I'm interested in using the Radar sensor SEN0306 for proximity detection of obstacles in front of a moving object. However, unless you have a profound knowledge of radar technology, the tutorial at https://wiki.dfrobot.com/24GHz_Microwave_Radar_Sensor_SKU:%20SEN0306 leaves some questions:

1. How does does the module detect multiple objects based on spectral lines exactly? From what I understood, every object throws back a phase shifted version of the transmitted signal and from the distance of this shift, the distance of the object is deduced. Is that about right?

2. Is the sensor able to penetrate objects? Is it possible that certain objects won't reflect at all?

3. I'd like to enclose the sensor in a weatherproof housing. Can it be covered with, say, 2-3 mm of ABS plastic and still function?

4. What happens if you have more than 5 objects? Is the sensor guaranteed to at least return the closest one?

5. What happens if an object is closer than 50cm?