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Project:
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Low-loss
Phase Shifters using GaAs Diode technology
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Investigators:
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Amit Nagra, Bob York
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Collaborators:
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Prof. Mark Rodwell and
students
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Funded
by:
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HRL unrestricted grant
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Description:
This work is part of a larger effort aimed at developing
low-cost and low-loss phase-shifters or delay lines for microwave and millimeter-wave
phased-array antenna systems. We use a planar transmission-line periodically
loaded with electronically-variable capacitances (varactor diodes) which gives an
electronically variable phase-velocity along the line. Through careful modeling
of the
losses these structures can be optimized for 4 dB loss on GaAs using 2 micron
design rules.
Currently we are developing incremental delay structures based on this technology,
and moving towards non-semiconductor control devices such as MEMs capacitive switches and
ferroelectric devices, as well as using micro machining techniques to lower loss and cost.
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| Publications: |
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Presentations:
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Pictures at right:
(top) Circuit concept for a
traveling-wave
phase shifter; (middle) drawing and photo of a GaAs prototype fabricated at UCSB; (c)
measured results for differential phase.
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