Patch array antenna for non-contact sensor to detect respiratory movement

Recently, numerous people are suffering from sleep apnea syndrome which is the respiratory problem during sleep, and lack of sleep would cause traffic accidents or even other diseases such as lifestyle-related diseases. In fact, it is quite difficult to be aware of those who have. This paper tries to solve early awareness by proposing a patch array antenna, which is designed for non-contact sensor to detect respiratory movement. The authors propose a four-element antenna to have the beam directivity that is changeable to the desired direction. The design and its calculation results are described.