Remote excitation of a bulk acoustic wave sensing platform

The remote excitation of the transverse shear mode (TSM) in bare AT-cut quartz crystals used in sensor applications would eliminate the deleterious effects introduced by the electrodes deposited on the quartz crystal. Antenna structures ranging from spiral coil antennas to simple line antennas have been examined for remote TSM excitation. However, factors such as the antenna type and orientation, the orientation of the crystals relative to the electric field emanating from the antenna and the geometry of the quartz sample, all of which are critical to efficient TSM excitation were often not addressed. In the present work, a study of the remote excitation of the TSM in AT-cut quartz as a function of the afore mentioned factors is performed. All of these factors were found to be critical to efficient TSM excitation. Finally, it is demonstrated that an electrode-less sensor array can be realized to detect multiple target analytes.