3. INTRODUCTION
•A Phase Shifter is two-port device whose basic function is
to provide a change in the phase of RF signal with
practically negligible attenuation.
6. FERRITE PHASE SHIFTERS
• THEORY
» Is the change in the effective permanent of ferrite with
the magnetic field
As the permeability increase the effectiveness of the
ferrite rod increases since guided wavelength is equal
to wavelength in space divided by effectiveness
(permeability), hence guide wavelength
decreases, which result in a change or RF insertion
phase.
7. Semiconductor Phase
Shifters
Planar/hybrid MIC Monolithic
Reciprocal Non reciprocal Reciprocal Non reciprocal
P-I-N GaAs FET GaAs FET GaAs FET GaAs FET
diode (Passive) (active switch) (passive) (active switch)
• Switched line • Switched path • Switched • Switched path
• Hybrid coupled line/loaded DGFET
• Loaded line line
• High-pass low- • Hybrid coupled
pass • High-pass low
• Switched -pass
network
8. DIGITAL PHASE SHIFTER
Specification of Digital Phase Shifter
Frequency 0.5 to 2.0 GHz
Phase Accuracy +/- 10
Amplitude Balance +/- 1.0 dB
V.S.W.R 1.7:1
Noise Figure 7 dB
0 dBm CW ~ +2- dBm
Input power
Max
Size 4.95 x 3.38 x 1.0 inch
Switching Speed 500 nSec
9. Basic terms connected to antenna array :
1.Insertion phase - It is the phase delay experienced by the RF signal between
its input and outputs ports.
2. Input VSWR - The input voltage standing wave ratio is defined as
VSWR = 1 + | S11 |
1 - | S11 |
3.Directivity - The ratio of the radiation intensity in a given direction from
the antenna to the radiation intensity averaged over all directions
D = 4 U / P rad
10. APPLICATIONS
• Used in a variety of communication and radar
systems
• microwave instrumentation and measurement
systems
• In industrial applications.
11. CONCLUSION
• Phased array radars are used for inertia less scanning and tracking. They
as well can be used for multi target tracking.
• Phased arrays can also be used for air traffic control at the airports.
• Other than defence applications, phase shifters are finding their place in
routine life.
• An American company is working on a project where phased arrays are
used for finding the blind stops on road while driving.
• With such high tech commercial application, driving on road will be safer.
• The phase shifter technology for phased arrays has no limitation either in
defence applications or in our daily life.
