1 / 32 SMart Antenna systems for Radio Transceivers (SMART) Arjan Meijerink TE Presentation – May 27 2008 University of Twente Faculty of Electrical Engineering,

1 / 32

SMart Antenna systems for Radio Transceivers (SMART)

Arjan Meijerink

TE Presentation – May 27 2008

University of TwenteFaculty of Electrical Engineering, Mathematics and Computer Science (EEMCS)

Centre for Telematics and Information Technology (CTIT)

Telecommunication Engineering Group (TE)

[email protected]

MWP » MWP in PAAs » SMART » Conclusions » Questions 2 / 32

Contents

1. Introduction;

2. System overview & requirements;

3. Optical beamformer:

4. Conclusions & future work

• Questions

MWP » MWP in PAAs » SMART » Conclusions » Questions » 3 / 42

1. Introduction: aim and purpose

Project aim:

Development of a novel Ku-band antenna for airborne reception of satellite signals

Purpose:• Live weather reports;• High-speed Internet access;• Live television through Digital Video

Broadcasting via satellite (DVB-s)

, using a broadband conformal phased array


1. Introduction: partners & funding

Project partners:

The SMART project is part of theEuripides project SMART

(Partners: EADS, CNAM, Radiall, CIMNE, Moyano)

Funding:


1. Introduction: specific targets

Specific project targets:

• Conformal phased array structure definition; • Broadband stacked patch antenna elements;• Broadband integrated optical beamformer

based on optical ring resonatorsin CMOS-compatible waveguide technology;

• Experimental demonstrator.


2. System overview & requirements

beamformerAntennaarray

RFfront-end to

receiver(s)

Frequency range: 10.7 – 12.75 GHz (Ku band)Polarization: 2 linear (H/V)Scan angle: -60 to +60 degreesGain: > 32 dBSelectivity: << 2 degreesNo. elements: ~1600Element spacing: ~/2 (~1.5 cm, or ~50 ps)Maximum delay: ~2 nsDelay compensation by phase shifters? beam squint at outer frequencies! (Broadband) time delay compensation required !

40x40

Continuous delay tuning required !

gain

beam width

scan angle

optical

with amplitude tapering

8x8

1

8x1


3. Optical beamformer: overview

OBFN chip

Antennaelements

RFfront-end to

receiver(s)

E/O O/E

NLR & Cyner UT/TE & LioniX

? ?

tunable broadband delays& amplitude weights.

?

controlblock

antenna viewing angle

plane position & angle

feedbackloop

Outline:• Ring resonator-based delays;• OBFN structure• OBFN control block;• E/O & O/E conversion;• System performance.


3. Optical beamformer: ORR-based delays

T

T4

1 0

T4

1

T2

1

2

T8

T4

T2

T6

0

2.1

T10

6.1

0

T2

1

8.0

4.0

f

Gro

up

d

ela

y

P

has

e

TFSR

1

Single ring resonator:

T : Round trip time;

: Power coupling coefficient;

: Additional phase.

• Periodic transfer function;• Flat magnitude response.• Phase transition around

resonance frequency;• Bell-shaped group delay response;• Trade-off: delay vs. bandwidth

T4

1 0

T4

1

T2

1

T2

1

f


3. Optical beamformer: ORR-based delays

Cascaded ring resonators:

• Rippled group delay response;• Enhanced bandwidth;• Trade-off: delay vs. bandwidth vs. delay ripple vs. no. rings;

ripple

bandwidth

T4

1 0

T4

1

T2

1

T2

1

f

T8

T4

T2

T6

0 G

rou

p

del

ay

T10

Or in other words: for given delay ripple requirements:

Required no. rings is roughly proportional to product of required optical bandwidth and maximum delay


3. Optical beamformer: 8x1 OBFN

8x1 Optical beam forming network (OBFN)

8 inputswith

tunabledelays 1 output

combining networkwith tunable combiners(for amplitude tapering)




8 inputswith






8 inputswith






8 inputswith






8 inputswith






8 inputswith



12 rings7 combiners 31 tuning elements


3. Optical beamformer: 8x1 OBFN chip

4.85 cm x 0.95 cm

1 cm

Heater bondpad

TriPleX Technology

Single-chip 8x1 OBFN realized inCMOS-compatible optical waveguide technology


3. Optical beamformer: OBFN measurements

OBFN Measurement results

1 ns ~ 30 cm delay distance in vacuum

5 6 16

5 6

5 6

7

7

out 27

8

8

8

15

out 1

out 4

out 314

9 10 19

9 10

9 10

11

11

out 611

12

12

12

18

out 5

out 8

out 7173 4

3 4

3 4

1 2

1 2

1 2

in

13

stage 1 stage 2 stage 3

L. Zhuang et al., IEEE Photonics Technology Letters, vol. 19,no. 15, Aug. 2007


3. Optical beamformer: OBFN control block

OBFN chip

Antennaelements

RFfront-end to

receiver(s)

E/O O/E


controlblock



feedbackloop

Outline:• Ring resonator-based delays;• OBFN structure;• OBFN control block;• E/O & O/E conversion;• System performance.



