Antennas & RF Sensors: Changing the Way We Live(from mobile telephony to electronic textiles and RFIDs)

John L. VolakisTh Ohi St t U i itThe Ohio State University

volakis@ece.osu.edu

Coupled

UncoupledUncoupled

Coupled

UncoupledUncoupled

L1C1

L3 LMC3

CM

(V1 I1) (V3 I3)

Coupled

UncoupledUncoupled

Coupled

UncoupledUncoupled

L1C1

L3 LMC3

CM

(V1 I1) (V3 I3)

0

L2C2

0

L3 LM

0

C3

0

CMLM(V2 I2) (V4 I4)

Inductive coupling

Capacitive coupling

0

L2C2

0

L3 LM

0

C3

0

CMLM(V2 I2) (V4 I4)

Inductive coupling

Capacitive coupling

1

Why so much interest in Antennas and RF Devices?

Miniaturization need for sensors and mobile systems

Compact communication systems with higher data rates

More than 50% of a system-on-a-chipconsists of passive RF devices

RF & Microwave Magazine 2006

Conformal antennas for commercial and military applications Multifunctionality to

decrease complexity & cost

IEEE Spectrum

2

Wireless World

3

4

Enabling RF Technology for Daily Life Convenience60 trillion wireless sensor till 2010-12, viz. 10,000 for every person in the world

Wearable Antennas and Sensors are being developed with conductive textiles to:Monitor Health (blood pressure, fluid levels etc.)

P iti D t ti

Engineered Substrates for:Miniaturization, Multifunctionality & Greater Bandwidth

Position DetectionDecrease Weight and Complexity of Existing

Wireless Devices

System design to communicate various h h

Challenges:• Convenient way of Substrate Patterning & Printing (Metamaterials) is not yet realizable• Integration of RF circuits is not realistic in existingRF components to each other • Integration of RF circuits is not realistic in existing technology (only in low constant materials)

From syringe

Coated matrix template

Repeat printing process on top of solid sheetsHealth Monitoring

Challenges:

Incorporate various RF technology (Bluetooth, GPS, Health Monitoring) into existing devices- Small RF devicesChallenges:

- Tissue Characterization- Understand effect of RF signals on human body- EM Compatibility with biological structure

Small RF devices- High gain antennas for far distance communication (GPS)

5

Sensor Systems/System on a Chip Overview

P D h i l dPurpose: Detect chemical agents and vapor mixed in the air at low levels.

Deployment: Sensor can be placed in theDeployment: Sensor can be placed in the air-ducts of air conditioning systems.

Size: 2-3cm per side. Fairly flat

6

RFID Everywhere

Automobile industryA i ti• Electronic Toll Collection• Access Control• Animal Tracking

Automobile industryAviation

• Animal Tracking• Inventory Control• Tracking Runners in

Races!2000 RFID points • Anti-Theft

PharmaceuticalsID CardsID Cards

7

Ohio State’s RFID Bug Tracking Radar Goes Up to 190ft (63m)

RF Front End1. 5.9 GHz CW

signal transmitted

2. Signal intercepted by tag (up to 200’ away), harmonic re-radiated

Xmit: 5.9 GHz

3. 11.8 GHz signal received, down-converted

~200’Transmit/Mixing Circuits

Proposed Array:

Rec: 11.8 GHz

4. IF Signal: Indicates presence of tag

Rec. Circuit

Proposed Array:-Xmit ~ 14” x 7”-Rec ~ 7” x 3.5”-Gain ~ 20 dBi

Meandered Loop Tag•Tag measures 9.5 mm x 9.5 mmmm.•9.5 mm ~ 0.19λat 5.91 GHz (Xmit freq.)

