Features

Picking the Pattern for a Stealth Antenna

A frequency selective surface that acts as an RF filter and helps reduce the radar cross-section of antennas consists of a pattern of geometrical objects. There are literally thousands of possibilities, and testing each one physically would take enormous amounts of time. With simulation, though, promising candidates can be found in just minutes.

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Potting Compounds Offer Superior Protection for Electronic Circuits

Product reliability is an absolute must for manufacturers to succeed in today’s competitive marketplace. As customers demand ever-increasing levels of performance at lower unit costs, it becomes increasingly challenging to ensure that electronic circuits operate as designed for a prolonged period of time. Delicate components, densely populated printed circuit boards (PCBs), confining packaging, and highly demanding service environments have the potential to lead to increased failure rates as a result of excessive heat build-up and electrical interference.

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Advanced Exercise Concepts for Long-Duration Spaceflight

Long-duration spaceflight poses many hazards to the health of a space exploration crew, including physiological deconditioning of the musculoskeletal and cardiovascular systems due to prolonged exposure to microgravity. To combat these adverse physical changes, the crew is required to perform both aerobic and resistive exercises. Onboard the International Space Station (ISS), the crew has access to the Advanced Resistive Exercise Device (ARED), the Combined Operational Load Bearing External Resistance Treadmill (T2), and the Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS). These devices provide the crew with the capability to perform a wide variety of exercises.

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Using Source Measure Units to Characterize High Power Semiconductors

Part 2: OFF-State Characterization Part 1 of this article, which appeared in the August 2013 issue of NASA Tech Briefs, dealt with ON-state characterization of high power semiconductors (link to Part 1). Part 2 concludes this discussion with an overview of OFF-state characterization. OFF-State Characterization The impact of the device on the overall circuit when the device is turned off must be investigated to understand overall product efficiency. For high-power devices, OFF-state characterization often requires a high-voltage instrument capable of sourcing hundreds or thousands of volts and measuring small currents. OFF-state characterization is often performed between two device terminals (regardless of the total number of device terminals), so a single SMU is often sufficient. However, an additional SMU can be used to force the device into its OFF state or add stress to certain terminals. Two primary DC tests are performed when the device is off: breakdown voltages and leakage currents.

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CompactPCI Steps Into the Future

CompactPCI Serial has proven to be a beneficial technology upgrade for a number of embedded systems designers accustomed to working with the legacy CompactPCI platform. Not only does CompactPCI Serial bring modern serial interfaces and a ruggedized connector scheme into play, but it also provides significant cost advantages while adhering to many known design principles, lessening a developer’s need to learn a new and complex technology.

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The Evolution of AdvancedTCA: From telecommunications to military, aerospace and security

The Advanced Telecom Computing Architecture (AdvancedTCA® or ATCA®) is a series of open standard computing platform specifications originally ratified in 2002 to meet the needs of carrier grade communications equipment, primarily for core network telecommunications applications. In the 11 years since ATCA products first appeared on the market, there have been numerous advances in the governing standard, the products available, and the products and applications that are driving its adoption and growth.

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Real-Time Software Enables Multi-Core PCs for Industrial Automation

As early as 25 years ago, industrial system integrators saw the great potential that the Windows operating system brought to PCs. They saw the possibility of using the advanced graphic capabilities that Windows offered versus the relatively primitive human interfaces of DOS-based applications and those of other proprietary OSes. Windows enabled the development of controllers with advanced human-ma chine interfaces (HMIs) that provide a whole new level of functionality, and make machines easier to use and maintain.

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