Liquid Metal-Based Frequency and Pattern Reconfigurable Yagi Antenna for Pressure Sensing

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

Title: Liquid Metal-Based Frequency and Pattern Reconfigurable Yagi Antenna for Pressure Sensing

Manuscript ID: sensors-3390690

In this paper, the author proposes a frequency and pattern reconfigurable Yagi antenna based on liquid metal switches for pressure sensing and health monitoring. The idea of this paper is not new. However, the paper is well organized. Reviewer has some comments below:

1. Provide the far-field distribution of the antenna.

2. Can the author describe the effects of pressure on an antenna using mathematical formulas?

3. The paper lacks a clear explanation of how the LM switches operate under different pressure levels. While the relationship between stress and resistance is mentioned, the detailed mechanism of how this affects the antenna's performance needs to be elaborated.

4. How does the performance of this proposal compare to antennas using PIN diodes or MEMS switches?

5. The paper mentions potential applications in health monitoring and stress sensing but does not provide experimental results for these use cases. Please discuss it in more detail.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The quality of English meets the requirement of Sensors.

Author Response

Please see attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is interesting work, however, some suggestions are:

1. consider the life time for such switch, how many bending can it last?

2. for automatical operation, will bending manichanisim (not shown in this paper yet) affects the performance of the radiation?

3. how much force is required for stress the switch, will the on/off changes linear to the force applied?

 

Author Response

Dear editor and reviewer:

Thank you for your email (dated January 24, 2025) in which you attached the reviewers and your valuable comments on our manuscript, titled “Liquid Metal-Based Frequency and Pattern Reconfigurable Yagi Antenna for Pressure Sensing” by Xiaofeng Yang, Xiang Ma, Jiayi Yang, Yang Li, Meiping Peng and Qi Zheng. The authors would like to thank you and the anonymous reviewers for careful reading as well as constructive and thoughtful suggestions. These comments and suggestions have significantly helped the authors to improve the quality of the paper. Moreover, they have also motivated the authors to carefully and deeply think over this research topic. Corresponding modifications have been made in the revised manuscript.

We have carefully revised the manuscript based on the suggestions provided by the reviewers, and the main parts of the revisions are highlighted in red. Below is the authors' detailed responses to the reviewers' suggestions. The reviewers' comments have been highlighted in italic and bold.

 

Sincerely yours,

Corresponding author: Meiping Peng

School of Information Engineering

Shaoguan University

Shaoguan, CHINA, 512005

 

• consider the life time for such switch, how many bending can it last?

Reply: Thanks for reminding us. The durability of liquid metal switches is good, after tens of thousands of presses and bends, the liquid metal switch can still be controlled to turn on and off through pressure.

 

2、for automatical operation, will bending manichanisim (not shown in this paper yet) affects the performance of the radiation? 

Reply: Thanks for reminding us. It will not affect. The radiator in this design is mainly dipole, and the liquid metal switch mainly affects the length of the reflector/director. The liquid metal switch will not affect the radiator.

 

3、how much force is required for stress the switch, will the on/off changes linear to the force applied?

Reply: Thanks for reminding us. When the pressure applied by the switch is in the range of 0N to 90N, the switch changes linearly with the applied force. When the pressure applied by the switch is greater than 90N, the switch resistance increases sharply, and the switch changes nonlinearly with the applied force. The switch state is open.

Reviewer 3 Report

Comments and Suggestions for Authors

1. In terms of antenna design analysis
   • Refinement of the optimization analysis of the antenna topology design: Although the current paper mentions the antenna topology design for the 2.4G working center frequency and gives the overall structure of the antenna, the switch position, and the antenna size data in Figure 1, the process of optimizing the antenna structure and size is not discussed. Further in-depth analysis can be carried out. For example, elaborate on the principle of the antenna structure design and explain how the final detailed parameters of the antenna size are optimized through analysis, with the help of antenna theory, so that readers can have a deeper understanding of the working mechanism of the antenna design. This is of great help in highlighting the importance of the subsequent antenna testing work.
   • In - depth analysis of the liquid metal switch design: When introducing the liquid metal switch design, it briefly describes the fiber - flexible structure of the liquid metal switch and the manufacturing process, but does not provide a detailed description of the switch design process. In - depth analysis should be carried out on the design process of the liquid metal switch of the antenna and its working micro - mechanism. Appropriate theoretical knowledge such as Faraday's law of electromagnetic induction should be combined for more detailed mathematical derivation and physical explanation, enabling readers to clearly understand the micro - mechanism of the response of the designed antenna switch.
2. In terms of simulation analysis research
   • A more comprehensive parameter sensitivity analysis and optimization are needed. Although the paper analyzes the relationship between some antenna parameters (such as the sleeve gap length, antenna size, etc.) and the antenna return loss S11 parameter and resonant frequency, as well as their impact on the antenna impedance matching, and also simulates and analyzes the S11 parameters and radiation patterns of the antenna in 4 states, it does not provide a detailed description of the 4 antenna states. Based on further description of the 4 antenna working states, the reasons for the different S11 parameters, single - direction patterns, bi - direction patterns, and opposite - direction patterns in the simulation can be analyzed in combination with the antenna radio - frequency radiation theory. Expand the scope of parameter research to obtain an antenna parameter configuration with better comprehensive performance, instead of just determining the optimal parameters based on the current simple simulation of parameter changes.
3. In terms of deepening the result discussion and application prospect
   • In - depth discussion on the comparison with existing antenna reconfiguration methods and technologies: In the conclusion part of the paper, although the advantages and application value of the designed antenna are elaborated, it should be further comprehensively and deeply compared with existing other antenna reconfiguration methods and technologies (such as PIN diodes, micro - electromechanical system switches, varactor diodes mentioned in the paper). Compare not only the intuitive indicators such as the working frequency band and size, but also conduct a detailed comparative analysis from multiple aspects such as monitoring accuracy, anti - interference ability, cost - effectiveness, and design difficulty. Clearly highlight the unique advantages and innovation points of the proposed liquid - metal frequency and pattern reconfigurable Yagi antenna, and objectively point out its limitations and improvement directions, so that readers can have a more accurate understanding of the status and development potential of this technology in the entire field.

Author Response

Please see attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

As revised manuscript shown, it has addressed all the relevant points that reviewers required and commented.

It is suggested to accept the manuscript in this form for publication in Sensors (MDPI).