8

Polyphase Multi-band Predistortion Linearization to Suppress Intermodulation Interference

9

RFID Reader System Remains a Challenge- RFID readers and tagging promise to revolutionize retail, gg g p

supermarket and warehouse shelving systems, including purchasing process and habits

Fading is a major issue. Spatial and

Re

R t il Sh lTwo distributed antennas mounted vertically behind t d d t il h lf

Fading is a major issue. Spatial and polarization diversity of the distributed antennas overcome fading in both static and dynamic environments.

eader

Retail Shelves

RFID Portalstandard retail shelf

Various metallic and non-metallic RFID tagged items arranged on shelves

Elongatedte

nna

Loaded pallet

d RFID

coveragribut

ed A

nt

ge areaDis

tr

Reader

Two distributed reader antennas on each sidewall 10

Container Product Tracking SystemsFor a typical container 10’x10’x40’ with tightly stacked cartons, we need to use 8 distributed antennas to illuminate entire container. Folded tags are also needed to

Container Side View

distributed antennas to illuminate entire container. Folded tags are also needed to get good performance.

10’

40’40

Folded tag deployment Antenna Deployment (Top View)

6’4’6’4’6’4’6’2’

Folded tag deployment

2’6”

We place 2 antennas to cover a 10’x10’x10’ volume of the container. For the entire container, we need 8 distributed antennas

11

Real Time THz Imaging of Excised TissueTARGET APPLICATION:Breast Cancer Detection 1 in 8 women will have breast cancer in their lifetime

Digital Processing

THz Imaging System Overview

Ti S lbreast cancer in their lifetime 96% curable if caught early-----------------American Cancer Society, Inc,

Tissue Sample

Surveillance Research

Current Breast Cancer

THz Detector Array

Object LensTHz Image

Working PrinciplesDetection Issues:X-rays not of sufficient resolution/information; also not desirable due to inherent

Direct detection of THz radiation using diodes having superior noise performance • Build compact detector layouts suitable for 2D arrays not desirable due to inherent

ionization.80% of biopsies unnecessary

E i d ti i i i

• Explore/optimize array topologies for maximum number of detectors (equivalently pixels), power transfer and detection performance• Investigate suitable imaging algorithms to be

12

Excised tissue imaging is desirable during operation but very slow

Investigate suitable imaging algorithms to be incorporated into the imager signal back-end• Frequencies: 100GHz, 500GHz, 800GHz

Body Worn Antenna Coverage with Diversity Module

20dB 20dB –– 30dB fluctuation reduces to 3dB 30dB fluctuation reduces to 3dB –– 4dB 4dB

dBm

]Antenna 3Antenna 4

ved

pow

er [

Antenna 1

mal

ized

rece

iv

Ant1- front torso

Ant2- back torso

Nor

m Ant3- R. shoulder

Ant4- L. shoulder

Module output

iWAT2009 13Azimuth angle [deg]

Rotator

Miniature Antennas and Arrays for THz Imaging

Multiband Antennas: Detection at multiple frequenciesSmaller size antennas to avoid aberrations

1um 3um94um

1um 3um94um

Antennas with controlled radiation patterns More antenna elements (pixels)

580um580um

Metamaterial

50um111u

m

18um

11.4

1.80.6

3um

1.8um

75um

3um1.8 50um11

1um

18um

11.4

1.80.6

3um

1.8um

75um

3um1.8

-15

-10

-5

0dB(S11)

ParasiticallyLoaded

280um

420um

280um

420um

Asymmetrically Fed

Much smaller

Metamaterial miniature antennas for small pixel size

300 400 500 600 700 800 900 1000-30

-25

-20

Frequency(GHz)

Dual band folded slot antenna for 500 &

500GHz 800GHz

Loaded Fed metamatetial-based multiple antennas for pattern control

Dual band folded slot antenna for 500 & 800GHz breast cancer detection

Imaging arrays with multiple detector (antenna

Photonic Crystals & Metamaterials

array) layouts for pattern diversity

Metamaterials High gain apertures and miniature arrays Negative refraction for sub-wavelength focusing

14

wavelength focusing

Wireless Landscape

1000 ?

50002005 Wireless Landscape1000 ??

50002005 Wireless Landscape

500

s)

?

100

Continually Evolving

802.15.3aUW B

500

s)

??

