vuxsajvbSABGhjasgahyujaxygazxhyuxbh bxabhabhxzHBjxzbhxahxshasiuaadsuhduieuddhsuuhhufhcb jxkzkAakaxkkx

1. EC 437 Satellite Communication
By
Dr. Taimoor Khan,
Associate Professor, Department of ECE,
Associate Dean (Academic),
National Institute of Technology Silchar (An Institute of National Importance under Ministry of Education,
Govt. of India), Silchar-788 010, Assam, India, M: +91-9411823416/+91-
9864782439, URL: http://ec.nits.ac.in/ktaimoor/
IETE-Prof SVC Aiya Memorial Award Winner
FIE India, FIETE India, SMIEEE, SMIEEE AP-S, SMIEEE MTT-S, SMURSI
Chair, IEEE Silchar Subsection
Faculty Advisor, IEEE MTT-S SBC, NIT Silchar
Regional Coordinator, IEEE AP-S Chapter Award Committee, IEEE AP-S Chapter Award Committee
and IEEE AP-S Paper Award Committee
Visiting Researcher, Queen's University Canada
Visiting Assistant Professor, Asian Institute of Technology Bangkok, Thailand
Taimoor Khan and Yahia M.M. Antar, “Band-Notch Characteristics in Ultra-Wideband Antennas” CRC
Press, Taylor & Francis, 2021, ISBN: 978-0-367-75472-3.
Taimoor Khan, Nasimuddin and Yahia M.M. Antar, “Elements of Radio Frequency Energy Harvesting and
Wireless Power Transfer Systems”, CRC Press, Taylor & Francis, 2020, ISBN: 978-0-367-24678-5.

2. Some Numerical Problems: Satellite Link Design
11/25/2022 2

3. 11/25/2022 3
Problem-1:
A geostationary satellite at a distance of 36000 Km form the surface of the Earth
radiates a power of 10 Watt in the desired direction through an antenna having a gain of
20 dB.
a. Calculate the power received by an antenna having an effective aperture of 10m2.
b. What would be the power density on the receiving site on the surface of antenna?
Solution:
2
4
x
R
A
G
P
A
F
P r
t
t
r
r



Given:
Gt = 20dB = 100
Pt = 10Watt
R = 36000 Km = 36×106 m.
Ar = 10 m2
a. Pr = 0.614×10-12 = 0.614 pW
b. F = Pr/Ar = 0. 0614×10-12 W/m2 = 0. 0614 pW/m2

4. 11/25/2022 4
Problem-2:
Compute the free-space path loss in dB for the following conditions:
a. For a path length of 10 Km at 4GHz operating frequency.
b. Earth station transmitting antenna EIRP = 50 dBW, satellite receiving antenna gain =
20 dB and received power at satellite = -120dBW.
Solution:
Given:
R = 10 Km = 1×104 m.
f = 4GHz = 4×109 Hz
a.
λ = c/f = (3×108)/(4×109) = 0. 075 m.
Now, Free space path loss (in dB) = 10
log10 Lp = 124.48 dB.
2
4







R
G
G
P
P r
t
t
r

 2
4








R
Lp
b. Receiver Signal Power,
Pr (dBW) = EIRP + Gr – Lp – La – Lta – Lra
Where: Pr = -120 dBW, EIRP = 50 dBW, Gr
= 20 dB, La (in dB) = 0
Lta (in dB) = 0, Lra (in dB) = 0 and LP = Path
Loss (in dB)?
Lp = 190 dB

5. Problem-3:
In Figure , Satellite A radiates an EIRP of 35dBW on the
downlink to an earth station whose receive antenna gain is
50dB. Emission from another satellite B located in the
vicinity of the first satellite produces interference to the
desired downlink. If the EIRP of the interfering satellite is
30dBW, determine the C/I ratio assuming that the path
loss on the downlink channel for both the satellites is the
same and the angle between line-of-sight between Earth
station and the desired satellite and the line-of-sight between
Earth station and the interfering satellite is 40.
Solution: The path loss on the downlink channel for both the satellites is the same. Hence the
overall C/I ratio is equal to the downlink C/I ratio. Hence,
EIRP = 35dBW, EIRP’ = 30dBW, G = 50dB, and θ = 40.
= 38.05dB

6. Problem-4:
In Figure, EIRP values of Earth stations A and B
are 80dBW and 75dBW, respectively. The transmit
antenna gains in two cases are 50dB each. If the
gain of the receiving antenna of the satellite is
20dB in the direction of Earth station A and 15dB
in the direction of Earth Station B. Determine the
C/I ratio at the satellite due to interference caused
by Earth Station B. Assume viewing angle of the
satellite from the two Earth Stations as 40.
Solution:
Given: EIRP = 80dBW, EIRP* = 75dBW, G = 20dB, G’ = 15dB, GI = 50dB and θ = 40
= 42dBW
= 43dB

7. Problem-5:
The angle formed by the slant ranges of two
geostationary satellites from a certain earth as shown in
Figure (right side) is 50. Determine the longitudinal
location of the two satellites given that the two slant
ranges of satellites A and B are 42100Km, and
42000KM, respectively. Given that the radius of the
geostationary orbit is equal to 42164Km.
Solution:
Given: dA = 42100Km, dB = 42000Km, r = 42164Km, θ =
50. β?
Cos β = 1-0.004 = 0.006. Therefore, β = 5.1260
Hence, the longitudinal separation between two satellite is 5.1260.