beam angle

delays + amplitudes

chip parameters (is and is)

heater voltages

NLR

DA conversion & amplification

calculation ARM7microprocessor

436

43

43

1

1

1

2

2

2

5

7



0 f

in outT T T

• Which settings for the is and is are optimal?• Metric: MSE of phase response in band of interest • Non-linear programming solver on PC (Matlab)

1 2 3

1 2 3

fR,1 fR,2 fR,3

( f )

Td



Result: data set with required values of is and is

as a function of required delay values (Tjs)

iij

i

ij

ii

ijijii

hgT

f

eT

d

cTbTa

2

2

)(

Store coefficients ai, ..., hi in microprocessor and calculate is and is “realtime” (<< 1 msec.)

Interpolation formulas:



OBFN chip

Antennaelements

RFfront-end to

receiver(s)

E/O O/E


controlblock



feedbackloop

Outline:• Ring resonator-based delays;• OBFN structure;• OBFN control block;• E/O & O/E conversion;• System performance.


3. Optical beamformer: E/O and O/E conversion

OBFN

electrical » optical optical » electrical

RF front-end

LNA

TIA

DM laser

chirp!

E/O and O/E conversions?• low optical bandwidth;• high linearity;• low noise

photo-diode



OBFN


RF front-end

LNA

TIA

CW laser

beat noise!

mod.


photo-diode



OBFN


RF front-end

LNA

TIA

mod.

CW laser


photo-diode



mod.

OBFN

RF front-end

LNA

spectrum

frequency

TIA


CW laser

10.7 GHz

12.75 GHz2 x 12.75 = 25.5 GHz

photo-diode



mod.

OBFN

RF front-end

LNALNB

spectrum

frequency

TIA


CW laser

2 x 2.15 = 4.3 GHz

950 MHz

2150 MHz

photo-diode



mod.

OBFN

RF front-end

filter

filter

LNB

spectrum

frequency

TIA

single-sideband modulation withsuppressed carrier (SSB-SC)


CW laser

1.2 GHz

SSB-SCBalanced optical detection:

cancels individual intensity terms;

mixing term remains;

reduces laser intensity noise;

enhances dynamic range.

Implementation of optical SSB modulation?

1. Optical heterodyning;

2. Phase shift method;

3. Filter-based method.

photo-diode



mod.

OBFN

RF front-end

filter

LNB

spectrum

frequency

TIA

single-sideband modulation withsuppressed carrier (SSB-SC)


CW laser

1.2 GHzFilter requirements:

• Broad pass band and stop band (1.2 GHz);

• 1.9 GHz guard band;

• High stop band suppression;

• Low pass band ripple and dispersion;

• Low loss;

• Compact;

• Same technology as OBFN.

1 chip !



Possible filter structures:Mach-Zehnder Interferometer (MZI):

Multi-stage MZI:

Ring resonator-based filters:

MZI + ring:



MZI + Ring

5 mm

Optical sideband filter chip in the same technology as the OBFN



Measured filter response

Wavelength (nm)

1549.6 1549.7 1549.8 1549.9 1550.0 1550.1 1550.2 1550.3 1550.4

Filt

er P

ower

Res

pons

e (d

B)

-35

-30

-25

-20

-15

-10

-5

0

MeasurementSimulation

20 GHz14 GHz

3 GHz

Frequency (GHz)

0 10 20 30 40

Filt

er

Po

we

r R

esp

on

se (

dB

)

-40

-30

-20

-10

0

Bandwidth—Suppression Tradeoff

25 dB

FSR 40 GHz



Spectrum measurement of modulated optical signal

Optical heterodyning technique:

f

f f f

f1

f

f1 f2

MZM OSBF SAfiber coupler

RF

f

f1 – f2

f

f2



Frequency (GHz)

1 2 3 4 5 6 7 8 9 10

Sig

nal M

agni

tude

(dB

m)

-65

-60

-55

-50

-45

-40

-35SSB-SC SignalDSB SignalFilter Response

Filt

er M

agni

tude

Res

pons

e (d

B)

-30

-25

-20

-15

-10

-5

0

Spectrum measurement of modulated optical signal



Further demonstration of chip functionality

MZM OSBF SAfiber coupler

RF

f

f1 – f2

Next steps:

• Demonstrate optical homodyning by balanced detection;

• Demonstrate delay of broadband RF signal in OBFN;

• Combine multiple signals in OBFN by optical phase-locking .

OBFN


3. Optical beamformer: noise performance

mod.