100

Continually Evolving

802.15.3aUW B

Future wireless systems will focus on high

10ate

(Mbp

s

50

802.16802 15 3 802.11a/g Fixed

UW B

802.11n

10ate

(Mbp

s

50

802.16802 15 3 802.11a/g Fixed

UW B

802.11n

y gdata rates to deliver content as rich as that in current wired systems

issi

on ra

UMTS / HSDPA /

802.11bWiFi1

5 Canopy

WiMax802.15.3

Bluetooth

Mobile/Nomadic802.16e / 20

issi

on ra

UMTS / HSDPA /

802.11bWiFi1

5 Canopy

WiMax802.15.3

Bluetooth

Mobile/Nomadic802.16e / 20

0.1

0.5

Tran

sm

BlackberryGSM/TDMA

GPRS/EDGE

UMTS / HSDPA / 1xEVDO

ZigBee802.15.4

Bluetooth802.15.1

0.1

0.5

Tran

sm

BlackberryGSM/TDMA

GPRS/EDGE

UMTS / HSDPA / 1xEVDO

ZigBee802.15.4

Bluetooth802.15.1

Range (meters)10 100 1000 10 000 100 000

y

1Range (meters)

10 100 1000 10 000 100 000

y

1

15

Antenna/RF Sensor Challenges and Solution Trends

Applications Solution Trendspp• Multifunctional Radios• Software Radios/Radars

Solution Trends• Materials

Magnetics films/Multiferroics• Short Range Giga-bit Comm.

& Data transferUWB i i f MH t

g• Composites (polymers,

mixed material systems, multi layered emulated• UWB imaging from MHz to

THz.• Sensing and monitoring

multi-layered, emulated anisotropy)

• High speed interconnectsg g• Identification• Body worn systems

g p• Structurally reinforced smart

skins (carbon nanotubes, i )• THz imaging ceramics )

ferroelectricferromagnetic

16

Military ChallengesMilitary Challenges• OSD report (Appendix C, p.9): Over the long term

2012-2030, JTRS, including wideband networking2012 2030, JTRS, including wideband networking waveforms (WNM), will provide a fully integrated information system network to include active and passive information operation management across the joint and combined environment. The system will also include a self-establishing and self healing smartalso include a self establishing and self healing smart network, which will automatically manage the RFdomain.

• WNM will operate from 225-400MHz, and is intended to enhance or replace currentintended to enhance or replace current systems such as the Single Channel Ground and Airborne Radio System (SINGARS, 30-88MHz), EPLRS (450-470 MHz), and Link 16. Gi th t t i l l th i• Given that typical wavelength size antennas are /2 long/wide (5m or ~15ft at 30MHz), they must not only be structurally embedded but also muchstructurally embedded, but also much smaller (miniature) than currently available to accommodate future real estate.

17

Future Smaller Aircraft Needs• Challenges

S ll i UAV d RF ti ( i ti i i– Small size UAVs and RF congestion (communications, imaging and information gathering on small platforms)− high speed communications: from 15kb/sec to

5Mbits/sec, 3000 times higher speedsg p− 30-5000MHz ultrawide band antennas (with wavelength

5m or 15ft) must be reduced in size by a factor of ~5-10 and integrated on small platforms with gains for high data ratesdata rates

− High gain/narrow-band antennas for radar, imaging, guidance, satellite communication, and other specific applications

t Gl b l H k S tC t i till---current Global Hawk SatCom antenna is still a (rotating) reflectors,

---future apertures must be conformal and suitable even for small UAVs

– Entire UAV surface may serve as a RF (smart) skin, implying structural integrity of the RF functional layers

– Volumetric exploitation to address low frequency performance is a major design and computational challenge.

– Multiphysics tools must address concurrent structural/fatigue and RF performance requirement; need for multiphysics design optimization tools

– UAV sections may be removable and re-bonded for multiple missions 18

Traditional antennas will be a thing of the past!!

Artificial or RealArtificial or RealMaterials?

