additive manufacturing for space antennas and rf components · 12/17/2018 1 xavier morvan1,3,...

12/17/2018 1

Xavier Morvan1,3, Olivier de Sagazan1,3, Ronan Sauleau1,3,Mauro Ettorre2,3, David González Ovejero2,3.

Additive Manufacturing

for Space antennas and RF Components

1) Université de Rennes 1

2) Centre National de la Recherche Scientifique – CNRS

3) Institut d’ Electronique et de Télécommunications de Rennes,UMR CNRS 6164, 35042 Rennes, France

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Saturn V ShuttleDelta IV-

HAriane 5 Falcon 9

Falcon

HeavySLS

Years 1967-1973 1981-2011 2004-pres. 2002-pres. 2011-pres. 2018-pres. Est. 2019

LEO

Payload

130000 24400 28000 22000 15960 (R)

22800 (E)

57000 100000

No. Flights 11 135 17 69 37 (R)

8 (E)

1

Cost per

Flight (M$)

2883 752 350 200 62 (R)

100 (E)

128 2860

Cost per

Kg ($)

21680 30819 12500 9091 4500 (R)

4386 (E)

2415 28600

D. C. Arney, A. W. Wilhite, P. R. Chai, C. A. Jones, ”A space exploration strategy that promotes international and commercial participation,”

Acta Astronautica, Volume 94, Issue 1, 2014, pp. 104-115, doi: 10.1016/j.actaastro.2013.07.011.

The Tyranny of The Rocket Equation

https://doi.org/10.1016/j.actaastro.2013.07.011

Credit: AI SpaceFactory/Plompmozes

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Technology developments (In order of increasing impact to the mission’s cost) to minimize the mass and, thus, the cost of space missions. :1. Low-cost systems2. Low-mass (lightweight) systems.3. Advanced propulsion4. In Situ Resource Utilization (ISRU).Additive manufacturing can be used to achieve these 4 goals.

Towards Low-Profile and Lightweight Payloads

At IETR, we focus on communications and science payload:- Tracking, Telemetry and Command (TTC)- Satellite communications- Radiometers and spectrometers

Credit: NASA/JPLCredit: NASA/JPL

Voyager 2 Galileo

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High-Gain Antennas for Space

Gain of an antenna (in a given direction) is defined as the ratio of the intensity, in a given

direction, to the radiation intensity that would be obtained if the power accepted by the antenna

were radiated isotropically.

In deep-space and satellite communications we need high directivity and gain to radiate the

power in the desired direction and, hence, satisfy the link budget.

From: C. A. Balanis, Antenna theory: analysis and design.

Wiley-Interscience, 2005.

Directivity of an antenna defined as the ratio of the radiation intensity in a given direction

from the antenna to the radiation intensity averaged over all directions.

Some basic definitions

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Examples of high-gain antennas for space with lightweight and low form-factor:

Deployable reflect-arrays Meshed deployable reflectors1)

Risks: deployment of both the feed and the mesh reflector or the reflectarray panels

Our approach: low-profile (flat) antennas integrated on the spacecraft chassis.

Advantage: getting rid of the deployment of the reflector and the feed.

High-Gain Antennas for Space

Credit: NASA/JPLCredit: NASA/JPL

1) M. Mobrem, S. Kuehn, C. Spier and E. Slimko, “Design and performance of Astromesh reflector onboard Soil Moisture

Active Passive spacecraft,” 2012 IEEE Aerospace Conf., Big Sky, MT, 2012, pp. 1-10.

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Advantages:

- on-surface control of aperture fields,

- beam shaping and pointing,

- simple feeding structure,

- low losses,

- low profile and low mass,

- low-cost and easy to fabricate.

a

6

Modulated metasurface (MTS) antennas: an inductive surface reactance supports the

propagation of a (dominantly) transverse magnetic (TM) surface-wave (SW), which is

gradually radiated. Radiation is achieved by periodically modulating the equivalent reactance

on the antenna aperture.

Modulated Metasurface (MTS) Antennas

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Motivation: Why metallic MTS?

Harsh environments include:

• Large thermal ranges.

• High radiation levels (as in Jupiter and its moons).

Advantage of all-metal designs:

• less susceptible to thermal variation.

• no dielectric property change due to high level of radiation.

G. Minatti et al., IEEE Trans. Antennas Propag., vol. 63, no.

4, pp. 1288–1300, Apr. 2015

D. González-Ovejero et al., Proc. 11th Eur. Conf. Antennas

Propag., Paris, France, 2017, pp. 3416-3418.

Fab and picture:

Cecile Jung, JPL-Caltech

All metal @sub-mm wavesPrinted patches

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N. Chamberlain et al., “Juno microwave radiometer patch array

antennas,” Proc. IEEE Antennas Propag. Soc. Int. Symp., Jun. 2009.

Credits: NASA/JPL-Caltech

JUNO

http://sci.esa.int/juice/

JUICE

Credits: NASA/JPL-Caltech

https://europa.nasa.gov

EUROPA LANDER

Need for high-gain antennas

able to survive harsh environments in space exploration

Motivation: Why metallic MTS?

12/17/2018

#1 Full-wave periodic solver for mapping a pillar of elliptical

cross-section to the relevant impedance tensor.

#2 From the periodic full-wave analysis, maps are constructed that link

an elliptical geometry to an impedance tensor, for a given surface

wave incidence direction.

