Study on the Shielding Effectiveness of Airborne Navigation Equipment Enclosures Under High-Intensity Radiated Fields (HIRFs)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments: 

1. the paper could strengthen its contribution by comparing CST predictions with other EM solvers (e.g., HFSS, FEKO) to confirm cross-platform validity.
2. A limitation, though, is that the experimental scope seems restricted to Class G conditions; extending to higher severity levels could provide stronger generalizability.
3. The research evaluates SE under frequency, polarization, and incidence angle variations, but environmental factors such as temperature or real-flight vibration effects on apertures were not considered, which could affect shielding performance.
4. Relying on a single-point calibration to predict remaining resonances is innovative but could be risky. If calibration is performed at a poorly representative point, predictions may fail. A sensitivity study on calibration accuracy would strengthen reliability claims
5. The research doesn’t deeply address long-term material degradation (e.g., corrosion, moisture ingress, thermal cycling), which can significantly alter shielding performance in aviation contexts.
6.  Claiming predictable and measurable improvements is a strong contribution. Still, the improvements should have been benchmarked against existing shielding standards or previous mitigation strategies to quantify relative advancement. 

Comments on the Quality of English Language

need to be improved

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The topic is timely. With increasing electromagnetic-threat environments (radars, transmitters, etc.), ensuring that airborne navigation equipment (especially GNSS receivers) are immune to HIRF is critical for safety and reliability. The paper addresses a real and important problem.

 

Internal components (connectors, cables, circuit boards) are simplified, which means actual coupling paths (especially via connectors or internal wiring) may not be fully represented. This limits the realism of the simulation.

 

The simulation uses a plane wave excitation with field strength ~200 V/m. In real HIRF conditions, field strengths, modulation, pulsed fields, or complex fields (reflections, polarization changes) may differ. The paper may not fully capture extreme or transient cases.

Although apertures are studied in shape, size, spacing, etc., the treatment of edges, seams, fasteners, gasketing is critical in practice. The paper may under-emphasize how seams or joints (panel joins, access doors) contribute to real world leakage.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript entitled, ‘Study on the Shielding Effectiveness of Airborne Navigation Equipment Enclosures under High-Intensity Radiated Fields (HIRF)’ reported Shielding Effectiveness of Airborne Navigation Equipment. The article should be modified according the following comments:

1. The abstract lacks specificity regarding the data presented in the study. It is recommended to highlight key findings or notable data to give readers a clearer understanding of the study's contributions.
2. Could the authors elaborate on how the surface current distributions shown in Figure 9 were obtained (e.g., simulation method, meshing strategy, boundary conditions)?
3. Are the color scales in Figure 9 consistent across frequencies to allow for a direct visual comparison of current intensity?
4. Could the authors elaborate on the physical mechanisms behind the pronounced resonance dips near 3.6 GHz and 8 GHz, particularly why they are more severe at lower incidence angles (0° and 30°)?
5. Are the SE values reported peak values or average values across certain bands? Clarifying this would help in comparing the effectiveness more precisely.
6. Could the authors provide more quantitative details on the geometry and dimensions of the apertures in Surfaces A, B, and C to clarify how these correlate with the observed SE trends?
7. What is the specific mechanism by which the horizontal dimension of Surface C enhances coupling with horizontally polarized fields? Has field mapping been used to visualize this interaction?
8. Some articles would be significance for your reference:

• Ganguly, S., Kanovsky, N., Das, P., Gedanken, A., & Margel, S. (2021). Photopolymerized thin coating of polypyrrole/graphene nanofiber/iron oxide onto nonpolar plastic for flexible electromagnetic radiation shielding, strain sensing, and non‐contact heating applications. Advanced materials interfaces, 8(23), 2101255.
• Alzahrani, F. M. A., Basha, B., Hammoud, A., Tamam, N., Alsufyani, S. J., Kebaili, I., ... & Al-Buriahi, M. S. (2024). Gamma attenuation and nuclear shieling ability of TeO2/Bi2O3/WO3 glass system. Radiation Physics and Chemistry, 223, 111985.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Detailed Comments to the Authors

1. Figures 3, 4, and 5 – lack of axis labels and limited geometric clarity.
   Figures 3–5 present the technical models of the enclosure and the locations of the probes; however, the X, Y, and Z axes are not labeled.
   This omission makes it difficult to precisely correlate the indicated points with their actual spatial coordinates inside the enclosure.
   Adding axis labels and a short description of the orientation (e.g., direction of the incident wave, position of the aperture, transmitting antenna location) would significantly improve interpretability.
   It is also unfortunate that the authors did not include a larger number of probe points, which would have allowed for a more detailed analysis of the electric field distribution inside the enclosure — particularly regarding local minima and maxima.
   A denser sampling grid would make it possible to observe local resonance effects and the modulation of the internal field.
   A similar and more detailed field visualization approach can be found in:
   Budnarowska, M.; Mizeraczyk, J. Determination of Shielding Effectiveness of a Subnanosecond High-Power EM Interference by an Enclosure with Aperture Using Time Domain Approach. Energies 2023, 16, 1931.
   https://doi.org/10.3390/en16041931

2. Figures 6 and 7 – poor readability and unclear color–curve correspondence.
   Figures 6 and 7 are difficult to interpret — even when the PDF is significantly zoomed in, it is not possible to clearly identify which colors correspond to which plotted curves.
   It is recommended to improve the color contrast, increase the line thickness, and add a clear legend (e.g., with numbers or symbols).
   Alternatively, the authors could consider splitting the plots into smaller subfigures (e.g., 6a, 6b) to improve clarity.

3. Figure 9 – missing current flow directions and time information.
   Figure 9 presents the surface current density on the enclosure, but its interpretation is limited because the directions of current flow are not indicated.
   Using the “arrows” visualization mode (for example, in CST Studio Suite) would help to illustrate the directions and circulation patterns of surface currents, providing a more complete picture of charge movement on the enclosure surfaces.
   Additionally, the figure lacks information about the specific time instant (or phase) at which the field distribution is presented, which is necessary to relate the results to the incident wave excitation and to interpret the resonance behavior.

4. Missing figure showing the EM excitation signal shape.
   The paper does not include any figure or description illustrating the shape of the EM signal used to excite the system during the HIRF experiment.
   Adding such a figure — for example, showing the time-domain waveform or frequency spectrum — would be highly beneficial for readers, as it would clarify the characteristics of the excitation signal and its impact on the internal field distribution.

5. Overly descriptive presentation of results.
   The results section often repeats obvious dependencies already visible in the plots (e.g., “SE decreases with larger apertures”).
   A more concise and informative way to present these findings would be to include a summary comparison table (e.g., listing ΔSE values for selected configurations), which would improve clarity and highlight the quantitative trends more effectively.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revisions are satisfactory. The manuscript can be accepted.

Comments on the Quality of English Language

need to be improved

Reviewer 3 Report

Comments and Suggestions for Authors

This can be published in its present form.

Reviewer 4 Report

Comments and Suggestions for Authors

After carefully reviewing the revised version of the manuscript, I am satisfied that the Authors have responded appropriately to the comments raised. The main concerns from the previous round have been, in my view, convincingly addressed. In its current form, the manuscript meets the journal’s scientific and formal standards and can be recommended for acceptance.