Design and Analysis of a Compact Meander Line Monopole Antenna

with Modified Feeding System for CubeSat Satellite

Zaid M. Khudair

1

and Jabir S. Aziz

2a

1

Department of Electronic & Communications, Al-Nahrain University, Jadriya, Baghdad, Iraq

2

Department of Computer Communications, Al-Rafidain University College, Palestine Street, Baghdad, Iraq

Keywords: CubeSat Antenna, Meander Line Antenna, Compact Antenna for CubeSat, Planer Antenna for CubeSat.

Abstract: Many universities were involved in projects related to the design, assembly and operation of nanosatellite

(CubeSat) to increase the experience level of researchers and students. The CubeSat is a concept emerged

after year 2000 with small size and cubic shape. The antenna is an important component that is used to

define the CubeSat size and to provide communication with the ground station. This paper introduces the

design and implementation of a miniaturized printed Meander line monopole antenna with modified feeding

system having a volume of (80mm×45mm×1.67mm) and operating at 439 MHz center frequency. The

antenna is fabricated on FR-4 substrate with dielectric constant of (ɛr = 4.3) and thickness of 1.6 mm. The

proposed antenna consists of symmetrical meandered lines and thin shorting stubs between these lines to

have a maximum size reduction and to be appropriate for the CubeSat size. The comparison between the

simulation and measurement results are provided. A reflection coefficient of -16.5 dB and bandwidth of 7

MHz were obtained at 439MHz. The antenna has an efficiency of 80% at this frequency.

a

https://orcid.org/0000-0002-0277-0880

1 INTRODUCTION

The small satellites are widely used by the

universities especially after the year 2000 to increase

the experience of students and space researchers.

These satellites are classified into mini, micro, nano

and pico satellites. The CubeSat belongs to the

picosatellite class. A one unit (1U) CubeSat is the

standard size for the CubeSat having a dimensions of

10cm×10cm×10cm and a weight no more than

1.33Kg(S.Gao, 2009). The CubeSats are used for

various purposes such as communications, imaging

and weather forecasting, military use such as spying

and to provide secure communication link (F. EM

Tubbal, 2015).

The antenna is one of the most important

components for the CubeSat as it provides the

connection with the ground station and ensures that

the CubeSat does not lost in space. The

communication system of CubeSat is a pivotal

system as the antenna of this system should realize

different tasks such as telemetry, tracking and

command (TTC), global positioning system (GPS),

global navigation system (GNS), payload data and

intersatellite cross links (Y. Yao, 2016).

The Ultra High Frequency (UHF) band is highly

used for the CubeSat, especially the frequency range

420-450 MHz, because the International

Telecommunication Union has allocated this

frequency band as the International satellite band (T.

Alam, 2018).

The CubeSat required antenna with wide

coverage or near omnidirectional radiation pattern to

be suitable for the TTC application of CubeSat.

Several types of antennas have been used as CubeSat

antennas such as microstrip patch, monopoles,

dipoles, helices and PIFA etc. Microstrip patch

antennas do not satisfy the omnidirectional radiation

pattern and will have a large size at the allocated

frequency band for the CubeSat. Monopoles and

dipoles are satisfy the omnidirectional radiation

pattern required for the TTC application but they are

required a deployment mechanism to be released out

of the CubeSat. These antennas are rolled around the

satellite before the deployment (Mehul K. S, 2016).

The antennas that required mechanical

deployment may increase the mission failure if the

antenna does not released out of the satellite. Several

CubeSat missions were failed as a result of antenna

deployment failed (Ogherohwo, 2015).

The small size of CubeSat makes it very difficult

to design antenna that does not need a mechanical

deployment, having a small size to be suitable for

the CubeSat size and does not cover all the CubeSat

face. The challenges was to design a planer antenna

operating at the allocated frequency band (420-450)

MHz with maximum size reduction and having a

wide coverage radiation or omnidirectional radiation

required for the TTC application of CubeSat.