19

Antenna Miniaturization ApproachesAntenna Miniaturization Approaches

Increase Antenna Electrical Size

Slow down currents flowing on antenna, using inductive and capacitive loading :

L1 effΖ μ2 2 eff∇ E+ω μ ε Ε = 0 Ζ =

Load antenna near fields with material εr,μr :

effυ = ,Ζ =g CL C effeff eff∇ E+ω μ ε Ε = 0,Ζ =weff eff εeff

Increase Radiation, Bandwidth and Efficiency Compared to un-miniaturized Antennas

,

Artificial Transmission Line (ATL) Material Loading20

Matching Networks Significantly Improves Low Frequency Performance

0

10

Final Operating Frequency 178 MH (60% t t l

-20

-105 segments

Possible matching Circuit from Optimization A d 80% Mi i i ti

15”MHz (60% total minimization)

-40

-30 Non OptimizedCase A(Best)Case A With Matching

2

0

2

from Optimization Around 80% Minimization

0.2 0.4 0.6 0.8 140

-6

-4

-2

-12

-10

-8

Non OptimizedCase A(Best)

Final Operating Frequency can go down to 175MHz

GAcase13.02d.FlarDipoleRun.2.case.1.iter.1.gen.8.run.44

0.15 0.2 0.25 0.3-14

Case A With Matching

21

Array planeMunk’s Current Sheet Antenna

superstrate

Z1+=jZotan(kdo)d

Array Geometry

do

Ground Plane

Impedance looking into theground plane is inductive

Capacitive load(realized via the i t di it linterdigitalcapacitor fingers) to cancelinductive ground gplane effect

Interdigital capacitive loads; As the frequency increasesInterdigital capacitive loads; As the frequency increases, capacitance increases to cancel inductive load caused by the ground plane. This results in nearly purely resistive impedance, giving rise to the large bandwidth

22

2-18GHz PerformanceF B d 2 18 GH

30308x8 Active Array Broadside Gain 30308x8 Active Array Broadside Gain

Frequency Band: 2-18 GHzPolarization: Dual LinearOverall Size: 22”x22”Total Elements: 2664 Dual PolActive Elements: 64 Dual Pol

20

2525

20

i)

20

2525

20

i)

Active Elements: 64 Dual PolAperture Thickness: 0.8”

5

10

15

Gai

n (d

Bi)15

10

5ain

(dB

i

5

10

15

Gai

n (d

Bi)15

10

5ain

(dB

i

-5

0

5G

CSA11 Measured w/ coupling plates

Theoretical 8X8 Unit Cell Gain

5

0

-5

Ga

-5

0

5G

CSA11 Measured w/ coupling plates

Theoretical 8X8 Unit Cell Gain

5

0

-5

Ga

0 4 W/element-10

2 4 6 8 10 12 14 16 18Frequency (GHz)2 4 6 8 10 12 14 16 18

Frequency (GHz)

-10-102 4 6 8 10 12 14 16 18

Frequency (GHz)2 4 6 8 10 12 14 16 18 Frequency (GHz)

-100.4 W/element

23

Frequency (GHz)Frequency (GHz)23

Enabling Miniaturization of Broadband Apertures

Just another way of capacitive coupling

Munk’s/Harris Corp. Current Sheet Aperture (CSA)Munk s/Harris Corp. Current Sheet Aperture (CSA)

Matching with Negative Elements

0 F 77pH

-1.45pF -256nH• Antenna final size: λ/12xλ/18• 3.5:1 bandwidth• No use of any material loading

3

Realized Gain before…

enna-128pF -18.5µH

0pF -77pH

Input

-3

0

3

240 to 1050MHz (4 5:1)

Ant

ep

Values from optimization

200 300 400 500 600 700 800 900 1000 1100

(4.5:1)

Keep (almost) th

Decrease the t i b

-1000

0500

Reactance

0

3

the same bandwidth

antenna size by 3

50 200 400 600 800 1000 1200

-2000

75150

2550 75 100 125 150 175 200 225 250 275 300

-382 to 275MHz

(3.5:1)

50 100 150 200 250 300

-150-75

075

After…25

…… benefits for magnetic materials are there

0

5

1 0

-1 5

-1 0

-5

tal G

ain

(dB

)

M3 ferrite

-2 5

-2 0

-1 5

Rea

lized

Tot

fre e s ta n d in go ve r in fin ite g ro u n d p la n e , h 1 = 3 ''

