Review Reports
- Stavros Drakakis1,*,
- Anastasios Michailidis1,2 and
- Dimitrios Tzagkas3
- et al.
Reviewer 1: Chenxi Zhao Reviewer 2: Anonymous Reviewer 3: Anonymous Reviewer 4: Gia Khanh Tran
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsNested inductors and on-chip baluns are utilized in the LNA design presented in this paper. These components are commonly employed in mm-Wave chip design. However, a critical limitation is the absence of measurement results. For RFIC design, relying solely on simulations is insufficient to validate performance. There are some comments:
1. Please provide the measurement results;
2. The designed 3dB bandwidth of S21 is 29-31GHz, but the bandwidth of S11 is 31-35GHz. They should be designed as consistently as possible.
3. The superiority of the optimized nested inductors can only be determined by comparing it with other similar papers.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe denotation symbols of S parameters are not advised to be put in the abstract.
Extensive results are shown, but unclear to readers regarding experimentally measured or numerically simulated. The simulation-only must be pointed out clearly in each section, particularly the results and captions of the figures.
It is a bold conclusion as defined by the authors - " addressed the challenges of magnetic coupling and crosstalk in compact RFIC designs". The authors attempted to address these challenges, however, lacking experimental prototype and measurement results to convince the validity of the designs.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThanks for the paper!
- I'm bit skeptic about the novelty in your work. Such LNA design and inductor design have been there by many groups. Can you please highlight what makes your work different from others?
- Have you fabricated the circuits? Could you please provide the measured data? Without that it is difficult to judge the quality of your work as there are so many papers in this frequency range with the results comparing the measurement and simulation.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe manuscript presented a comprehensive layout-level design and verification methodology for Low-Noise Amplifiers (LNAs) targeting both RF and mmWave applications in a 22 nm FD-SOI CMOS process. It introduced a nested inductor structure for RF bands that minimized silicon area while accounting for magnetic crosstalk through EM simulations using Ansys RaptorX. For mmWave operation, the study proposed a differential LNA design employing on-chip baluns, with performance optimization supported by a machine learning–based automation framework. The methodology integrated EM-based extraction and validation to ensure design accuracy and performance consistency across frequencies. Simulation results demonstrated that nested inductors effectively reduce area with minor trade-offs in performance, while differential topologies with baluns enhance high-frequency operation, offering a unified, area-efficient LNA design framework from RF to mmWave. Regardless of interesting contents, the reviewer has the following comments that wish the authors to resolve in the next round of review.
1) The study relied heavily on simulation and EM extraction results. No fabricated chip measurements were provided to validate real-world performance, limiting the practical verification of the proposed techniques. Please elaborate this point.
2) The nested inductor initially caused degradation in key S-parameters (S11, S21, S22) and gain before re-tuning. Although later optimized, this highlighted potential design sensitivity and raises questions about robustness. Please explicitly explain about the robustness issue.
3) The manuscript lacked comparison with other state-of-the-art LNA implementations in 22 nm FD-SOI or similar nodes. Including benchmarks for gain, NF, and area efficiency would strengthen the claim of novelty and superiority. Please elaborate this point.
4) The authors acknowledged that the nested inductor concept became less effective at mmWave frequencies, but the paper provided limited exploration of how to overcome this limitation or extend applicability beyond RF.
5) The workflow—combining EM extraction, manual layout tuning, and machine-learning-based optimization—appeared complex and may not be easily reproducible without access to specific commercial tools (e.g., Ansys RaptorX).
6) The paper was dense and highly technical, with long sections of analytical derivation. Improved organization (e.g., a concise design methodology flowchart or summary table of main findings) would enhance readability.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe revised manuscript addresses most of the issues I raised. However, the most critical issue of supplementing test results has not been resolved. As noted by other reviewers, simulation results alone in this frequency band are insufficient to fully demonstrate the performance.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIt remains unclear to readers and reviewers whether the results are experimentally measured or simulated. A statement in a specific location is not easily legible. The authors are advised to add keywords such as 'simulated results' or 'models' to the captions of all figures derived from modelling and simulations.
Furthermore, the name, version, vendor, and limitations of the EM simulator(s) utilised are not reported for reproducible purposes.
Measurement results may be needed to back up some of the claims and optimisation reported in the simulated results, unless the authors can justify the simulations by benchmarking with other simulators or theoretical results.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThanks for your explanations!
But I still suggest you to fabricate the circuit to compare your design methodology with the real time measurement.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
Comments and Suggestions for AuthorsFor RFIC design, relying exclusively on simulations fails to provide sufficient validation of practical performance.
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe overall unit of FoM is unclear in equation 17. The physical implication of FoM and the related unit should be indicated and explained clearly.
Check Table 8 - FoM1 should be FoM1 .
Author Response
The authors would like to sincerely thank the reviewers for their comments and suggestions. In the replies to the comments below, the authors address the concerns raised by the reviewers. All replies can be found in the attached PDF.
Author Response File: Author Response.pdf