1. 1 / 32 SMart Antenna systems for Radio Transceivers (SMART) Arjan Meijerink TE Presentation – May 27 2008 University of Twente Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) Centre for Telematics and Information Technology (CTIT) Telecommunication Engineering Group (TE) a.meijerink@utwente.nl

2. 2 / 32MWP » MWP in PAAs » SMART » Conclusions » Questions Contents 1.Introduction; 2.System overview & requirements; 3.Optical beamformer: 4.Conclusions & future work Questions

3. 3 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 1. Introduction: aim and purpose Project aim: Development of a novel K u -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

4. 4 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 1. Introduction: partners & funding Project partners: The SMART project is part of the Euripides project SMART (Partners: EADS, CNAM, Radiall, CIMNE, Moyano) Funding:

5. 5 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 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 resonators in CMOS-compatible waveguide technology; Experimental demonstrator.

6. 6 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 2. System overview & requirements beamformer Antenna array RF front-end to receiver(s) Frequency range:10.7 – 12.75 GHz (K u band) Polarization:2 linear (H/V) Scan angle: -60 to +60 degrees Gain:> 32 dB Selectivity:<< 2 degrees No. elements:~1600 Element spacing:~ /2 (~1.5 cm, or ~50 ps) Maximum delay:~2 ns Delay 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

7. 7 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: overview OBFN chip Antenna elements RF front-end to receiver(s) E/OO/E NLR & CynerUT/TE & LioniX ?? tunable broadband delays & amplitude weights. ? control block antenna viewing angle plane position & angle feedback loop Outline: Ring resonator-based delays; OBFN structure OBFN control block; E/O & O/E conversion; System performance.

8. 8 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: ORR-based delays  f f  Group delay  Phase 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  f f

9. 9 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 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  f f  Group delay Or in other words: for given delay ripple requirements: Required no. rings is roughly proportional to product of required optical bandwidth and maximum delay

10. 10 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering)

11. 11 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering)

12. 12 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering)

13. 13 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering)

14. 14 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering)

15. 15 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN 8x1 Optical beam forming network (OBFN) 8 inputs with tunable delays 1 output combining network with tunable combiners (for amplitude tapering) 12 rings 7 combiners  31 tuning elements

16. 16 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: 8x1 OBFN chip 4.85 cm x 0.95 cm 1 cm Heater bondpad TriPleX Technology Single-chip 8x1 OBFN realized in CMOS-compatible optical waveguide technology

17. 17 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN measurements OBFN Measurement results 1 ns ~ 30 cm delay distance in vacuum L. Zhuang et al., IEEE Photonics Technology Letters, vol. 19, no. 15, Aug. 2007

18. 18 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN control block OBFN chip Antenna elements RF front-end to receiver(s) E/OO/E NLR & CynerUT/TE & LioniX control block antenna viewing angle plane position & angle feedback loop Outline: Ring resonator-based delays; OBFN structure; OBFN control block; E/O & O/E conversion; System performance.

19. 19 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN control block beam angle delays + amplitudes chip parameters (  i s and  i s) heater voltages NLR DA conversion & amplification calculation ARM7 microprocessor

20. 20 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN control block Which settings for the  i s and  i s are optimal? Metric: MSE of phase response in band of interest Non-linear programming solver on PC (Matlab) 11 22 33 11 22 33  f R, 1  f R, 2  f R, 3  ( f )  TdTd

21. 21 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN control block Result:data set with required values of  i s and  i s as a function of required delay values ( T j s)  Store coefficients a i,..., h i in microprocessor and calculate  i s and  i s “realtime” (<< 1 msec.) Interpolation formulas:

22. 22 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: OBFN control block OBFN chip Antenna elements RF front-end to receiver(s) E/OO/E NLR & CynerUT/TE & LioniX control block antenna viewing angle plane position & angle feedback loop Outline: Ring resonator-based delays; OBFN structure; OBFN control block; E/O & O/E conversion; System performance.

