Dual-Band Low-Noise Amplifier for GNSS Applications

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a study on an LNA (Low Noise Amplifier) that supports simultaneous operation on the L1/L5 bands for GNSS. The research focuses on the detailed specifications of an LNA designed for dual-band operation.

However, regarding the paper's originality, the proposal of a dual-band configuration using an existing LNA structure is somewhat limited. Additionally, the paper includes redundant explanations that could be simplified. The following revisions and changes are necessary:

1. In Figures 2 and 3, the inductor used for matching is labeled as "Lgg" However, it is referred to as "Lg" in the text. This discrepancy should be corrected.

2. In Figure 3, it is stated that the dual-band matching at the 1.4 GHz center frequency is optimized using the Lgg inductor and the M1/M5 transistors. However, this optimization seems difficult to achieve without the assistance of LS1 and LS5. Please verify if these components are identical.

3. The paper should also illustrate how the input impedance of the LNA changes during Dual/Single mode operation.

4. The measurement results already include simulation data, making certain sections redundant. This content should be consolidated and presented more concisely, including a description of the measurement environment.

5. In Table 5, it is recommended to emphasize the strengths of the proposed design by highlighting the FoM (Figure of Merit).

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses in the attached Word file and the corresponding revisions in track changes in the re-submitted files.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1. One of the critical parameters for LNAs, is their linearity. Authors have not mentioned about the linearity requirement of GNSS applications. It must be added to the abstract, introduction, and performance summary and comparison table (Table 5). Linearity could be shown by IIP3 or P1dB for the LNAs.

2. How much is the highest level of protection provided by the ESDs? 1kV, 2kV? This must be mentioned to the paper. Also, due to the operating limitations caused by the ESDs, it is suggested to be added to Table 5 as well.

3. Please discuss the quality factor of the employed inductors considering their effects over the gain and noise figure.

4. The gate-source capacitors (Cex1 and Cex5) are implemented as real capacitors in your layout implementation or by parasitic? How much is their sizes? 

5. Please emphasis your contribution generally. For example the LNAs in Figure 3 are conventional configurations. Please mention what is the novelty of the work. Are the other dual-bands implemented with complying different configurations? reflect your emphasizing ideas in Table 5.

6. After Table 5, please provide a comprehensive discussion. You can add FOMs to table 5 and it will be helpful to understand the superiority of your work compared with the previous works.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses in the attached Word file and the corresponding revisions in track changes in the re-submitted files.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

It has been revised to reflect the review comments.

Author Response

Thank you very much for taking the time to review this manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have replied to the previous comments carefully. However, there are some suggestions to improve the readability of the paper for the audience.

Please specify the desired frequency (band) with vertical lines for Figures 5, 6, 7, 8, 9, 10, 11, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 26, and 28. The mentioned figures do not reflect any information if you do not annotate the frequency and the values of the simulated parameters and measure results at the desired frequencies.

Author Response

Please see the attachment

Author Response File: Author Response.pdf