Several miniaturization techniques are used to

reduce the antenna size such as: the slots in the

radiating patch, the use of high permittivity

materials, shorting pins and meander line antennas.

Meander line antennas are perfect choice for the

CubeSat as it is a transformation for the monopoles

and dipoles antennas and it is a one type of the

microstrip antennas. By meandering the patch the

path of the flowing surface current will be increased

and this will lowering the resonance frequency and

makes the antenna radiates at lower frequency than

the wire antenna of same length (Ogherohwo, 2015).

In this paper, a printed meander line monopole

antenna with modified feeding system is represented

to remove the need for deployment mechanism and

to increase mission reliability. The antenna designed

to fit the size of 1U and 2U Cubesat and cover less

than a half of the Cubesat face which has dimensions

of 80mm×45mm×1.67mm. The antenna is fabricated

on FR-4 substrate with dielectric constant of (ɛr =

4.3) and thickness of 1.6 mm. The antenna operates

at the licensed lower UHF band 435.5 – 442.5 MHz.

2 ANTENNA DESIGN

REQUIREMENTS FOR

CUBESAT

The CubeSat communication system effectiveness is

determined by the link budget and one of the

important components is the performance of the

antenna. The size of the antenna on the CubeSat

structure is dependent on the operating frequency.

The CubeSat antenna must realize different

functions which are guaranteed in each CubeSat

communication mission and these functions are (The

CubeSat Program, 2009):

 Transmit a tracking signal

which allows the

ground stations to follow the position of the

satellite.

 Download telemetry data to the ground station

and receive commands.

For CubesSat applications the following

limitations and requirements should be considered in

the design of the CubeSat antenna:

 According to NASA regulations, the

dimensions can be selected as 1U CubeSat (10

x 10 x 10 cm3), so the antenna should compact

and fit the Cubesat size.

 CubeSat antenna must have wide coverage or

omnidirectional radiation for TTC purposes.

 The antenna should not cover all the Cubesat

face to provide additional space for the solar

panels.

3 FREQUENCY AND ANTENNA

TYPE SELECTION

The International Amateur Radio Union (IARU) is

an organization which is responsible for regulating

the radio spectrum among radio amateurs worldwide

for a better use of it and as shown in Table 1. The

frequency should be one of the regulated VHF, UHF

or S-Band allocated for CubeSat missions (N. Mohi,

2015 and NASA Group, 2014).

Table 1: Frequency allocation for satellite.

Option

1

Option

2

Option

3

Option

4

Frequency

Band (MHz)

144-

146

420-

450

1260-

1270

2400-

2450

Figure 1: The most frequency band used in Cubesat.

0

50

100

150

200

250

300

1.6 –

1.65

GHz

10 -

15

GHz

140 -

150

MHz

2 –

2.5

GHz

420 –

450

MHz

5.5 –

6 GHZ

8 –

8.5

GHz

900

1000

MHz

No. Of Antennas

0.719424460431655

3.59712230215827

4.55635491606715

5.75539568345324

8.39328537170264

11.031175059952

65.2278177458034

Percentage %

Figure 2: The most antenna type used for Cubesat.

Based on the collected information and standards

for the CubeSat deployed in orbit during the period

2000 - 2019, the analysis of these data lead to build

the Figs. (1) and (2). These Figures help us to select

the frequency band and the antenna type as follows:

 According to Figure 1, most of the Cubesat

antenna operates at the licensed lower UHF

band (420 – 450 MHz).

 According to Figure 2, most of the Cubesat

antenna uses dipole or monopole type.

4 MEANDER LINE ANTENNA

The meander line antenna can be designed by a set

of horizontal and vertical lines and the combination

of these lines will form the turns of meander line

antenna as shown in Fig.3. The meander line

antenna is a transformation of monopole and dipole

antenna and was proposed to reduce antenna size by

bending the monopole into right angle pends and

these pends will form the antenna. The idea of a

meander line antenna is to fold the conductor back

and forth to make the antenna size smaller

(Ogherohwo, 2015 and M. J. Ma, 2010).