23. 23 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion OBFN electrical » opticaloptical » electrical RF front-end LNA TIA DM laser chirp! E/O and O/E conversions? low optical bandwidth; high linearity; low noise photo- diode

24. 24 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion OBFN electrical » opticaloptical » electrical RF front-end LNA TIA CW laser beat noise! mod. E/O and O/E conversions? low optical bandwidth; high linearity; low noise photo- diode

25. 25 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion OBFN electrical » opticaloptical » electrical RF front-end LNA TIA mod. CW laser E/O and O/E conversions? low optical bandwidth; high linearity; low noise photo- diode

26. 26 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion mod. OBFN RF front-end LNA spectrum frequency TIA electrical » opticaloptical » electrical CW laser 10.7 GHz 12.75 GHz2 x 12.75 = 25.5 GHz photo- diode

27. 27 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion mod. OBFN RF front-end LNALNB spectrum frequency TIA electrical » opticaloptical » electrical CW laser 2 x 2.15 = 4.3 GHz 950 MHz 2150 MHz photo- diode

28. 28 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion mod. OBFN RF front-end filter LNB spectrum frequency TIA single-sideband modulation with suppressed carrier (SSB-SC) electrical » opticaloptical » electrical CW laser 1.2 GHz SSB-SC Balanced 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

29. 29 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion mod. OBFN RF front-end filter LNB spectrum frequency TIA single-sideband modulation with suppressed carrier (SSB-SC) electrical » opticaloptical » electrical CW laser 1.2 GHz Filter 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 !

30. 30 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion Possible filter structures: Mach-Zehnder Interferometer (MZI): Multi-stage MZI: Ring resonator-based filters: MZI + ring:

31. 31 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion MZI + Ring 5 mm Optical sideband filter chip in the same technology as the OBFN

32. 32 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion Measured filter response 20 GHz14 GHz 3 GHz Bandwidth—Suppression Tradeoff 25 dB FSR 40 GHz

33. 33 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion Spectrum measurement of modulated optical signal Optical heterodyning technique:  f f  f f  f f  f f f1f1  f f f1f1 f2f2 MZMOSBFSA fiber coupler RF  f f f 1 – f 2  f f f2f2

34. 34 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion Spectrum measurement of modulated optical signal

35. 35 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: E/O and O/E conversion Further demonstration of chip functionality MZMOSBFSA fiber coupler RF  f f f 1 – f 2 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

36. 36 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: noise performance mod. OBFN filter LNB thermal noise TIA thermal noise shot noise phase & intensity noise sky noise + = RF noise non-linear modulator optical losses Losses, noise, and distortion

37. 37 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: noise performance

38. 38 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 3. Optical beamformer: noise performance O/E E/O Optical Beam Forming Network RF 1 RF 2 RF 3 equivalent receiver equivalent antenna P in / M P in Equivalent antenna gain antenna patterns number of antennas amplitude tapering Noise temperature sky noise receiver noise (LNB + OBF) P out noise temp. gain analog optical link, multiport RF component, two-port

39. 39 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 4. Conclusions & future work Conclusions: A novel optical beamformer concept employing a fully integrated, ring resonator-based OBFN and filter-based optical SSB-SC modulation was 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.

40. 40 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 4. Conclusions & future work 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.

41. 41 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » 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

42. 42 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » Questions Questions?

43. 43 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased Array Antenna : single antenna

44. 44 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased Array Antenna: multiple antennas

45. 45 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased Array Antenna: beam steering

46. 46 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased Array Receive Antenna: delays T 2T2T

47. 47 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased array antenna: beamforming network antenna 1 antenna 2 antenna 3 + + T 2T2T

48. 48 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. A: Phased array antenna: beamforming network T2T2T 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.

49. 49 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and why? What? 1. Performing microwave functions in optical domain; 2. Control microwave components by means of photonics. E/Ooptical circuitO/E RF inRF out microwave circuit RF inRF 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

50. 50 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and why? 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.

51. 51 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and why? 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?

52. 52 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and 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?

53. 53 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and 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?

54. 54 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. B: Microwave Photonics: what, and 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:

55. 55 / 42MWP » MWP in PAAs » SMART » Conclusions » Questions » App. C: OBFN measurement setup Phase-shift method: