Semiconductors & ICs

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

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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

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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

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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

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Advanced Ultra-Thin Integrated Electronics on Membranes

Flexible integrated circuits are integrated with other circuitry on flexible membranes. A method of fabricating flexible assemblies comprising flexible integrated circuits bonded onto or into flexible membranes has been developed. The method provides for bonding of thinned (more specifically, thin enough to be flexible) integrated-circuit chips to the membranes and for electrical connection of the integrated circuits to other circuitry on or in the membranes. The method is expected to enable the further development of a variety of membrane-based flexible, lightweight electronic systems and assemblies — for example, phasedarray antenna assemblies comprising integrated-circuit transmitting/ receiving (T/R) modules further integrated with arrays of transmission lines and antenna radiator elements.

Posted in: Semiconductors & ICs, Briefs

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MMIC Amplifiers for 90 to 130 GHz

Output power exceeds that of prior solid-state amplifiers operating above 110 GHz. The figure shows two monolithic microwave integrated-circuit (MMIC) amplifier chips optimized to function in the frequency range of 90 to 130 GHz, covering nearly all of F-band (90 – 140 GHz). These amplifiers were designed specifically for local-oscillator units in astronomical radio telescopes such as the Atacama Large Millimeter Array (ALMA). They could also be readily adapted for use in electronic test equipment, automotive radar systems, and communications systems that operate between 90 and 130 GHz.

Posted in: Semiconductors & ICs, Briefs, TSP

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Microrectenna: A Terahertz Antenna and Rectifier on a Chip

Microscopic rectennas would supply DC power to microdevices. A microrectenna that would operate at a frequency of 2.5 THz has been designed and partially fabricated. The circuit is intended to be a prototype of an extremely compact device that could be used to convert radio-beamed power to DC to drive microdevices (see Figure 1).

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