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TITLE OF THE ARTICLE DESIGN ,SIMULATION AND DEVELOPMENT OF CKT DIAGRAM TO INCREASE ACTIVE RADAR SEEKER’S LOCK-ON TIME
AUTHORS: ILAPAVULURIUMAMAHESHWARRAO,SCIENTIST, ADITYA BHARTI, SCIENTIST, PROGRAMME-AD/RCI,DRDO, KANCHAN BAGH(PO), HYDERABAD-500058, ANDHRA PRADESH,INDIA
ACTIVE RADAR SEEKERS
•: Active Radar Seekers used in INTERCEPTORS plays an
important role in Ballistic missile defence. Although there are
other guidance techniques available for Interception of ballistic
targets
•Homing guidance of the INTERCEPTOR is achieved by
ACTIVE RADAR SEEKERS Which have Several advantages in
the Scenario.
•The ACTIVE RADAR SEEKERS Which are now used have
MICROWAVE TUBES Which gets heated when the
TRANSMITTER is switched on for more time. The Transmitter
lock on time is limited by the transmitter radiation time i.e. only
30 seconds.We have designed a ckt to increase seeker lock-on-
timeto 100 seconds.
CHARACTERISTICS AND ADVANTAGES OF THE DESIGNED SIMULATED DEVELOPED CKT DIAGRAM
•Also the weight of seeker used in present day INTERCEPTORS have a constraint on
the limited RANGE and also Less payload(lowweight warheads).
•In INDIA We are trying to develop SOLID STATESEEKER TRANSMITTERS Which
will be realized in The very near future.How ever we are trying for excellence through
indigenous development in all fields in particular defence research and development
organization through our internal private partners co-operation.
• TECHNOLOGY goes on changing by every time.
•There is a revolution in technology in every field. Technology denied is technology
gained. How ever what existing seekers we have we can’t discard them and say they
are absolete.
•Hence we have designed a circuit diagram having a Y-CIRCULATOR
•Or Power divider to the first input has the seeker tx output.
•pulses.
•THE CKT HAS BEEN SIMULATED ALSO WITH RF AND MICROWAVESOFTWARE ADVANCED
DESIGN SYSTEMS2011 A.
• THE SIMULATED CKTS ARE SHOWN IN THE SLIDES
•THE RESULTS ARE PLOTTEDAS RETURN LOSS AND S11, S12(S-PARAMETERS.
•THE RETURNLOSS AT 17.5 GHZ IS -76DB AND VSWR IS ALMOST 1.0
•The advantage of this circuit is that the LOCK ON TIME OF
SEEKER IS increased to 100 seconds.Even though the
transmitter is on for 30 seconds the echoes start coming
even after the radiation is swiitchedoff.
•Ther is a great need to modify or design the present
existing active radar seekers which use only microwave
tubes and hence there gets a limitation of
activeradarseekers in terms of not only lock -ontime but
also heating effects of microwave tubes used in the
transmitter.
•The second output is directly connected to the SEEKERS SLOTTED
WAVEGUIDE ANTENNA. OR Other wise SEEKER TX.OUTPUT can be directly
connected to the slotted waveguide array antenna inorder not to disturb the
SEEKER. Only the Y-CIRCULATOR 3rd output requires power tapped from any
transmitter part. The Y-CIRCULATOR 3rd output is attenuated and fed to OR –
GATE(ADDER) Or a Power combiner to which a VCXO(VOLTAGE
CONTROLLED CRYSTA OSCILLATOR Whose output similar to seeker tx
output except that the pulse period is 100 seconds.
•The output of OR-GATE(ADDER) OR POWERCOMBINER gets radiated by a
secondary antenna which in this case is an APERTURE COUPLED
MICROSTRIP PATCH ANTENNA.
•We have Simulated this using MATLAB SIMULINK THE DIAGRAM is
included . 2 DISCRETE PULSE GENERATORS having pulse durations 30
seconds and 100 seconds are added by an adder and displayed in 3
oscilloscopes. The First OSCILLOSCOPE has 100 second pulses and 30
second pulses intermixed with each.The second oscilloscope displays 30
seconds pulses the third oscilloscope displays the 100 seconds
DESIGN OF CIRCUIT DIAGRAM FOR INCREASE OF SEEKER LOCKON TIME
Y
SEEKER Tx O/P
CIRCULATOR
1 (i/p)
2 O/P
SEEKER ANTENNA
3 O/P
ATTENUATOR
OR GATE SECONDARY ANTENNA
VCXO
Note: This Circuit can be incorporated in any type of Radar Seeker
ADDITION OF 100 SECONDS & 30 SECONDS PULSES
OSCILLOSCOPE OUT PUT OF 100 SECONDS & 30 SECONDS PULSES
8/10
POWER DIVIDER (LUMPED CKT) DIAGRAM
m1freq=dB(S(1,1))=-28.611
17.49GHz
m2freq=dB(S(1,2))=-3.017
17.50GHz
15.5 16.0 16.5 17.0 17.515.0 18.0
-50
-40
-30
-20
-10
-60
0
freq, GHz
dB
(S(1
,1))
17.49G-28.61
m1
dB
(S(1
,2))
17.50G-3.017
m2
m1freq=dB(S(1,1))=-28.611
17.49GHz
m2freq=dB(S(1,2))=-3.017
17.50GHz
-77
-76.5
-76
-75.5
-75
-74.5
-74
-73.5
-73
14 15 16 17 18 19
Series1
Series2
S11 (dB)S12 (dB)Plots of Power Divider
FREQUENCY(GHz) Vs RETURNLOSS dB
S-PARAMETERS AND RETURNLOSS PLOTS OF LUMPED CKT POWER DIVIDER
Y-Circulator(MicrostripLine)
11 12 13 14 15 16 17 1810 19
-20
-15
-10
-5
-25
0
freq, GHz
dB(S
(1,1
))
Readout
m1
dB(S
(1,2
))
17.24G-3.044
m2
m1freq=dB(S(1,1))=-21.132
17.29GHz
m2freq=dB(S(1,2))=-3.044
17.24GHz
S- Parameters of Y-Circulator
SECONDARY ANTENNA
GEOMETRY OF APERTURE COUPLED MICROSTRIP PATCH ANTENNA
THANK YOU ALL
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