The document discusses different types of microwave phase shifters. It describes that a phase shifter is a two-port device that provides a fixed or variable phase shift of an RF signal with minimal attenuation. It then focuses on ferrite phase shifters, which use ferrite materials to provide a variable phase shift by changing the bias field of the ferrite. The document also discusses distributed phase shifters, active vs. passive phase shifters, analog vs. digital phase shifters, and fixed vs. variable phase shifters.

1. Microwave Phase-Shifter
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2. Phase shifter is a two-port device whose basic function
is to provide a change in phase (fixed or variable) of RF signal
with insignificant attenuation
What is phase-shifter?
t
time delay
buffer
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time delay
mixer

3. Ferrite phase shifter
two-port devices that provide a variable phase
shift of the transmission path by changing the
bias field of the ferrite
Ex: nonreciprocal waveguide latching phase shifter
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4. Ferrite phase shifter
Ferroelectric material (BST) either
forms the entire microwave substrate on which
the conductors are deposited (thick film/bulk
crystal)
or a fraction of the substrate with thin BST film
or a fraction of the substrate with thin BST film
sandwiched between the substrate and the
conductors
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5. circuits rely on the principle that because part or all
of the microwave fields pass through the
ferroelectric layer, the phase velocity of waves
propagating on these structures can be altered by
changing the permittivity of the ferroelectric layer
Ferrite phase shifter
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6. Ferrite phase shifter
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7. Combines the low-loss properties of BST at
microwave frequency with the distributed
transmission line philosophy of the MEMS phase
shifter
This provides wide bandwidth and ease of design
Ferrite phase shifter: Advantages
This provides wide bandwidth and ease of design
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8. amount of capacitive loading due to the ferroelectric film
cannot be easily varied to optimize phase performance
conductor losses are high in this structure due to the high
dielectric constant of the ferroelectric film on which the
transmission lines are fabricated
Ferrite phase shifter: Disadvantages
tunability of the film is not efficiently utilized
control voltages required for this approach tend to be
very high
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9. Distributed phase shifter
created by adding tunable reactance to a transmission line
adjusting the reactance alters the phase velocity of the
signal propagating along the line, varying its electrical
length, and therefore the phase shift
changing the phase velocity also changes the
characteristic impedance of the transmission line, so
impedance mismatch can occur as the circuit is tuned
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10. Distributed phase shifter
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11. Active – powered device that electronically amplifies
the signal while performing a phase shift operation
Passive – No power is added, but the device attenuates
a signal as a part of the operation
Active & Passive Phase Shifters
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a signal as a part of the operation

12. Analog – Phase shifting is continuously
variable
Digital – A discrete set of phase shifts
Analog & Digital Phase Shifters
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13. Lower loss
Lower cost of parts
Analog phase shifter advantages
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14. o immunity to noise on control lines
o more uniform performance, unit-to-unit
o ability to achieve flat phase over wide bandwidth
o less susceptible to phase pulling when embedded
in networks not perfectly impedance-matched
Digital phase shifter advantages
in networks not perfectly impedance-matched
o easier to assemble
o potentially higher power handling and linearity
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15. Fixed Phase Shifter
F.P.S is extra transmission line section of specific length
that shifts the phase of e.m wave w.r.t transmission line
Depending on bias current, wave travelling along
transmission line Have additional travelling path
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16. Variable Phase Shifter
Use mechanical or electronic means to achieve a dynamic
range of phase difference
Short-circuits, hybrid circuits or dielectric slab with variable
Position can create phase shift
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