5G Antenna Design for Mobile Phones

Transcription

1 3DS.COM Dassault Systèmes 11/30/2018 ref.: 3DS_Document_2015 5G Antenna Design for Mobile Phones 29 November 2018, 17h00 CET Marc Rütschlin Rodrigo Enjiu, Brian Woods, Marcel Plonka, Tilmann Wittig, Jean Hong, Dassault Systèmes Kun Zhao, Zhinong Ying, Olof Zander, Thomas Bolin, Sony Mobile Communications

2 What is the Promise of 5G? Latency 1 ms 5G Autonomous driving Augmented reality Virtual reality Tactile internet 10 ms 100 ms 1000 ms Disaster alert Automotive call Sensor network monitoring <1 Mbps Device remote control Real time gaming Bi-directional remote control Personal cloud Multi-person video call Emergency service connectivity Wireless cloudbased office Video streaming 1 Mbps 10 Mbps 100 Mbps >1 Gbps Data rate

3 Mobile Phone CAD Model Simulation Model

4 Mobile Phone Parts Frame (Aluminum) Modules (cameras, etc.) PCB components PCBs and shielding Glass screen with conductive OLED back Back (Aluminum or glass) Battery Wireless charging Connector

5 Mobile Phone Antenna Design Frequency Range 1 Sub 6 GHz Traditional antenna design Challenge: space KPIs: TRP, TIS, SAR GHz 5G array placeholder Spacer for antennas Frequency Range 2 mm-wave (28 GHz) 4 element chip antenna Challenge: integration KPIs: EIRP, CDF, Power Flow GHz Spacer for antennas 5G array placeholder

6 Key Simulation Challenges Model Complexity How much can we simplify? Human body properties How do model this at 28 GHz? Simplify Safety? Effect on coverage?

7 Outline Introduction Antenna Design for sub 6 GHz Band Antenna Design for mm-wave Band Human Exposure Certification Conclusion

8 5G at Sub 6 GHz Frequencies 5G Sub 6 GHz 4G LTE 5G Sub 6 GHz 4G LTE elaa, Wi-Fi mm-wave 5G TDD in freq. range 1 (EU): GHz Initially, communication with mobile devices will use multiple standards in the sub 6 GHz frequency range. mm-wave used for fixed links

9 Previous Generation Mobile Device Matched antennas in mobile phone 3 2G (E-GSM) 4G (IMT-E) 3G (DCS) 4 WLAN 2

10 Can We Re-use Antennas in Our New Device??

11 Antenna Re-use Challenges Does not fit properly Could be moved, but too high when mounted New matching networks required Overlaps with other components

12 Answer: No. Antennas Need to be Redesigned. 3G 3G 4G 4G

13 Antenna Requirements (Available space) Main available space (2 mm depth) space along edges (5 mm depth)

14 New Antenna Design Options in Antenna Magus Objective: find candidate designs which might work in the available space. Candidate for WLAN antenna?

15 Antenna Placement in Device is Critical Same WLAN antenna in 5 different locations good placement locations Different designs required for different locations 5

16 Antenna Placement in Device is Critical Same WLAN antenna in 5 different locations poor placement locations

17 Antenna Placement Excites Structural Resonances Current distribution for good and bad placement locations 1 4

18 S11 in db Reducing Model Complexity Can we simplify the model for quicker simulation? 1 Battery power connection Frequency in GHz

19 Model Details are Important All key components and connections between them must be included in model. Connected Disconnected

20 New Antenna Options for 5G in Antenna Magus Key Challenge: 400 MHz bandwidth at 3.6 GHz Geometric constraint: 10 x 20 x 2 mm volume

21 Consider Some Broadband Antenna Options Initial Antenna Magus design of two broadband antennas

22 Consider Some Broadband Antenna Options Integrated in phone and matched in GHz frequency range

23 Another Option: a Simple Broadband PIFA Free Space Design Integrated Matched Performance

24 Simple PIFA Design workflow Step 3 Initial Design Step 2 Step 4

25 Simple PIFA Design workflow Step 3 Initial Design Step 4 Installed performance (un-matched)

26 Simple PIFA Initial Design Installed Performance Phone structure resonances (placement dependent) Antenna resonance

27 Simple PIFA Design workflow Initial Design Re-design (400MHz higher frequency) Step 4 Installed performance (un-matched)

28 Simple PIFA Design workflow Initial Design Re-design (400MHz higher frequency) Installed performance (un-matched)

29 Simple PIFA: Re-design Installed Performance Strong coupling to phone structure resonances Antenna resonance

30 Simple PIFA: Matched Installed Performance

31 Simple PIFA: Matched Installed Performance Farfield performance at 3.6 GHz Radiation efficiency

32 Conclusion for Sub 6 GHz 5G Antenna Design Bandwidth is a key challenge! Free-space performance is not always a good indicator of installed performance. Extensive simulation studies are required to identify the best candidate designs. An efficient model setup and simulation workflow is critical!

