Passive and wireless pressure sensor

An apparatus for use with a reader circuit which has a self-resonant frequency, the apparatus comprising:

• a resonant circuit having inductive conductors;
• and
• a compressible dielectric shaped to form a plurality of separated portions tapered nearer one of the inductive conductors, and configured and arranged to deform to fill in gaps within material of the compressible dielectric in response to applied pressure for increasing effective permittivity and to support the respective inductive conductors, the inductive conductors being separated by the compressible dielectric and the compressible dielectric including separated portions of the dielectric material that are configured with the inductive conductors to compress and expand in response to changes in pressure, and to operate with the inductive conductors to provide:
• a first state in which the compressible dielectric is in a first state of compression corresponding to a first pressure applied to the compressible dielectric, and in which the resonant circuit exhibits a first resonant frequency in response to an external energy field, the first resonant frequency being based upon the first pressure, and
• a second state in which the compressible dielectric is in a second state of compression corresponding to a second pressure that is different than the first pressure applied to the compressible dielectric, and in which the resonant circuit exhibits a second resonant frequency in response to the external energy field, the second resonant frequency being based upon the second pressure and being different than the first resonant frequency, wherein the first and second resonant frequencies are greater than the self-resonant frequency of the reader circuit.

An apparatus for use with a reader circuit which has a self-resonant frequency, the apparatus comprising:

• a structured elastomeric dielectric layer configured and arranged with microstructures that are separated by gap regions, the microstructures and gap regions being configured and arranged to exhibit a changed dielectric constant of the structured elastomeric dielectric layer in response to applied pressure;
• and
• a resonant circuit including first and second inductive coils,
• the first and second inductive coils being configured and arranged with a resonant frequency that varies in response to changes in the dielectric constant due to the applied pressure, the first and second inductive coils being separated by compressible dielectric material of the structured elastomeric dielectric layer and the first and second inductive coils being positioned to rotate in opposite directions relative to one another,
• at least one of the inductive coils being configured and arranged to receive wireless energy, and
• the first and second inductive coils being configured and arranged to use the wireless energy to transmit a wireless signal that is based upon the dielectric constant and indicative of the applied pressure, wherein the resonant frequency of the resonant circuit is greater than a self-resonant frequency of the reader circuit.