Abstract: A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

Abstract: Improved surface acoustic wave structures (or elements) that can be used to realize any of a wide variety of dispersive or non-dispersive transversal SAW filters that are distinct from prior known means for producing such filters are disclosed. The devices and structures may include stepped acoustic wave delay modification elements that can be used to implement transversal filter impulse response functions in a manner analogous to the use of interdigital transducers. The structures disclosed are of particular usefulness to implement SAW devices at high frequencies where normal photolithographic resolution would prove limiting. Aspects and embodiments of the present invention would be useful to produce SAW devices for use in a wide variety of applications, including as components in cell phones, in radar and other communications and electronic systems, and as wired or wireless sensors or sensor-tags.

Abstract: Enhanced surface acoustic wave (SAW) sensors and SAW sensor-tag wireless interface devices, including low loss devices, devices that enable enhanced use of time diversity for device identification, and devices suitable for use in band-limited environments (such as ISM band) and for use in ultra-wideband applications are disclosed. Antennas for use with both SAW sensors and/or tags, and wireless transceiver systems also are disclosed, including antennas suitable for operation in conductive media and in highly metallic environments, said antennas being used to activate and read said SAW sensors and/or tags. SAW sensors and sensor-tags and related methods for measuring scaled voltage and current in electrical conductors via measurements of the electric and magnetic fields thereof are disclosed.

Abstract: Enhanced surface acoustic wave (SAW) sensors and SAW sensor-tag wireless interface devices, including low loss devices, devices that enable enhanced use of time diversity for device identification, and devices suitable for use in band-limited environments (such as ISM band) and for use in ultra-wideband applications are disclosed. Antennas for use with both SAW sensors and/or tags, and wireless transceiver systems also are disclosed, including antennas suitable for operation in conductive media and in highly metallic environments, said antennas being used to activate and read said SAW sensors and/or tags. SAW sensors and sensor-tags and related methods for measuring scaled voltage and current in electrical conductors via measurements of the electric and magnetic fields thereof are disclosed.

Abstract: Enhanced surface acoustic wave (SAW) sensors and SAW sensor-tag wireless interface devices, including low loss devices, devices that enable enhanced use of time diversity for device identification, and devices suitable for use in band-limited environments (such as ISM band) and for use in ultra-wideband applications are disclosed. Antennas for use with both SAW sensors and/or tags, and wireless transceiver systems also are disclosed, including antennas suitable for operation in conductive media and in highly metallic environments, said antennas being used to activate and read said SAW sensors and/or tags. SAW sensors and sensor-tags and related methods for measuring scaled voltage and current in electrical conductors via measurements of the electric and magnetic fields thereof are disclosed.

Abstract: A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

Abstract: Enhanced surface acoustic wave (SAW) sensors and SAW sensor-tag wireless interface devices, including low loss devices, devices that enable enhanced use of time diversity for device identification, and devices suitable for use in band-limited environments (such as ISM band) and for use in ultra-wideband applications are disclosed. Antennas for use with both SAW sensors and/or tags, and wireless transceiver systems also are disclosed, including antennas suitable for operation in conductive media and in highly metallic environments, said antennas being used to activate and read said SAW sensors and/or tags. SAW sensors and sensor-tags and related methods for measuring scaled voltage and current in electrical conductors via measurements of the electric and magnetic fields thereof are disclosed.

Abstract: A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

Abstract: The subject of the present invention is a set of SAW (surface acoustic wave) based sensor tag device embodiments system for remotely sensing and/or providing identification information. These sensor/tag devices would operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification number and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. As such the device is elegantly simple, low-cost, and rugged. The device is wirelessly interrogated by the interrogator which is described elsewhere.

Abstract: An apparatus and method for distinguishing between sensors that are to be wirelessly detected is provided. An interrogator device uses different, distinct time delays in the sensing signals when interrogating the sensors. The sensors are provided with different distinct pedestal delays. Sensors that have the same pedestal delay as the delay selected by the interrogator are detected by the interrogator whereas other sensors with different pedestal delays are not sensed. Multiple sensors with a given pedestal delay are provided with different codes so as to be distinguished from one another by the interrogator. The interrogator uses a signal that is transmitted to the sensor and returned by the sensor for combination and integration with the reference signal that has been processed by a function. The sensor may be a surface acoustic wave device having a differential impulse response with a power spectral density consisting of lobes.

Abstract: A surface acoustic wave device includes a piezoelectric substrate on which is formed a transducer that generates acoustic waves on the surface of the substrate from electrical waves received by the transducer. The waves are carried along an acoustic track to either a second transducer or a reflector. The transducers or transducer and reflector are formed of subsections that are constructed to operate at mutually different frequencies. The subsections of at least one of the transducers or transducer and reflector are out of alignment with respect to one another relative to the transverse of the propagation direction. The out of aligned subsections provide not only a frequency component but also a time to the signal output signal. Frequency response characteristics are improved. An alternative embodiment provides that the transducers and/or reflectors are continuously tapered instead of having discrete frequency subsections.

Abstract: The subject of the present invention is a set of SAW (surface acoustic wave) based sensor tag device embodiments system for remotely sensing and/or providing identification information. These sensor/tag devices would operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification number and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. As such the device is elegantly simple, low-cost, and rugged. The device is wirelessly interrogated by the interrogator which is described elsewhere.

