RF & Microwave Electronics

Low-Power Wireless Body Area Network (WBAN) Communication System

Applications include astronaut health monitoring, parts tracking, and sensing. Lyndon B. Johnson Space Center, Houston, Texas NASA seeks semi-passive, RFIDenabled wearable tags for inventory tracking and astronaut body area network applications. Wearable sensor tags can be printed on astronaut clothing or suits, and are powered by printed thin film batteries and/or via energy harvesting. Energy is harvested by flexible solar cells or from the kinetic energy of the astronaut’s motion by minimizing the power requirement of the suit electronics. A tag antenna functions while being flexed or bent, which normally occurs with clothing. Tags communicate with the astronaut body area network. The functions of the RFID system can be extended to include low-data-rate telemetry for bio-monitoring utilizing wearable RFID-enabled biosensors.

Posted in: Briefs

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RF System MATLAB Model Simulation Using a Variety of Data Sources

NASA’s Jet Propulsion Laboratory, Pasadena, California During the development of the Soil Moisture Active-Passive (SMAP) High-Power Amplifier (HPA), a power glitch was observed with the characteristic of producing small 0.1-0.3 dB jumps in power across temperature. In order to troubleshoot this glitch behavior, a nonlinear model that could describe the saturation behavior of the HPA across temperature was desired. However, nonlinear device models were not available for the transistors and components within the HPA. Measured data of the HPA subassemblies were available but were of various formats, including s-parameters, nonlinear pin-pout curves, and fixed losses over temperature, and not easily modeled within commercial EDA (electronic design automation) simulation tools. This tool was built to be able to understand the gain/power distribution stackup and the sensitivities to power changes in the HPA over temperature.

Posted in: Briefs

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Designing Antenna and Electronic Systems for Space and Airborne Applications

Across all industry sectors electronic systems such as antennas and sensors are becoming ubiquitous in support of wireless communication, sensing and power transfer. These are examples of the practical realization of the "Internet of Things". In the aerospace sector, such technologies are playing an increasingly important role in advanced technologies. For example, highly instrumented and connected aircraft are supporting condition based maintenance and health monitoring techniques. Remotely piloted systems are becoming more autonomous and delivering increasing amounts of intelligence, surveillance and reconnaissance data to support the warfighter. At the same time, the industry is expected to deliver these more advanced capabilities at lower cost, in a smaller and lighter footprint and with increased robustness, reliability and resilience.

Posted in: On-Demand Webinars, On-Demand Webinars, Electronics, Antennas, Sensors

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Antenna Basics

This white paper describes the basic functionality of antennas. Starting with Hertz's Antenna model followed by a short introduction to the fundamentals of wave propagation, the important general characteristics of an antenna and its associated parameters are explained.

Posted in: White Papers, White Papers

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dB or not dB? Everything you ever wanted to know about decibels but were afraid to ask...

True or false: 30 dBm + 30 dBm = 60 dBm? Why does 1% work out to be -40 dB one time but then 0.1 dB or 0.05 dB the next time? These questions sometimes leave even experienced engineers scratching their heads. Decibels are found everywhere, including power levels, voltages, reflection coefficients, noise figures, field strengths and more. What is a decibel and how should we use it in our calculations? This Application Note is intended as a refresher on the subject of decibels.

Posted in: White Papers, White Papers

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Introduction into Theory of Direction Finding

Applications of direction finding While direction finding for navigation purposes (referred to as cooperative direction finding) is becoming less important due to the availability of satellite navigation systems, there is a growing requirement for determining the location of emitters as the mobility of communications equipment increases:

Posted in: White Papers, White Papers

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Spectrum Analyzer Fundamentals – Theory and Operation of Modern Spectrum Analyzers

This primer examines the theory of state-of-the-art spectrum analysis and describes how modern spectrum analyzers are designed and how they work. That is followed by a brief characterization of today's signal generators, which are needed as a stimulus when performing amplifier measurements.

Posted in: White Papers, White Papers

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