Large-Scale Terahertz Active Arrays in Silicon Using ...€¦ · Recent Progress and New Challenges...

Large-Scale Terahertz Active Arrays in Silicon Using Highly-Versatile

Electromagnetic Structures(Invited Paper)

Cheng Wang, Zhi Hu, Guo Zhang,Jack Holloway and Ruonan Han

Dept. of Electrical Engineering and Computer ScienceMicrosystem Technology LaboratoriesMassachusetts Institute of Technology

Enabling

Technology

Applications

(Demos)

Today

The Dawn of a New Terahertz Era

2


3

Cost &

Size

System

Complexity

The Next THz Era

Enabling

Technology

Applications

(Demos)

Today


4

Cost &

Size

System

Complexity

The Next THz Era

Enabling

Technology

Applications

(Demos)

Today

Recent Progress and New Challenges

5

2006 2008 2010 2012 2014 20161E-5

1E-4

1E-3

0.01

0.1

1

10

DC

to

TH

z R

ad

iati

on

Eff

icie

nc

y (

%)

Year

0.2 0.3 0.4 0.5-15

-10

-5

0

5

10

Po

ut (

dB

m)

fout

(THz)

[IMS 2013][ISSCC 2013]

[ISSCC 2012]

[ESSIRC 2013]

[ISSCC 2014]

[T-MTT 2014]

[ISSCC 2014]

10-2

1

10-4

[ISSCC 2008]

[ISSCC 2011]

[VLSI 2011]

[ISSCC 2012]

[ESSIRC 2012][ISSCC 2013]

[ISSCC 2014]

[IMS 2013]

Our Work

Our Work

Our Work

[ISSCC 2015]

Our Work

[ISSCC 2015]

[R. Han, etc., IEDM 2016]

Recent Progress and New Challenges

6

2006 2008 2010 2012 2014 20161E-5

1E-4

1E-3

0.01

0.1

1

10

DC

to

TH

z R

ad

iati

on

Eff

icie

nc

y (

%)

Year

0.2 0.3 0.4 0.5-15

-10

-5

0

5

10

Po

ut (

dB

m)

fout

(THz)

[IMS 2013][ISSCC 2013]

[ISSCC 2012]

[ESSIRC 2013]

[ISSCC 2014]

[T-MTT 2014]

[ISSCC 2014]

10-2

1

10-4

[ISSCC 2008]

[ISSCC 2011]

[VLSI 2011]

[ISSCC 2012]

[ESSIRC 2012][ISSCC 2013]

[ISSCC 2014]

[IMS 2013]

Our Work

Our Work

Our Work

[ISSCC 2015]

Our Work

[ISSCC 2015]

[R. Han, etc., IEDM 2016]

What are the true advantages of using silicon IC for THz hardware (besides low cost, baseband integration…)?

Large-Scale Terahertz Active Array

7

Integration Capability of Silicon Chips

Homogeneous Array• Power combining• Beam collimation• Beam steering• …

Heterogeneous Array• Broadband sensing• Parallel signal processing• Waveform generation• …

Outline

Background

Homogeneous Array: 1-THz Radiation SourceMulti-Functional Mesh Structure

Chip Prototype in SiGe and Measurement Results

Heterogeneous Array: 220-to-320GHz Frequency-Comb SpectrometerHigh-Parallelism Architecture and THz Molecular Probing Module

Chip Prototype in CMOS and Measurement Results

Gas-Sensing Demonstration

Conclusion8

Outline

Background






Conclusion9

Beam Collimation in a Radiator Array

10

-90 900-60 -30 30 60Angle (degree)

No

rma

lize

d P

ow

er

(dB

)

-30

-20

-10

0

-90 900-60 -30 30 60Angle (degree)

No

rma

lize

d P

ow

er

(dB

)

-30

-20

-10

0

-90 900-60 -30 30 60Angle (degree)

No

rma

lize

d P

ow

er

(dB

)

-30

-20

-10

0

D=λ/4 D=λ/2 D=λ

D

θ

Array of N coherent radiation sources enables: Power combining from a large number of solid-state devices