Abstract: An apparatus and method for distinguishing between sensors that are to be wirelessly detected is provided. An interrogator device uses different, distinct time delays in the sensing signals when interrogating the sensors. The sensors are provided with different distinct pedestal delays. Sensors that have the same pedestal delay as the delay selected by the interrogator are detected by the interrogator whereas other sensors with different pedestal delays are not sensed. Multiple sensors with a given pedestal delay are provided with different codes so as to be distinguished from one another by the interrogator. The interrogator uses a signal that is transmitted to the sensor and returned by the sensor for combination and integration with the reference signal that has been processed by a function. The sensor may be a surface acoustic wave device having a differential impulse response with a power spectral density consisting of lobes.

Abstract: A temperature measurement system is characterized by at least one passive surface acoustic wave (SAW) temperature sensor. The sensor includes at least one piezoelectric substrate having an interdigital SAW transducer disposed upon the piezoelectric substrate for conversion of an RF signal into an acoustic wave and vice versa. At least three additional SAW elements are also disposed on the substrates in a manner such that they define two acoustic propagation paths that are non-parallel relative to the crystal axes of the substrates, and such that the temperature coefficients of delay in the two tracks differ. The SAW elements receive a signal from the SAW transducer and produce response signals. The response signals combine to produce a signal with a power spectral density such that the integrated power within each of two specified portions of the spectrum provides an indicator of the temperature.

Abstract: A surface acoustic wave device includes a piezoelectric substrate on which is formed a transducer that generates acoustic waves on the surface of the substrate from electrical waves received by the transducer. The waves are carried along an acoustic track to either a second transducer or a reflector. The transducers or transducer and reflector are formed of subsections that are constructed to operate at mutually different frequencies. The subsections of at least one of the transducers or transducer and reflector are out of alignment with respect to one another relative to the transverse of the propagation direction. The out of aligned subsections provide not only a frequency component but also a time to the signal output signal. Frequency response characteristics are improved. An alternative embodiment provides that the transducers and/or reflectors are continuously tapered instead of having discrete frequency subsections.

Abstract: A hydrogen detecting system is characterized by a passive surface acoustic wave (SAW) sensor. The sensor includes a piezoelectric substrate having a self assembled monolayer arranged on at least a portion of the substrate to create a hydrophobic surface. A palladium nanocluster thin film is deposited on the monolayer and an interdigital SAW transducer is disposed upon the piezoelectric substrate for conversion of an RF signal into an acoustic wave and vice versa. At least one additional SAW element is also disposed on the substrate and spaced from the SAW transducer. The SAW element receives a signal from the SAW transducer and produces a response signal. The response signal is modified by the palladium nanocluster film due to a change in conductivity of the palladium nanocluster film upon exposure to hydrogen. This change in the response signal is measured by an interrogator, and yields a measure of the hydrogen concentration to which the sensor was exposed.

Abstract: A surface acoustic wave (SAW) sensor and an interrogator that transmits a noise source to the sensor for receiving an interrogation signal that is processed and compared to the source signal provides pressure and temperature measurements. One SAW sensor a single interdigital transducer serving as both an input and an output transducer for generating and detecting a SAW, and coded reflectors in a mirrored arrangement opposing the single interdigital transducer. The piezoelectric substrate is supported in a hermetically sealed package such that pressure on the package causes distortion of the substrate transducer surface and thus SAW velocity changes that reflect changes in pressure. Characteristic temperature coefficients of delay for the substrate are directly translated into a temperature value.

Abstract: A pressure and temperature sensor includes a sealed insulating package and an elastic, piezoelectric substrate deformably supported within the package. At least three surface-acoustic-wave resonators are affixed to a bottom of the substrate. A first and a second resonator are positioned in parallel relation along the substrate. A third resonator has a long axis nonparallel to the long axes of the first and the second resonator. The temperature coefficients of the first and second resonators are substantially equivalent; that of the third is different from those of the first and the second resonator, for permitting a temperature change to be sensed. Electrical connectors extend between the resonators to the outside of the package. A sensing system also includes an antenna for sending and receiving electromagnetic signals to and from the device.

Abstract: Surface-acoustic-wave transducers include interdigital electrode fingers alternately connected to hot and ground bus bars. The gap between two adjacent electrodes has a relative tap weight proportional to the voltage difference between the two electrodes. A set of subtransducers connected in series, a string, has two ends that are connected to the major bus bars; several strings are connectable to a single pair of major bus bars. In string weighting a plurality of strings make up the number of different tap weights within the transducer. Here every subtransducer is preferably of minimal length, for example, nominally one wavelength. Since the full bus bar voltage is divided equally between the N subtransducers, the voltage at each tap is 1/N, and the length of the string is nominally N+1 wavelengths. Therefore, for a length of the transducer all taps have the same tap weight within each string.

Abstract: Surface-acoustic-wave transducers include interdigital electrode fingers alternately connected to hot and ground bus bars. The gap between two adjacent electrodes has a relative tap weight proportional to the voltage difference between the two electrodes. A set of subtransducers connected in series, a string, has two ends that are connected to the major bus bars; several strings are connectable to a single pair of major bus bars. In string weighting a plurality of strings make up the number of different tap weights within the transducer. Here every subtransducer is preferably of minimal length, for example, nominally one wavelength. Since the full bus bar voltage is divided equally between the N subtransducers, the voltage at each tap is 1/N, and the length of the string is nominally N+1 wavelengths. Therefore, for a length of the transducer all taps have the same tap weight within each string.