designing rf antennas for wearable electronics and the
TRANSCRIPT
1 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Designing RF Antennas for Wearable Electronics and The Internet of Things (IoT)
Sudhir Sharma
ANSYS Corp.
Michael Schaaf
Synapse
2 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Agenda
• Industry trends and key business initiatives
• Synapse case study
• Q/A
3 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Market Driver: Our Need For Real-Time Information And Decision-Making
Wearable Technology
© Cisco
Internet of Things
4 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Trend: Implications For High-Tech Industry
Miniaturization
• IC transistor features shrink to <20 nanometers
• Smaller form factor – from handheld to servers
Green and Reduced Power Consumption
• Increased power efficiency
• Regulation for reducing use of hazardous materials
Higher Speed and Broadband
• Designing for 100 Gbit per second channels
• Multiple wireless technologies within each product
Mobility and Platform Integration
• Voice, video, internet on single platforms
• More software and electronics in all industries
5 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Initiatives: Focus Of High Tech Companies
Adopt System Engineering Approach
a holistic, multi-disciplinary and collaborative approach to
designing and maintaining complex systems
Optimize Power, Performance, and Cost
to deliver affordable high performance products for
mobile computing
Optimize Signal Integrity, EMC, & Thermal/
Mechanical
to reduce electromagnetic interference
Improve Reliability
to address increased structural, thermal and
electro migration challenges
Design Reliable Wireless Communication Systems
to deliver robust performance in complex surrounding
environment
Initiate Green Product Development
to comply with governmental regulations & market demands
6 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Old Paradigms Single physics Testing Through Physical Prototypes Few Design Points Studied Compartmentalized Design and Verification
New Paradigms Comprehensive Solution • Electronics • Structural • Thermal Virtual Prototyping • Coupled physics • High-performance computing • Design optimization Collaborative • Electronic specification • Engineering knowledge
management
New Paradigm: Comprehensive Solutions
7 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
ANSYS HFSS simulation helped improve the design of body worn electronics
• 5X improvement in antenna range • 25% reduction in design cycle
8 © 2014 ANSYS, Inc. May 9, 2014 ANSYS Confidential
Connect with me on LinkedIn: Sudhir K. Sharma
E-mail me directly: [email protected]
Explore our solutions for electronic simulation: www.ansys.com/high-tech
Follow us on social media: www.ansys.com/Social@ANSYS
Join us at booth #1413 at the Design Automation Conference, San Francisco
Further information:
9
9 May 2014 Synapse Confidential
SYNAPSE & ANSYS HFSS
WEARABLES WEBINAR
MIKE SCHAAF
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ABOUT SYNAPSE PRODUCT DEVELOPMENT
Synapse helps leading companies deliver breakthrough experiences through
technology. Fueled by solving impossible engineering challenges, we develop
products that transform brands and accelerate advances in technology
www.synapse.com
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WHAT SYNAPSE DEVELOPS
■ Connected Devices
■ Guest Experiences
■ Wearable Devices
■ Enterprise Software Solutions
■ Consumer Electronics
■ Health and Fitness
■ Transferable Tech
NIKE+ FUELBAND 2012-2013 VIABLEWARE RAIL 2012
PROPELLER SENSOR 2011 NIKE+ SPORTWATCH GPS
POWERED BY TOMTOM 2011
PANASONIC AVIONICS SYSTEM
(PROTOTYPE) 2009
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WHAT DESIGNS LOOK LIKE
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HISTORY OF ANSYS HFSS
Left: Press Release, October, 1990 Ansoft Corporation
ships the High Frequency Structure Simulator (HFSS)
for exclusive sale by the Hewlett Packard Company.
16 hours in 1990
3 seconds in 2007!
Below: Ansys has come a long way since then.
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WHAT WE ARE TALKING ABOUT TODAY
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WHY WEARABLES?
■ High value placement
■ More pervasive and less invasive
■ Speed of data assimilation
To generate the right data with sensors in the right place
and a way to view or share that data instantly.
Left: Google Glass kicked off the wearable tech trend. Middle: Sproutling, a San Francisco based startup, is developing
a new baby monitor. Right: Armour39® is a heart rate monitor that displays performance stats via mobile app and/or a
display watch.
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WHY WEARABLES EXAMPLE
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WHEN WILL WE HAVE THE TECH FOR IOT? NOW!