M3-ferrite cylindrical cavity

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0-4 0

-3 5

-3 0

in fin ite g ro u n d p la n e , w 1 = 3 '', w 2 = 4 '', h 1 = 3 ''in fin ite g ro u n d p la n e , w 1 = 1 '', w 2 = 1 '', h 1 = 3 ''in fin ite g ro u n d p la n e , w 1 = 1 '', w 2 = 1 '', h 1 = 4 ''in fin ite g ro u n d p la n e , w 1 = 1 '', w 2 = 1 '', h 1 = 5 ''

0 5’’0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0F re q u e n c y (M H z )

0.5

26

Limitation of current magnetic materials & losses

•Existing materials turn out to be “very” lossy at UHF frequencies, for

Material losses cause gain reduction

freeantenna applications

•Losses cancel out the miniaturization obtained by the

free space

miniaturization obtained by the ferrites

•Material losses need to be lower than 0 005 in order for the ferrite

tanδ must be <0.005

Material specifications

than 0.005 in order for the ferrite loading to be beneficial

Gain reduction appears as shifting up in frequency

p

•εr=μr(impedance matching)

•losses<0.005(<500 MHz)

ε μ values : 8 14

f : -15dB frequency, losses

fo : -15dB frequency, lossless • εr, μr values : 8 - 14

27

Antenna Miniaturization Techniques

1 Slow down current flow by1. Slow down current flow by material loading• Homogeneous material (broadband)• Inhomogeneous, anisotropic material

k

k

cvg

g p(narrowband)

• Magnetic Material (narrowband, bias required)

2. Control current phase velocity by

kcvp

2. Control current phase velocity by controlling L and C of equivalent transmission line model

k

L L

C CC

L L

C CC

v 1effL

Z

28

effeffp CL

veff

c CZ

Temex Microwave Ferrite Materials Catalog, http://www.temex.net/temex/catalog/TEM01.pdf

28

Eploiting 3D Anisotropy…•3D anisotropy modifies the k- diagram of the material medium

• Concurrent slow wave velocity & impedance matching lead to small RF devices with high sensitivity and high gain vs bandwidth.

k

cvg

kv

Material DNA• RBE modeFrozen Modes• DBE mode

k k

cvp

Flat sections, imply slow velocity

• DBE mode• MPC modek

• math concepts to RF designs and actual antenna realizationsFlat sections, imply slow velocity

1060

90

120

0

5

30

210

240 300

150

330

180 0

DDMMeasurementHFSS

x

240

270

300

Concept

y

12dB vs. 1.7dB Simulations FabricationTesting

100% apertureefficiency 29

Realization and Demonstration of Degenerate BandEdge (DBE) Mode in a Periodic Assembly

3456

E|m

ax

x

zy

PEC5-folds amplification

12

15

3210012

Layer #

|

Field profile for reception

yiE

φ=52.5o

3

6

9|H

|/|H in

c|

Field profile for reception3 Layers=0.96cm

0.28 λ05 7.5 10 12.5 15 17.5 20

0

3

Frequency(GHz)

New FEM Domain Decomposition Tools required (for 16M DOFs):

1 4GB 30GBFeeding Schemes: Slot on ground plane, dipole in B1 layers

Easier to implement, external feed/matching

---1.4GB vs 30GB---CPU: 2.5 hrs

5

1060

90120

Simulated (DDM)Measured (OSU-ESL)Measured (NASA)

030150

180 0

Directivity:10.15dB, over 100% aperture efficiency

210

240270

300

330

30

Performance of the Degenerate BandEdge -DRA Antenna

104

th

Optimal Curve

Leaky Wave DRA 102

n x

Ban

dwid

t yRegionRegion

2

100

Gai

n

0 5 10 15 20 25 3010-2

kaλo/8.12 λo/8.12

λo/1845o

DBE Antenna Prototype

Hybrid DBE Mode DRA Antenna 31

Emulation of Anisotropy using Standard Printed Lines

32

Printed Lines with Lumped Elements allow for much Greater Control of the Dispersion Diagram and Propagation Properties