Figure 3: Meander Line Structure.

5 PRIMARY DESIGN OF THE

PROPOSED MEANDER LINE

ANTENNA

The primary design of printed meander line antenna

was designed using CST microwave studio. The

antenna was designed depending on the equations

(1), (2), (3) and the parametric study on the antenna.

The height of the substrate was found by:

ℎ





0.3𝑐

2𝜋𝑓

√

ɛ



(1)

The length of the patch was calculated for the

equation:

𝐿



=

𝑐

2

𝑓



ɛ



(2)

Where ɛ



the effective dielectric constant.

Figure 4: The primary design of meander line monopole

antenna.

The antenna printed on FR-4 substrate (ɛ



=4.3) of

a thickness h=1.6 mm and area of W×L. The feed

line was chosen to have a length of Lf and width of

Wf to provide the 50Ω impedance matching as

shown in Fig.4.

0

20

40

60

80

100

120

140

No. Of Antennas

Types of antennas

Figure 5: The return loss of the primary designed antenna.

The antenna size was appropriate for the CubeSat

size as it has dimensions of 80×45 mm which is

suitable and covering less than a half of the CubeSat

face. The antenna operates at 578 MHz with return

loss of -14.4 dB as shown in Fig. 5. The operating

frequency was inappropriate for the TTC application

of CubeSat which required being in the range of the

licensed band (420-450) MHz. The radiation

efficiency was about 87% which is suitable value for

the antenna. The values of the antenna dimensions

are chosen using the above equations and are shown

in Table 2.

Table 2: The dimensions of the primary designed antenna.

Dimension

Description

Value(mm)

L

Total antenna length

80

W

Total antenna width

45

Ll

The meandered line width

3

Ls

The spacing between turns

2

Wl

The meandered line length

40

Ll1

The length of the line

between the feed line and

the antenna

22.5

Lf

The feed line length

20

Wf

The feed line width

3.14

Lg

The ground plane length

20

In order to reduce the operating frequency of the

antenna to be appropriate for TTC application of

CubeSat the antenna required to be modified.

6 MODIFIED MEANDER LINE

ANTENNA AND THE

PARAMETRIC STUDY

Some modifications were applied on the primary

design in order to reduce the operating frequency to

be suitable for the CubeSat application. These

modifications are discussed in the below subsections:

6.1 Ground Plane Modification

In order improve the antenna radiation, radiation

efficiency and to reduce the coupling between the

antenna and the CubeSat structure, some

modifications were applied on the ground plane. The

effect of changing the ground plane dimensions are

shown in Fig. 6 and 7.

Figure 6: The effect of the ground plane length on the

return loss.

Figure 7: The effect of the ground plane width on the

return loss.

6.2 Meander Lines and Feed Line

Modifications

The modifications on the number of turns, the

spacing between turns, the line width and the feed

line were applied in order to reduce the operating

frequency. Also, a thin conducting pin was added

between the lined to reduce the path of the surface

current and this will leads to reduce the operating

frequency. The parametric study on all of these

modifications was done as shown in Fig. 8, 9 and 10.

Figure 8: The effect of increasing the number of lines on

the return loss.

Figure 9: The effect of changing the line width on the

return loss.

Figure 10: The effect of changing the thin pins width on

the return loss.

7 PROPOSED PRINTED

MEANDER LINE MONOPOLE

ANTENNA WITH MODIFIED

FEEDING SYSTEM

The final design for the modified printed meander

line monopole antenna which composed of

symmetrical meandered lines and thin conducting

pins between these lines is shown in Fig. 11.

Figure 11: Proposed meander line monopole antenna.

The values of the final dimensions for the proposed

antenna are shown in Table 3. From the table it can

be seen that the antenna dimensions are suitable for

the CubeSat size which are 80×45 mm. This size

will leave additional space for the solar cells and

cover less than a half of the CubeSat face.

