System and method for the wireless sensing of physical properties

A sensor for wirelessly determining physical properties of a medium, comprising:

• a first layer on which is disposed a first plate and an inductor coil;
• a second layer having a hole;
• a third layer on which is disposed a second plate, the first plate facing the second plate through the hole in the second layer, the first and second plates forming a capacitor, the inductor coil being electrically coupled between the first plate and the second plate;
• and,
• the capacitor and the inductor forming a self-contained resonant circuit, the capacitor being variable in response to pressure of the medium, and, the inductor being adapted to allow inducement of a current in the resonant circuit when the sensor is subjected to a time-varying electromagnetic field.

A sensor for wirelessly determining physical properties of a medium, comprising:

• a first end layer having a first plate;
• at least one middle layer having a hole and a conductive loop surrounding the hole, the conductive loops being electrically coupled thereby forming an inductive coil;
• a second end layer having a second plate, the first and second plates facing each other through the hole in said at least one middle layer forming a capacitor, the first and second plates being electrically coupled at opposite ends of the inductor coil;
• and
• the capacitor and the inductive coil forming a self-contained resonant circuit, the capacitor being variable in response to pressure of the medium, and, the inductor being adapted to allow inducement of a current in the resonant circuit when the sensor is subjected to a time-varying electromagnetic field.

A sensor for wirelessly determining physical properties of a medium, comprising:

• a self-contained resonant circuit comprising a capacitor, an inductor, and a resistor;
• the resistor being variable in response to the presence of a chemical species in a medium;
• and
• the inductor being adapted to allow the inducement of a current in the resonant circuit from a transmitted electromagnetic field.

A sensor for wirelessly determining physical properties of a medium, comprising:

• a self-contained resonant circuit comprising a capacitor, an inductor, and a resistor;
• the resistor being variable in response to the temperature of the medium, wherein a bandwidth of the resonant circuit varies with the resistance of the resistor;
• and
• the inductor being adapted to allow the inducement of a current in the resonant circuit when the sensor is subjected to a time-varying electromagnetic field.

A sensor having a resonant circuit for wirelessly determining physical properties of a medium, comprising:

• means for providing a capacitance in the resonant circuit which is variable in response to the ambient pressure of the medium;
• means for providing an inductance in the resonant circuit;
• means for providing a resistance in the resonant circuit;
• means for providing a resistance in the resonant circuit which is variable in response to the temperature of the medium;
• and
• means for inducing a current in the resonant circuit when the sensor is subjected to a time-varying electromagnetic field.

A sensor having a resonant circuit for wirelessly determining physical properties of a medium, comprising:

• means for providing a capacitance in the resonant circuit;
• means for providing an inductance in the resonant circuit;
• means for providing a resistance in the resonant circuit, the resistance being variable in response to the temperature of the medium, wherein a bandwidth of the resonant circuit varies with the resistance;
• and
• means for inducing a current in the resonant circuit when the sensor is subjected to a time-varying electromagnetic field.

A system for sensing physical properties of a medium, comprising:

• a transmitter adapted to transmit an excitation signal;
• a sensor adapted to be placed in the medium, the sensor having a resonant circuit which is capable of being electromagnetically coupled to the transmitter, the resonant circuit having a natural frequency which varies with an ambient pressure of the medium and a bandwidth which varies in response to a temperature of the medium;
• a receiver adapted to receive a modified excitation signal which results from the electromagnetic coupling of the resonant circuit to the transmitter;
• and
• a logical circuit electrically coupled to the receiver, the logical circuit being adapted to determine the ambient pressure of the medium based on the natural frequency of the resonant circuit manifested in the modified excitation signal, and the logical circuit being adapted to determine the temperature of the medium based upon a bandwidth of the resonant circuit manifested in the modified excitation signal.

