Surface acoustic wave sensor or identification device with biosensing capability
A surface acoustic wave sensor or identification device has a piezoelectric material, and an interdigitated transducer (IDT) input/output mounted on the piezoelectric material for receiving a radio frequency (RF) signal and propagating a corresponding surface acoustic wave along a surface of the piezoelectric material. An IDT finger electrode array is mounted on the piezoelectric material and is operable to communicate with the IDT input/output for transmission of a modified RF signal from the device. The IDT finger electrode array has at least one finger electrode segment whose propagating characteristics are controlled to control the nature of the modified RF signal. A biolayer is mounted on the piezoelectric material and is associated with the finger electrode segment, and a fluidic chamber is associated with the biolayer. In use, the fluidic chamber contains fluid which, if a predetermined substance to be sensed or detected is present, operates to modify the biolayer which in turn controls the nature of the modified RF signal.
1. A surface acoustic wave sensor or identification device having:
a piezoelectric material,
an interdigitated transducer (IDT) input/output mounted on the piezoelectric material for receiving a radio frequency (RF) signal and propagating a corresponding surface acoustic wave along a surface of the piezoelectric material,
an IDT finger electrode array mounted on the piezoelectric material and operable to communicate with the IDT input/output for transmission of a modified RF signal from the device,
said IDT finger electrode array having at least one finger electrode segment whose propagating characteristics are controlled to control the nature of the modified RF signal,
a biolayer mounted on the piezoelectric material and associated with the finger electrode segment, and
a fluidic chamber associated with the biolayer and which in use contains fluid which, if a predetermined substance to be sensed or detected is present, operates to modify the biolayer which in turn controls the nature of the modified RF signal.
2. A sensor or identification device according to claim 1 wherein the IDT finger electrode array comprises a reflector array.
3. A sensor or identification device according to claim 1 wherein the IDT finger electrode segment comprises a modulated IDT array.
4. A sensor or identification device according to claim 1 wherein the fluidic chamber has an inlet and an outlet whereby in use the fluid flows through the chamber from the inlet to the outlet.
5. A sensor or identification device according to claim 1 wherein said at least one finger electrode segment has at least one pair of interdigitated fingers which communicate with the fluidic chamber.
6. A sensor or identification device according to claim 5 wherein said at least one pair of interdigitated fingers project into the chamber.
7. A sensor or identification device according to claim 1 wherein the modified RF signal is detected within a detection algorithm located within the main interrogation unit.
8. A detection algorithm according to claim 7 wherein the modified RF signal is detected by comparison to a reference frequency.
9. A detection algorithm according to claim 7 wherein the modified RF signal is detected by comparison to a reference phase.
10. A detection algorithm according to claim 7 wherein the modified RF signal is detected by comparison to a reference modulation code.