Beam collimation through wave interference

The far-field radiation intensity increases by N2

Optimum Element Pitch: λ/2

High-Density, Large-Scale Active Array on Chip

• If the λ/2 pitch is achieved:‒ >10/mm2 radiators at

300 GHz can be built

‒ Dopt is ~300μm(with εr,eff≈3)

• High effective isotropicallyradiated power (EIRP) may be maintained in the mid-THz range

‒ Long transmission distance

11

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

Be

am

Wid

th (

de

gre

e)

Frequency (THz)

100

101

102

103

104

105

106

107

108

# o

f Co

here

nt R

ad

iato

rs

1 Antenna

(JSSC 2002)

2 m

m

2.2 mm

4 Antennas

(ISSCC 2013)Optical Antenna Array

Note: Calculations Based on a 10mm2 Active Area


12

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

Be

am

Wid

th (

de

gre

e)

Frequency (THz)

100

101

102

103

104

105

106

107

108

# o

f Co

here

nt R

ad

iato

rs

1 Antenna

(JSSC 2002)

2 m

m

2.2 mm

4 Antennas

(ISSCC 2013)

1 mm

16 Antennas


Our Work


1.3

mm

1.6mm

Radiators

VC

Os

+B

uff

ers

Other PLL Blocks

1.895 1.9 1.905 1.91 1.915-100

-90

-80

-70

-60

-50

Frequency (GHz)

Po

we

r (d

Bm

)

Frequency Locked

Free Running

Frequency (Hz)

PN

(d

Bc/H

z)

-67.4dBc/Hz @ 100KHz

-87.2dBc/Hz @ 10MHz

Phase Noise After Locking

10K 100K 1M 10M 100M-100

-90

-80

-70

-60

-50

• 320-GHz Array w/ PLL in SiGe BiCMOS

• 4x4 elements in 1-mm2 area

• 3.3mW total radiated power (EIRP: 24mW)

[R. Han, ISSCC 2015]


• ~100/mm2 radiator density should be possible

‒ Only 3° of beamwidth using 10-mm2 chip area(~1000 coherent radiators)

• Large challenges‒ Signal generation at 1 THz

‒ Available radiator area:100×100μm2

‒ Highly scalable array architecture

13

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

Be

am

Wid

th (

de

gre

e)

Frequency (THz)

100

101

102

103

104

105

106

107

108

# o

f Co

here

nt R

ad

iato

rs

1 Antenna

(JSSC 2002)

2 m

m

2.2 mm

4 Antennas

(ISSCC 2013)

1 mm

16 Antennas


Our Work

??


Implementation Challenges

14

0

100

200

300

400

500

0 40 80 120 160 200 240 280

Me

as

ure

d f

ma

x (

GH

z)

(In

terc

on

ne

ct

Inc

lud

ed

)

Technology Node (nm)

CMOSSiGe

[R. Shmid, et al., IEEE Trans. Electron Devices 2015]

Cutoff Frequency of

Silicon Devices

f0 x 42. Frequency Quadrupler

1. Fundamental (f0) Oscillator

4. Filters for Unwanted Harmonics f0 2f0 3f0 4f0

λf0/4=λ4f0

3. Antenna at 4f0 λ4f0/2

λ4f0/2

Available Area

High-Order Harmonic Radiation

f0=250GHz, fout=4f0=1THz

Low device speed requires high-order harmonic generation‒ Optimal device conditions at all harmonic frequencies should be met

The available area is too small for all these necessary functions

Enabling Technology: Versatile EM Designs

• A multi-functional electromagnetic structure around the transistors to simultaneously perform all the above tasks

‒ Orthogonality of various EM wave modes

‒ Multi-order standing-wave interference in the near field 15

λ4f0/2

Multi-Functional Structure

3. Antenna at 4f0 λ4f0/2

1. Fundamental (f0) Oscillator

λf0/4=λ4f0

4. Filters for Unwanted Harmonics f0 2f0 3f0 4f0

f0 x 42. Frequency Quadrupler


16

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

Be

am

Wid

th (

de

gre

e)

Frequency (THz)

100

101

102

103

104

105

106

107

108

# o

f Co

here

nt R

ad

iato

rs

1 Antenna

(JSSC 2002)

2 m

m

2.2 mm

4 Antennas

(ISSCC 2013)

