08-08-2012, 12:13 PM
Ferrite devices
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Phase shifter
• Based on the “Faraday Rotation”, phase shift were been
proposed in Microwave circuits. Those component are
called “Gyrator”
• The Two port network has folloing modules:
– 90 degree Twist
– Ferrite component with 90 degree phase shift
Isolator
• Isolator is working in the same mechanism of
“Phase shifter”.
• Isolator is a two port network, it allows the
power flow in one direction and rejects signals
from opposite side.
• Working:
– At port 1, the vertically polarized wave is twisted
about 45 degree by wave guide twist.
– And opposite 45 degree rotation is taken place at
ferrite rod
– In opposite direction: the ferrite and wave guide twist
makes 90 degree rotation.
– This polarized wave is absorbed by “Resistive card"
Circulator
• We already knew that “it’s impossible to constrcut three port network with
Matched, reciprocal and lossless propetries”.
• Lossless and Reciprocal: Tee Junctions
• Matched and Reciprocal: Power Divider
• Lossless and matched : Circulator
• Consider and perfectly matched three port network,
Circulator – Three port