Experimental validation of a novel bulk acoustic wave sensor read-out circuit

Abstract

The feasibility of the scheme to realize the novel bulk acoustic wave (BAW) sensor readout circuit has been verified by simulation, but further experimental verification is needed. Using the film bulk acoustic resonator (FBAR) with about 1.5 GHz series resonant frequency as the device under test (DUT), we designed and fabricated microstrip six-port network and detector on PCB which meet the requirements of FBAR resonant frequency measurement bandwidth (1.3 – 1.7 GHz). We obtained the measurement result of the reflection coefficient frequency (Γ-f) curve of the simulated DUT (50 Ω SMA matched load) by using radio frequency signal generator and oscilloscope. Comparing the measurement results from six-port reflectometer and vector network analyzer (VNA), we found they were quite consistent. We verified through experiment that “the six-port reflectometer-based BAW sensor readout circuit” can be used for the measurement of FBAR resonant frequency. Our research is useful for the practical BAW sensor development and the VNA on a chip (VNA-on-chip) design.