X-Band Nanosatellite Telecommunication System Design

X-Band Nanosatellite

Telecommunication System Design

Master student: AL-SALIHI IBRAHEEMALKHALIL EMAD KHUDHUR

Samara 2020

Supervisor: Associate professor I.A. Kudryavtsev

[email protected]

Master thesis

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Contents

1. Relevance and the goal of the thesis.

2. Analysis the telecommunication system performance.

a) Simulating an X-Band telecommunication system.

i. Orbital selection.

ii. Telecommunication components.

iii. Link budget calculation.

b) Formulate the requirements of the antenna to improve the X-Band telecommunication system.

3. Microstrip patch antenna review.

4. Antenna design and simulation.

a) 1st step: tuning the antenna parameters.

b) 2nd step: Obtaining the circular polarization.

c) 3rd step: Improve antenna performance by using parasitic patch technique.

d) 4th step: Improving the antenna by using reflector technique.

e) 5th step: Improving the antenna performance by using an additional parasitic patch.

5. Re- simulation the telecommunication system.

6. Conclusion.

X-Band Nanosatellite telecommunication system Design

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Relevance and the goal of the thesis

In Nanosatellite there are many limitations affect the link connection between the Nanosatellite and ground

station:

1- link reliability depends on distance and path loss for x band frequencies is more significant.

2- Number and dimensions of the solar panels are limited which influence the quantity of the power can be

absorbed from the sun(≈2W), which also effects on the power can be generated to the communication system

and payloads

3- Time connection is about few minutes due to the high-speed movement of the Nanosatellite.

Also, there are other factors such as type of modulation techniques and coding methods that affect the

performance of the X-band telecommunication system of the nanosatellite.

Our goal is to develop an X-Band telecommunication system for Nanosatellite by designing and simulating antenna to satisfy the

requirements of telecommunication system enhancement.

Figure1- Nanosatellite

telecommunication system

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Analysis the telecommunication system performance

a) Simulating an X-Band telecommunication system.

i. Orbital selection.

ii. Telecommunication components.

iii. Link budget calculation.

b) Formulate the requirements of the antenna to improve the X-Band telecommunication system.

Our mission selected to perform a short-term earth observation that required high data rate.

The circular orbit selected for the mission is the low Earth orbit (LEO) with an altitude of 300 km.

i. Orbital selection

Orbital shape Circular orbit

Orbital position Low earth orbit (LEO)

Height of apogee (ha) 300 km

Height of perigee (hp) 300 km

Semi major axis (a) 6678 km

Eccentricity (e) 0

Inclination (I) 98.61°

Table 1 - Orbital parameters

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Analysis the telecommunication system performance

Figure 3 - Micro X-Band HDR-TM transmitter

Figure 2 - ASC Signal 7.6m C & X-Band Low PIM Tx/Rx Earth Station Antenna

Transmitter specification

Dimension 96×90×24 (𝑚𝑚3)

Operation frequency X-Band-(8025-8400) MHz

Data rate From (2.8 to 50) Mbps up to 100 Mbps

Modulation type Offset-QPSK

Power consumption <7 W for 1W RF output power·

< 10W for 2W RF output power

Eb/N0 2.7 dB

BER 10E-9

Mass 300 g

Applications Earth observation

RF output power 30 – 33dBm, with 1-dB step

Table 3 - Transmitter specifications

Ground station specification

Antenna type Parabolic reflector antenna

Antenna diameter 7.6 m

Hub/Enclosure Dimensions: Diameter 1.33 m, depth 1.17 m

Frequency band receive (7.5 - 8.4) GHz

Antenna gain 54.7 dBi

Polarization circular polarization

Axial-Ratio 1.2 dB

Beam width 0.3°

Tx power capacity 750 W

Table 2 - Ground station specifications

ii. Telecommunication components

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Link budget calculation

elevation angle(𝛿) 5°

Slant Range (𝑆) 1499.5 km

Center frequency (downlink) 8.142 GHz

BER 1 × 10−9

Eb/N0 2.7 dB

Data rate 2.8 Mbps

Power of transmitter 1.5 W

Assumed Antenna gain of nanosatellite 5 dBi

Ground station Tx Power 750 W

Gain of ground station 54.7 dBi

BW of ground station receiver 30.5 MHz

DL. link margin (𝐸𝑏/𝑁0 method) 11.8 dB

DL. link margin (𝑆𝑁𝑅 method) 1.4 dB

Table 4 - Simulation X-Band telecommunication system

iii. Link budget calculation

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Nanosatellite antenna requirements

Microstrip patch antenna requirements

Dimensions Less than 100×100×20 (𝑚𝑚3)

Operation frequency X-Band

Feeding Coaxial feed

Impedance 50 𝛺

Polarization Circular polarization

Bandwidth >150 MHz

Gain More than 8 dBi

Beam width Less than 35°

S-Parameter Less than minus 10 dB

Table 5 - Nanosatellite antenna requirements

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Microstrip patch antenna review

Microstrip patch antenna specifications

Dimensions 25.95 × 25.95 × 1.575

(𝑚𝑚3)

