emerson & cuming microwave absorbers for high frequencies … · emerson & cuming microwave...

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Emerson & Cuming Microwave Products NV, Belgium

HF Technology Seminar 2012 Eindhoven

Emerson & Cuming microwave absorbers for high frequenciesused in automotive applications


Emerson& Cuming Microwave Products global presence

Eccosorb absorber material with its different applications

Increasing frequencies in electronic equipment

Automotive radar and sensors in their frequency range and usage

Challenge to develop and measure absorber material at high frequencies

High frequency application using broadband absorber versus narrow band

Eccosorb MMI and Eccosorb MF at high frequencies & high quantities

Emerson & Cuming Microwave absorbers used in automotive radar systems.

Content :


Manufacturing plantMassachusetts

USA

Sales outletFrance

Sales outletUK

Sales outletHong Kong

Manufacturing plantWesterloBelgium

Agents & distributors

Sales outletFrance

Manufacturing plantHyderabad

India

Emerson & Cuming Microwave Products Global presence


Emerson & Cuming Microwave Absorbers

What are microwave absorbers ?- Products to modify, absorb or control unwanted

microwave radiating signals

Where are absorbers mainly used ?- Reduction radar cross section signature- Antenna pattern improvement- Test environments (enclosures)- Circuit board cavity resonance surpression


Space (Galileo satellite) Military (naval)

AutomotiveTelecom

Eccosorb absorber material on different applications

RFID

Antennas


Pro’s & Con’s:

- Accurate and fast signal processing- Compact housings (miniaturization)- Expensive components

Frequency bands :

- Millimetre wave (GHz) : 30-300 GHz (λ = 10-1mm)- Sub-millimetre / Terrahertz / Far-Infra-Red : 300 GHz- ~10 THz (λ = 1mm – 30µm)

Applications :

- Military (radar and detection)

- Telecommunication (point to point links)

- Astronomy (ALMA)

- Automotive (adaptive cruise control, lane control, parking aid) !!!

Increasing frequencies !!!


FRONT LOOKING SR-RADAR 24 GHz

FRONT LOOKING LR-RADAR 77 GHz

REAR LOOKINGRADAR (Video)

PARKING AID SENSOR 48 KHz

BLIND SPOT SENSOR 24 GHz

LIDAR (IR+Video)

BLIND SPOT SENSOR 24 GHz

VIDEO (24GHZ/IR)

OVERVIEW AUTOMOTIVE RADAR SYSTEMS

LIDAR (IR+Video)


Radar distance coverage and dedicated frequencies


Market penetration (mio.) for obstacle detection sensors in passenger cars (Europe) 2006 - 2015

Today Emerson & Cuming served > 3 million radar systems


Narrowband absorberEccosorb SF-U-24Eccosorb MF-PP

Broadband absorberEccosorb MMI- (W)

Eccosorb MF-PP

24 GHz77 GHz

Specific frequencies used in automotive radar systems


10 GHz cavity• Clear resonance• Hot spots

Resonances & cavities

60 GHz cavity• Sporadic resonances• Quasi free space

30 GHz cavity• Resonance more spread• Many hot spotsResonant absorber

Broadband absorber


Short wavelength = errors on parameter measurements

Understanding ε and μ when simulating absorber at high frequencies

Minor measurement inaccuracies can induce large errors in defining RF-parameters.

Measurement samples : very small dimensions and tight tolerances

Define adequate measurement set-up related to chemical composition

Health and safety requirements, Reach and RoHS.

High investment cost for RF measurement equipment.

Challenges to develop high frequency absorber material


Low frequency measurement set-up

• Frequency band : 2 GHz – 40 GHz

• Bi-static measurement at 10° angleof incidence (=normal incidence), reflectivity measurement only

• Large flat samples are required300 x 300mm

• Dynamic range = 50 dB.

• High sensitivity with increasing frequency

NRL-Arch set-up


High frequency measurement set-up

Quasi-optical measurement system

• Gaussian beam <> Flat wave front

• Frequency band : 40 GHz – 110 GHz

• Flat sample– 30 x 30 mm (radiation area)– 100 x 100 mm (clamping)

• Dynamic range = 100 dB.

• S11/S21 <> Refl / IL and calculate Eps/Mu


Measurements at high frequencies with “quasi optical” set-up

Epsilon/Mu : Would be ideal for use in RF-simulations Lots of errors

Reflectivity (dB) and Insertion Loss (dB) measurement : Gives data about free space behaviour, far field – near field condition No information for “in cavity situation”

Attenuation (db/cm) : expresses the amount of energy loss when a wave goes through the material Is calculated out of ε and μ Does not give data on the reflected power

Absorption loss (%) expresses the amount of absorption calculated from both components

reflectivity level and insertion loss.


Examination magnetic & dielectric material at high frequency

• Reduced attenuation with magnetic based material above 35 GHz

• Dielectric absorbers significant better performance

DielectricMagnetic


Reflectivity level Eccosorb MMI-U-W

MMI-U-W Horizontal polarization

-35

-30

-25

-20

-15

-10

-5

040 50 60 70 80 90 100 110

Frequency (GHz)

Ref

l (dB

)

Eccosorb MMI-U-W = dielectric filled absorber.Wedge shaped @ 3,5 mm thickness with excellent reflectivity performance


Reflectivity level Eccosorb MMI-U-W on both polarisations


10

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10040 50 60 70 80 90 100 110

Frequency (GHz)

Typical absorption loss with Eccosorb MMI

Eccosorb MMI = dielectric filled absorber, flat sheet material@ 0,5 mm thickness with excellent performance andlow production cost.


Typical absorption loss with Eccosorb MF-PP

Eccosorb MF-PP = magnetic absorbing material.Flat sheet material @ 1,7 mm thickness with excellent performanceand low production cost.

0

10

20

30

40

50

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10040 50 60 70 80 90 100 110

Frequency (GHz)


FROM GRANULATE TO APPLICATION !!

Development mouldable absorber :

ECCOSORB MMI-PP + ECCOSORB MF-PP


Moulded absorbers cost effective answer to high volume opportunities

Main DRIVER = COST !! ..... moulding vs. machining

Opportunity to design complex 3D shapes

General tolerances : +/- 0,1mm (max. : 0,03mm)

Schrinkage : < 0,5%

Draft angles on specific surfaces : < 2°

MOQ : > 1k (related to shape complexity)

Minor deficiencies on product due to injection moulding technique


77 GHz Automotive radar system equipped with ECCOSORB moulded absorber materials


Examples of moulded absorber covers using Eccosorb MF-PP-120 and Eccosorb MMI-PP


Automotive applications using Eccosorb absorber materials


Emerson & Cuming Microwave Products NVMr. J. KenisTel. : +32 478 50 30 [email protected]

EEMC - CoimexMr. A. NausTel. : 03 [email protected]

emerson & cuming microwave absorbers for high frequencies … · emerson & cuming microwave...

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