PowerPoint Presentation · generation and radiation Antenna array requires λ/2 spacing ~70μm x...

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1 RFIC2017 RTU2B-2 Fully-Scalable 2D THz Radiating Array: A 42-Element Source in 130-nm SiGe with 80-μW Total Radiated Power at 1.01THz Zhi Hu and Ruonan Han MIT, Cambridge, MA, USA RTU2B-2 Student Paper Finalist

Transcript of PowerPoint Presentation · generation and radiation Antenna array requires λ/2 spacing ~70μm x...

1

RFIC2017

RTU2B-2

Fully-Scalable 2D THz Radiating Array: A

42-Element Source in 130-nm SiGe with

80-μW Total Radiated Power at 1.01THz

Zhi Hu and Ruonan Han

MIT, Cambridge, MA, USA

RTU2B-2

Student Paper

Finalist

2

RFIC2017

Outline

• Motivation and Challenges

• Design of Oscillator

• Formation of 1-THz Oscillating-Radiating Array

• Measurement Results

• Conclusions

RTU2B-2

3

RFIC2017

Applications of high-power

high-frequency THz source

RTU2B-2

ISSCC2013

ISSCC2012

ISSCC2015

JSSC2015

JSSC2014

VLSI2015 ISSCC2016

T-MTT2015

0.2 0.4 0.6 0.8 1.0 1.2 1.4-30

-20

-10

0

10

Co

here

nt

Rad

iate

d P

ow

er

(dB

m)

Frequency (THz)

Array

Non-Array

• Building coherent radiating

array at higher frequency is

more challenging

High-Resolution Imaging

Bio-Molecule Spectroscopy

High-Precision Vibrometry

[F. Schuster et al.,

ISSCC, 2011.]

[T. Globus et al.,

Convergent Science

Physical Oncology, 2016.]

[G. Bissinger, D. Oliver,

Sound & Vibration, 2007.]

Path to high-power

1-THz radiator

Pushing Frequency and Power Limit of THz Radiator

4

RFIC2017

Why Building 1-THz Radiating Array Is Difficult?

RTU2B-2

1 THz > fmax of all silicon-based

transistors (fastest: 450 GHz in IHP S13G2)

Efficient high-order harmonic

generation and radiation

Antenna array

requires λ/2 spacing

~70μm x 70μm for

each radiating unit

Very limited area to fit in

all necessary components

Array scale can

be very large

Accumulation of phase error between units due to

inter-unit injection can cause severe beam tilting

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RFIC2017

Call for Compact Multi-Functional Array Unit

RTU2B-2

Array Unit OscillatorPhase-

Synchronizing

Coupler

1-THz

Antenna

Harmonic

Filter

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RFIC2017

Our Slotline-Bound-Array Solution

RTU2B-2

• Differential oscillators plus slotlines accomplish all tasks

– Each unit oscillates at f0 = 250 GHz and radiates 4f0 = 1 THz

7

RFIC2017

Outline

• Motivation and Challenges

• Design of Oscillator

• Formation of 1-THz Oscillating-Radiating Array

• Measurement Results

• Conclusions

RTU2B-2

8

RFIC2017

Multi-Functional Array Unit

RTU2B-2

Array Unit OscillatorPhase-

Synchronizing

Coupler

1-THz

Antenna

Harmonic

Filter

9

RFIC2017

Oscillator Pair Capable of Efficient Harmonic Generation

RTU2B-2

• At f0 (250 GHz), two oscillators are forced to oscillate differentially

• For even-order harmonics from two oscillators, including 4f0 = 1 THz

– They are in-phase, hence repelled from slotline (feedback loop)

– No dissipation at base, more power is delivered outwards

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RFIC2017

Maximize Oscillation at f0 in Single Oscillator

RTU2B-2

2

*

21 12

1

11 12

1/ ,

arcsin Re Im( )/

opt

TL TL opt

A V V y y

Z g A y A

0 100 200 300-270

-240

-210

-180

Op

tim

um

Ph

ase S

hif

t an

g(A

op

t) (

deg

)Frequency (GHz)

Δφ = 84°

• Phase delay of V2 should be compensated

– Intrinsic delay of IC

– Undesired feed-forward current Ifeed

• Use self-feeding topology to adjust phase

[R. Spence, Linear Active Networks, 1970.]

