Abstract: Packages for wireless temperature sensor nodes are described. These wireless temperature sensor nodes are suitable for sensing the temperature of remote objects, such as objects that are difficult to access. These packages are designed to enhance the sensor's ability to sense temperature. For example, these packages may be designed to provide a low thermal resistance path between the object and the temperature sensor, a high thermal resistance between an antenna of the wireless temperature sensor node and the object, and at least in some embodiments, immunity to vibrations. One such package includes means for providing a thermal conductive path from the temperature sensor to a thermally conductive support in contact with the object (for example with a thermal resistance less than 10 K/W), and means for thermally conductively decoupling the circuit board from the thermally conductive support (for example by at least 100 K/W).

Abstract: Described herein are techniques for improving the signal-to-noise ratio of a wireless sensor platform. The device that interrogates a wireless sensor node (an interrogator) may be configured to determine the quantity to be measured by extracting information from multiple echoes produced in response to multiple interrogation pulses or produced due to multi-path propagation. Although different echoes may have been transformed to different extents, the echoes may share unique characteristics that are specific to the wireless sensor node that produced them. Accordingly, the SNR may be improved by keeping only portions of the received signal that exhibit such characteristics. The SNR may be further improved by summing the echoes together. In some embodiments, the echoes may be summed together in a coherent fashion, thereby producing an echo having an amplitude greater than the amplitude of each of the received echoes.

Abstract: Columnar multi-axis microelectromechanical systems (MEMS) devices (such as gyroscopes) balanced against undesired linear and angular vibration are described herein. In some embodiments, the columnar MEMS device may comprise at least two multiple-mass columns, each having at least three proof masses and being configured to sense rotation about a respective axis. The motion and mass of the proof masses may be controlled to achieve linear and rotational balancing of the MEMS device. The columnar MEMS device may further comprise one or more modular drive structures disposed alongside each multiple-mass column to facilitate displacement of the proof masses of a respective column. The MEMS devices described herein may be used to sense roll, yaw, and pitch angular rates.

Abstract: Remote keyless entry (RKE) systems and devices are described. The RKE devices include one or more passive radios that respond to an interrogation signal from an interrogating device such as a vehicle. The passive radio sends a responsive signal that can include a decaying portion representing a ringdown signal. The passive radio includes a SAW resonator in some situations.

Abstract: A passive wireless sensor may be wirelessly coupled with an interrogator. The sensor uses multiple antennas to receive an interrogation signal from the interrogator and compares a path length difference between the signal received at each antenna. The path length difference changes based on the relative position of the sensor and interrogator. Using the path length difference, the sensor transmits a response signal to the interrogator. The interrogator analyzes the response signal to determine sensor position. The interrogator compares the determined sensor position to a previous known sensor position to determine if an attack has occurred, such as a replay, counterfeit, or tampering attack. The sensor may include cryptographic circuitry that scrambles the response signal, thwarting an attack such as a sniffing attack. The interrogator may include multiple antennas and determine a position of the sensor by calculating an angle-of-arrival that enhances a signal from the sensor, via beamforming.

Abstract: Columnar multi-axis microelectromechanical systems (MEMS) devices (such as gyroscopes) balanced against undesired linear and angular vibration are described herein. In some embodiments, the columnar MEMS device may comprise at least two multiple-mass columns, each having at least three proof masses and being configured to sense rotation about a respective axis. The motion and mass of the proof masses may be controlled to achieve linear and rotational balancing of the MEMS device. The columnar MEMS device may further comprise one or more modular drive structures disposed alongside each multiple-mass column to facilitate displacement of the proof masses of a respective column. The MEMS devices described herein may be used to sense roll, yaw, and pitch angular rates.

Abstract: A passive wireless sensor may be wirelessly coupled with an interrogator. The sensor uses multiple antennas to receive an interrogation signal from the interrogator and compares a path length difference between the signal received at each antenna. The path length difference changes based on the relative position of the sensor and interrogator. Using the path length difference, the sensor transmits a response signal to the interrogator. The interrogator analyzes the response signal to determine sensor position. The interrogator compares the determined sensor position to a previous known sensor position to determine if an attack has occurred, such as a replay, counterfeit, or tampering attack. The sensor may include cryptographic circuitry that scrambles the response signal, thwarting an attack such as a sniffing attack. The interrogator may include multiple antennas and determine a position of the sensor by calculating an angle-of-arrival that enhances a signal from the sensor, via beamforming.

Abstract: Columnar multi-axis microelectromechanical systems (MEMS) devices (such as gyroscopes) balanced against undesired linear and angular vibration are described herein. In some embodiments, the columnar MEMS device may comprise at least two multiple-mass columns, each having at least three proof masses and being configured to sense rotation about a respective axis. The motion and mass of the proof masses may be controlled to achieve linear and rotational balancing of the MEMS device. The columnar MEMS device may further comprise one or more modular drive structures disposed alongside each multiple-mass column to facilitate displacement of the proof masses of a respective column. The MEMS devices described herein may be used to sense roll, yaw, and pitch angular rates.