33 Outline Introduction Antenna Design for sub 6 GHz Band Antenna Design for mm-wave Band Human Exposure Certification Conclusion

34 mm-wave Antenna Design (for the mobile phone) Aim: High data rate communication Design goal: full spherical coverage Design challenge: antenna integration Operational challenge: blockage by user

35 Chip Antenna Concept Parasitic Elements Fused Silica ε r = 3.8 tan δ = Active Elements Patch Antennas Distribution Network

36 Antenna Integration in Phone with Dielectric Cover Add plastic cover Add glass cover? Add metal cover??

37 Radiation from Array Placed Behind Plastic Cover Intended radiation Guided wave effects in dielectrics E-field at 28 GHz Reflection

38 Angle of Incidence [ ] Magnitude [db] Reflection Due to Plastic Cover 80 Reflection < 6 GHz mmwave Frequency in GHz < -10

39 Plastic & Glass: Dielectric Design Problem plane wave Dielectric Layer ε R h h/λ_0 (ε_r )

40 Plastic & Glass: Dielectric Design Problem Region h/λ_0 (ε_r ) Region Region 43

41 Thickness [mm] Plastic & Glass: Dielectric Design Problem Optimum Thickness Optimum Permittivity ABS Plastic, ε = 2. 6 h = 1 mm Glass, ε = Permittivity, ε R h = 2 mm Aluminum Oxide, ε = 9. 0 h = 3 mm Angle of Incidence [ ] Angle of Incidence [ ]

42 Plastic & Glass: Dielectric Design Problem Local Lens LATERAL CUT Glass ε = 6.84 tan δ = mm 0.77 mm

43 Antenna Behind Glass Back Boresight scanning With Lens Without Lens

44 Antenna Behind Glass Back Return Loss Total Efficiency Without Lens With Lens η T With Lens Without Lens

45 Antenna Behind Glass Back Scanning to θ = 30º With Lens Without Lens 49

46 Metal Back Design Can we integrate mm-wave antennas in metal backed phones? Radome with FSS (Frequency Selective Surface) Passband Can we apply techniques from radome design? Stopband 50

47 Basic FSS Design Loaded Radome View of the Layers 1.00 mm Dielectric Metal Top View of the FSS 0.45 mm dielectric ε r = mm

48 1.18 mm Optimization at Unit Cell Level 0.20 mm Optimization Goal Reflection < 10 db s. t GHz < f < 29.5 GHz 0 < θ < mm Optimization done over full frequency range and scan angle range.

49 Angle of Incidence [ ] Angle of Incidence [ ] Magnitude [db] Optimization at Unit Cell Level Return Return Frequency in GHz Frequency in GHz < -10

50 Magnitude, [db] Tolerance Analysis 0 Perpendicular Polarization Spread: 0.9 GHz 9 db Spread: 1.2 GHz 4 db Worst case bandwidth: 2 GHz Frequency, [GHz] 5 μm tolerance

51 Integration of FSS in Phone How big should the FSS region be?

52 Integration of FSS in Phone 13x15 17x19 21x23

53 Integration of FSS in Phone 13x15 17x19 21x23

54 Integration of FSS in Phone 13x15 17x19 21x23

55 mm-wave in Phone Two Several Arrays Arrays How many do we need? What is good performance? 1x4 slot array

56 Evaluation of mm-wave Antenna Quality What criteria do we use to evaluate quality of the antenna solution? Phone materials? Number, position of arrays?? Configuration 50% CDF Material provided courtesy of Kun Zhao and Zhinong Ying, Sony Mobile Communications All material provided by Sony is related to mock-ups, prototyping and simulation. No material shown is related to any commercial phone.

