A Novel Wideband 1 × 8 Array Dual-Polarized Reconfigurable Beam-Scanning Antenna

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a 1×8 linear array antenna with dual-linear polarization reconfigurability and beam scanning capabilities for the 3.0-4.0 GHz band. The design is based on a novel switchable vertically crossed balanced feed (VCBF) structure using PIN diodes. The authors have provided both simulation and measurement results to validate the design. The antenna achieves a wide bandwidth, good gain, and demonstrates beam scanning across the operational band. The design concept is interesting and the paper presents a good amount of data. However, the manuscript requires significant revisions to improve its clarity, accuracy, and scientific depth. Some comments and questions for the authors are listed below:

- The paper's conclusion incorrectly states the design is based on a "varactor resonator array". It uses PIN diodes. This is a fundamental error and must be corrected throughout the manuscript if it appears elsewhere.

- The captions for Figure 3, Figure 5, and Figure 7 are incorrect and do not match the content of the figures. For example, Figure 5's caption lists incorrect frequencies for subplots (b) and (c). Please revised the figures' captions and legends thoroughly.

- The ~1.5 dBi difference between simulated and measured gain is significant. The current explanation ("fabrication tolerances, material property variations, and errors introduced during the measurement process") is too generic. The authors should provide a more detailed analysis about this discrepancy.  Could this be due to connector/cable losses not accounted for in the simulation, unexpected mutual coupling effects, or inaccuracies in the PIN diode model?

- The paper does not discuss the effect of mutual coupling between the array elements. Given the element spacing of 60 mm (~0.6λ at 3.0 GHz), coupling effects could be present. A brief analysis or discussion of S-parameters between adjacent ports would strengthen the paper.

- The text explains the bias states '00' for x-pol and '01' for y-pol. The authors should clarify if the other two possible states ('10' and '11') are used or why they are not.

- The operation of the VCBF and its biasing circuit is the core novelty but is poorly explained. The beamforming excitation setup is not described. Could you please provide a detailed schematic diagram of the VCBF feeding network, including the locations of all eight PIN diodes (D1-D8) and the DC biasing circuit for ports k1 and k2?

- The explanation for the phase calculation is poorly worded and confusing. The mention of "echoes" and "received signal" is more suited for a radar context. This section should be rewritten.

- To better situate the work, please add a comparison table that contrasts this antenna's performance (bandwidth, gain, scan range, polarization modes, size) with other state-of-the-art reconfigurable arrays from the literature.

Comments on the Quality of English Language

The overall English language is understandable, but there are numerous grammatical errors, typos, and awkward sentences that detract from the paper's professionalism.

Line 18: "scanning angles of 45, 40, and 30" - add the unit symbol for degree.

Line 18: "in the 3.0, 3.5, and 4.0 GHz" - should be "at 3.0, 3.5, and 4.0 GHz"

Line 71: "the a 4×4 array propotype"

Line 124: "in the are consistent"

Line 146: Add a space between the value and the unit: "-1.1V"

Line 173: "diodes used are the Infineon BAR64-02V [23]" - incorrect reference. The correct reference should be [27].

Line 253: "Phi=0" - use the symbol.

Line 290: "approximately 10" - add the unit symbol for degree.

Author Response

We would like to express our gratitude to Reviewer 1 for all the constructive comments and suggestions. These comments have been invaluable and greatly helpful in improving the manuscript. The revised content is highlighted in yellow in the revised version. We have fully considered all comments from Reviewer 1, and detailed responses can be found in the cover letter.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper is devoted to the modeling of multi-element radio-communication antennas. A modeled 1x8 dual-polarization reconfigurable antenna with a VCBF structure was also constructed, allowing for measurements. The measurement results are presented in clear graphs. There was a significant overlap between the simulation results and the physical measurement results. The article is practically devoid of an analytical section, making it difficult to draw conclusions about the initial assumptions, which are only briefly described. The antenna array operates in the 3-4 GHz range, ensuring its applicability in 5G/6G mobile systems. A brief state-of-the-art was also prepared, allowing for an understanding of whether similar design solutions are already in use. The article is written in an accessible manner, using relatively simple technical language, which will certainly increase its readership. To improve the quality of the paper, several corrections and extensions are recommended:

1) The motivation for the research should be clearly stated and several examples of antenna array designs that enable similar tasks to be performed on a base station or wireless access point mast should be provided.

2) A table should be provided listing the initial parameters of the antenna array, assumed before the simulation. What was the design model, and where did the initial sizes of the planar modules and the microwave paths come from?

3) The PIN diode is a key element in the antenna array, so its parameters should be cited in the body of the article, especially those crucial to the project. The summary should be presented in tabular form.

4) The simulation tool should be described, including antenna material parameters, which were partially mentioned in the body of the article. A table should also be provided.

5) Major note: A presentation of the measurement setup, including models of the measuring instruments, is appreciated.

6) Major note: The authors mention the antenna's immunity to interference, but there is a lack of analytical descriptions related to the design, as well as sample simulation or measurement results. It is recommended to add this component to the test set to confirm the predictions.

7) Other detailed minor notes:

1. Figure 1: Please label the figures, dividing them into (a) and (b);
2. Figure 1: In the figure caption, please eliminate the "=" sign if the ":" sign is used;
3. Figure 7 (b): In the figure caption, change the caption to "y-pol";
4. Line 283: For power level differences given in dBm, use the dB unit, as this is a difference in logarithms (eliminating the 1 mW reference).

Author Response

We would like to express our gratitude to Reviewer 2 for all the constructive comments and suggestions. These comments have been invaluable and greatly helpful in improving the manuscript. The revised content is highlighted in yellow in the revised version. We have fully considered all comments from Reviewer 2, and detailed responses can be found in the cover letter.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a well-designed dual-polarized reconfigurable antenna array with beam-scanning capabilities. The work is relevant and technically sound. Below are some suggestions to further strengthen the paper:

1. A deeper analysis of the operational principles of the cross-slot and parasitic patch, such as through an equivalent circuit model or parametric study.
2. The ~1.5 dBi discrepancy between measured and simulated gains should be supported by a more detailed error analysis.
3. Key measured beam-scanning metrics such as gain consistency, side-lobe levels, and beamwidth variation across scan angles should be included to fully characterize scanning performance.
4. The large element spacing (d = 60 mm) may introduce grating lobes at certain scan angles. The authors should evaluate and discuss whether grating lobes appear within the operational scan range.
5. To better contextualize the novelty and contributions of this work, the literature review could be strengthened by incorporating recent papers on reconfigurable antennas, including: DOI: 10.1109/OJAP.2023.3336762 and 10.1109/TVT.2025.3580083.

Author Response

There comments for the reviewer.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have revised the manuscript well. All concerns of the reviewer have been addressed. The manuscript is up to the mark and can be accepted for publication. 

Reviewer 2 Report

Comments and Suggestions for Authors

Almost all the reviewer comments included in the previous version of the peer-review were taken into account. Thank you for introducing corrections and explanations to the paper in accordance with the reviewer's recommendations. I have no further comments.

Reviewer 3 Report

Comments and Suggestions for Authors

The revisions have been made effectively, and the manuscript is now suitable for acceptance.