Abstract: Columnar multi-axis microelectromechanical systems (MEMS) devices (such as gyroscopes) balanced against undesired linear and angular vibration are described herein. In some embodiments, the columnar MEMS device may comprise at least two multiple-mass columns, each having at least three proof masses and being configured to sense rotation about a respective axis. The motion and mass of the proof masses may be controlled to achieve linear and rotational balancing of the MEMS device. The columnar MEMS device may further comprise one or more modular drive structures disposed alongside each multiple-mass column to facilitate displacement of the proof masses of a respective column. The MEMS devices described herein may be used to sense roll, yaw, and pitch angular rates.

Abstract: Packages for wireless temperature sensor nodes are described. These wireless temperature sensor nodes are suitable for sensing the temperature of remote objects, such as objects that are difficult to access. These packages are designed to enhance the sensor's ability to sense temperature. For example, these packages may be designed to provide a low thermal resistance path between the object and the temperature sensor, a high thermal resistance between an antenna of the wireless temperature sensor node and the object, and at least in some embodiments, immunity to vibrations. One such package includes means for providing a thermal conductive path from the temperature sensor to a thermally conductive support in contact with the object (for example with a thermal resistance less than 10 K/W), and means for thermally conductively decoupling the circuit board from the thermally conductive support (for example by at least 100 K/W).

Abstract: Described herein are techniques for improving the signal-to-noise ratio of a wireless sensor platform. The device that interrogates a wireless sensor node (an interrogator) may be configured to determine the quantity to be measured by extracting information from multiple echoes produced in response to multiple interrogation pulses or produced due to multi-path propagation. Although different echoes may have been transformed to different extents, the echoes may share unique characteristics that are specific to the wireless sensor node that produced them. Accordingly, the SNR may be improved by keeping only portions of the received signal that exhibit such characteristics. The SNR may be further improved by summing the echoes together. In some embodiments, the echoes may be summed together in a coherent fashion, thereby producing an echo having an amplitude greater than the amplitude of each of the received echoes.

Abstract: One-axis and two-axis vibratory gyroscopes include a unitary resonator structure conceptually having four beams interconnected in a cross-hatch configuration. While each beam can be considered a unitary piece of material, each beam's attachment to two cross beams conceptually divides the resonant beam into a central section between the attachment points and two tail sections aft of the attachment points. The attachment points are preferably nodal points of the beam with respect to both a drive mode shape and a sense mode shape of the beam for the resonant mode in which the resonator is configured to operate. Thus, the location where two beams intersect is preferably a nodal point for both beams. The tail sections of each beam allow the resonant mode of the resonator to be carefully configured.

Abstract: A single photo mask can be used to define the three critical layers for the piezoelectric MEMS device, specifically the top electrode layer, the piezoelectric material layer, and the bottom electrode layer. Using a single photo mask removes the misalignment source caused by using multiple photo masks. Furthermore, in certain exemplary embodiments, all electrical interconnects use underpass interconnect. This simplifies the process for defining the device electrodes and the process sequence for achieving self-alignment between the piezoelectric element and the top and bottom electrodes. This self-alignment is achieved by using an oxide hard mask to etch the critical region of the top electrode, the piezoelectric material, and the bottom electrode with one mask and different etch chemistries depending on the layer being etched.

Abstract: One-axis and two-axis vibratory gyroscopes include a unitary resonator structure conceptually having four beams interconnected in a cross-hatch configuration. While each beam can be considered a unitary piece of material, each beam's attachment to two cross beams conceptually divides the resonant beam into a central section between the attachment points and two tail sections aft of the attachment points. The attachment points are preferably nodal points of the beam with respect to both a drive mode shape and a sense mode shape of the beam for the resonant mode in which the resonator is configured to operate. Thus, the location where two beams intersect is preferably a nodal point for both beams. The tail sections of each beam allow the resonant mode of the resonator to be carefully configured.

Abstract: A single-axis resonating beam gyroscope uses a special arrangement of support tethers that maximizes the Q (quality factor) and minimizes stress sensitivity. The tethers are located at the nodal points of the beam with respect to a predetermined drive mode and are approximately one-fourth the length of the beam. Also, the tethers do not extend above or through the nodal points of the beam, which would be difficult to produce in typical MEMS fabrication processes. Embodiments typically use electrostatic drive and sense transduction. Trim electrodes may be used to compensate for any erroneous modal coupling.

Abstract: A single photo mask can be used to define the three critical layers for the piezoelectric MEMS device, specifically the top electrode layer, the piezoelectric material layer, and the bottom electrode layer. Using a single photo mask removes the misalignment source caused by using multiple photo masks. Furthermore, in certain exemplary embodiments, all electrical interconnects use underpass interconnect. This simplifies the process for defining the device electrodes and the process sequence for achieving self-alignment between the piezoelectric element and the top and bottom electrodes. This self-alignment is achieved by using an oxide hard mask to etch the critical region of the top electrode, the piezoelectric material, and the bottom electrode with one mask and different etch chemistries depending on the layer being etched.