Patent ID: 7456752

Claim:
A fluid sensor comprising: a substrate; and a tuned RLC circuit configured on the substrate, the tuned RLC circuit including an inductor coil and a capacitor coupled through said substrate, and a film configured to limit exposure of the inductor coil to fluid, the film having one or more windows positioned such that fluid exposure is defined by the one or more windows, wherein fluid introduced through the one or more windows can cause a short in the RLC circuit; wherein an exposure to an electrically conductive fluid causes a shift in resonant frequency form a first to a second non-zero frequency through a change in inductance of the circuit; wherein the one or more windows in the film is covered with a material that becomes conductive upon exposure to a fluid containing a specific component or class of components and; wherein there are multiple windows at least two of which are independently covered with differing receptive/reactive compounds that become conductive in response to exposure to differing components of the fluid.