Forbidden Frequency BandP

Propagation Band Structure• Flatter higher Q/gain (slow velocity)• Inflection point high Q, greater bandwidth (slow velocity, excellent

t hi t di l t i i t f

quen

cy

q y

SIP k= points

RB

E

SIP matching at dielectric interface – zero acceleration)• kd = 0 lower frequency resonance (small size)

kd t d d DBE/

Freq

• kd = standard DBE/resonance

Realization: 4-port circuit model

0 2

Propagation Constant (K)

Port 1

Port 3

Port 2

Port 4C

LC

CC

Microstrip TRLs

Patent Pending

Very low resonances achievable Dashed: Ordinary materials

p g ( )L

CC

Series Chip Capacitors Parallel Chip Inductors

Engineered Crystals to Control k- diagramInterdigital Capacitors

Shunt Inductors

33

Equivalent Circuit Realization of the DBE Antenna (TL pair with Controlled Coupling, Patent Disclosure)

Bloch analysis (with transfer –ABCD matrices)

L1 = L2 = L3 = 1nH,

Capacitively Loaded TLs: Coupling Capacitor tunes DBECoupled

UncoupledUncoupled

Hz)

L1 L2 L3 1nH,C1 = 10pF, C2 = C3 = 1pF

L1C1

0

L3 LMC3

0

CMLM

(V1 I1)

(V I )

(V3 I3)

(V I )

Uncoupled Phase shift Coupled Coupling capacitor and requ

ency

(GH

CM = 0.5pF

CM = 1.5pF

CM = 2 5pF

L2C2

0

L3 LMC3

0

(V2 I2) (V4 I4)

Inductive coupling

Capacitive coupling

Uncoupled – Phase shift difference due to separate LC loading emulates anisotropic ε tensor

Coupled – Coupling capacitor and inductors realize propagation in rotated anisotropic ε tensor

K – Bloch Wave Number

F CM = 2.5pF (DBE)

DBE design Guidelines: K Bloch Wave Number

ncy

(GH

z)

CM = 2.5pF (DBE)

DBE design Guidelines: Unit cells with capacitively loaded TLs (C > L) are tuned to DBE via coupling capacitor (CM). Inductively loaded (thin) TLs (L < C) are tuned to DBE through inductive coupling (LM). Pros & Cons of CM tuning: CM can be easily realized with chip capacitors.

K – Bloch Wave Number

Freq

uenHowever (C > L) TLs are very thick on low contrast substrates.

Pros & Cons of LM tuning: Thin TLs have L > C. But, realizing LM on printed circuits is challenging (needs transformers) Combination of thick and thin TLs for miniaturization & CM tuning

34

DBE Antenna Design Using Lumped Circuit Model

Choose Circuit Layout Suitable for Circular Cascading 1

Coupling Coupling capacitor

2 Microstrip and Lumped Element Realization via Full Wave Simulators

C1 C2

CM

C2 C1

p g Coupling capacitor

Loading

L1 L2 L2 L1

CL

Capacitively Loaded Lines

Substrate: Duroid, ε=2.2 tanδ = 0.00092 inch x 2inch x 0.125inch(5.08 cm x 5.08 x 0.3175cm) Same with Ground Plane

capacitor = 1pf

Loaded Lines

GH

z) CM = 0 pF

CM 0 5 F

Coupling Freq

uenc

y ( CM = 0.5pF

CM = 0.65pF (DBE)

K – Bloch Wave Number35

Optimal Antenna Size Using DBE ModePrinted on High r Substrate

0.85 inch (2.16 cm)

50 ΩCoaxial Cable

H = 0.5 inch (1.27 cm)Measured 3~3.5% Bandwidth

Coaxial Cable (Capacitively Coupled)

0.88 inch (2.24 cm)

Substrate: Alumina, ε=9.6 tanδ = 0.00032 inch x 2inch ~ (5.08 cm x 5.08 cm) (Same with Ground Plane)

4.25 dB Gain at 1.445 GHz CoorsTek AD-995 substrate: Alumina ε = 9.7 2inch x 2inch x 50mil

