This document describes a microwave life detection system that can locate human subjects buried under rubble after an earthquake. It operates at frequencies like 1150MHz or 450MHz and can detect breathing and heartbeat signals through up to 10 feet of rubble. The system works by sending microwaves through the rubble, detecting signals reflected back that are modulated by movement from the heart and lungs, and identifying the presence of life. It has advantages over other methods like using dogs or cameras in being able to detect life under thick barriers.

1. Guided by: Presented by:
V P Vinturaj Prince P
Roshna Miss S5 EL, Roll. NO: 26
Renjith M K
Lecturers in Electronics
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2.  INTRODUCTION
 CONVENTIONAL METHODS
 MICROWAVES
 THE ELECTRO MAGNETIC SPECTRUM
 PROPERTIES OF MICROWAVES
 PRINCIPLE OF OPERATION
 COMPONENTS OF BLOCK DIAGRAM
 RESULT
 ADVANTAGES
 DISADVANTAGES
 CONCLUSION
10/07/2018 Dept of EL, GPTC Kasaragod 08

3.  Microwave life detection system is used to locate human subjects buried
under earthquake rubble or various barriers constructed.
 By the advent of this system the world death rate may decrease to greater
extent because large percentage of death occur due to earthquake.
 This system operates at 1150 MHz or 450MHz.
 Thus it can detect the breathing and heartbeat signals of human subjects
through earthquake rubbles or construction barrier up to 10ft thickness.
 The manmade and natural disasters have become common in the last
decades and due to these, buildings tend to collapse on people.
10/07/2018 Dept of EL, GPTC Kasaragod 08

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5.  Microwaves are electromagnetic wave with wavelengths
varying from 1mm to 1m and frequencies between 300MHz
and 300GHz.
 This broad definition includes both UHF and EHF.
 In all cases microwave includes the entire SHF band (3 to
3GH, or 10 to 1cm) at minimum.
10/07/2018 Dept of EL, GPTC Kasaragod
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7. Microwave is an
electromagnetic
radiation of short
wavelength.
They can reflect by
conducting surfaces just
like optical waves since
they travel in straight
line.
Microwaves are easily
attenuated within short
distances
Increased
bandwidth
availability
Improved directive
properties
Power
requirement are
quite low
Less fading effect
and higher
reliability
10/07/2018 Dept of EL, GPTC Kasaragod 08

8. Microwave is sent
through rubble to
detect vital signs of
life
Microwave would
reflect back from
some objects
When the beam
hits the body the
signal reflected
with an additional
modulation created
by movement of
heart and lungs
The reception of
modulated
signals shows
the presence of
alive human
inside the rubble
10/07/2018 Dept of EL, GPTC Kasaragod 08

9.  L (or) S band frequency say 1150MHz
 UHF band frequency say450 MHz
 The microwave life detection system can works on different range
of frequencies from L-and (2GHz) to X –band (10GHz)
 But X-band microwave is unable to penetrate deep into the rubble.
It can penetrate rubble up 1.5ft. In the thickness (5 layers of
bricks)
 while L-band penetrate the rubble of about 3 ft in thickness(10
layers of bricks)
Depth of penetration depends up on frequency .i.e. it needs low frequency and more
wavelength.
But microwave have low wavelength and high frequency ,thus less is the
penetration power
But in comparison to x-ray, gamma ray , cosmic rays …..microwave have high
penetration power.
10/07/2018 Dept of EL, GPTC Kasaragod 08

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12.  The wave radiated by the antenna 1 penetrates the earthquake
rubble to reach the buried person
 The reflected wave received by the antenna to consist of large
reflected waves from the rubble and a small reflected wave
from the person’s body
 The large clutter from the rubble can be cancelled by a clutter
cancelling signal
 The small reflected wave from the person’s body could not be
cancelled by a pure sinusoidal cancelling because his/ her
movements modulate it
 Output of the clutter cancellation circuit is automatically
adjusted to be of equal amplitude and oppose it phase as that of
the clutter from the rubble
10/07/2018 Dept of EL, GPTC Kasaragod 08

13. 1. PHASE LOCKED OSCILLATOR:
 A phase-shift oscillator is a simple electronic oscillator containing an
inverting amplifier elements.
 Here the phase locked oscillator generates a very stable EM wave say
1150MHz with output power say 400mW.
2. DIRECTIONAL COUPLER:
 A directional coupler is a 4 port network that is designed to divide and
distribute power.
 The device is normally used to split the input signal and distribute power .
 The coupled output from the directional coupler can be used to monitor
frequency and power level on the signal without interrupting the main
power flow in the system.
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15. 3. CIRCULATOR:
 A circulator is a ferrite device with usually three ports.
 That is, energy in port1 predominantly exits port 2, energy into port 2
exit port 3, and energy into port 3 exits port 1.
10/07/2018 Dept of EL, GPTC Kasaragod 08

16.  4. ANTENNA SYSTEM:
 The dual antenna system has two antennas, which are
energized sequentially by an electronically controlled
microwave single-pole double-throw(SPDT).
 The SPDT switch turns on and off at a certain frequency .
 Each antenna acts separately .
 Each act simultaneously as the radiating element and
receiving element .
 It radiates EM wave through the earthquake rubble to reach the
trapped human subjects and at the same time it receives the
reflected EM wave from the rubble and the human subjects.
10/07/2018 Dept of EL, GPTC Kasaragod 08

17. 5. CLUTTER CANCELLATION SYSTEM:
 In any remote sensing instrument the clutter caused by
undesirable objects surrounding the detectable subject must be
cancel to the optimum level.
 The clutter canceller forms the heart of life detection system.
 The clutter cancellation unit consists of
1.A digital controlled phase shifter
2.A fixed attenuator
3.A RF amplifier
4.A digitally controlled attenuator
10/07/2018 Dept of EL, GPTC Kasaragod 08

18. METHODS
1. Utilization of dogs
2. Optical devices
3. Acoustic life
detectors
4. Rescue robot
 But the dogs can only detect the dead
persons but this consumes precious time
 The optical device requires expert
operators and cannot be used in
inaccessible area
 This is simple to use but requires quiet
working environment and difficult to
reach in critical situation
 Such robots can navigate deep into the
rubble by using temperature sensor but
unable to trap once they are out of range.
LIMITATIONS
10/07/2018 Dept of EL, GPTC Kasaragod 08

19.  Remote life sensing could be a powerful tool in applications
where access to the subject is limited.
 The frequency 2.45GHz .i.e. L-band frequency and this is free
for use by commercial applications, so we expect a minimum
interference with other devices during our tests.
 If a minute movement of the victim is observed then detection
can be done.
10/07/2018 Dept of EL, GPTC Kasaragod 08

20.  Project is expensive but once it is implemented the expense can
be reduce lower extend.
 The L-band frequency is unable to penetrate more metal like
structure but it can penetrate over 10 layers of bricks .
 The involvement of clutter signal may destroy the vital
information of life signs
 But if the proper modulation is used one can receive the vital
signs efficiently.
10/07/2018 Dept of EL, GPTC Kasaragod 08

21.  Thus a new sensitive life detection system using microwave
radiation for locating human beings buried under earthquake
rubble has been designed .
 This system operating either at L or S band ,UHF band can
detect the breathing and heart beat signs of human beings
buried under earthquake rubble.
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