OBFNfilter

LNB thermal noise

TIA thermalnoise

shot noisephase &intensity

noise

sky noise + = RF noise

non-linear modulator

optical losses

Losses, noise, and distortion





O/EE/O

OpticalBeam

FormingNetwork

RF1

RF2

RF3

equivalentreceiver

equivalent antennaPin / M

Pin

Equivalent antenna gain• antenna patterns• number of antennas• amplitude tapering

Noise temperature• sky noise• receiver noise (LNB + OBF)

Pout

Pout

noise temp.

gain

analog optical link, multiport

RF component, two-port

OBFLNBskysys TTTT



Conclusions:• A novel optical beamformer concept employing

a fully integrated, ring resonator-based OBFNand filter-based optical SSB-SC modulationwas introduced and partly demonstrated;

• Main advantages of this concept are:– low loss and large instantaneous bandwidth;– continuous tunability (high resolution);– relatively compact and light-weight realization;– inherent immunity to EMI;– potential for integration with optical distribution network;

• The dynamic range of the phased array receiver system is not significantly reduced by the optical beamformer.



Future work:• Characterize demonstrator chipset;• Finalize software for control block;• Build up beamformer demonstrator;• Integrate with rest of system (array + front-end);• Scale up demonstrator to >1000 antenna elements.


Acknowledgement

UT/TE:

Chris Roeloffzen

Leimeng Zhuang

David Marpaung

Bas den Uyl

Mark Ruiter

Timon Vrijmoeth

Jorge Pena Hevilla

Robbin Blokpoel

Tomas Jansen

Roland Meijerink

Jan-Willem van ‘t Klooster

Liang Hong

Eduard Bos

Wim van Etten

NLR:

Jaco Verpoorte

Pieter Jorna

Adriaan Hulzinga

Guus Vos

Rene Eveleens

Harm Schippers

Cyner Substrates:

Marc Wintels

Hans van Gemeren

LioniX:

Arne Leinse

Albert Borreman

Marcel Hoekman

Douwe Geuzebroek

Robert Wijn

Rineke Groothengel

Melis Jan Gilde

René Heideman

Hans van den Vlekkert


Questions

Questions?


App. A: Phased Array Antenna : single antenna


App. A: Phased Array Antenna: multiple antennas


App. A: Phased Array Antenna: beam steering


App. A: Phased Array Receive Antenna: delays

T2T


App. A: Phased array antenna: beamforming network

antenna 1

antenna 2

antenna 3

+

+

T

2T


App. A: Phased array antenna: beamforming network

T2T

to receiver

combiner

Challenges:• Small beam width;• High gain; • Low sidelobes;• Agile steering;• High bandwidth;• High resolution;• Low costs.

High number of antenna elements;

Amplitude tapering; Fast tuning; True time delays; Continuous tunability; High integration level.


App. B: Microwave Photonics: what, and why?

What?

1. Performing microwave functions in optical domain;

2. Control microwave components by means of photonics.

E/O optical circuit O/ERF in RF out

microwave circuitRF in RF out

photonic control

Microwave Photonics (MWP): [Capmany & Novak, Nature Photonics 2007]

the study of photonic devices

operating at microwave frequencies

and their application to microwave and optical systems



What?

1. Signal generation, for instance– RF carriers;– ultra-short (UWB) pulses;

2. Signal transport/distribution, for instance– sub-carrier multiplexing (SCM) for CATV distribution;– antenna remoting for e.g. RADAR;– Radio-over-Fiber distribution in wireless access networks;

3. Signal processing, for instance– high-frequency filtering;– up/down conversion;– A/D conversion;– beamforming for phased array antennas.



Inherent advantages of photonics:• huge bandwidth (~200 THz for optical fiber);• low-losses (<0.2 dB/km for optical fiber);• compact & light-weight;• immune to EMI;• galvanic separation between blocks

no induction, high-voltage protection, common grounding;• flexible: transparent to signal frequency and format;• loss & dispersion low over large bandwidth

low signal distortion;

Why?



Trends in enabling technologies:• Advances in components for E/O & O/E conversion:

high-frequency directly-modulators lasers, modulators, detectors;

• Advances in photonic integrated circuits:– low losses;– complex structures;– reproducibility;– packaging;– costs for mass fabrication;

• Other enabling technologies: CMOS, microwave, ...;

Why?



Trends in application areas, a.o. wireless communications:

• Ever higher frequencies (xx GHz) and capacities (Gbps);

• Smaller cell sizes high density of access points;

• Increasing complexity (dyn. spectrum all., channel adaptation);

• Increasing demand for flexibility; some functions become difficult/impossible in microwave/CMOS; desirable to centralize functionality, by means of Radio-over-Fiber;

But: MWP + electronics are not necessarily competitive

future trend: advancing integration of electronics and photonics

(MEMPHIS!)

Why?



• Component design (modulators, detectors, photonic ICs):– requirements (bandwidth, loss, ...);

– fabrication technology;

– packaging/system integration;

• Design of efficient system architectures;• Performance analysis and improvement (SNR, DR);• Keep the costs low!

Challenges:


App. C: OBFN measurement setup

Phase-shift method:

π2

) () () (

RF

2 1 g f

50/50coupler

network analyzer

100 MHz

modDUT

1 2

PCpolarizer EDFA

tunablelaser

RF out

opticaldetector

opticaldetectorPMF

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1 / 32 SMart Antenna systems for Radio Transceivers (SMART) Arjan Meijerink TE Presentation – May 27 2008 University of Twente Faculty of Electrical Engineering,