Microwave Humidity Sensor for Early Detection of Sweat and Urine Leakage

Round 1

Reviewer 1 Report

The manuscript describes the design and experimental implementation (in a lab setting) of an hunimidity detector based in microwaves. The data seems sounds but the authours should  discuss the practical issues such:

1) which are de advantages compared to a simple conductivity sensor made of a polyelectrolyte or conducting polymer

2) how difficult is to implement the electronic device without a network analyzer.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, a humidity sensor is proposed.

Both the topic and the technology are interesting for electronics journal. However, I have some concerns related to the novelty of the paper and to the methodology used in the experimental characterization.

Probably the FUT region in Fig.1 (used in the simulation to change the dielectric constant) should be extended to the connector planes and to the edge of the board on the side of the stub. Indeed, when you immerse the sensor in the liquid, it seems unfeasible ensuring the contact only with the FUT zone of Fig. 1 (avoiding the contact with the rest of the board and connectors on that side).

It would be interesting also observing the S11 behavior.

I suggest to compare the performance and operation of your sensor with this recently published article, reporting similar results: Cardillo, E.; Tavella, F.; Ampelli, C. Microstrip Copper Nanowires Antenna Array for Connected Microwave Liquid Sensors. Sensors 2023, 23, 3750. https://doi.org/10.3390/s23073750.

From the experimental analysis, it seems that the behavior of the sensor does not depend on the dielectric constant variation but on the number of drops that is not the purpose of the paper. The authors should clarify this aspect concerning the working principle of their sensor and the methodology shown to demonstrate the sensor principle.

Moreover, the novelty compared to the existing literature might be disclosed..

The english quality is acceptable

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper (electronics-2390025) reported a microwave humidity sensor for early detection of sweat and urine leakage. The application object is interesting and the techniques used are adequate. However, there are many problems in presentation, results, and discussion and analysis. As such, a major revision is needed before possible acceptance. My specific comments are as follows:

1.        Abstract: Important performance data of the sensor should be provided.

2.        Introduction: The authors presented the research background around microwave technology, but lacked a discussion on humidity sensors, humidity sensing materials, and applications.

3.        Sensing region in Figure 1: What is the humidity sensing material for microwave humidity sensor?

4.        The humidity sensing mechanism is recommended to be described in detail, including water molecule adsorption/desorption mechanisms, and may refer to Sens. Actuators B Chem. 317 (2020) 128204.

5.        The testing system and methods for humidity sensor are unclear. How does humidity occur?

6.        The response and recovery times, as important parameters for humidity sensor, need to be provided.

7.        Does the proposed humidity sensor have sensing performance advantages? It is recommended to compare with other humidity sensors.

8.        Application demonstration needs to be provided.

9.        A space is required between units and numbers.

10.     Many references are outdated, it is recommended to cite the latest three years. In addition, the format of the references should be checked.

11.     Check English Writing.

 Minor editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors addressed all my concerns.

Reviewer 3 Report

I carefully checked the response and revised manuscript. My concerns have been considered and addressed properly, and publication is recommended.

In the proof stage, check the format requirements of the journal, such as references (correct abbreviation of journal name)