In-situ nonlinear calibration of a RF signal chain

2018 ◽  
Author(s):  
Nevena Rakuljic ◽  
Carroll Speir ◽  
Eric Otte ◽  
Jeff Bray ◽  
Corey Petersen ◽  
...  
Keyword(s):  
Rf Signal ◽  
Nonlinear Calibration

RF Microwave Switches Based on Reversible Metal-Semiconductor Transition Properties of VO2 Thin Films: An Attractive Way To Realise Simple RF Microelectronic Devices

2008 ◽  
Vol 1129 ◽  
Author(s):  
Frédéric Dumas-Bouchiat ◽  
Corinne Champeaux ◽  
Alain Catherinot ◽  
Julien Givernaud ◽  
Aurelian Crunteanu ◽  
...  
Keyword(s):  
Thin Films ◽  
Geometrical Parameters ◽  
Si Substrates ◽  
Thermally Activated ◽  
Microelectronic Devices ◽  
Microwave Switches ◽  
Vo2 Thin Films ◽  
Insertion Losses ◽  
Rf Signal

AbstractMicrowave switches in both shunt and series configurations are developped using semiconductor to metal (SC-M) transition of vanadium dioxide (VO2) thin films deposited by in situ pulsed laser deposition on C-plane sapphire and SiO2/Si substrates. The influence of geometrical parameters such as the length of the switch is shown. The VO2-based switches exhibit up to 30-40 dB average isolation of the radio-frequency (RF) signal on a very wide frequency band (500 MHz-35 GHz) with weak insertion losses, when thermally activated. Furthermore, they can be electrically activated. Finally these VO2-based switches are integrated in the fabrication of innovative tunable band-stop filters which consist in a transmission line coupled with four U-shaped resonators and operate in 9-11 GHz frequency range. Its tunability is demonstrated using electrical activation of each VO2-based switch.

IN-SITU CHARACTERIZATIONS OF 1–200 MHz RADIO FREQUENCY SIGNAL COUPLING WITH HUMAN BODY

2012 ◽  
Vol 24 (03) ◽  
pp. 285-294 ◽  
Author(s):  
Zedong Nie ◽  
Tengfei Leng ◽  
Wenchen Wang ◽  
Feng Guan ◽  
Bangyu Huang ◽  
...  
Keyword(s):  
Human Body ◽  
Great Promise ◽  
Area Network ◽  
Coupling Loss ◽  
Signal Attenuation ◽  
In Situ Experiments ◽  
Rf Signals ◽  
The Difference ◽  
Rf Signal

Wireless communication within body proximal has shown great promise for the construction of body sensor network (BSN) and body area network (BAN), wherein multiple master and slave nodes were typically deployed on different human body sites for physiological measurements or personal entertainment. We reported the in-situ experiments to characterize body-proximal electric coupling over various carrier frequencies (1–200 MHz), multiple subjects and different body postures. To improve the signal fidelity and minimize the ground return path, all experiments were performed in a shielded radiofrequency (RF) chamber with single electrode configuration and battery-operated transmitter/receiver — the setup has never been reported in other literatures. Results obtained from 15 subjects quantified the attenuation patterns of the RF signal coupling with human body. The average coupling loss was approximately 24 dB at 30 MHz whist the receiver electrode was attached at a distance of 10 cm from the transmitter electrode, and the on-body coupling loss followed a two-piecewise fitting over distance. In comparison, 30 MHz RF signals propagated 1 m from body to air and from air to air were attenuated 70 dB and 80 dB, respectively. The standard deviations representing different subjects and daily variations were less than 2 dB at 30 MHz when the coupling distance was 10 cm. The difference in signal attenuation was always less than 2 dB for various postures including standing, sitting and squatting. It concluded that the RF signal within the frequency range of 25–30 MHz is capable of providing a robust and subject-independent wireless link for body-proximal BSN/BAN applications.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Structural Studies on Mitotic Spindle Fibres

1978 ◽  
Vol 36 (3) ◽  
pp. 615-626
Author(s):  
J.R. Mcintosh
Keyword(s):  
Chemical Composition ◽  
Mitotic Spindle ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Chemical Studies ◽  
Medical Interest ◽  
Spindle Fibres

The mitotic apparatus is a structure of obvious biological and medical interest, but it has proved to be a difficult cellular machine to understand. The chemical composition of the spindle is only slightly elucidated, largely because of the difficulties in preparing useful isolates of the structure. Chemical studies of the mitotic spindle have been reviewed elsewhere (Mcintosh, 1977), and will not be discussed further here. One would think that structural studies on the mitotic apparatus (MA) in situ would be straightforward, but even with this approach there is some disagreement in the results obtained with various methods and by different investigators. In this paper I will review briefly the approaches which have been used in structural studies of the MA, pointing out the strengths and problems of each approach. I will summarize the principal findings of the different methods, and identify what seem to be fruitful avenues for further work.

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