High efficiency sea water monopole antenna

1. RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY
PUDHUCHERRY
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
High-Efficiency Sea-Water Monopole Antenna using
acrylic tube for
Maritime Wireless Communications
By:
Aarthi R (18TC0301)
Nitthya Sree T Y (18TC0324)

2. Contents
• Abstract
• Introduction
• Objective
• Liquid Antenna
• Existing Model
• Problems of Existing Model
• Pin Diagram
1. Transmitter
2. Receiver
3. Embedded system
• RF wireless access
• Components Used

3. Abstract
This monopole antenna consists of a feeding probe and a seawater cylinder held
by a clear acrylic tube. In comparison to the dynamic type sea water monopole
antenna in our structure is relatively simple, mainly consists of acrylic tube filled
with sea water and top loaded feeding probe.
A new transparent and reconfigurable sea water monopole antenna is well suited
for maritime wireless communication.
Our antenna as higher efficiency due to an efficient feeding structure and thick sea
water cylinder used. The concept of our project is to save the fuel, time and life of
submarine and water bound vehicles.

4. Objective
To understand the structure of the components of the sea-water monopole
antenna which are explained in detail

5. Introduction
For a liquid antenna, the fluid that carries charged particles in the
form of ions is used as the radiating medium.
Due to the fluidity, the fluid can be pumped into a plastic tube and
thereby ―deployed when the antenna is activated. When
deactivated, the fluid can be pumped out or drained and the tube can
also be removed, resulting in very small occupation space and radar
cross section (RCS).
Based on this design, a feeding probe loaded with nut and washer
was introduced to improve the performance of the monopole water
antenna.

6. LIQUID ANTENNA
 For a liquid antenna, the fluid that carries charged particles in the form of ions
is used as the radiating medium.
 Due to the fluidity, the fluid can be pumped into a plastic tube and thereby
“deployed” when the antenna is activated.
 When deactivated, the fluid can be pumped out or drained and the tube can
also be removed, resulting in very small occupation space and radar cross
section (RCS).
 Thus, the most simple yet promising liquid conductor that may be used in
antennas for good performance is water with relative permittivity & r 4 81,
and conductivity o ¼ 4 S=m. Also, water is eco friendly, easily available, and
cheap material for an antenna to be designed.

7. Structure of the antenna

8. Existing Model
Uses magnetic induction properties of sodium chloride (salt) in seawater to
transmit and receive communication signals.
The device works by pumping a stream of seawater through a current probe.
The height of the seawater stream determines the antenna’s frequency.
The width of the stream determines the antenna’s bandwidth. The antenna
requires a relatively small footprint and can be modified to accommodate
multiple frequencies and bandwidths by stacking current probes and adding
additional spray nozzles.

9. Problems of Existing Model
Height of the stream depends on the distance to be transmitted.
Efficiency of this sea-water monopole antenna is low because the thin sea-water stream is not
an efficient radiator.
It is also known that the thinner the stream becomes, the larger is the loss resistance and the
lower is the radiation efficiency.
Stream disperses at higher altitude resulting in loss of signal.
In case of yagi-uda antenna it has very low gain of around 20db, it’s obstructive in nature, it
needs large number of elements, its prone to noise and atmospheric conditions. Since it’s a main
drawback to use this antenna in noisy ocean atmospheric conditions.
The switching states are low as well.

10. RF WIRELESS ACCESS
RF wireless will have a transmitter and a receiver both are coupled through radio
frequency on air media. Transmitter will have carrier frequency generator, Modulation
signal inputs, Mixer (If single data transfer) or Mixer with encoder (if in case of multi
channel requirement) and a device converts electrical signals in to electromagnetic
signal (TX). The distance coverage can be increased by increasing the power of
transmission, without affecting others frequency. Data security is possible by adopting
good encryption techniques.
Receivers will have a receiver, demodulator to reject carrier signal and separates
modulation signal for further processing, decoder to decode the encoded data. In Rf the
decoders are generally PLL ( Phase Locked Loop) . PLL ‘s will have a local oscillator and
an external frequency inputs .When both the frequencies are matching output will be
delivered.

11. Submarine parameters to be found
• Engine temperature
• Turbine temperature
• Smoke
• Fire sensor level

15. Physical structure of PIC16F877A
Power supply
Embedded
Micro Controller
Crystal
oscillator
RS 232 CHIP
OUTPUT TO
COMPUTER

16. PIC16F877A
40 pin
Powerful (200 nanosecond instruction execution)
easy-to-program (only 35 single word instructions)
CMOS FLASH-based 8-bit microcontroller.
RS232 CONVERTOR
The Max 232 is a dual RS-232 receiver / transmitter.
2 onboard charge pump voltage converters which generate +10V and –10V power supplies from a single
5V power supply.
Four level translators, two are RS232 transmitters that convert TTL CMOS input levels into + 9V RS232
outputs. The other two level translators are RS232 receivers that convert RS232 inputs to 5V TTLCMOS
output level.
Applications
Suitable for all RS232 communications.
Voltage regulator for input voltage up to 5.5V (used in power supply Section of computers, peripherals,
and modems).

17. A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes
in pressure, acceleration, temperature, strain, or force by converting them to an electrical
charge.
In our project it is used to sense any force or strain of the turbine.
Wireless Receiver of 433.92 Mhz carrier frequency and 33 – 37 Khz modulation frequency
is used. The LED will glow for the corresponding signal Receiving. HD 12 D is the chip used
for this purpose, letter D – Decoder (PLL type Decoder employed)
Wireless Transmitter of 433.92 Mhz carrier frequency and 33 – 37 Khz modulation
frequency is used. HD 12 E is the chip used for this purpose, letter E – Encoder
Components Used

18. Bismuth oxide Thermistor employed to find out temperature of the turbine which
produces power to the Submarine, Most of the submarine accidents happened because
of this. It is essential to find out temperature, this component is a NTC (Negative
Temperature Coefficient) type thermistor ,i.e increase in temperature decrease in
resistance
Advantages of Acrylic:
Highly resistant to variations in temperature. Up to 17 times
the impact resistance of ordinary glass. Half the weight of glass
and ideal for precision machining. Highly resistant to many
different chemicals.