A system for sensing physical properties of a medium, comprising:

• means for transmitting an excitation signal;
• a sensor adapted to be placed in the medium, the sensor having a resonant circuit which is capable of being electromagnetically coupled to the transmitter, the resonant circuit having a natural frequency which varies with an ambient pressure of the medium, and a bandwidth which varies in response to the temperature of the medium;
• means for receiving a modified excitation signal which results from the electromagnetic coupling of the resonant circuit to the transmitter;
• and
• means for determining the ambient pressure of the medium based on the natural frequency of the resonant circuit, the resonant frequency being determined from the modified excitation signal;
• and
• means for determining the temperature of the medium based upon the bandwidth of the resonant circuit, the bandwidth being determined from the modified excitation signal.

A system for sensing physical properties of a medium, comprising:

• means for transmitting an excitation signal;
• a sensor adapted to be placed in the medium, the sensor having a resonant circuit which is capable of being electromagnetically coupled to the transmitter, the resonant circuit having a natural frequency which varies with an ambient pressure of the medium, and a bandwidth which varies with a temperature of the medium;
• means for receiving a modified excitation signal which results from the electromagnetic coupling of the resonant circuit to the transmitter;
• and
• means for determining the ambient pressure of the medium based on the natural frequency of the resonant circuit, the resonant frequency being determined from the modified excitation signal;
• means for determining the temperature of the medium based upon the bandwidth of the resonant circuit, the bandwidth being determined from the modified excitation signal;
• the resonant circuit further comprising
• a predetermined inductance;
• a capacitance which varies in response to the ambient pressure of the medium, thereby altering the natural frequency of the resonant circuit;
• and
• a resistance disposed in the resonant circuit which varies in response to the temperature of the medium, thereby altering the bandwidth of the resonant circuit.

A method for sensing physical properties of a medium, comprising the steps of:

• transmitting an excitation signal;
• inducing a current in a coil inductor of a resonant circuit with the transmitted excitation signal;
• resonating the current at the natural frequency of the resonant circuit;
• varying the natural frequency of the resonant circuit with a pressure of the medium in which the resonant circuit is placed;
• varying a bandwidth of the resonant circuit in response to a temperature of the medium;
• receiving a modified excitation signal which results from the inducement of the current in the coil inductor;
• determining the pressure of the medium from the natural frequency of the resonant circuit;
• and
• determining the temperature of the medium based upon the bandwidth of the resonant circuit.

A method for sensing physical properties of a medium, comprising the steps of:

• transmitting an excitation signal;
• inducing a current in a coil inductor of a resonant circuit with the transmitted excitation signal;
• resonating the current at the natural frequency of the resonant circuit;
• varying a resistance in the resonant circuit in response to a temperature of the medium in which the resonant circuit is placed, thereby proportionally varying a bandwidth of the resonant circuit;
• receiving a modified excitation signal which results from the inducement of the current in the coil inductor;
• and
• determining the temperature of the medium from the bandwidth of the resonant circuit.

A system for sensing physical properties of a medium, comprising:

• a transmitting antenna configured to transmit a time-varying electromagnetic field into the medium;
• an impedance analyzer coupled to the transmitting antenna, the impedance analyzer determining an impedance of the transmitting antenna over a predetermined range of frequencies;
• a sensor adapted to be placed in the medium, the sensor having a resonant circuit which is capable of being electromagnetically coupled to the transmitting antenna, the resonant circuit having a bandwidth which varies with the presence of a chemical element in the medium;
• and
• a logical circuit electrically coupled to the impedance analyzer, the logical circuit being adapted to determine the presence of the chemical element in the medium based on the bandwidth of the resonant circuit as determined by the impedance analyzer.

A system for sensing physical properties of a medium, comprising:

• a transmitting means for transmitting a time-varying electromagnetic field into the medium;
• an analyzer means for determining an impedance of the transmitting means over a predetermined range of frequencies, the analyzer means being coupled to the transmitting means;
• a sensor adapted to be placed in the medium, the sensor having a resonant circuit which is capable of being electromagnetically coupled to the transmitting means, the resonant circuit having a bandwidth which varies with the presence of a chemical element in the medium;
• and
• means for determining the presence of a chemical element in the medium based on the bandwidth of the resonant circuit as determined by the analyzer means.