#3 The impedance surface is sampled on a regular Cartesian

lattice, with the same cell size as the database.

#4 Each impedance sample is implemented using a metallic pillar

inside the corresponding lattice cell.

a<<λ

ah

a

b φ

ARφ

h

0

0

0

Z jX 1 cos

Z Z jX sin

Z jX 1 cos

sw

sw

sw

M

M

M

0 0X 0.8 ; 0.4

6; 1.235mm

2sw

c

M M

Nc a

N a

Zxx+

Zxy+ Zyy

+

5λ@32 GHz

Ideal Zxx+ Synthesized Zxx

+

Error

9

Design of modulated MTS antennas

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Fabricating a Prototype

At submillimeter-waves waves (300 GHz): deep reactive ion etching (DRIE).

Fabrication and picture by Dr. Cecile Jung (JPL/Caltech)

D. Gonzalez-Ovejero, C. Jung-Kubiak, M. Alonso-delPino, T. Reck, and G. Chattopadhyay, “Design, fabrication and testing of a modulated

metasurface antenna at 300 GHz,” in Proc. 11th Eur. Conf. Antennas Propag., Paris, France, Mar. 19–24 2017, pp. 3416–3418.

@ 300 GHz

Credit: NASA

and Wikipedia

The right fabrication technique

for each frequency range

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CAD model: MTS and feeder

D. González-Ovejero, N. Chahat, R. Sauleau, G. Chattopadhyay, S. Maci and M. Ettorre, “Additive Manufactured Metal-

Only Modulated Metasurface Antennas,” IEEE Trans. Antennas Propag., vol. 66, no. 11, pp. 6106-6114, Nov. 2018.

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Fabricating a Prototype

High Speed Milling with Hurco VM10Hsi, 30 000 rpm

with NS tool 2flutes

End-mills used: radius Ø0,4mm (300 mm/min) and

Ø0,2mm (180 mm/min) for finishing.

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Hybrid fabrication method:

CNC milling for block 2 and the feeding

circuit on the back of block 1

Metal additive manufacturing for the

metasurface on the front side of block 1.

13

Fabricating the Prototype

Laser Beam Melting (LBM) with LaserForm AlSi10Mg material on a ProX DMP 320.

AlSi10Mg alloys typically present an electric conductivity of 2x107 S/m.

“3D Systems Customer Innovation Center (CIC),” Leuven, Belgium, 2017. https://www.3dsystems.com

C. Silbernagel, I. Ashcroft, P. Dickens, and M. Galea, “Electrical resistivity of additively manufactured AlSi10Mg for use

in electric motors,” Additive Manufacturing, vol. 21, pp. 395–403, Mar. 2018.

https://www.3dsystems.com/

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View of the fabricated antenna and feeding network

Block 1 - front Block 1 - back

Block 2 - front

Drill for

dowel pin

Drill for

dowel pin

Input WR-28 Drill for

dowel pin

Drill for

dowel pin

14

Fabricated prototype



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31.8-32.3 GHzDSN Band

Measurements: S11

15



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frequency = 30.00 GHz

φ = 0° φ = 90°

Measurements: Directivity Patterns

Radiation pattern measurements by Dr. Laurent Le Coq (IETR, Université de Rennes 1)



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φ = 0° φ = 90°





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φ = 0° φ = 90°





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φ = 0° φ = 90°





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φ = 0° φ = 90°





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φ = 0° φ = 90°





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φ = 0° φ = 90°M

easu

red

Sim

ula

ted

(C

ST

)




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Measurements: Directivity

Measured directivity: shift in frequency with respect to the predicted one.

Reduction in the maximum directivity level.

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Inspection by SEM pictures

Estimated roughness:

Ra = 5-10 µm

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Accounting for Roughness in EM Simulations

Excellent agreement when one accounts for the surface roughness.

Surface roughness: main issue in AM of mm-wave metasurface antennas

Estimated roughness: Ra = 5-10 µm

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Before After

Improving the Surface Roughness

• We use side-milling to improve the surface

roughness.

• Nominal dimensions of the structure have been

extended 0.02 mm outwards to account for the

material removed during side-milling.

• At Ka band an accurate positioning tolerance

is crucial for a successful side-milling.

0.8 mm 0.8 mm

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Improving the Surface Roughness

Before After

Next step: use in a split-block waveguide and measure losses

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Conclusions

• We have presented an all-metal metasurface structure, which may be useful

for space exploration in harsh environments.

• The proposed structure consists of cylinders with elliptical cross-section.

• We have designed a prototype to cover the 31.8-32.3 GHz DSN band.

• We have manufactured the Ka-band prototype by combining classical CNC

milling with metal additive manufacturing.

• The prototype has been tested yielding satisfactory results, except for a

frequency shift.

• Current research lines:

• Increase the surface accuracy of the metallic MTS.

• Reach the level of maturity already achieved by designs based on

printed patches (amplitude tapering, multi-beam capability, dual-

frequency).

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Thank you!

Acknowledgements:

• Université de Rennes 1 M2ARS platform.

• Dr. N. Chahat, Dr. C. Jung-Kubiak, Dr. G. Chattopadhyay (JPL/Caltech, USA).

• Prof. Stefano Maci (Università degli Studi di Siena, Italy).

• Aide d’Installation Scientifique Rennes Metropole

• CPER Project SOPHIE / STIC & Ondes

additive manufacturing for space antennas and rf components · 12/17/2018 1 xavier morvan1,3,...

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