Electrical/Electronics

Microelectronic Repair Techniques for Wafer-Level Integration

Goddard Space Flight Center, Greenbelt, Maryland Wafer-level integration was employed to mount the microshutter array for the James Webb Space Telescope (JWST) and the detector-read-out hybrid for TIRS (Thermal Infrared Sensor). In the case of the JWST substrate, two conductors (polysilicon and aluminum) separated by a silicon oxide insulating layer were fabricated on a roughly 85-mm-square silicon wafer. The size of the substrate, the density and length of the conductive traces, and the requirement of zero shorts and zero opens on the finished device necessitated nearly impossible cleanroom requirements. Techniques were developed to repair the inevitable shorts and opens created during the wafer fabrication process. The wafers were repaired to zero shorts and zero opens without degradation of device performance.

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Multi-Gigabit-Rate Radiation Hard Bus

Goddard Space Flight Center, Greenbelt, Maryland A concept was developed for a multi-gigabit-rate, radiation-hardened (RH) bus that would support open-system architecture and provide a cost-effective, high-speed interconnect. This concept is based on Advanced Science and Novel Technology Company’s SerDes system, which supports a variety of interfaces, and operates at frequencies from DC to more than 15 GHz. The design of the improved SerDes is based on the company’s proprietary library of RH cells and functional blocks using annular FETs (field-effect transistors) that are available in commercial CMOS (complementary metal-oxide-semiconductor) technologies. Bus architecture and preliminary SerDes circuit design have been accomplished during this phase. At the time of this reporting, the complete chip was to be designed and fabricated in the next phase.

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Dust Removal from Solar Cells

This system is easily integrated with current solar cell panel designs. John H. Glenn Research Center, Cleveland, Ohio Photovoltaic cell arrays are used on robotic rovers on the Mars surface, but dust accumulation on the surface of the solar cells reduces their exposure to light radiation and thus degrades their performance. Dust that accumulates without being removed limits the life of the rover’s power systems. Similarly, terrestrial solar arrays suffer from dust accumulation, especially when located in desert areas, which reduces their effectiveness. Technologies for re moval of the dust or preventing it from settling have been proposed and are being researched, but none were yet implemented on the rovers. These techniques include mechanical means, blowing stored gas, blowing pumped gas, electrically charging the surface, repelling the dust, and other techniques.

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Minimally Obstructed Communication via Acoustic Modems in Fluid-Filled Pipes

This technology can be used in the oil industry, as well as in various underwater operations. NASA’s Jet Propulsion Laboratory, Pasadena, California An acoustic modem that uses a separate phased-array transmitter and receiver has been conceived that allows the communication of high-frequency acoustic waves sideways to the transducer along the fluid-filled pipe. The transducer allows directing waves between the transmitter and the receiver with potentially minimal interferences with the piping walls. In addition, another method of directly sending communication signals up- and down-hole has been conceived that uses angled piezoelectric ring transducers.

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Biofeedback System for Optimal Athletic Performance

Langley Research Center, Hampton, Virginia ZONE (Zeroing Out Negative Effects) is a method of biofeedback training for optimal athletic performance. ZONE is designed to improve athletes’ responses to stress, anxiety, and loss of concentration during competition. In the training environment, when the user successfully attains an optimal target state of psychophysiological functioning, the technology informs and/or rewards the user through real-time physical changes in the athletic equipment. For example, in the training setting, a golfer can work toward optimal concentration in the act of putting, leading to improved performance in real situations.

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Methods for Clock and Reset Synchronization in a CMOS Integrated Circuit

These methods ensure fault-free operation in high-integrity systems. Lyndon B. Johnson Space Center, Houston, Texas In high-integrity systems, a method of assuring integrity called a self-checking pair is employed. A self-checking pair is a logical grouping of two of the same devices performing the same operation and cross-checking each other to ensure correct operation. In this manner, a single fault on one will be detected by its partner, and the appropriate action can be taken to both recover the fault and ensure the fault does not propagate.

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Wideband MMIC Distributed Amplifier-Based Microwave Power Module

The solid-state module operates as a radar, communication, or navigation system. John H. Glenn Research Center, Cleveland, Ohio This innovation is a wideband, high-power, high-efficiency, all-solid-state microwave power module (SSMPM) or amplifier for a multifunction spacecraft payload that operates, depending on the need, as a radar system, communication system, or navigation system. The construction of the module is based on a wideband multi-stage amplifier design. The low-power stage is a high-efficiency GaAs pHEMT-based MMIC (monolithic microwave integrated circuit) distributed amplifier. The medium-power stage is either a high-efficiency GaAs pHEMT (high-electron-mobility transistor) or GaN HEMT-based MMIC distributed amplifier. The high-power stage is a high-efficiency GaN HEMT-based MMIC distributed amplifier.

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