DAR ES SALAAM INSTITUTE OF TECHNOLOGY

DEPARTMENT OF ELECTRONICS AND TELECOMMUNICATION ENGINEERING

WAVE PROPAGATION AND ANTENNA

ETU 07418

EMMANUEL C. MASYEBA (Reg. No. 100602G8404)

QUESTION ONE

Write the frequencies of operation for radios and TVs allocated by TCRA in Tanzania.

i. Frequencies of Radios for given Regions (in Mhz)

Dar Mwanza Arusha Tanga Mbeya Iringa Morogoro Shinyanga Dodoma K'njaro TBC 87.5 89.2 91.6 89.6 92.3 92.3 - 89.2 87.7 91.6

Clouds Fm

88.4 88.1 87.9 96.0 87.8 - 88.5 87.5 101.4 -

Radio One

89.7 102.7 95.3 - - - - - 100.8 97.2

RFA 98.9 89.8 89 99.3 88.8 88.8 93.8 88.2 89 88.2 Kiss Fm 89.3 88.7 89.9 - 88.2 89.2 90.2 96.4 - 89.9 Capital

Fm 101 101.2 102.1 - 100 100 88.9 - 97.3 103.3

Sibuka 94.5 95.5 104.6 - 97.6 - - 97.8 92 - Radio Maria

104 106 106.7 - 91.9 90.4 102 - - 106.7

ii. Frequencies for given TV stations. (in Mhz)

Frequency TBC ITV 3642 PULSE 3644 CAPITAL 3642 STAR TV 3884 AGAPE 3900 CHANNEL 10 3908 EATV 3642

QUESTION TWO.

Derive the Friis equation based on free space loss.

Solution:

Consider the following transmitter antenna and receiver antenna configuration

Where R = the distance between the transmitter and receiver antennas respectively

Let, Pr be the Power of the receiver antenna

Pt be the Power of the transmitter antenna

Such that = 42 Where P = Power density of the spherical surface area of the antenna

The maximum power that can be delivered to a matched load by a receiving antenna ( ), is given by = , where is the Effective Aperture of the receiving antenna.

But for any antenna: =

Where G is the gain of the antenna, and is the wavelength.

Tx Transmitter

Rx Receiver

R

From

= Substituting = 42 into =

Such that = () Watts Then for an isotropic antenna, where G=1, and the power received is:

= () Watts Expressing Friis in Decibels

= () Since = /, where c is the speed of light (3 x 108 m/s) = ()()( )

= ()()( )

= .

()() Taking 10 log of both sides we get the ratio of Pr /Pt in dB:

= .

()()

= (. ) = . () ()

Hence shown.

QUESTION THREE

Design a dipole antenna that operates at a frequency of 88Mhz. give the radiation pattern and gain.

Solution:

Code used in the dipole antenna configuration

The power gain in the dipole antenna at 88 MHz

The resulted radiation pattern after simulation