1 mm

16 Antennas

(ISSCC 2015)

1 mm

91 Antennas

(RFIC 2017)Optical Antenna Array

Our Work


1 mm

• 1-THz Array in 130-nm IHP SiGe BiCMOS

• 91 coherent radiator in 1-mm2 area

• 0.1-mW total radiated power(EIRP: 20mW)

[Z. Hu and R. Han, IEEE RFIC, Jun. 2017

(Best Student Paper Award-2nd Place)]

Fundamental Oscillation at f0=250GHz

• At f0, each square slot line behaves as a pair of λ/4 standing-wave resonators

17

Q≈20 @ 250GHzCap

Cap

ABCD B

C D

AB

C D

B

C

@ f0

λf0/8

λf0/8 AC Short

λf0/4

Optimal Fundamental Oscillation

Multi-Order Standing Wave Interference

• Unwanted harmonics (@ f0, 2f0, 3f0) are canceled by near-field interference

18

Cap

Cap

Cap

Cap

ABCD B

C D

AB

C D

B

C

AB

C D

B

C

AB

C D

B

C

AB

C D

B

C

ABCD B

C D ABCD B

C D ABCD B C D

@ f0

Cap

Cap

Cap

Cap

250-GHz Oscillation

Radiation Suppression and Energy Recycling of Harmonics 1-THz Radiation

λ/4

@ 2f0

λ/2

@ 3f0

3λ/4

@ 4f0

λ

No Separate Filter is Needed

High-Density Radiation at 1 THz

• The 1-THz standing waves in all horizontal slots are in phase‒ Effective backside radiation (ηrad,sim=63%)

‒ On average, each oscillator (4x7 in total) drives 2 slot dipole antennas

19

AB

C D

B

C

ABCD B C D

@ 4f0=1THz

Cap

Cap

λ/2 @

1THz

Slot Dipole

Antenna

91 Coherent Antennas (D≈λ/2)

Measurement Results: Frequency and Spectrum

• Oscillation frequency is determined by a sub-harmonic SBD mixer‒ Weak radiation leakage at f0

‒ Measured fundamental frequency: 252.5 to 254.1 GHz

‒ 4f0 output: 1.01 to 1.016 THz 20

Power Supplies

VB

GNDVCC

Spectrum Analyzer

(Tektronix RSA3303A)

WR-3.4

AntennaWR-3.4

Mixer

IF

Amplifier

Chain

Signal Generator (Keysight E8257D)

LO=15.8GHz

1.0 1.1 1.2 1.3252

253

254

Me

as

ure

d fOSC,fund (

GH

z)

VB (V)

f0 = 16fLO + foffset

Measurement Results: Radiated Power

• The radiated power is measured by a calibrated WR-1.0 zero-biased diode detector

‒ Measured total radiated power: 80 μW

‒ Measured beam directivity: 24 dBi (θ-3dB=11°)

‒ Measured EIRP: 20 mW21

Simulation

Measurement

H-Plane

-90 -60 -30 0 30 60 90

-40

-30

-20

-10

0

Phi (degree)No

rmalized

Re

ce

ive

d P

ow

er

(dB

)

E-PlaneSimulation

Measurement

-90 -60 -30 0 30 60 90

-40

-30

-20

-10

0

Theta (degree)No

rmalized

Re

ce

ive

d P

ow

er

(dB

)

Measurement Results: Radiated Power

• The measured radiated power is further verified by a photo-acoustic (TK) power meter with large aperture

22

Power

Supply

Function

Generator

VB

GND VCC

Trigger

TK Processing Unit

Signal

Heater PC

TK Powermeter

(30Hz)

Comparison with the State-of-the-Arts in Silicon

• The achieved radiated power is 10x higher than prior silicon-based radiation sources in the mid-THz range

‒ 100x higher EIRP than prior arts

• Even larger scale with higher power should be possible

23

[RFIC 2017]

Outline

Background






Conclusion24

Wave-Matter Interactions for Material Sensing

25

THz Spectrometer for Gas Sensing

26

MoleculeFrequency

(GHz)Toxic? Flammable?

