Phase detection of the two-port FPW sensor for biosensing

This study reports the phase detection of the two-port flexural plate wave (FPW) sensor for designing and integrating the miniature system and provides a comprehensive methodology for portable using in the biosensor applications of severe acute respiratory syndrome coronavirus (SARS-CoV). The miniature system mainly utilizes the concept of the frequency divider that involves a divider, a time-based oscillator and a gate to reduce the high frequency, and the FPW sensor is fabricated using microelectromechanical systems (MEMS) technologies for producing a potable biosensing detector. The results demonstrate that the insertion loss decreased about -1.15% dB/degrees C, and the phase delay was about 2.05 degrees/(1000 cP). The phaseshift resolution was about 10 mV per degree, and the original frequency of 4.2 MHz was divided by 100 to reduce the frequency to 42 kHz. The SARS-CoV could be detected via the S protein binds to the human angiotensin-converting enzyme 2 (hACE2) as a functional receptor, which would cause the phase delay due to the combining of the antibody with the antigen. Therefore, the feasibility studies provide the information that phase detection is an appropriate low-cost technology via frequency divider for fabricating of the miniature biosensors.