On the Road to 5G Advances in Enabling Technology: A Materials Perspective

Transcription

1 On the Road to 5G Advances in Enabling Technology: A Materials Perspective

2 Agenda Brief summary of 5G Material choices PTFE, thermosets & newer resin systems Detailed electrical characterization Dielectric constant Insertion loss Selecting the best copper choice for the application PCB manufacturing consideration Building multilayer boards Plating impact on circuit losses Open Q&A session 2

3 Rogers ACS Value Proposition Over 60 years experience in high frequency materials Broadest portfolio of high performance circuit materials solutions First to market with differentiated, hightech new products Reliability and quality customers can count on Collaborative problem solving with customers and strong design and fabrication support Strong OEM and fabricator relationships True global footprint 3

4 Rogers ACS Markets 2016 Market leader of high frequency PCB materials for over 60 years Aerospace, Defense & High Reliability Communications Infrastructure Auto, Medical Security DTH Satellite Services Mobile Internet Devices High Speed Digital Chip Scale Packaging 4

5 Brief Summary of 5G 5

6 Mobile Data Driving Infrastructure Evolution & Growth Mobile data grew 4000X in past 10 years, will grow 8X by 2020 Mobile video represents 55% of data in 2015, growing to 75% in 2020 Global mobile devices per capita will be 1.5 by 2020 Smart phones & phablets will be ~50% of all devices by

7 Defining 5G: 7

8 Spectrum & Key Technologies for 5G Spectrum Allocation Sub6 GHz 20 to 40 GHz +60 GHz Key Technologies Massive MIMO Antennas Complex MLB structures 8

9 Material Choices 9

10 What PCB Materials are of Interest for 5G? Short Term: < 6GHz Sensitive to Dk and thickness variation (3GHz to 6GHz) Higher Thermal Conductivity High Dk for compact PA design MLB processing compact designs Longer term: > 20 GHz (mmwave) Thin low loss dielectrics, smooth copper for frequency bands up to 77 GHz. Mechanical properties suitable for active device integration 10

11 High Frequency PCB Material Choices Dk 10 GHz Df 10 GHz CTE TC Comments PTFE Low Dk 2.2± High PTFE content, no much glass, lowest loss PTFE Mid Dk 3.0± Best balance of low loss and cost Thermoset MidDk 3.48± Ease of fabrication delivers lowest cost solution Thermoset HighDk 6.15± Dk similar to LTCC but with conventional PCB processing for lower costs LCP 2.9± Ultrathin dielectrics 11

12 Reduction in Temperature Rise Using Smooth Foil 3.3 GHz testing at 85 Watts on 50Ω microstrip 10mil RO4350B IL = 1.5 db 34 C rise Insertion loss (db/in) RO4350B Insertion Loss With Different Copper Foil Types 0.010" laminate RO4350B Standard Laminate RO4350B LoPro Laminate mil RO4350B LoPro IL = 1.0 db 19 C rise Frequency (GHz) Thermal image is the top view of circuit and in a black band area Black band is less than 1/10 wavelength and has insignificant impact on insertion loss (IL) The reported IL is for an 8 long circuit and 3.3 GHz 12

13 Detailed Electrical Characterization 13

14 Factors Affecting Insertion Loss Dk, Df, Thk Copper roughness Surface finish 14

15 Dielectric Constant vs Frequency: LowDk, PTFE These materials offer a very stable Dk over two decades, less than 0.05 in change 15

16 Dielectric Constant vs Frequency: MidDk, PTFE Very stable with an 0.05 change Dk over two decades LCP materials change is 0.1 over the same frequency range 16

17 Dielectric Constant vs Frequency: MidDk, thermoset Using rough ED copper change is 0.15 for the two decades Same materials with smooth copper changes 0.075, due to the reduced effect on dispersion by using smoother copper foil 17

18 MMWave Insertion Loss: PTFE materials Dk and Copper Effects DiClad 880 (2.2) vs RO3003 (3.0), with ED & RLD copper Lower Dk of DiClad 880 helps reduce conductor loss due to wider 50Ohm trace RLD copper offers lower loss, smooth foils are optimal at millimeter wave frequencies 18

19 Insertion Loss Measurements RO3003, RO4350B and CLTEAT Laminates Comparing RO3003 and RO4350B up to 30GHz CLTEAT data is modeled using MWI Smooth and rough copper comparison 19

20 PCB Manufacturing Considerations 20

21 Thermoset Materials Designed for MLB s Ideal for Integrated 5G system CTE (Coefficient of Thermal Expansion) X,Y matched to copper minimizes bow and twist of PCB allows construction of hybrid MLB s Low CTE Z and high Tg plated through hole reliability Fabricate similar to conventional FR4 Effect on electrical performance 21

22 Surface Finish Effect on Insertion Loss Plating finish increases insertion loss due to higher resistivity of metals vs. copper (except for silver) 22

23 Current Density Models for Microstrip Transmission Line Circuits Models were done using the Professional version of Sonnet Software Rev Material is 20mil thermoset DK 3.5 laminate with standard ½ oz. ED copper 50 ohm microstrip transmission line Frequency is at 2.6 GHz Top view of microstrip transmission line circuit 23

24 Comparison of Various Surface Finishes Actual impact of plating will be dependent on grade actual circuit configuration (thickness, copper type) 24

25 Open Q&A Session 25