Patent ID: 8636953

Claim:
A SAW sensor, comprising: a piezoelectric substrate; a first IDT disposed on a main surface of the piezoelectric substrate and configured to generate a surface acoustic wave when a high-frequency signal is applied thereto; a second IDT disposed on the main surface of the piezoelectric substrate and configured to receive the surface acoustic wave from the first IDT and to convert the surface acoustic wave received into an electrical signal that is output therefrom; and a detector portion disposed on the main surface of the piezoelectric substrate at a location thereof which is between the first IDT and the second IDT, and configured to cause delay in the surface acoustic wave and to change in mass in correspondence to reaction with and/or sorption of a target provided in a specimen delivered thereto; wherein the high-frequency signal is input to the first IDT as a one pulse signal having an applying time that is at least as long as a time subtracted an arrival time of a direct wave attributable to electromagnetic coupling between the first IDT and the second IDT from a delay time of the surface acoustic wave at the detector portion, and that is less than an arrival time at the second IDT of a third response wave of the surface acoustic wave from the first IDT.