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RFIC2017

Outline

• Motivation and Challenges

• Design of Oscillating Unit

• Formation of 1-THz Oscillating-Radiating Array

• Measurement Results

• Conclusions

RTU2B-2

12

RFIC2017

RTU2B-2

• Two λ/4 @ f0 transmission lines (short open)

• E-shaped pattern composes the boundary of oscillating unit

• Resonator is implemented by slotlines

Expose Oscillation Using Branched Resonator

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RFIC2017

Reson

ato

r 1

Reson

ato

r 2

Reson

ato

r 3

Zresonator

Structure of a Complete Oscillating Unit

RTU2B-2

100 200 300 400

0

200

400

600

800

1000

1200

Res

on

ato

r Im

ped

an

ce

Ma

gn

itu

de (

Oh

m)

Frequency (GHz)

• Oscillators sealed by three resonators

– Two branched resonators

– One broadband open

• In-shunt resonators present Q = 18

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RFIC2017

Interface Adjacent Units Using Branched Resonator

RTU2B-2

……

Single Abut

Vertically

• Horizontal slotlines on the border (2x1 case) are merged

• Vertical slotlines on the border (1x2 case) run parallel

……

Abut

Horizontally

2D

Expansion

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RFIC2017

Multi-Functional Array Unit

RTU2B-2

Array Unit OscillatorPhase-

Synchronizing

Coupler

1-THz

Antenna

Harmonic

Filter

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RFIC2017

Coupling (at f0) between Horizontally Adjacent Units

RTU2B-2

Single-Node Injection vs. Distributed Phase Synchronization

[B. Razavi, JSSC, 2004.]

Phase at every

point is synced,

even if there is

mismatch of ω0

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RFIC2017

Coupling (at f0) between Vertically Adjacent Units

RTU2B-2

• Branched resonator shared phase relationship determined

• Use slotline for the purpose of array-wide in-phase radiation (discuss later)

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RFIC2017

Multi-Functional Array Unit

RTU2B-2

Array Unit OscillatorPhase-

Synchronizing

Coupler

1-THz

Antenna

Harmonic

Filter

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RFIC2017

90°

Radiation Cancellation at f0 (250 GHz): Vertical

RTU2B-2

• Vertical slotlines pairs do not radiate

– E-field in left and right slotlines balance out

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RFIC2017

Radiation Cancellation at f0 (250 GHz): Horizontal

RTU2B-2

• Horizontal slotlines pairs do not radiate

– E-field in left and right slotlines balance out

-66dBi

Antenna Gain at f0

A' B' C'ABC

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RFIC2017

Radiation Cancellation at 2f0 (500 GHz): Horizontal

RTU2B-2

• Horizontal slotlines do not radiate

– E-field in central slotlines balance out with top/bottom slotlines

A' B' C'ABC

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RFIC2017

180°

Radiation Cancellation at 2f0 (500 GHz): Vertical

RTU2B-2

• Vertical slotlines pairs do not radiate

– E-field in left and right slotlines balance out

Antenna Gain at 2f0

-12dBi

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RFIC2017

Radiation Cancellation at 3f0 (750 GHz)

RTU2B-2

• Horizontal slotlines pairs do not radiate

– E-field in left and right slotlines balance out

A' B' C'ABC

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RFIC2017

270°

Radiation Cancellation at 3f0 (750 GHz)

RTU2B-2

• Vertical slotlines pairs do not radiate

– E-field in left and right slotlines balance out

Antenna Gain at 3f0

-30dBi

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RFIC2017

Multi-Functional Array Unit

RTU2B-2

Array Unit OscillatorPhase-

Synchronizing

Coupler

1-THz

Antenna

Harmonic

Filter

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RFIC2017

Radiation at 4f0 (1 THz) from Single Unit

RTU2B-2

• All horizontal slotlines pairs radiate in-phase

• Vertical slotlines do not radiate

Antenna Gain at 4f0

9dBi

A' B' C'

