standard reference materials for 5g and microwave

COMMUNICATIONS TECHNOLOGY LABORATORY

iNEMI 5G/mmWave Tech Topic Series (May 6, 2021)

Standard Reference Materials for 5G

and Microwave Materials at NISTNate Orloff

Listen to the recorded webinar: https://youtu.be/Q40zKFWdEgU

https://youtu.be/Q40zKFWdEgU

COMMUNICATIONS TECHNOLOGY LABORATORY 2

Today’s talk is going to tell you how we do this…

The other talks inspired me to take new data and show you something new

JGS2 Fused Silica to 325 GHz


“fixing the standards of weights and measures

throughout the United States”

Articles of Confederation

“The Congress shall...fix the standard of weights and

measures…“

US Constitution

“Uniformity in the currency, weights, and measures of

the United States is an object of great importance…”

G. Washington

"Weights and measures may be ranked among the

necessities of life to every individual of human society"

J. Q. Adams

National Institute of Standards and Technology?

NIST fixes weights and measures


Where is NIST? What do you do?

4

Promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and

technology in ways that enhance economic security and improve our quality of life.

~300 scientists

Boulder, CO

~1500 scientists

Gaithersburg, MD

Develop standards, measurements, and technology


NIST defines axes and how well we know them

Traceability means everyone’s axes are the same and …

NIST measures from 10 Hz to 1.1 THz


Did we need traceability for 4G? Why is 5G different?

It’s easy to take this pyramid for granted

2870 SRM


(Some) 5G handsets overheat due to energy efficiency

Pros: Super fast.

Cons: You’ll need an ice cooler


Why are some phones overheating?

*Figures here are for illustration of

the idea and are not used in phones

or the reason deployed phones

overheat


One potential problem could be the material models

?

Vendor measures here 5G works here

1 GHz 30 GHz

Loss ta

ng

en

t

Model

Actual

This is a random phone


Even if you measure at mmWaves it still could be wrong

2G, 3G, 4G, 4G LTE products

Company test and measurement

In-house standards

Factory calibrations

NMI

SI

5G mm-wave products


In-house standards

SI

Permittivity traceability

for current technology


for 5G mmWave

Traceability

gap


How can we fill the mmWave traceability gap?

Don’t worry we are going to break down all these steps

mmWave

traceability

gap1 Measure

S-parameters

Map to

permittivity3 We are done right?4Get

dimensions2

Cavity

Sample


The first step is to measure the resonators

Goodness of fit estimates uncertainties in resonance frequency and losses

Measure

S-parameters1


*This is specific to this cavity and not general

13

After fitting, we get ‘fit’ source of uncertainty

We also need the dimensional uncertainty

Fit

uncertainty

Dimensional

Uncertainty ?

Measure

S-parameters1


How can we get ‘dimensional’ sources of uncertainty?

NIST’s coordinate measurement machine service can measure the cavity

2 Dimension

Cavity

Cavity


We need a CMM because the dimensions are small…

2 Dimension

cavity

Cavity

Cross section of a 10 GHz

We think we can get down to a couple nm’s with NIST’s CMM techniques


We need the sample dimensions too!

We think we can get down to a few nm’s with either of these techniques

1 Dimension

sample

Sample

Optical laser interferometer

Stylus profilometer


The next step is to understand the theory

Red = From dimensional metrology and Blue = From fitting S-parameters

Map to

permittivity3 𝜔𝑐 − 𝜔𝑐𝑠

𝜔𝑐=𝑉𝑠

ത𝐸𝑐 ⋅ ഥ𝐷𝑠 − ത𝐸𝑠 ⋅ ഥ𝐷𝑐 − ഥ𝐻𝑐 ⋅ ത𝐵𝑠 − ഥ𝐻𝑠 ⋅ ത𝐵𝑐 𝑑𝑉

𝑉𝑐ത𝐸𝑐 ⋅ ഥ𝐷𝑐 − ഥ𝐻𝑐 ⋅ ത𝐵𝑐 𝑑𝑉

𝜖𝑠,𝑟 ≈1

2

𝑉𝑐𝑉𝑠

Δ𝜔

𝜔𝑐+ 1 𝜖𝑠,𝑖 ≈

1

4

𝑉𝑐𝑉𝑠

𝑄𝑐 − 𝑄𝑠𝑄𝑐𝑄𝑠


*This is specific to this cavity and not general

18

Next, we perform a full uncertainty analysis

Dimensional uncertainty is the dominant source of uncertainty for our case

Fit

uncertainty

Dimensional

Uncertainty

Are we

done yet?4


Finally, we have the SRM? Now what?

