Semiconductors & ICs

Low-Temperature Supercapacitors

Electrolyte compositions are designed to extend the low-temperature operational limit. An effort to extend the low-temperature operational limit of supercapacitors is currently underway. At present, commercially available non-aqueous supercapacitors are rated for a minimum operating temperature of –40 °C. A capability to operate at lower temperatures would be desirable for delivering power to systems that must operate in outer space or in the Polar Regions on Earth.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Radiation-Insensitive Inverse Majority Gates

These gates would be implemented as microscopic vacuum electronic devices. To help satisfy a need for high-density logic circuits insensitive to radiation, it has been proposed to realize inverse majority gates as microscopic vacuum electronic devices. In comparison with solid-state electronic devices ordinarily used in logic circuits, vacuum electronic devices are inherently much less adversely affected by radiation and extreme temperatures.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Dual-Input AND Gate From Single-Channel Thin-Film FET

These transistors show potential as large-area, low-cost electronic circuitry on rigid and flexible substrates. A regio-regular poly (3-hexylthiophene) (RRP3HT) thin-film transistor having a split-gate architecture has been fabricated on a doped silicon/silicon nitride substrate and characterized. RRP3HT is a semiconducting polymer that has a carrier mobility and on/off ratio when used in a field effect transistor (FET) configuration. This commercially available polymer is very soluble in common organic solvents and is easily processed to form uniform thin films. The most important polymer-based device fabricated and studied is the FET, since it forms the building block in logic circuits and switches for active matrix (light-emitting-diode) (LED) displays, smart cards, and radio frequency identification (RFID) cards.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Split-Block Waveguide Polarization Twist for 220 to 325 GHz

This device is superior to conventional twisted rectangular waveguides for submillimeter wavelengths. Figure 1. A Channel Having Asymmetric Steps is cut into the lower block.An identical channel is cut into the upper block. Then with the help ofalignment pins, the blocks are assembled so that the two channels mergeinto one channel that makes a transition between two orthogonal orientationsof a WR-3 waveguide.A split-block waveguide circuit that rotates polarization by 90° has been designed with WR-3 input and output waveguides, which are rectangular waveguides used for a nominal frequency range of 220 to 325 GHz. Heretofore, twisted rectangular waveguides equipped with flanges at the input and output have been the standard means of rotating the polarizations of guided microwave signals. However, the fabrication and assembly of such components become difficult at high frequency due to decreasing wavelength, such that twisted rectangular waveguides become impractical at frequencies above a few hundred gigahertz. Conventional twisted rectangular waveguides are also not amenable to integration into highly miniaturized subassemblies of advanced millimeter- and submillimeter- wave detector arrays now undergoing development. In contrast, the present polarization-rotating waveguide can readily be incorporated into complex integrated waveguide circuits such as miniaturized detector arrays fabricated by either conventional end milling of metal blocks or by deep reactive ion etching of silicon blocks. Moreover, the present splitblock design can be scaled up in frequency to at least 5 THz.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Error-Detecting Counters for FPGA and ASIC State Machines

Inconsistencies between main and auxiliary counts would be detected. Error-detecting counters have been proposed as parts of fault-tolerant finite state machines that could be implemented in field-programmable gate arrays (FPGAs) and application-specific integrated circuits that perform sequential logic functions. The use of error-detecting counters would complement the fault-tolerant coding schemes described in “Fault-Tolerant Coding for State Machines” (NPO-41050), in this issue on page 55. Counters are often used in state machines in cases in which it is necessary to represent large numbers of states and/or to count clock cycles between certain states. To ensure reliability, it is necessary to ensure that the counters are as free of faults as are the other parts of the state machines.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Efficient G4FET-Based Logic Circuits

Fewer G4FETs than conventional transistors would be needed to implement logic functions. A total of 81 optimal logic circuits based on four-gate field-effect transistors (G4FETs) have been designed to implement all Boolean functions of up to three variables. The purpose of this development was to lend credence to the expectation that logic circuits based on G4FETs could be more efficient (in the sense that they could contain fewer transistors), relative to functionally equivalent logic circuits based on conventional transistors.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Circuit and Method for Communication Over DC Power Line

New technique usable in harsh, high-heat environments, allows for networking and smart vehicle operation with no additional wiring beyond power. A circuit and method for transmitting and receiving on-off-keyed (OOK) signals with fractional signal-to-noise ratios uses available high-temperature silicon-on-insulator (SOI) components to move computational, sensing, and actuation abilities closer to high- temperature or high- ionizing radiation environments such as vehicle engine compartments, deep-hole drilling environments, industrial control and monitoring of processes like smelting, and operations near nuclear reactors and in space. This device allows for the networking of multiple, like nodes to each other and to a central processor. It can do this with nothing more than the already in-situ power wiring of the system. The device’s microprocessor allows it to make intelligent decisions within the vehicle operational loop and to effect control outputs to its associated actuators. The figure illustrates how each node converts digital serial data to OOK 18-kHz in transmit mode and vice-versa in receive mode; though operations at lower frequencies or up to a megahertz are within reason using this method and these parts.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>