Carbon Monoxide (CO) 230.538001 Y Y

Sulfur Dioxide (SO2) 251.199668

Hydrogen Cyanide (HCN) 265.886441 Y

Hydrogen Sulfide (H2S) 300.511959 Y

Nitric Oxide (NO) 250.436966 Y

Nitrogen Dioxide (NO2) 292.987169 Y

Nitric Acid (HNO3) 256.657731 Y

Ammonia (NH3) 208.145904 Y

Carbonyl Sulfide (OCS) 231.060989 Y Y

Ethylene Oxide (C2H4O) 263.292515 Y

Acrolein (C3H4O) 267.279359 Y

Methyl Mercaptan (CH3SH) 227.564672 Y

Methyl Isocyanate (CH3NCO)

269.788609 Y

Methyl Chloride (CH3Cl) 239.187523 Y Y

Methanol (CH3OH) 250.507156 Y Y

Acetone (CH3COCH3) 259.6184 Y Y

Acrylonitrile (C2H3CN) 265.935603 Y Y

[Source: HITRAN.org]

0 0.3 0.6 0.9 1.2

40

60

80

100

Tra

ns

mit

tan

ce

(%

)

16O

12C

32S

Frequency (THz)

𝜸 =𝟐𝑱 + 𝟏 𝒉𝑩𝒆−𝒉𝑩𝑱(𝑱+𝟏)/𝒌𝑻

𝒌𝑻Absorption Intensity:

Quantum Number

J≈40

J=1

-5 50

Frequency Offset From

231.060983GHz (MHz)

100%

85%

70%

Wide Detection Range High Sensitivity High Selectivity

Dual-THz-Comb Spectrometer

27

IF

f (GHz)220 320

Transmitter

f (GHz)220

Receiver

320

• Conventional single-tone sensing scheme– Bandwidth-efficiency tradeoff

– Long scanning time(~3 hours for 100-GHz bandwidth)

IFB,-n

~IFB,n-1 f (GHz)220 320 f (GHz)220 320

IFA,-n

~IFA,n-1

THz Comb A

Spectrum of Comb A Spectrum of Comb B

fIF

THz Comb B• Our scheme using bilateral THz

frequency combs– Each circuit block maintains peak

performance in a narrow band

– Simultaneous scanning using 20 comb lines(>20x increased speed)

220-to-320GHz Comb-Based CMOS Spectrometer

28

Hemispheric

silicon lens

CMOS chip

[C. Wang and R. Han, IEEE ISSCC, Feb. 2017]

• 10 molecular-probing THz transceivers‒ Key technology: multi-function, energy-efficient electromagnetic structures

• Seamless coverage of the 220 to 320 GHz band with kHz resolution

Operation of the Transceiver Unit Core

29

• Optimum device conditions created via a multi-functional EM structure‒ Slot 1: resonator at f0 and antenna at 2f0

‒ Slot 2: power recycle path at f0 and leakage blocker at 2f0

• Simultaneous transmit/receive function

[C. Wang and R. Han, IEEE JSSC, Dec. 2017]

High-Parallelism Broadband Architecture

• The relaxed tunability requirement allows the introduction of device positive feedback and higher device gain

‒ 43% simulated doubler conversion efficiency

• The total spectral scanning time is reduced by more than 20x, leading to high energy efficiency

30

η=18%, w/o

feedback

η=43%, with DTL

feedback

η (%)

Gmax

Original Transistor (W/L=12µ/60n)

Transistor with

DTL Feedback

fmin fmax

Tim

e P

er

Sa

mp

le

fmin fmax

Ave

rag

e T

ime

Pe

r

Sa

mp

le

20x

Single-Tone Spectrometer Dual-Comb Spectrometer

CH

1

CH

2

CH

3

CH

4

CH

17

CH

18

CH

19

CH

20

CMOS Chip Prototype

• TSMC 65nm bulk CMOS process (fmax=250GHz)‒ Chip area: 2×3mm2

• 10 transceivers (doubler+receiver+antenna), 9 mixers, 40 amplifiers, operating at 0.1~0.3 THz