This on-wafer kit makes your measurements traceable and so much more

1 cm

On-wafer traceability

for 5G mmWave

2G, 3G, 4G, 4G LTE products


In-house standards

Factory calibrations

NMI

SI


for 5G mmWaves


This kit can let you calibrate those pesky ICs and…

On-wafer traceability

for 5G mmWave

1

2JGS2 Fused Silica to 325 GHz


Finally, here’s where I walk through the new stuff

1 cm

Get R and L

from simulation2 Finite-element

simulations4 Map to dielectric

constant5

GOAL!

Get 𝛾 from

mTRL1 Get C and G

from 𝛾3

𝑅𝑠𝑖𝑚

𝐿𝑠𝑖𝑚

𝐶𝐺


1 cm

22

We use a probe station to measure each device

Our devices make a ‘calibration kit’ that produces the propagation constant

Cable Cable

Vector

network

analyzer

On-wafer measurement1


We measure all these coplanar waveguide devices

Get the

capacitance1.31.1

Make a

guess1.2

Multiline

TRL

Check the

calibration1.5

Model the

resistor1.4

NIST software can run through these checks as we take data


Our device of choice is a coplanar waveguide

Substrate

Signal

Ground

Ground

ℓ

𝑅 𝐿

𝐺𝐶

Δ𝑥

These circuit parameters describe how a wave propagates

1 cm

Get 𝛾 from

mTRL1


The 𝐶 is related to the electric field

105

102

103

104

V/m

1 cm

Get 𝛾 from

mTRL1


multiline TRL produces the propagation constant

26

𝛾 = (𝑅 + 𝑖𝜔𝐿)(𝐺 + 𝑖𝜔𝐶) = 𝛼 + 𝑖𝛽

𝛼 = attenuation constant 𝛽 = phase constant

The black line is a prediction from the simulation

Data

Simulation

Data

Simulation

Get 𝛾 from

mTRL1

Grey region is

the uncertainty There is grey

here too!

Fused Silica Fused Silica


The simulation also lets us compute 𝑅 and 𝐿

27

We only need the dc resistivity and the geometry of the CPW

Simulation with 𝜌𝑑𝑐Data with constant C

Simulation with 𝜌𝑑𝑐Data with constant C

Get R and L

from simulation2

𝑅 ≈ ℜ𝛾2

𝑖𝜔𝐶

𝐿 ≈1

𝜔ℑ

𝛾2

𝑖𝜔𝐶

Grey region is

the uncertainty

Grey region is

the uncertainty



Use the simulated 𝑅 and 𝐿 and measured 𝛾

28

Now we can compute 𝐶 and 𝐺

Get C and G

from 𝛾3

𝐺 + 𝑖𝜔𝐶 =𝛾𝑚𝑇𝑅𝐿2

𝑅𝑠𝑖𝑚 + 𝑖𝜔𝐿𝑠𝑖𝑚

𝛾𝑚𝑇𝑅𝐿 𝑅𝑠𝑖𝑚, 𝐿𝑠𝑖𝑚Fused Silica Fused Silica



The 𝐶 and 𝐺 from our ac and dc measurements

29

Get C and G

from 𝛾3

Measured C

Measured C from a resistor

Measured G

Assumption from a resistorGrey region is

the uncertainty

Our last is to compute the permittivity


Let’s talk about a parallel plate capacitor

30

𝐶 relates to 𝜖 through geometric factors that we can compute!

𝐶 = 𝜖𝐴

𝑑

Permittivity

Capacitance

slope =𝐴

𝑑

Finite-element

simulations4


We can do this exact thing in simulation

31

𝜖 = 3.78

Finite-element

simulations4

𝜖 = 3.95

All we need to do is a linear fit to map from 𝐶 to 𝜖

Grey region is

the uncertainty!

Fused Silica


And here is the result for our JGS2 fused silicaMap to dielectric

constant5

JGS2 Fused Silica to 325 GHz


Map to dielectric

constant5 We did the same thing for the loss

In this case, the loss is so low (tan𝛿 < 0.0001) we just get nonsense

Measured 𝜖𝑟Measured 𝜖𝑟 from a resistor

Measured 𝜖𝑖Measured 𝜖𝑖 from a resistor

JGS2 Fused Silica to 325 GHz JGS2 Fused Silica to 325 GHz


How are we going to get this technology to you?

We are working to develop these kits this year

This is a 4” FS wafer

NIST Calkit


Take home messages for this talk

35

Industry needs a 5G mmWave SRM

We will use a resonator and dimensional

metrology with some fitting

On-wafer techniques can get you

permittivity to very high frequencies

You can correct your axes and your ICs

5G mmWave SRM’s will have test

coupons and companion on-wafer kits

You can correct your axes and your ICs+


Summary of the program to date

36

Thanks

And thanks to iNEMI

Urmi, Mike (s), Say, Malgorzata, Marzena,

Chiawen, and the whole team!

standard reference materials for 5g and microwave

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