Operation frequency 10 GHz



Gain 7.64 dBi

S-Parameter ~ - 13 dB

Table 6 – 1st review Nanosatellite antenna

specifications

1st review Nanosatellite antenna

Wayan Suparta, Mardina Abdullah, Mahamod Ismail, Space Science and Communication for Sustainability, ISBN 978-981-10-6574-3, Library of

Congress Control Number: 2017952532, Springer Nature Singapore Pte Ltd. 2018

Figure 5 – Gain of the 1st reviewed antenna Figure 4 -Antenna integrated with the 1U satellite

body

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Microstrip patch antenna review

Microstrip patch antenna specifications

Dimensions 24 × 24 × 2.3 (𝑚𝑚3)

Operation frequency 8.2 GHz



Gain 6.5 dBi

S-Parameter ~ - 30 dB

Table 7 – specifications of the 2nd reviewed

Nanosatellite antenna

2nd review Nanosatellite antenna

Figure 7 – radiation pattern of the 2nd reviewed

antenna

Figure 6 - front view of the X-Band Single

Element Patch Antenna

EnduroSat's X-BAND SINGLE ELEMENT PATCH ANTENNA

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Design and simulation process of patch antenna

1st step: tuning the antenna parameters

Radius of The Patch (mm) 11.5

Thickness of The Patch (mm) 0.035

Size of The ground (mm*mm) 50×50

Thickness of The Ground (mm) 0.035

Size of The Substrate (mm*mm) 50×50

Thickness of The Substrate (mm) 0.8

Table 8 - parameters of the antenna

Theoretical calculation

𝐹 =8.791×109

𝑓𝑟 𝜖𝑟= 0.529

𝑎 =𝐹

1+2ℎ

𝜋𝜖𝑟𝐹ln

𝜋𝐹

2ℎ+1.7726

1/2 ≈ 0.53 cm

𝑎𝑒 = 𝑎 1 +2ℎ

𝜋𝑎𝜖𝑟ln

𝜋𝑎

2ℎ+ 1.7726

1/2≈ 0.9 cm

Figure 8 - Front view of the 1st step antenna structure

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Antenna design and simulation

Figure 9 - The antenna structure of the 2nd step

2nd step: Obtaining the circular polarization 3rd step: Improve antenna performance by using stacked parasitic patch technique

Figure 10 - Antenna dimension of the 3rd step

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Figure 11 - The antenna structure of the 4th step: (a) Front view with dimensions, (b) Side view with dimensions

(b)(a)

4th step: Improving the antenna by using reflector technique

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Figure 12 - Front view of the 5th step without 2nd substrate

5th step: Improving the antenna performance by using coplanar parasitic patch technique

Figure 14 - S-Parameters of the final simulationFigure 13 - Far-field of the final simulation

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Desired results Achieved results

Dimension < 100×100×20 (mm^3) Dimension 66×66×15 (mm^3)

Operation frequency X-Band Operation frequency X-Band

Feeding Coaxial feed Feeding Coaxial feed

Impedance 50 Ω Impedance 𝑆11 = 45.7 Ω

𝑆21= 49.9 Ω

Polarization Circular polarization (AR < 3 𝑑𝐵) Polarization Circular polarization (AR = 0.26 dB)

Bandwidth More than 150 MHz Bandwidth 200.98 MHz

Gain More than 8 dBi Gain 11.1 dBi

Beam-width < 35 degrees Beam-width 29.9 degrees

S-Parameter Less than -10 dB S-Parameter 𝑆11 = - 28 dB

𝑆21 = -60.323 dB

Table 9 - Comparison between desired results and achieved results

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Figure 15 – Antenna structure mounted on 3U CubeSat: (a) front view, (b) side view

(a) (b)

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Re - simulation the X-Band telecommunication system

elevation angle(𝛿) 5°

Slant Range (𝑆) 1499.5 km

Center frequency (downlink) 8.142 GHz

BER 1 × 10−9

Eb/N0 2.7 dB

Data rate 6 Mbps

BW of ground station receiver 30.5 MHz

Power of transmitter 1 W

Assumed Antenna gain of nanosatellite 11.1 dBi

Ground station Tx Power 750 W

Gain of ground station 54.7 dBi

DL. link margin (𝐸𝑏/𝑁0 method) 13.3 dB

DL. link margin (𝑆𝑁𝑅 method) 6.2 dB

Table 10 - Re-Simulation X-Band telecommunication system with the usage of the designed antenna

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Conclusion

As it can be seen from simulation results that the X-Band telecommunication systemdeveloped by designing patch antenna which is satisfy developing requirements interms of:

• Enhancing the data rate from (2.8 Mbps) to (6 Mbps).

• Reducing the power consumption of the transmitter from (1.5 W) to theminimum (1 W).

• Increasing the link budget from (𝐸𝑏/𝑁0method = 11.8 dB, SNR method = 1.4 dB)to become (𝐸𝑏/𝑁0 method = 13.3 dB and SNR method = 6.2 dB).

THANK YOU

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X-Band Nanosatellite Telecommunication System Design