The document discusses various types of antennas used in wireless communication systems including Wi-Fi dipole antennas, FM dipole antennas, parabolic dish antennas, whip antennas, sectored antennas, and microwave antennas. It provides details on the operating principles, applications, and simulations of these antennas. Key points covered include that Wi-Fi dipoles operate at 2.4 GHz, FM dipoles are used for VHF reception between 87.5-108 MHz, parabolic dishes concentrate signals at their focal point, and sectored and microwave antennas are used in cellular base stations for directional transmission.

1. Antennas and Propagation
Wi-Fi Dipole
FM Dipole
Horn Antenna
Sector Antenna
Microwave Antenna
DEPT OF EEE, KATHMANDU UNIVERSITY 1
Presented by,
Pukar Bhandari
Nikesh Devkota
Nilesh Maharjan
Srijan Shakya

2. Wi-Fi Dipole
› The most common indoor Wi-Fi antenna is the half
wavelength dipole.
› One half of the dipole is white wire that extends to the left
while the other half of the dipole is metal cylinder.
DEPT OF EEE, KATHMANDU UNIVERSITY 2

3. Wi-Fi Dipole
› Each half is electrically insulated from the other and is
approximately ¼ wavelength long.
› The operating frequency of Wi-Fi Dipole is 2.4 GHz and its
wavelength is 0.125m.
› The antenna has a gain of about 2dBi (i.e. 2dB
improvement over an isotropic source) The higher the
gain the better the antenna should perform.
DEPT OF EEE, KATHMANDU UNIVERSITY 3

4. Wi-Fi Dipole Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 4

5. Wi-Fi Dipole Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 5

6. FM Dipole Antenna
› Dipole antennas are often used for the reception of VHF
FM broadcasts(30 to 300 MHz)
› The FM broadcast band extends from 87.5 MHz up to 108
MHz.
› The length of the dipole is determined by the frequency
of operation.
DEPT OF EEE, KATHMANDU UNIVERSITY 6

7. FM Dipole
› The operating frequency of the FM station was found to
be 88.4 MHz.
› The operating wavelength was calculated to be 3.3914
meters.
› The length of the dipole will be half the wavelength.
DEPT OF EEE, KATHMANDU UNIVERSITY 7

8. FM Dipole Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 8

9. FM Dipole Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 9

10. Parabolic Dish Antenna
› The most well known reflector antenna is the parabolic
reflector antenna commonly known as a satellite dish
antenna.
› The parabolic shape of a dish reflects the signal to the
dish’s focal point.
DEPT OF EEE, KATHMANDU UNIVERSITY 10

11. Parabolic Dish Antenna
› Mounted at the dish’s focal point is a device called horn
antenna. A horn antenna is pointed towards a parabolic
reflector.
› Theoretical gain of a dish increase as the frequency
increases.
› The smaller dish antenna typically operate somewhere
between 2 and 28 GHz.
› They have a very high gain (30-40 dB is common).
DEPT OF EEE, KATHMANDU UNIVERSITY 11

12. Radiation Pattern of Parabolic Dish Antenna
DEPT OF EEE, KATHMANDU UNIVERSITY 12

13. Whip Antenna
› Antenna consisting of a straight flexible wire or rod.
› Bottom end of the whip is connected to radio receiver
and transmitter.
› Name derived from whip-like motion that it exhibits when
is disturbed.
› Most common whip antenna is quarter wave whip
antenna.
› These antennas are used in HF, VHF and UHF.
› It is used as antennas for walkie-talkies, FM radios and
automobiles.
DEPT OF EEE, KATHMANDU UNIVERSITY 13

14. Whip Antennas
› It has an omnidirectional radiation pattern.
› Vertical whip antennas are widely used for non-directional
radio communication, where the direction to transmitter
to receiver is unknown or constantly changing for
example in portable FM radio receiver , walkie-talkies.
› Length of the dipole is determined by wavelength of radio
waves used.
DEPT OF EEE, KATHMANDU UNIVERSITY 14

15. Whip Antenna as Vehicle Antennas
› A quarter wave vertical whip antenna is used in
automobiles.
› It has a single element one quarter wavelength long.
› Whips mounted on the vehicles use the
metal roof of the vehicle as a ground plane.
DEPT OF EEE, KATHMANDU UNIVERSITY 15

16. Whip Antenna Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 16

17. Whip Antenna Simulation
DEPT OF EEE, KATHMANDU UNIVERSITY 17

18. Antennas Used in Base Transceiver
Station(BTS)
DEPT OF EEE, KATHMANDU UNIVERSITY 18
Sectored Antenna
Microwave Antenna

19. Antennas Used in Base Transceiver
Station(BTS)
› Sectored Antenna
DEPT OF EEE, KATHMANDU UNIVERSITY 19
Array of Dipoles

20. Sectored Antenna
› A sector antenna is a type of directional microwave
antenna with a sector-shaped radiation pattern.
› The word "sector" is used in the geometric sense; some
portion of the circumference of a circle measured in
degrees of arc. 60°, 90° and 120°
› The Sector antennas are used in an array fashion
according to the requirements(WiMax/CDMA/GSM/LTE).
› Inside the long sector antennas, they are typically
vertically stacked dipoles roughly a wavelength apart, and
about a quarter wavelength in front of a metallic back-
plane.
DEPT OF EEE, KATHMANDU UNIVERSITY 20

21. Sectored Antenna
› Cell sectoring use directional antennas to reduce co-
channel interference in a cellular system.
› When sectoring is employed, the channels used in a
particular cell are broken down into sectored groups and
are used only within a particular sector.
DEPT OF EEE, KATHMANDU UNIVERSITY 21
Figure: Cell Sectoring

22. Sectored Antenna
› Radiation Pattern
› The antenna radiates a horizontal fan-shaped beam, sharp in
the vertical axis so it doesn't spill over into neighboring
sectors.
› To increase or widen the coverage area, and thus the number
of served clients, several sector antennas are installed on the
same
DEPT OF EEE, KATHMANDU UNIVERSITY 22

23. Sectored Antenna
› The coverage area, which is determined by the projection
of the radiation pattern on the ground, can be adjusted
by changing the downtilt of the pattern.
› Mechanical Tilt is adjusted for maximum and minimum
coverage area radiation.
› Electrical tilt is used for increasing and decreasing of
beam radiation.
DEPT OF EEE, KATHMANDU UNIVERSITY 23

24. Sectored Antenna
DEPT OF EEE, KATHMANDU UNIVERSITY 24
Screw for
adjusting
electrical
tilt

25. Microwave Antenna
› This antenna works on the microwave frequency.
› The microwave antenna that we observed operated at
frequency of 17.7-19.7GHz.
› It is used to connect the Base Transceiver Station(BTS) to
the Base Station Controller(BSC).
› For this BTS,BSC is in Banepa.
› It is a point-to-point link through air. So, it is used where
there is no optical link.
DEPT OF EEE, KATHMANDU UNIVERSITY 25

26. Microwave Antenna
› It is a highly directional antenna. So, it is used in point-
to-point links.
DEPT OF EEE, KATHMANDU UNIVERSITY 26
Figure: Radiation Pattern of Microwave Antenna