57 When is a 5G mm-wave Antenna Good? Objective: good spherical coverage when scanning the beam quantified by CDF* 6 EIRP beams Total EIRP pattern *Cumulative Distribution Function CDF EIRP = P(EIRP DUT (theta, phiሻ < EIRPሻ Antenna module e.g. EIRP = 10.5 CDF = 50% 50% of total sphere is covered by EIRP > 10.5 dbm

58 Antenna module 3GPP Specifications for Mobile Phone Antennas Objective: good spherical coverage when scanning the beam 6 EIRP beams Total EIRP pattern NOTE 1: NOTE 2: 3GPP Specification* defines: Peak value: CDF = 100% Spherical CDF = 50% Operating band Min peak EIRP (dbm) n n n n NOTE 1: Minimum peak EIRP is defined as the lower limit without tolerance Operating band Min EIRP at 50 t %-tile CDF (dbm) n n n260 8 n Minimum EIRP at 50 %-tile CDF is defined as the lower limit without tolerance The requirements in this table are only applicable for UE which supports single band** in FR2 **Multi-band specification is agreed but not in standard yet. *Mobile phone, power class 3

59 Simulated Antenna Patterns for Sony Demo Glass back cover 28 GHz 2x2 patch array 5 EIRP beams Metal bezel

60 Simulated Antenna Patterns for Sony Demo For each solid angle (direction) the beam with highest EIRP is chosen. Total EIRP pattern 5 EIRP beams

61 Total Coverage of the 5 Beams D Mapping of 3D farfield θ φ

62 Cumulative Distribution Function of EIRP Single array on back cover: CDF = 50% at EIRP = 10 dbm Peak EIRP is normalized to 22.4 dbm in this simulation. Operating band Min EIRP at 50 t %-tile CDF (dbm) n n n260 8 n

63 Cumulative Distribution Function of EIRP Two arrays, one on each side: CDF = 50% at EIRP = 15 dbm Peak EIRP is normalized to 22.4 dbm in this simulation.

64 Multiple Array/Phone Configurations Study the effect on spherical coverage Antenna panel 1 Back cover Phone frame Front cover Antenna panel 2 (optional) Antenna panel 3 (optional) Simulation Assumption Display Full Full Full Partial Full Full Full No. of antenna panels on front No. of antenna panels on back Phone frame material Metal Metal Metal Metal Metal Metal Metal Back cover material Glass Plastic Glass Glass Plastic Glass Plastic Front cover material Glass Glass Glass Glass Glass Glass Glass

65 Conclusion for mm Wave 5G Antenna Design Integration is the challenge. Thin materials become electrically thick at mm-wave frequencies. Radome design techniques apply for phone cover design. Specific post-processing needed to evaluate antenna performance.

66 Outline Introduction Antenna Design for sub 6 GHz Band Antenna Design for mm-wave Band Human Exposure Certification Conclusion

67 Human Exposure Compliance Simulation Sub 6 GHz: field penetration into human existing SAR standards applicable mm-wave: low field penetration into human power flow in planes around device of interest Electric field at 3.6 GHz Electric field at 28 GHz Power flow at 28 GHz

68 SAR Compliance Models CTIA auto-gripping hand with spacer SAM phantom (tilt position)

69 Compliance Regulations in Frequency Range 1 Standard SAR regulations apply in sub 6 GHz frequency range.

70 Specific Absorption Rate (SAR) at 3.6 GHz Maximum 10 g averaged SAR is below 1 W/kg limit

71 Modelling the Human Body at 28 GHz? 1.7 m 1.7 m height 1000 λ Primary interest: fields outside the body Don t model the interior of the body. λ 0 = 10.7 mm λ d = 17 mm

72 CATIA Human Design & CST Assembly Modelling

73 Hybrid Simulation Setup The hybrid workflow hides the fine detail of the phone from the large model simulation.

74 Effect of User Upper Array Phone alone Effect of hand Effect of user

75 Blockage Effects Finger Spread Finger partially covering the array what s the effect on performance?

76 Blockage Effects Finger Spread There is an effect, but the array should still work. Evaluation of potential use cases could guide antenna placement.

77 Compliance Regulations in Frequency Range 2 Low field penetration into body Consider power flow on planes near device 30 cm 2 cm 2 cm

78 Compliance Regulations in Frequency Range 2 Low field penetration into body Consider power flow on planes near device V 30 cm H 2 cm H 2 cm V At 28 GHz 30 cm 180 λ Don t mesh volume!

79 Compliance Regulations in Frequency Range 2 Low field penetration into body Consider power flow on planes near device Power 2 cm from device Power 2 cm from device V 28 GHz H

80 Outline Introduction Antenna Design for sub 6 GHz Band Antenna Design for mm-wave Band Human Exposure Certification Conclusion

81 What is the Promise of 5G? High data rate low latency communication is coming soon to a phone near you. Antenna design is a key enabler. Balancing performance and safety compliance requires accurate modelling of the phone and the user. 5G antenna design challenges can be overcome by using the advanced simulation tools of Dassault Systèmes.

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