Abstract: A coupling loop or antenna is provided that can be used with a system that determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. A cable attached to the coupling loop provides maximum isolation between the energizing signal and the sensor signal by maximizing the distance between the coaxial cables that carry the signals and maintaining the relative positions of the coaxial cables throughout the cable assembly.

Abstract: The present invention determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency or set of frequencies and a predetermined amplitude. The energizing signal is coupled to the sensor via magnetic coupling and induces a current in the sensor which oscillates at the resonant frequency of the sensor. The system receives the ring down response of the sensor via magnetic coupling and determines the resonant frequency of the sensor, which is used to calculate the measured physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal.

Abstract: The present invention determines the resonant frequency of a wireless sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency. The system receives the ring down response of the sensor and determines the resonant frequency of the sensor, which is used to calculate a physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal. The system identifies false locks by detecting an unwanted beat frequency in the coupled signal, as well as determining whether the coupled signal exhibits pulsatile characteristics that correspond to a periodic physiological characteristic, such as blood pressure.

Abstract: The present invention determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency or set of frequencies and a predetermined amplitude. The energizing signal is coupled to the sensor via magnetic coupling and induces a current in the sensor which oscillates at the resonant frequency of the sensor. The system receives the ring down response of the sensor via magnetic coupling and determines the resonant frequency of the sensor, which is used to calculate the measured physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal.

Abstract: A sensor suitable for in vivo implantation has a capacitive circuit and a three-dimensional inductor coil connected to the capacitive circuit to form an LC circuit. The LC circuit is hermetically encapsulated within an electrically insulating housing. An electrical characteristic of the LC circuit is responsive to a change in an environmental parameter.

Abstract: A sensor for wirelessly determining a physical property within a defined space comprises an electrical resonance and has a high quality factor Q. The quality factor Q is sufficiently high that a signal generated by the sensor can be received outside the defined space. The sensor may optimally have a dielectric coating.

Abstract: A coupling loop or antenna is provided that can be used with a system that determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The coupling loop includes multiple loops. Preferably two tuned loops are used for transmitting the energizing signal to the sensor and an un-tuned loop is used for receiving the sensor signal from the sensor. Orientation features on the housing for the coupling loop and the sensor are provided to assist in positioning the coupling loop relative to the sensor to maximize the coupling between the sensor signal and the coupling loop.

Abstract: In the disclosed method of manufacturing an implantable wireless sensor, a cavity is etched in one side of a first substrate. A conductive structureare formed on the base of the cavity. A second conductive structureare formed on a surface of a second substrate, and the two substrates are mutually imposed such that the two conductive plates and coils are disposed in opposed, spaced-apart relation. A laser is then used to cut away perimeter portions of the imposed substrates and simultaneously to heat bond the two substrates together such that the cavity in the first substrate is hermetically sealed.

Abstract: The present invention determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency or set of frequencies and a predetermined amplitude. The energizing signal is coupled to the sensor via magnetic coupling and induces a current in the sensor which oscillates at the resonant frequency of the sensor. The system receives the ring down response of the sensor via magnetic coupling and determines the resonant frequency of the sensor, which is used to calculate the measured physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal.

Abstract: The progress of a endovascular aneurysm repair can be monitored by inserting a pressure transducer sensor using a catheter into the sac during endovascular aneurysm repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of loading the sensor into a catheter, and deploying into the aneurysm sac. This invention also has other applications for measuring physical properties in patients or in other sites.

Abstract: Apparatus for probing, sensing, testing penetrating and sampling a medium generally includes an actuator (12) for generating vibrations at ultrasonic frequencies and a horn (14) coupled to the actuator (12) for amplifying the actuator vibrations along with a non-rotating coring and drilling bit (16) for penetrating the medium. A bit (16) includes a drill stem (20) attached to the horn (14) and a bore (26) extends through the bit (16), horn (14) and actuator (12) for withdrawal of samples. A free mass (36) is disposed between the horn (14) and the drill stem (20) for oscillating therebetween in response to the actuator vibration for causing migration of medium debris around and through the actuator bore for effectively self-cleaning of the bit (16). The hammering action of the free mass (36) is used for penetration of the medium and for analysis of the medium though the use of spaced apart accelerometers (92 and 94).

Abstract: The progress of a endovascular cardiac repair can be monitored by inserting a pressure transducer sensor using a catheter into a chamber of the heart during endovascular repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of folding or rolling the sensor into a cylinder, loading it into a catheter, and deploying into the heart chamber by allowing it to unroll or unfold, either by itself or facilitated by the incorporation of a super-elastic alloy component.

Abstract: The progress of a endovascular cardiac repair can be monitored by inserting a pressure transducer sensor using a catheter into a chamber of the heart during endovascular repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of folding or rolling the sensor into a cylinder, loading it into a catheter, and deploying into the heart chamber by allowing it to unroll or unfold, either by itself or facilitated by the incorporation of a super-elastic alloy component.

Abstract: Apparatus for probing, sensing, testing penetrating and sampling a medium generally includes an actuator (12) for generating vibrations at ultrasonic frequencies and a horn (14) coupled to the actuator (12) for amplifying the actuator vibrations along with a non-rotating coring and drilling bit (16) for penetrating the medium. A bit (16) includes a drill stem (20) attached to the horn (14) and a bore (26) extends through the bit (16), horn (14) and actuator (12) for withdrawal of samples. A free mass (36) is disposed between the horn (14) and the drill stem (20) for oscillating therebetween in response to the actuator vibration for causing migration of medium debris around and through the actuator bore for effectively self-cleaning of the bit (16). The hammering action of the free mass (36) is used for penetration of the medium and for analysis of the medium though the use of spaced apart accelerometers (92 and 94).

Abstract: The progress of a endovascular aneurysm repair can be monitored by inserting a pressure transducer sensor using a catheter into the sac during endovascular aneurysm repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of folding or rolling the sensor into a cylinder, loading it into a catheter, and deploying into the aneurysm sac by allowing it to unroll or unfold, either by itself or facilitated by the incorporation of a super-elastic alloy component.

Abstract: The progress of a endovascular cardiac repair can be monitored by inserting a pressure transducer sensor using a catheter into a chamber of the heart during endovascular repair and then using a small, hand-held read out device to measure pressure easily, safely, inexpensively and accurately. In one aspect a sensor is introduced into the body by the steps of folding or rolling the sensor into a cylinder, loading it into a catheter, and deploying into the heart chamber by allowing it to unroll or unfold, either by itself or facilitated by the incorporation of a super-elastic alloy component.