A Q-band RF-MEMS tapered true time delay line for fusion plasma diagnostics systems

In this work, we present the design and demonstration of a novel MEMS-based true-time delay (TTD) unit for microwave imaging reflectometry (MIR) diagnostics of thermonuclear fusion plasmas. The TTD unit is designed using a coplanar waveguide loaded with extended tuning range cantilever-type varactor...

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Bibliographic Details
Published in2015 IEEE MTT-S International Microwave Symposium pp. 1 - 3
Main Authors Danqing Fu, Bey, Yusha A., Domier, Calvin, Luhmann, Neville C., Xiaoguang Liu
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.05.2015
Subjects
Delays
Focusing
Image resolution
Meteorology
phaseshifters
rf-mems
Tokamaks
true time delay
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Summary:In this work, we present the design and demonstration of a novel MEMS-based true-time delay (TTD) unit for microwave imaging reflectometry (MIR) diagnostics of thermonuclear fusion plasmas. The TTD unit is designed using a coplanar waveguide loaded with extended tuning range cantilever-type varactors. The capacitance value of the varactors are tapered at the input and output ports, allowing for better impedance matching in the highly loaded case. More than 360° and 600° phaseshift was demonstrated at 30GHz and 50 GHz, respectively with a figure of merit better than 60°/dB over the entire frequency range. As a TTD unit, the device can provide near constant delay of 0-33 ps adjustable in an analog fashion. To the authors' knowledge, this is the best TTD unit demonstrated to date in terms of maximum adjustable delay range and FoM in Q-band.
ISSN:0149-645X
2576-7216
DOI:10.1109/MWSYM.2015.7167068