Characterization Technique for a Doppler Radar Occupancy Sensor
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn this contribution, the authors propose a technique aimed to test the performance of a single-channel continuous wave Doppler-radar based occupancy sensor.
The manuscript is well written and organized. The text is clear and the English level good.
Such a kind of test technique will be very interesting for those researchers interested in this field.
I have some minor comments:
If available, Fig. 1 might be replaced with a better-quality picture.
As described in the text, since you are using a single channel radar receiver, you are affected by the null problem. Your solution to avoid a too low SN during measurements close to the null points, is to increase the initial distance between the antenna and target by some fractional amount for each iteration. This solution works very good. However, how does your system operate in a real case, if the human subject is in the null point? Maybe you are considering that, due to the physiological random body motion, the human real motion will slightly vary from a measurement to the next one thus avoiding the null problem in at least one of two consecutive measurements (similarly to the movement reproduced by your moving reflector)?
Moreover, since you are not using an IQ receiver, what is the maximum displacement that you can measure with your radar? Are you limited to a fraction of the wavelength?
If yes, can you obtain wrong displacement measurements also for tiny physiological random body motion, whose extent will be added to the measurement? These concepts can be better explained for the readers.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe topic of this manuscript entitled: "Characterization Technique for a Doppler Radar Occupancy Sensor " falls within the profile and scope of the Electronics.
Recommendation – Consider after minor changes
In the work the Doppler-radar based occupancy sensor has been presented.
Comment:
- The configuration of emitting-receiving radar was not revealed. If it is one antenna so why in equation (1), which is the so called “radar equation”, there exist two gains (Gt and Gr). The coefficient U should also be explained for this study.
- The type of antenna should be presented to give the information about wave polarization. Vertical vs horizontal polarization results in different interference level when reflecting from floor. The antenna pattern is also useful especially along sidelobes.
- The tricorner reflector was used to simulate breathing motion. This choice should be more argued especially of RCS but in context of the angular characteristics of RCS. In addition, breathing breast motion is different forward comparing to the side directions.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe test methodology you present should be evaluated a bit more in detail. Accuracy measurements of e.g. the programmed and resulting position of the target and its moving frequency. Further the used DUT parameters (especially signal parameters) should be explained in more detail.The missing information is also present when you describe your filtering process. Here I would like to see e.g. the number of FFT points, what window function has been applied to the windowed data to reduce spectral leackage and so on. In the results section a more extensive statistical presentation of the results would be desired.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
