((50 + 50)) / 2 = 25 obviously doesn't hold;

Formula (3) is identical to Formula (4);

In L176, ????,? and ????,? are not present in the formula;

L302, -10dBm should be -10dB;

Formula (15) is missing a "1" after the "<";

The graph in Figure 18 does not match its caption;

L527-L529, isolation should be characterized by S23, not S12 or S13;

The graph in Figure 26 does not match its caption;

The conclusion in L639-L640 contradicts earlier text.

 

5) The conclusion in L246-L247, "Return loss was below -20 dB over the entire band 246 (3.3:3.8 GHz)," is evidently inconsistent with Figure 7(b).

 

6) Figure 6 is not mentioned in the main text.

 

7) L462 references Figure 19, yet Figure 19 is not present in the article.

 

8) What accounts for the significant difference between Figure 26 and Figure 20?

 

9) The logical flow of the text is unclear:

For example:

Introduction is too lengthy and occupies a substantial portion without highlighting the significance of the work;

L112-113 should clarify under what conditions and in comparison to what the 27% PAE improvement occurred;

The image and description of Figure 8 do not match the narrative;

L480-L481 references "The blue solid line with a square symbol on the curves represents this design." which involves Figure 21, but Figure 21 hasn't been introduced prior in the text;

Table 4 doesn't specify which data is simulation-based and which is experimental, making it difficult to ascertain the meaningfulness of comparisons.

 

10) Abbreviation usage is too casual:

For example:

L96 uses the abbreviation "ADS" without prior definition;

L156 uses the abbreviation "OBO" without prior definition;

L430 uses the abbreviation "SMD" without prior definition.

 

11) In L177, "According to theoretical considerations," should be accompanied by a reference.

 

12) Formula (16) can be directly cited from a reference.

 

The issues highlighted above include many intolerable errors. From a scientific standpoint, the author's assertions are not entirely baseless. However, considering the quality of writing, it's challenging for reviewers not to cast doubt on the results and conclusions presented in the article. It is recommended that after thorough proofreading and careful revision, the article be resubmitted for consideration.

Extensive editing of English language required.

Author Response

Dear Reviewer,

Please see the attached file, which contains the answers to your valuable comments. Thanks.

Best regards

Author Response File: Author Response.pdf

Reviewer 2 Report

Overall, the article describes a DPA design exercise with many details and references to theory. For being a scientific article, it reports a lot of known theory that could be somehow taken for granted. For example, section 2 consists of well-known theory; therefore, I would suggest eliminating this section or strongly reducing it to the minimum needed to explain the proposed design. Also, Section 3.3 contains known theory and can be minimized. Section 3.1 could be moved to the discussion of the search for optimum impedances in Section 3.4, and Section 3.4 itself could be minimized by removing all known load-pull procedural steps. In my opinion, small-signal stability analysis in Section 3.5 should be moved as the first paragraph.

Among the DPA-based techniques mentioned in the Introduction, the authors should include dual-input Doherty, which leverages digital processing of the inputs to synthesize optimal splitting and can be enhanced by optimization, e.g., as demonstrated by M. Mengozzi et al., in "Automatic Optimization of Input Split and Bias Voltage in Digitally Controlled Dual-Input Doherty RF PAs," published in Energies, vol. 15, no. 13, p. 4892, Jul. 2022, and C. Kantana et al., in "A Hybrid Heuristic Search Control Assisted Optimization of Dual-Input Doherty Power Amplifier," presented at the 2021 51st European Microwave Conference (EuMC) in London, United Kingdom, 2022, pp. 126-129.

Beyond reporting DPAs and other PA architectures at different frequencies, it could be useful to report similar PA designs at similar frequencies, using similar technologies, in order to have a better comparison with the state-of-the-art.

In Section 4, the authors could include a list of the values of all relevant components, dimensions of the microstrip lines, substrate, etc., since they are not very visible from Fig. 16. The authors propose a comparison between simulation and measurements for the power divider and the matching networks, but they do not show the complete PA design. Please add a photo. Moreover, is Fig. 29 the measurements of the designed PA? Why not compare this data with simulations? Please clarify. Please also explain the measurement environment, hardware, and settings.

At line 302: "The reflection coefficient of any PA must be less than -10dBm." do the authors mean -10 dB?

Author Response

Dear Reviewer,

Please see the attached file, which contains the answers to your valuable comments. Thanks.

Best regards

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

1. L54-58, "Also GaN devices...52.6 GHz," is unrelated to the article's main topic and can be deleted.

 

2. L60-L65 references a table (Table 1) that lists related developments. This table can be removed. Please note that you are publishing a research paper, not a review. Unless you intend to compare your work with others' achievements, simple citations are sufficient.

 

3. Sections 2 and 3.1 devote too much space to explaining basic concepts, formulas, and conclusions from referenced literature. Remember that you are publishing a research paper, not a textbook. You need not be concerned that your readers won't understand fundamental concepts.

 

4. L196, oh, there's a second Table 1.

 

5. Sections 3.3 and 3.4 spend an unusually large amount of space on conventional input-output matching networks and stability analysis. Please be aware that you are publishing a research paper, not a lab report.

 

6. L379-L380, there was no prior discussion of the design of the three types of Doherty power amplifiers.

 

7. L393-L394, "This design is abbreviated as (UPD with HS) based on the results shown in Fig. 21," can be deleted.

 

8. L380-L405 mention Fig.21 five times, but they are actually referring to Fig.13.

 

9. Fig. 13 includes two sets (a) and (b), but the latter two should be (c) and (d).

 

10. Starting from L408 to the end of the article, most of the figure numbers are incorrect.

 

11. L474, Table 4 actually refers to Table 3.

 

12. L502-L504, this is an exaggerated expression.

 

The author's desire to comprehensively showcase experimental and simulation details is commendable, but excessive and unnecessary content will quickly test the reader's patience. Research papers must be concise and to the point. Moreover, sloppy writing and obvious errors are not tolerable. It is recommended to carefully revise the paper.

Minor editing of English language required.

Author Response

Dear Reviewer,

Please see the attached file, which contains the answers to your valuable comments. Thanks.

Best regards,

Author Response File: Author Response.pdf

Reviewer 2 Report

Thanks for replying to my comments and for improving the manuscript.

Author Response

Dear Reviewer,

Please see the attached file, which contains the answers to your valuable comments. Thanks.

Best regards,

Author Response File: Author Response.pdf