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APPLICATIONS OF THE IOT
■ Mapping disease
● GPS, biometric vitals
■ Digital identification
● Unique biometric characteristics
■ Customization and control
● Proximity (GPS, BLE, NFC), interface
■ Human insight
● Collection and communication
of data
SENSORS + MACHINE-TO-MACHINE COMMUNICATION (M2M)
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RF CHALLENGES WITH WEARABLES
■ Material selection based on
• Comfort
• Fashion
• Durability
• Allergens
■ Resistance to personal products
■ Waterproofing
Above: Instabeat Heart Rate Monitor
Above: News Headline, Allergic
Reactions Cause Fitbit To Recall Wrist-
worn Force Fitness Tracker
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3 RF HEAVY HITTERS
Absorption Materials
Antenna Size
Above: Renderings of
a wrist band
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RF NEAR THE BODY
■ Absorption because your a bag of
water
■ Comfort & size = movement
● S11 match shifts due to the influent of
the body
● Efficiency changes
■ Body movement
● Rotations causes gain variation
● Generally hurts the link budget
HUMAN BODY IMPLICATIONS
Bottom Right: S11
variation due to
movement
Top Right: Model of an
oscillating wrist
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THE COMPLEXITY OF WEARABLES
■ Human body modeling
■ Size variations
■ Simulating movement
Low Resolution Medium Resolution High Resolution
(4 mm version) (2 mm version) (accurate version)
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HUMAN BODY MODEL
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THE SIMPLE WRIST
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MOVEMENT OF THE HUMAN BODY MODEL
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S11 VARIATION DUE TO MOVEMENT
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WE THINK ABOUT USE CASE FIRST
Understanding your user
● How often does sampling need to
occur? (heart monitor & footfalls)
● User Interaction Rate
● Comfort
Drives the engineering
● Power
● Connection Interval
● Experience
● Connection Technology
● Link Budget
UNDERSTAND YOUR USER
Above: GPS Running watch example.
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UNDERSTAND THE RF PROBLEM
Above: Currents in an antenna
Typical Frequencies
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SIMPLE ARCHITECTURE WORKFLOW
ME/ID Concept
RF Concept
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SIMPLE STARTING POINT
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SIMULATION TIMES
■ Rapid development requires rapid sim times
■ Keep sims times less than an hour until CAD is final
■ Multi core license is well worth the money
■ We run large sims on remote machines
■ Small jobs are run on laptops
■ Cloud computing is also an option
■ Parametric sweeps and optimizations are typically run overnight
■ Analytical Derivative Function using Optimetrics to speed understanding of
design space
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RAPID MODEL WORKFLOW
Above and Below: ME refinement
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COMPLEXITY OF ORGANIC 3D MODELS
■ Developing 3D elements within curve
surfaces is extremely important
■ Simplify CAD and HFSS model to solve
quickly and allow rapid iterations
■ Imported CAD to modeled surfaces
increases solve times
■ There are several methods to simplify CAD
● Sweep simple geometric shapes based on
polylines
● Use HFSS meshing views to and controls to
reduce tetrahedron counts
● Use imported CAD and manipulate with CAD
simplification tool like SpaceClaim
Simplifying CAD
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COMPLEXITY OF 3D ORGANIC SHAPES
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MATERIAL SELECTION
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SAME PAGE ENGINEERING
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SENSITIVITY ANALYSIS
■ Sensitivity is some that needs to be verified throughout the project
■ Many real world factors conspire to reduce bandwidth
■ Many unintended modifications can cause shifts in the antenna resonance
point
■ The desire for rapid development can lead to missing elements that effect
the physical design
■ Informed knowledge of where short cuts can be taken is crucial
■ As in most RF generally, BW is protection against sensitivity
■ Wearable antenna design is a tradeoff between footprint and BW
● Small antennas tend to be narrowband
● We want to widen the BW while minimizing footprint
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MP DESIGN / SENSITIVITY
■ Working element is ported into
Solidworks for ME interference checks
■ ME architecture generally requires
manufacturability changes affecting
RF antenna
■ ME CAD architecture is imported back
into HFSS and crossed checked with
RF design concept
WORKFLOW
ME import
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CAD IMPORT
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ALPHA LOCK
WORKFLOW
■ RF antenna sensitivity is finalized
■ Detailed RF verification and reaction
to ME changes
■ Typically begin generating prototypes
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CHARACTERIZATION
■ S11 testing in the lab and in a Satimo
chamber validates design for mass
production
■ Environmental and sensitivity testing
validates design
WORKFLOW
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SCRIPTING HFSS FOR SPEED
■ Trigonometric functions are more easily defined in a script
■ Scripting allows each 3D point to be broken into its constituent points
■ Trace widths, separation, height etc can all be parameterized easily
■ Parameterized models allow early rapid design space exploration
■ Parameterized models also enables later automated optimization
■ 3-Dimensional antenna concepts are difficult to parameterize
■ Python scripts offer a simple way to scale elements
● Number of elements in an antenna
● Fractal elements
● Number of turns in a coil
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FLAT COIL PYTHON SCRIPT EXECUTION
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WHY BOTHER USING SCRIPTS
+ Organization of complex values
+ Reuse
+ Minor changes provide major impact
- Script debug is difficult
PLUSES AND MINUSES
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THE TAKEAWAYS
■ RF challenges and design considerations for the human body
■ Start early and sync often with your ME design team
● Rapid development requires parallel workstreams
● We need to be flexible in design to allow for ID material choices
■ How we leverage HFSS
● Scripting enables parameterization
● Parameterization enables rapid development
■ View the deck again at:
synapse.com/blog/post/ansys-hfss
■ Visit the ANSYS booth at DAC!
● Mike presents again June 2nd at 2PM