ABC

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RFIC2017

1-THz Radiating Array

RTU2B-2

λ/2 @ 1 THz

λ/2 @ 1 THz

Radiating Slotline

• In-phase radiation from all units is

achieved by CPW and slotline coupling

• 1-THz antennas are spaced by λ/2 in both

horizontal and vertical directions

• Equivalently, the array is like an “active

planar wave front” with big aperture

underpinned by transistors

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RFIC2017

Outline

• Motivation and Challenges

• Design of Oscillator

• Formation of 1-THz Oscillating-Radiating Array

• Measurement Results

• Conclusions

RTU2B-2

29

RFIC2017

RTU2B-2

SiGe Chip Prototype

Dummy

Cut for the

Symmetry

of the Cell

1mm

• Technology: IHP S13G2 SiGe BiCMOS

– fmax = 450 GHz

• Area: 1 mm2

• Array scale

– 42 units

– 91 antennas

• DC Power: 1.1 W

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RFIC2017

Measurement of Spectrum of Leaked Fundamental

RTU2B-2

• Chip is attached to a half-ball silicon lens and radiates into backside

• Due to device mismatch, there will be little of f0 wave leaking out, with

which we can confirm f0 and hence 4f0

1.0 1.1 1.2 1.3252

253

254

Me

as

ure

d fOSC,fund (

GH

z)

VB (V)

f0 = 16fLO + foffset

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RFIC2017

Measurement of Total Radiated Power

RTU2B-2

Measurement using VDI WR-1.0 zero-bias diode detector

• Total radiated power of 1 THz (from ZBD): 80μW (-11dBm)

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RFIC2017

Measurement of Total Radiated Power

RTU2B-2

• Total radiated power of 1 THz (from ZBD): 80μW (-11dBm)

• Total radiated power of all harmonics (from TK): 100μW

Measurement using large-aperture Thomas Keating photo-acoustic powermeter

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RFIC2017

Measurement of Radiation Pattern

RTU2B-2

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

)

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

)

• Measured using zero-bias diode detector

• Peak directivity: 24dBi

• EIRP: 13dBm

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RFIC2017

Performance Comparison

RTU2B-2

• Highest total radiated power

• Highest EIRP

Reference This Work MTT2015 ISSCC2011 ISSCC2016 VLSI 2015

Circuit TypeOscillator

Array (4f0)

Active

Multiplier (6f0)

Active

Multiplier (5f0)

Passive

Multiplier (10f0)

Passive

Multiplier (5f0)

Output Frequency (THz) 1.01 0.99 0.82 1.33 0.73

Radiated Power (dBm) -10.9 N/A N/A -22.7 -21.3

EIRP (dBm) 13.1 -37 -17 -13 -22.2

Input RF Power (dBm) N/A 8 14 18 13.8

DC Power (W) 1.1 4 3.7 0 0

Chip Area (mm2) 1.00 3.28 3.22 0.36 0.26

Technology 0.13μm SiGe 0.25μm SiGe 0.25μm SiGe 65nm CMOS 65nm CMOS

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RFIC2017

Conclusions

RTU2B-2

• A high-power 1-THz radiator featuring 2D-coupled array architecture

– Large array scale

– Directive radiated beam

• Compact multi-functional structure will be an important component

in future THz circuits

This Work

ISSCC2013

ISSCC2012

ISSCC2015

JSSC2015

JSSC2014

VLSI2015 ISSCC2016

T-MTT2015

0.2 0.4 0.6 0.8 1.0 1.2 1.4-30

-20

-10

0

10

Co

he

ren

t R

ad

iate

d P

ow

er

(dB

m)

Frequency (THz)

36

RFIC2017

Acknowledgements

• Analog Devices Inc.

• MIT/MTL GaN Energy Initiative

• MIT Center for Integrated Circuits and Systems (CICS)

• Singapore-MIT Alliance for Research and Technology (SMART)

• Prof. Qing Hu at MIT for chip testing support

• Dr. Mehmet Kaynak at Leibniz-Institut für innovative Mikroelektronik

(IHP) for chip fabrication support

RTU2B-2

37

RFIC2017

RTU2B-2

Fully-Scalable 2D THz Radiating Array: A

42-Element Source in 130-nm SiGe with

80-μW Total Radiated Power at 1.01THz

Zhi Hu and Ruonan Han

MIT, Cambridge, MA, USA

RTU2B-2

Student Paper

Finalist