This project developed prototype germanium telluride switches, which can be used in RF applications to improve SWAP (size, weight, and power) and signal quality in RF systems. These switches can allow for highly reconfigurable systems, including antennas, communications, optical systems, phased arrays, and synthetic aperture radar, which all have high impact on current National Security goals for improved communication systems and communication technology supremacy. The final result of the project was the demonstration of germanium telluride RF switches, which could act as critical elements necessary for a single chip RF communication system that will demonstrate low SWAP and high reconfigurability
This paper reports on a near-zero power inertial wakeup sensor system supporting digital weighting of inputs and with protection against false positives due to mechanical shocks. This improves upon existing work by combining the selectivity and sensitivity (Q-amplification) of resonant MEMS sensors with the flexibility of digital signal processing while consuming below 10 nW. The target application is unattended sensors for perimeter sensing and machinery health monitoring where extended battery life afforded by the low power consumption eliminates the need for power cables. For machinery health monitoring, the signals of interest are stationary but may contain spurious mechanical shocks.
The Defense Advanced Research Project Agency has identified a need for low-standby-power systems which react to physical environmental signals in the form of an electrical wakeup signal. To address this need, we design piezoelectric aluminum nitride based microelectromechanical resonant accelerometers that couple with a near-zero power, complementary metal-oxide-semiconductor application specific integrated circuit. The piezoelectric accelerometer operates near resonance to form a passive mechanical filter of the vibration spectrum that targets a specific frequency signature. Resonant vibration sensitivities as large as 490 V/g (in air) are obtained at frequencies as low as 43 Hz. The integrated circuit operates in the subthreshold regime employing current starvation to minimize power consumption. Two accelerometers are coupled with the circuit to form the wakeup system which requires only 5.25 nW before wakeup and 6.75 nW after wakeup. The system is shown to wake up to a generator signal and reject confusers in the form of other vehicles and background noise.
The defense community desires low-power sensors deployed around critical assets for intrusion detection. A piezoelectric microelectromechanical accelerometer is coupled with a complementary metal-oxide-semiconductor comparator to create a near-zero power wakeup system. The accelerometer is designed to operate at resonance and employs aluminum nitride for piezoelectric transduction. At a target frequency of 160 Hz, the accelerometer achieves sensitivities as large as 26 V/g. The system is shown to require only 5.4 nW of power before and after latching. The combined system is shown to wake up to a target frequency signature of a generator while rejecting background noise as well as non-target frequency signatures.