Integrated Circuit for Radio Astronomy Correlators Supporting Large Arrays of Antennas

NASA’s Jet Propulsion Laboratory, Pasadena, California Radio telescopes that employ arrays of many antennas are in operation, and ever-larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas, N, the cost and power consumption of cross-correlation are proportional to N2, and dominate at sufficiently large N. As radio telescopes get larger, there is a need to provide digital-signal-processing electronics that are smaller and less power-hungry than would be implied by the extrapolation of existing designs.

Posted in: Briefs, Electronics & Computers, Software, Antennas, Integrated circuits, Radio equipment


Fabrication of Silicon-Leg Isolated Bi-Cr Thermopiles

Goddard Space Flight Center, Greenbelt, Maryland The objective of this innovation was to develop a methodology of fabricating thermopile detectors using standard semiconductor fabrication techniques. The goal was to develop a fabrication process that minimized the roughening of the Si legs during patterning of the metallic couples, and to enable delineation of the Si legs without the use of highly toxic or carcinogenic chemicals. Another key requirement was at least 50% optical absorbance across the spectral band.

Posted in: Briefs, Electronics & Computers, Optics, Fabrication, Semiconductors, Silicon alloys


Current Source Logic Gate

John H. Glenn Research Center, Cleveland, Ohio High-temperature electronic integrated circuits have been demonstrated in silicon carbide (SiC) depletion mode MESFETs. This process is only capable of producing depletion mode n-channel MESFET transistors. With only this type of transistor, designing a logic gate is a challenge. A previous logic gate design that can be constructed in the current process has performed well. This invention improves upon the previous design by increasing output voltage range and decreasing the physical layout size of a logic gate. This logic gate circuit consists of depletion mode MESFET/JFET transistors and resistors that can be constructed with SiC depletion mode n-channel MESFETs.

Posted in: Briefs, Electronics & Computers, Integrated circuits, Switches, Transistors


Design of Double Layer Rectenna Array for Fault Isolation of Schottky Diode in Operation Beyond V-Band Frequencies

Langley Research Center, Hampton, Virginia Microwave power transmission using rectenna technology has attracted a strong interest in conjunction with wireless electric power delivery to infrastructure and subjects located at a remote place. A typical rectenna, which is a major component of the wireless power transmission technology, consists of an antenna, a Schottky diode, and low-pass filters for low-frequency electromagnetic wave isolation in the device. To obtain high efficiency, an electromagnetic wave is collected through a high-resonance antenna, and the AC mode of coupled wave energy is delivered to a Schottky diode that rectifies AC power into DC power. By connecting rectennas in series or parallel, or in mixed way — as well as enlarging the receiving area — the rectenna array can capture microwave energy into a desirable mode of high power.

Posted in: Briefs, Electronics & Computers, Antennas, Capacitors


The Advantages of LWIR SLS Thermal Cameras

A relatively new type of photon detector material for infrared cameras offers a solution for scientists and engineers who need to record fast thermal transients or capture crisp still images of high speed objects or events. This material, called Type II Strained Layer Superlattice, or SLS, can match or exceed most of the performance of analogous detector materials such as indium antimonide (InSb) or mercury cadmium telluride (MCT). This article compares LWIR SLS detectors to MWIR InSb and LWIR MCT detectors, with specific attention to their integration times, temperature ranges, filtering needs, and uniformity.

Posted in: White Papers, Aeronautics, Defense, Electronics & Computers


High-Bandwidth, Wide Field-of-View, Ultra-Sensitive, Radiation-Hardened, Short-Wave Infrared (SWIR) Receiver

Goddard Space Flight Center, Greenbelt, Maryland Every LiDAR design faces the classic balancing act of signal versus noise. In order to maximize the range of a LiDAR, a receiver must amplify fractions of a micro-amp of photo current into a usable range for signal processing to occur, but without adding significant amounts of noise. Additionally, LiDAR receiver designs must exhibit very wide dynamic ranges because of the uncertainty in return signal amplitude. Meeting all these requirements in a small size, weight, and power form factor while keeping costs low is a major challenge.

Posted in: Briefs, Electronics, Electronics & Computers, Amplifiers, Lidar, Noise


Magnetometer for Vectorized Field Sensing via Zero-Field, Spin-Dependent Recombination in Silicon Carbide Microelectronics

This self-calibrating, solid-state-based magnetometer is intended for miniaturized applications in high-temperature and high-radiation environments. NASA’s Jet Propulsion Laboratory, Pasadena, California The proposed technology involves the sensitive detection of magnetic fields using the zero-field, spin-dependent recombination (SDR) phenomenon that naturally arises from atomic-scale, deep-level defects intrinsic to silicon carbide (SiC) microelectronics. The SDR phenomenon enables the fabrication of SiC-based magnetic field sensing diodes that are ideal for the development of miniaturized and purely electrical-based magnetometers.

Posted in: Briefs, Electronics, Electronics & Computers, Microelectromechanical devices, Magnetic materials, Test equipment and instrumentation


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