Portable Network Analyzers For Full Characterization Of FBAR Sensors: Influence Of Readout Parameters On Sensor Performance

The commercial readout electronics of thin film bulk acoustic wave resonators (FBARs) are typically implemented via free-running or phased-locked oscillators. Oscillators cannot provide the user with the full characterization of the sensor. Recently, the tendency of many network analyzer (NA) manufactures is towards miniaturized and less expensive systems. This opens up the possibility of commercializing FBARs coupled to a compact NA readout system. We have assessed how the configuration of the NA (IF bandwidth, acquisition points) directly affects the final performance of an FBAR sensor in terms of acquisition time, limit of detection and final resolution. Additionally, we have also studied how the presence of unwanted spurious modes can affect this sensor performance, despite the use of a fitting algorithm for frequency shift extraction. Acquisition times and limit of detection can be reduced below 100 ms and 0.5 kHz respectively, allowing resolutions in the fg range for our sensors.