‒ DC power: 1.7 W 31

3 mm

2m

m

Testing Board

WR-3 Even-Harmonic Mixer

Setup for Radiation Spectrum and Pattern Testing

Experimental Results

32

Span=10kHz

RBW=10Hz

Antenna Pattern of One Line (265GHz)Average Phase Noise: -102dBc/Hz @ 1MHz

Measured Down-converted IF Spectra of all Comb Lines Spectrum of a Comb Line at 265GHz

Experimental Results

33

• Total radiated power of the 10 comb lines: 5.2 mW– Highest in silicon

• Minimum detectable signal: 0.1 fW (-130 dBm) @ τ=1 ms

Effective Isotopically-Radiated PowerNoise Figure of Each Channel

(SSB, Antenna Loss Included) This work

TST

2016

On-wafer measured with an

assumed 50% radiation efficiency Radiated

RFIC

2016

RFIC

2015

ISSCC

2015

ISSCC

20161

PBW

JSSC

2013

TST

2015MTT

2012

CSICS

2012 ISSCC

2016

ISSCC

2015

This work

TST

2016



RFIC

2016

RFIC

2015

ISSCC

2015

ISSCC

20161

PBW

JSSC

2013

TST

2015MTT

2012

CSICS

2012 ISSCC

2016

ISSCC

2015

This work

TST

2016



RFIC

2016

RFIC

2015

ISSCC

2015

ISSCC

20161

PBW

JSSC

2013

TST

2015MTT

2012

CSICS

2012 ISSCC

2016

ISSCC

2015

Spectroscopy Demonstration

• Low pressure is applied to eliminate the spectral broadening due to the inter-molecular collisions

• Wavelength modulation is used to reduce the impacts of the standing wave inside the gas chamber 34

Comb A Comb BGas Chamber

fIF

fm 2fm

LNABPFDetector

IFi

L=70 cm, Pressure =3 Pa

WM input

fref+Δf/6·sin(2πfmt)

Signal SourceSignal Source

Lock-in amplifier

fref – fIF/6

GPIB

GPIB

fm

Laptop

fm

Output

Spectral

line

Freq

Am

pli

tud

e

Time

Time

Acetonitrile (CH3CN)

Spectroscopy Results

• Sensitivity: 11 ppm for OCS, 14 ppm for CH3CN, 3 ppm for HCN…

‒ 10-100 ppt with standard gas pre-concentration

• Any polar molecule heavier than HCN can be detected

• Spectral linewidth is ~1MHz, leading to absolute specificity

O C S

CH3CN

CH3CN

OCS

SNR Pressure

BW=78Hz

279.6825 279.6840 279.6855 279.6870

-4

-2

0

2

4

1st-

Ord

er

De

riv

ati

ve o

f T

ran

sm

iss

ion

(a

.u.)

Frequency (GHz)

-45

0

45

90

135

180

225

Ph

as

e S

hift (D

eg

ree)

Conclusions• Using CMOS/BiCMOS device technologies not only enables “THz

frontend + analog/digital baseband” integration, but may also directly enhance the THz-circuit performance

‒ Homogeneous arrays: high-density coherent wave interference Large total radiated power

Ultra-narrow beam generation

‒ Heterogeneous arrays: high-parallelism EM spectral sensing Broadband coverage

Optimal energy efficiency

• Key technology: versatile THz circuits with multi-functional structures

36

A unified design framework:device, circuit, electromagnetism and architecture, all rolled into one

Acknowledgement

• Other Group Members:M. Kim, M. Ibrahim, M. I. Khan,

X. Yi, J. Mawdesley, J. Maclver, Z. Wang

• Collaborators:B. Perkins (MIT Lincoln Lab), S. Coy (MIT),

Q. Hu (MIT), M. Kaynak (IHP)

37

• Sponsors:

Large-Scale Terahertz Active Arrays in Silicon Using Highly-Versatile

Electromagnetic StructuresCheng Wang, Zhi Hu, Guo Zhang,Jack Holloway and Ruonan Han

Dept. of Electrical Engineering and Computer ScienceMicrosystem Technology LaboratoriesMassachusetts Institute of Technology

Large-Scale Terahertz Active Arrays in Silicon Using ...€¦ · Recent Progress and New Challenges...

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Transcript of Large-Scale Terahertz Active Arrays in Silicon Using ...€¦ · Recent Progress and New Challenges...