Antenna Performance of LTE Enabled Hand-Held Tablets Derek Campbell

Transcription

1 Antenna Performance of LTE Enabled Hand-Held Tablets Derek Campbell EM Software & Systems (USA), Inc. Hampton, VA Mobile Antenna Systems Las Vegas, NV December 12 13,

2 Motivation Tablets Becoming Increasingly Popular Tablet Sales +5.9% Since Last Year Traditional PC Sales -10.6% Since Last Year Long Term Evolution (LTE) Coverage Increasing Commercial LTE service Commercial LTE network deployment on-going or planned LTE trial systems (pre-commitment)

3 LTE MIMO Multiple Input Multiple Output (MIMO) Up to 4 x 4 Configuration Closed-Loop Scheme Facilitates Optimal Mode Technology Transmit Diversity Spatial Multiplexing Beamforming Advantages Throughput (Reliability) # Streams (Data Rate) Suppress Interference Frequency Bands Flexibility Speeds up Deployment 700, 900, 1800 & 2600 MHz

4 LTE Design Challenges No Design Restrictions on Mobile Device Size Preferences Impose Design Challenges Cross-Correlation Matching & Isolation Electromagnetic Interactions With User Specific Absorption Rate (SAR)

5 Meander-Line Loaded Planar Monopole Antenna 5

6 Multi-Band LTE Antenna Ultra-Wideband Planar Monopole MHz Meandering Microstrip Line is Loaded Provides Resonance at LTE 700 MHz Band 5 Frequency Bands MHz MHz MHz MHz MHz Size 88 x 50 x 1.6 mm Yuan Yao, etc., Multiband Planar Monopole Antenna for LTE MIMO Systems, International Journal of Antennas and Propagation, Vol. 2012, Article ID

7 Multi-Band LTE Antenna Excellent Matching Across LTE Bands Reflection Coefficient < -6 db

8 Surface Mesh Solved MoM/SEP (Surface Equivalence Principle) Mesh Size: 1.74 mm Triangles: 7,280 Peak Memory: 3.48 GB Runtime: 10 min/freq 8 Processors

9 Performance 760 MHz 9

10 Performance 2600 MHz 10

11 Two Antenna Elements Integrated on Generic Tablet 11

12 Isolation Techniques 1 Characteristic Modes Analysis Systematic Approach Two Orthogonal Elements Achieve Pattern Diversity Zero Separation Reduces Size Passive Elements Not Required Gopinath Gampala and C.J. Reddy, Compact Antenna for MIMO LTE Mobile Phone Applications, Microwave Journal, March 2012

13 Isolation Techniques 2 Physical (Half Wavelength) Separation Often Too Large Orthogonally Polarized Elements

14 Radiation Pattern Both Ports Excited Resource Value Unknowns Runtime 40 seconds Memory 49 MB

15 Total Gain Pattern Diversity P1 Excited & P2 Loaded P2 Excited & P1 Loaded

16 Polarization Diversity Theta Gain P1 Excited & P2 Loaded P2 Excited & P1 Loaded

17 Phi Gain Polarization Diversity P1 Excited & P2 Loaded P2 Excited & P1 Loaded

18 System Integration Model Includes 2 Antennas, LCD Display, Case, Battery, PCB Height Width Depth Model 193 mm mm 9.9 mm ipad Mini 200 mm mm 7.2 mm Resource Value Unknowns 138,144 Runtime 5.24 hrs Memory 143 GB

19 Improved Matching & Isolation * Thank You, Dr. Jussi Rahola at Optenni for Providing Assistance 19

20 S-Parameters (Before) 20

21 Efficiency (Before)

22 Matching Circuit Design Read Impedance Data Touchstone Format Specify Target Frequency Bands Available Components Inductors, Capacitors, Resistors Transmission Lines Two Port S-Parameter Blocks Efficiency Optimized, Not Impedance Match

23 Matching Circuit

24 S-Parameters (After) 24

25 Efficiency (After)

26 Channel Capacity Analysis * Thank You, Mr. Oliver Stäbler at AWE for Providing Assistance 26

27 Channel Capacity Calculated from Channel Matrices Measurements Processing Ray Data from Fixed Transmitter in Specified Environment for Different Positions of Receiver Channel Matrix: Hf SNR: ρ

28 Indoor Environment WinProp Software Calculates Channel Capacity AWE Communications Results Presented at Conference*

29 Specific Absorption Rate 29

30 SAR Guidelines FCC Guidelines Regarding SAR United States: 1.6 Watts Europe: 2 Watts Sample SAR Values Phone SAR (Digital) BlackBerry Curve Motorola RAZR HD 1.56 Nokia Lumina Motorola Droid RAZR 1.45 Apple iphone Samsung Galaxy S4 0.45

31 Gripping Details Solver: MoM/SEP Mesh Triangles Mesh Size Tablet 46, mm Hand 1, mm Results Presented at Conference*

32 Radiation Pattern Both Ports Excited Operating at 2600 MHz

33 Design Challenges Simulation Results Conclusion Design Multi-Band Antenna System Integration in Tablet Optimized Impedance Matching Computed Channel Capacity SAR LTE Evolves 8 x 8 MIMO Systems Increased Spatial Correlation

34 Contact Information Derek Campbell (757) x404 EM Software & Systems (USA), Inc. Hampton, VA emssusa.com feko.info 34