On the Implementation of a Compact Vertical DC Biasing Network with Significantly Reduced RF Components for Phase-Shifter-Free Beam Steering
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPlease see the attachment.
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors present an efficient approach for reducing the number of RF components required for PIN-diode-controlled phase shifting by routing the DC bias vertically and away from the RF lines and radiating elements. The paper is well written, and the technical content is presented clearly, making it suitable for publication after addressing the following minor revisions:
1) The fabricated antenna array should be presented in greater detail, including top, bottom, and side-view photographs. The different layers, antenna elements, DC bias lines, radiators, antenna feeds, PIN diodes, and other relevant traces/components should be clearly labeled.
2) Although dual-polarization performance is presented in Figure 4, the beam steering results are only demonstrated for the co-polarized case. The beam steering performance for the cross-polarized case should also be provided.
3) The performance results shown in Figure 4 should be discussed in greater detail.
4) It is unclear whether Element 1 and Element 2 in Figure 5 correspond to the same elements labeled in Figure 1. If they are the same, the authors should clarify the polarization configuration of Element 3 in Figure 5. If they are different, the element labels in Figure 5 should be renamed to avoid confusion with the elements shown in Figure 1.
5) In the comparison table, the authors should also include the phase-shift ranges achieved in the referenced works.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper presents a design for a compact dual polarized antenna element that utilizes a vertical DC biasing network to significantly reduce the quantity of RF choke inductors required for phase control to achieve beam steering at 3.5 GHz. I have the following comments:
- It would be good to complement the introduction with applications on beam steering such as wireless communications and sensing [REF01].
- Please explain how does the localized heating of the PIN diodes during the ON state affect the dielectric properties of the F4B substrate, specifically the $\epsilon_r=4.2$ value?
- Why was a substrate thickness of 0.502 mm chosen for both the radiator and the bias network given that thinner substrates often lead to narrower impedance bandwidths also the operating band is 3.4 to 3.6 GHz.
- Explain how the transition between U1D0 and U0D1 affects the overall quality factor of the radiating element.
- How does the complexity of the vertical DC biasing network scale as the array size increases from 1x3 element configuration to a larger NxM architecture?
- Kindly simulate the active reflection coefficient for all three beam states to ensure impedance stability during steering.
- Please provide more information on the design. For instance, what is the maximum RF power that the phase control structure can handle before the PIN diodes reach their nonlinear region?
- It would be good to a add a discussion section on potential applications of the proposed compact dual polarized antenna element.
- Kindly rewrite the conclusions better to better represent the findings of the paper.
References
[REF01] “On the Secrecy-Sensing Optimization of RIS-assisted Full-Duplex Integrated Sensing and Communication Network.” in IEEE Transactions on Wireless Communications, vol. 25, pp. 9530-9547, 2026, doi: 10.1109/TWC.2025.3645048
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe reviewer has no question.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe reviewer has no further comments.
