scholarly journals Improved RF Power Extraction from 1.55um Ge-on-SOI PIN Photodiodes with Load Impedance Optimization

2010 ◽  
Author(s):  
Andrew L Huard
Keyword(s):  
Rf Power ◽  
Load Impedance ◽  
Power Extraction ◽  
Pin Photodiodes

Improved RF power extraction from 1.55µm Ge/Si n-i-p photodiodes with load impedance optimization

2010 ◽  
Author(s):  
Andrew L. Huard ◽  
Molly Piels ◽  
Anand Ramaswamy ◽  
John E. Bowers ◽  
Dennis Derickson
Keyword(s):  
Rf Power ◽  
Load Impedance ◽  
Power Extraction

scholarly journals An accurate modeling technique for antennas and nonlinear RF power amplifier mixed simulation

2011 ◽  
Vol 3 (6) ◽  
pp. 647-655 ◽  
Author(s):  
Georges Zakka El Nashef ◽  
François Torrès ◽  
Sébastien Mons ◽  
Tibault Reveyrand ◽  
Edouard Ngoya ◽  
...  
Keyword(s):  
Radiation Pattern ◽  
Behavioral Model ◽  
Rf Power ◽  
Load Impedance ◽  
Rf Power Amplifier ◽  
Modeling Methodology ◽  
Active Antennas ◽  
Macro Modeling ◽  
Output Load ◽  
The Impact

The design of agile active antennas requires an efficient modeling methodology in order to quantify the impact of other components on the array radiation pattern, and especially the influence of power amplifiers (PA). Therefore, the performance prediction of PA on TX chains is of prime importance. This article describes two different approaches for active antenna applications. The first one concentrates on PA macro-modeling, which takes into account a large output load impedance mismatch with a voltage standing wave ratio up to 4:1. A PA behavioral model based on nonlinear scattering functions was developed and extracted from CW measurements. The model validity was checked by comparison with the measured data. The second one describes a novel technique for synthesizing a given radiation pattern, whereas taking into account the mutual coupling and calculated matching impedances (ZL ≠ 50 Ω) of each antenna in the array according to frequency and pointing angle.

scholarly journals Software-Based Adaptive Protection Control Against Load Mismatch for a Mobile Power Amplifier Module

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1226
Author(s):  
Jeon ◽  
Jung ◽  
Kang
Keyword(s):  
Power Amplifier ◽  
Rf Power ◽  
Load Impedance ◽  
Rf Power Amplifier ◽  
Protection Method ◽  
Measurement Results ◽  
Digitally Controlled ◽  
Nominal Condition ◽  
Rf Performance ◽  
Mismatch Condition

A closed-loop protection method for a radio frequency (RF) power amplifier (PA) module applicable to mobile handsets has been introduced. The load impedance of the PA was adaptively sensed by an embedded impedance detector which was digitally controlled and the system adjusted PA power using a feedback circuit to keep the PA safe based on a load mismatch detection. For verification, a two-stage hetero junction bipolar transistor (HBT) PA module for handsets was fabricated and tested against load mismatch. Measurement results showed that the technique could help PA survive at a 0.5V larger collector bias voltage condition than when the technique was not applied for the same mismatch condition with an acceptable RF performance degradation at nominal condition.

Investigation of ultra-thin films of YBa2Cu3O7−δ grown on MgO

1990 ◽  
Vol 48 (4) ◽  
pp. 6-7
Author(s):  
S.K. Streiffer ◽  
C.B. Eom ◽  
J.C. Bravman ◽  
T.H. Geballet
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
Multilayer Structures ◽  
Rf Power ◽  
Oxygen Loss ◽  
Transmission Electron ◽  
Single Target ◽  
Mtorr Argon

The study of very thin (<15 nm) YBa2Cu3O7−δ (YBCO) films is necessary both for investigating the nucleation and growth of films of this material and for achieving a better understanding of multilayer structures incorporating such thin YBCO regions. We have used transmission electron microscopy to examine ultra-thin films grown on MgO substrates by single-target, off-axis magnetron sputtering; details of the deposition process have been reported elsewhere. Briefly, polished MgO substrates were attached to a block placed at 90° to the sputtering target and heated to 650 °C. The sputtering was performed in 10 mtorr oxygen and 40 mtorr argon with an rf power of 125 watts. After deposition, the chamber was vented to 500 torr oxygen and allowed to cool to room temperature. Because of YBCO’s susceptibility to environmental degradation and oxygen loss, the technique of Xi, et al. was followed and a protective overlayer of amorphous YBCO was deposited on the just-grown films.

Analysis of Sputtered Zinc Oxide Films

1980 ◽  
Vol 38 ◽  
pp. 416-417
Author(s):  
T. A. Emma ◽  
M. P. Singh
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Piezoelectric Materials ◽  
Oxide Films ◽  
Optical Quality ◽  
Zno Films ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Sputtered Films ◽  
Zinc Oxide Films

Optical quality zinc oxide films have been characterized using reflection electron diffraction (RED), replication electron microscopy (REM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Significant microstructural differences were observed between rf sputtered films and planar magnetron rf sputtered films. Piezoelectric materials have been attractive for applications to integrated optics since they provide an active medium for signal processing. Among the desirable physical characteristics of sputtered ZnO films used for this and related applications are a highly preferred crystallographic texture and relatively smooth surfaces. It has been found that these characteristics are very sensitive to the type and condition of the substrate and to the several sputtering parameters: target, rf power, gas composition and substrate temperature.

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