1) A new microwave life detection system has been designed to locate humans trapped under earthquake rubble by detecting their breathing and heartbeat signals using microwaves. 2) The system works by transmitting microwave beams through rubble to detect small modulations in the reflected signal caused by a person's movements. Complex signal processing is used to cancel out interference from the rubble itself. 3) The detected signals are then analyzed using a microprocessor or microcontroller to determine if life is present and the condition of any trapped individuals, allowing for rapid search and rescue operations.

1. Presented By:-
 Md Akram Hossain
 Md Nurujjaman
Life Detection System Using
Microwave L- band

2. ABSTRACT
“An earthquake causes loss of many human lives every year as
humans are trapped under collapsed debris or earthquake
rubble”

3. 8/5/2017
3

4. INTRODUCTION
• A new revolutionary microwave life detection system, which is
used to locate human beings buried under earthquake rubble, has been
designed. This system operating at certain frequency can remotely
detect the breathing and heartbeat signals of human beings buried
under earthquake rubble.
• By proper processing of these signals, the status of the person
under trap can be easily judged. The entire process takes place within
a few seconds as the system is controlled by a microprocessor (8085)
or microcontroller unit.

5. PRINCIPLE OF OPERATION
• The basic principle is that when a microwave beam of certain
frequency [L (or) S band (or) UHF band] is aimed at a
portion of rubble (or) collapsed building under which a person
has been trapped, the microwave beam can penetrate through
the rubble to reach the person.
• When the microwave beam focuses the person, the reflected
wave from the person’s body will be modulated (or) changed by
his/her movements, which include breathing and heartbeat.
Simultaneously, reflected waves are also received from the
collapsed structures.

6. COLLAPSED
BUILDING
REFLECTED
BEAM
LIFE DETECTION
SYSTEM
MICROWAVE
BEAM

7. Block diagram :

8. WORKING
1) The wave radiated by the antenna 1 penetrates the earthquake
rubble to reach the buried person.
2) The reflected wave received by the antenna 2 consists of a large
reflected wave from the rubble and a small-reflected wave from the
person’s body.
3 ) The large clutter from the rubble can be cancelled by a clutter-
cancelling signal.
4 ) The small reflected wave from the person’s body couldn’t be
cancelled by a pure sinusoidal cancelling because his/her movements
modulate it.
5 ) The output of the clutter cancellation circuit is automatically
adjusted to be of equal amplitude and opposite phase as that of the
clutter from the rubble.

9. 6 ) Thus, when the output of the clutter cancellation circuit is
combined with the directional coupler 3 (3 dB), the large clutter from
the rubble is completely cancelled. 7 ) Now, the output of the
directional coupler 3 (3 dB) is passed through a directional coupler 4
(6 dB).
8 ) One-fourth of the output directed is amplified by a RF pre-
amplifier and then mixed with a local reference signal in a double
balanced mixer.
9 ) Three-fourth of the output is directed by a microwave detector to
provide dc output, which serves as the indicator for the degree of the
clutter cancellation.
10 ) When the settings of the digitally controlled phase shifter and the
attenuator are swept the microprocessor control system, the output of
the microwave detector varies accordingly.

10. MAJOR COMPONENTS
LAPTOP
DUAL ANTENNA
CLUTTER
CANCELLATION
MICROWAVE
CIRCUIT

11. DUAL ANTENNAS
The dual antenna system has two antennas, which are
energized sequentially by an electronically controlled
microwave single-pole double-throw (SPDT) switch.
The switch turns on and off at a frequency of 100 Hz which is
much higher than the frequency range of the breathing and
heartbeat signals between 0.2 Hz and 3 Hz.
In this dual-antenna system, the two antenna channels are
completely independent.

13. Clutter cancellation system:
1. Send the signal to the rubble through antenna 1.
2. Receive the signal from the rubble through antenna 2.
3. Check the detector output. If it is within the predetermined limits
go to step 5.
4. Otherwise send the correction signal to the digitally controlled
phase shifter 1 and attenuator and go to step 1.
5. Check the sensitivity of the mixer. If the optimum go to step 7.
6. Otherwise send the correction signal to the digitally controlled
phase shifter 2 to change the phase and go to step 1.
7. Process the signal and send it to the laptop.

14. • The phase locked oscillator is
used to generate a very stable
EM wave of 2GHz range.
• Power dividers and directional
couplers , couple part of the
transmission power in a
transmission line by a known
amount out through another
port.
• In this system , 10dB coupler is
used to divide the power into
1/10th and 9/10th part while 3dB
coupler divides power into two
equal parts.
Microwave
Circuit
Phase
Locked
Oscillator
Directional
Couplers
Circulator

15. Frequency spectrum of background noise
Frequency spectrum of breathing and heartbeat
RESULT:

16. ADVANTAGES:
• The process is very easy.
• The frequency 2.45 GHz i.e. L-band frequency and this is free for use by
commercial applications.
• No need to use heart beat and the breathing sensor. Our interest in just
to observe the minute movement of the victim.
DIS-ADVANTAGES:
• Project is expensive.
• The L- band frequency is unable to enter more metal like structure but it
can enter over 10 layers of bricks

17. CONCLUSION:
This life detection system operating either at L (or) S band, UHF band
can detect the breathing and heartbeat signals of human beings under
earthquake rubble. By this system the world death rate as a cause of
natural disaster may decrease to a great extent.

18. Thank you