8. Problem-6:
In a point-to-point satellite communication system, the carrier signal strength at the satellite as
received over the uplink is 40dB more than the strength of the interference signal from an
interfering Earth Station. Also, the strength of the signal power received at the desired Earth
Station over the downlink is 35dB more than the strength of the interference signal power due to
an interfering satellite. Determine the total carrier-to-interference ratio of the satellite link.
Solution:
Given, (C/I)U = 40dB = 10000 and (C/I)D = 35dB = 3162.28
The Overall Carrier-to-Interference Ratio:
= 2402.53 or 33.8dB
Problem-7: Problem-8:

9. Some Numerical Problems: Noise Consideration

10. 11/25/2022 10
Problem-1:
A 12 GHz receiver consists of an RF stage with gain G1 = 30 dB and noise temperature
T1 = 20 K, a down converter with gain G2 = 10 dB and noise temperature T2 = 360 K
and an IF amplifier stage with gain G3 = 15dB and noise temperature T3 = 1000 K.
Take reference temperature be 290 K. Calculate (a) Effective noise temperature of the
system. (b) Noise figure of the system.
Solution:
Given:
T1 = 20 K,
T2 = 360 K,
T3 = 1000 K,
G1 = 20 dB,
G2 = 10 dB and
G3 = 15dB
Ti =290 K
a. Teq = 20.46 K
b. F = 1+Teq/Ti
= 1+20.46/290
= 1.07

11. 11/25/2022 11
Problem-2:
A 12 GHz receiver consists of an RF stage with gain G1 = 30 dB and noise temperature
T1 = 20 K, a down converter with gain G2 = 10 dB and noise temperature T2 = 360 K
and an IF amplifier stage with gain G3 = 15dB and noise temperature T3 = 1000 K.
Take reference temperature be 290 K. Calculate the overall noise figure from the
individual noise figure specifications.
Solution:
Given:
T1 = 20 K,
T2 = 360 K,
T3 = 1000 K,
G1 = 20 dB,
G2 = 10 dB and
G3 = 15dB
Ti =290 K
F1 = 1+T1/Ti= 1.069
F2 = 1+T2/Ti= 2.24
F3 = 1+T3/Ti= 4.45
F = 1+Teq/Ti
Now the overall noise figure is
F = F1+(F2-1)/G1+(F3-1)/G1G2
= 1.069 + 0.00124 + 0. 000345
= 1.07

12. 11/25/2022 12
Problem-3: Consider the receiver side of the satellite link as shown below:
Satellite
Antenna
(GA, TA)
Feeder
(L1, T1)
LNA
(L2, T2)
Down
Converter
(L3, T3)
It is given that GA = 60 dB, TA = 60 K, L1 = 0.5dB, T1 = 290 K, G2 = 60 dB, T2 = 140 K
and T3 =10000 K. Determine G/T ratio in dB/K referred to input of low noise amplifier.
Solution:
Noise temperature as referred to input of low noise amplifier is
TSI = TA/L1+ T1(L1-1)/L1+ T2+ T3/G2
= 60/1.12 + 290(1.12-1)/1.12 + 140 + 10000/1000000
= 224.65 K
Gain as refereed to input of the low noise amplifier is G = GA-L1= 60- 0.5 = 59.5 dB
And
T = TSI = 224.65 K. Hence,
G/T = G-10 Log10 224.65 = 59.5 – 23.5 = 36 dB/K

13. Thank You
11/25/2022 13

14. EC-437 Satellite Communications
Professional Core Elective–II
Unit 1 Introduction to Satellites and Their Applications: Introduction to satellite, History of Evolution of
Satellites, Applications, Evolution of Launch vehicles, Future Trends
Unit 2 Orbital Aspects: Orbit and Trajectory, Basic Principles of Orbiting Satellites, Orbital Mechanics, Orbital
Parameters, Injection Velocity and Resulting Satellite Trajectories, Types of Orbits.
Unit 3 Satellite Launch and In-orbit Operations: Acquiring the Desired Orbit, Satellite Launch Sequence, Orbital
Perturbations, Satellite Stabilization, Orbital Effects on Satellite’s Performance, Eclipses, Sun Transit Outage,
Looks Angles of a Satellite, Earth Coverage and Ground Tracks.
Unit 4 Satellite Hardware and Subsystems: Various Satellite Subsystems, Attitude and Orbit Control, Tracking,
Telemetry and Command Subsystem, payload, Antenna Subsystems.
Unit 5 Satellite Link Design Fundamentals: Transmission Equation, Link Parameters, Link Calculations, C/N, G/T,
EIRP, Back-off Calculation.
Unit 6 Earth Station: Types of Earth Station, Architecture, Design Considerations, Earth Station Hardware, Satellite
Tracking.
Unit 7 Communication Techniques: Amplitude Modulation, Frequency Modulation, Pulse Communication Systems,
Sampling Theorem, Digital Modulation Techniques-ASK, FSK, PSK, DPSK, QPSK, Offset QPSK;
Multiplexing Techniques-FDM, TDM, OFDM, Spread Spectrum Techniques, Multiple Beam, Spot Beam.
Unit 8 Multiple Access Techniques: Introduction, FDMA, SCPC Systems, MCPC Systems, TDMA, TDMA Burst,
TDMA Frame Structure, Unique Word, Frame Efficiency, Frame Acquisition and Synchronization, FDMA vs.
TDMA, CDMA, SDMA.
Unit 9 Recent Trends: Applications, Challenges of Transponders, VSATS, DTH Television, Satellite Telephony,
Satellite Radio
Texts/References Books:
1. Satellite Communications, Dennis Roddy, TMH.
2. Satellite Communications, Timothy Pratt, Charles W. Bostian and Jeremy E. Allnutt, Wiley India Pvt Ltd.
3. Digital Satellite Communication, T.T. Ha, MHE.
4. Satellite Communications, Maini & Agrawal, Wiley India Pvt Ltd.
5. Communication System by Simon Haykin.
6. Modern Digital and Analog Communication System by B.P. Lathi.