Table 3: The final dimensions of the proposed antenna.

Dimension Description Value(mm)

L Total antenna length 80

W Total antenna width 45

Ll The meandered line width 2

Ls The spacing between turns 2

Ws 1 The spacing between the pins

and the meandered lines

3

Wl The meandered line length 40

Ll 1 The length of the line

between the feed line and the

antenna

8

Lf The feed line length 12

Wf The feed line width 3.14

Lg The ground plane length 8

Wg The ground plane width 25

Wp The thin pins width 0.5

h The substrate height 1.6

7.1 Simulation Results

All the simulation results of the proposed antenna

were in the regulated and accepted ranges for the

CubeSat application. The operating frequency and

the return loss for the proposed antenna are shown in

Fig.12. The proposed antenna operates at 439 MHz

with a return loss of – 16.5 dB.

Figure 12: The return loss and operating frequency of the

proposed antenna.

The proposed antenna has a good radiation

efficiency of 80% at 439 MHz as shown in Fig.13.

The gain of the proposed antenna was recorded as a

positive value of 0.3 dB at 439 MHz for the

proposed antenna. This value of gain is acceptable

value as the TTC application does not required an

antenna with high gain.

Figure 13: The radiation efficiency of the proposed

antenna.

Fig. 14 shows the 2-D pattern of the far field

directivity for the proposed meander line monopole

antenna and Fig. 15 shows the 3-D pattern of the far

field directivity for the proposed antenna. The

proposed antenna has achieved wide coverage or

near Omni-directional radiation pattern at the

required frequency. The surface current of the

proposed meander line antenna is shown in Fig. 16.

Figure 14: 2-D pattern of the far field directivity of the

proposed antenna.

Figure 15: The 3-D pattern of the far field directivity for

the proposed antenna.

Figure 16: The surface current of the proposed antenna.

7.2 Fabrication Results

The proposed printed meander line monopole

antenna with modified feeding system was

fabricated on FR-4 substrate of dielectric constant

ɛ



=4.3 of a thickness 1.6 mm as shown in Fig.17.

The return loss of the fabricated antenna was

measured using Vector Network Analyzer (VNA).

The antenna was firstly tested without the CubeSat

and then tested when located on the fabricated

structure of CubeSat. Fig.18 shows the fabricated

antenna when located on 1U CubeSat structure.

Figure 17: The fabricated antenna (Front view and Back

view).

Figure 18: The fabricated antenna with 1U CubeSat.

The return loss and the operating frequency of

the fabricated and simulated design of the proposed

antenna when tested with and without the CubeSat

structure are shown in Fig. 19. It can be seen from

the figure that the fabricated antenna resonates at

lower frequency than the simulated design. The

fabricated antenna radiates at 423 MHz when tested

without the CubeSat which is in the range of the

licensed band (420-450 MHZ). The value of S11 in

VNA was -11.5 dB at 423 MHz. The measured band

width is 11 MHz at -10 dB which is suitable for the

application of TTC of CubeSat.

The return loss of the antenna was -12.8 dB at

419 MHz when the antenna located on the CubeSat,

That’s mean the antenna resonate at lower frequency

when located on the CubeSat as shown in Fig. 19.

The band width was increased to 15 MHz compared

to the bandwidth of the antenna without the

CubeSat. From the collected measurements of the

fabricated antenna, the results of the fabricated

antenna are all in the acceptable ranges and suitable

for real-time applications of TTC of CubeSat.

Figure 19: The fabricated and simulated results of the

proposed antenna.

8 COMPARISON WITH OTHER

WORKS

Several types of CubeSat antennas were designed in

the last few years. These designs are different in

dimensions, lower edge frequency, upper edge

frequency and bandwidth. This section presents a

comparison between the designed antenna and

different antennas were designed for the CubeSat

applications in terms of size, operating frequency,

bandwidth, and compatibility of CubeSat. The

comparison also includes the factor Bandwidth to

Dimension Ratio (BDR) in order to provide an

equitable comparison between models in different

bands. The BDR was calculated depending on below

equation (3) and (4). Table 4 presents the

comparison between the designed antenna and other

CubeSat antennas.

-25

-20

-15

-10

-5

0

300 350 400 450 500 550 600

S-Parameters (dB)

Frequency / MHz

Measured with CubeSat

Measured without CubeSat

𝐵𝐷𝑅 =

𝐵𝑊%

𝜆𝑙𝑒𝑛𝑔𝑡ℎ × 𝜆𝑤𝑖𝑑𝑡ℎ

(3)

𝐵𝑊% =

2(

𝑓

ℎ−

𝑓

𝑙)

(

𝑓

ℎ+

𝑓

𝑙)

× 100%

(4)

Where λ is the wavelength of the lower end

resonance frequency, BW% is the percentage

bandwidth, 𝑓ℎ is the higher end resonance

frequency and 𝑓𝑙 is the lower end resonance

frequency.

Table 4: Comparison with other works.

Antenna Dimensions Bandwidth BDR

Compatibility

of CubeSat

Inverted F

Antenna

(T. Alam,

2018)

100 × 100

mm

0.149λ ×

0.149λ

447.5 –

453.5

MHz

1.33%

59.9

Compatible

with CubeSat

But cover all

the CubeSat

face and have

design

complexity

Patch

Antenna

(Y. Yao,

2016)

110 × 110

mm

0.57λ ×

0.57λ

1575 -

1721 MHz

8.85%

27.2

Not compact

enough. Does

not cover the

licensed

lower UHF

band (420-

460 MHZ)

Dipole

Antenna

(Mehul K. S,

2016)

200 mm

0.14λ

220 - 267

MHz

19.3%

137.8

Compatible

with CubeSat

but need

complex

deployment

mechanism

Monopole

Antenna

(E. Pittella,

2013)

175 mm

0.25λ

435-438

MHz

0.68%

2.7

Compatible

with CubeSat

but have

Deployable

complexity

Microstrip

Patch

(G.

Kakoyiannis,

2008)

120 × 170

mm

0.17λ ×

0.25λ

435 - 437

MHz

0.45%

10.5

large and not

compatible

with 1U

CubeSat

Meander line

monopole

(J. Fan, Z.

Lei, 2014)

155 × 52

mm

0.22λ ×

0.074λ

426-436

MHz

2.3%

143.74

Too large and

not

compatible

with 1U

CubeSat

Proposed

Design

80 × 45

mm

0.11λ ×

0.06λ

434 - 444

MHz

2.2%

333.3

Compatible

with 1U and

2U CubeSat

and free from

deployment

complexity

9 CONCLUSION

The small size of CubeSat and the low operating

frequency represent the major challenge to design a

miniaturized antenna with acceptable performances.

This paper presents antenna design geometry for

CubeSats. The proposed antenna topology is based

on the meander line type. The antenna was

simulated, implemented and tested successfully. The

size of the designed antenna (80mm×45mm) was

suitable for the CubeSat size and cover less than a

half of the CubeSat face which gives additional

space for the solar panels and other components.

Finally, the antenna have been designed on FR-4

substrate using CST software, also it has been

implemented, and the measurements of the

implemented antenna match the results of the design

with insignificant errors due to the limited ability of

the fabrication machine and other limitations.The

work in this thesis can be extended in the future by

using high dielectric constant substrate can be used

to increase the miniaturization level. More than one

miniaturization techniques can be used to increase

the miniaturization level. Gain and bandwidth

enhancement of a miniaturized meander line so that

the antenna can be used for both TTC application

and payload data communication. Lowering the

effect of the CubeSat structure on the antenna.

ACKNOWLEDGMENT

The authors would like to acknowledge Dr. Ghassan

N. Jawad from the University of Baghdad for

providing the measurement results.

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