The antenna has dimensions of ~λ0/9.6 x λ0/9.3 x λ0/16 at 1.445 GHz

Realization of these elements on devices with self-scanning capabilitiesshould provide for satellite to

This design seems to be the smallestantenna anywhere for the given gain and bandwidth

should provide for satellite to handheld communication

36

DBE Antenna with Lumped Capacitor Loading

Electric field at DBE Resonance

Antenna Layout

20-5

0

45-45

Measured Gain

1inch = 2.54cm Capacitively coupled coax Measured

S

-10-15dB

90

135

-90

135

20 % shift

B(S

11)

ency

(GH

z) CM = 0 pF

CM = 0.5pF

CM = 0.65pF ency

(GH

z) CM = 0 pF

CM = 0.5pF

CM = 0.65pF -6

-4

-2

0

2

(dB

)

S11135-135

180

20 % shift 0.4%BW2dB Realized GainExplore 20%shift in

dB

K – Bloch Wave Number

Freq

ue

p(DBE)

K – Bloch Wave Number

Freq

ue

p(DBE)

2 2.2 2.4 2.6 2.8 3-16

-14

-12

-10

-8

Frequency (GHz)S

11

CM=0pF

CM=0.5pF

6.3dB Gain (w/o capacitors)

1.8dB Gain

presonance frequency for reconfiguration (time varying DBE antenna)

CM = 0pF (0.9% BW)

CM = 0.5pF (0.4%BW)

CM = 0.65pF (DBE) (0.25% BW)

Thicker substrate increases the6.9dB Broadside Directivity

Frequency (GHz)

Radiation efficiency is 35% due to the lossy lumped elements

37

Thicker substrate increases the bandwidth: 125mil = 0.25% BW vs. 275mil 1.5%BW

Varactor Loaded Tunable Antennas

Antenna Design Experimental verificationVaractors (cm) Skyworks smv-1405 varactors:

2.67pF (0V bias) - 0.63pF (30V bias)

Antenna Design Experimental verification

Control signal (18nH)

Control ground (18nH)RF inputAntenna Footprint (on εr=2.2 substrate): 2" × 2" × 0.25"

λ /4 0 × λ /4 0 × λ /31 @ 1 490GHz (cm = 0 0pF) Tunable from 1 12GHz to 1 31GHzλ0/4.0 × λ0/4.0 × λ0/31 @ 1.490GHz (cm = 0.0pF) λ0/4.3 × λ0/4.3 × λ0/35 @ 1.366GHz (cm = 0.5pF)λ0/4.8 × λ0/4.8 × λ0/39 @ 1.218GHz (cm = 1.0pF)λ0/5.4 × λ0/5.4 × λ0/43 @ 1.087GHz (cm = 1.5pF)

Tunable from 1.12GHz to 1.31GHz

Improving antenna performance: Improving antenna performance: 1) Varactors tunable from 0pF to 2pF (1GHz – 1.5GHz)2) Low loss varactors3) Smaller capacitances for higher frequencies

Higher order K-ω Diagram Using Multiple Transmission Lines

Coupled

UncoupledUncoupled

(V I ) (V I )

Coupled

UncoupledUncoupled

Coupled

UncoupledUncoupled

(V I ) (V I )

1I

1V

2I

4I

4V

I

11L11C 21L

21CM1C

M3C

1I

1V

2I

4I

4V

I

11L11C 21L

21CM1C

M3C

Realization of Symmetric SIP:SIP at ~2 9GHz

L 1C 1

0

L 2C 2

0

L 3 L M

L 3 L M

C 3

0

C 3

0

C MLM

(V1 I1)

(V2 I2)

(V3 I3)

(V4 I4)

Inductive coupling

Capacitive coupling

L 1C 1

0

L 2C 2

0

L 3 L M

L 3 L M

C 3

0

C 3

0

C MLM

(V1 I1)

(V2 I2)

(V3 I3)

(V4 I4)

Inductive coupling

Capacitive coupling

2V2I

3V3I

5I

5V

6I

6V

12L12C

13L13C

22L22C

23L23C

M2C

M3C

2V2I

3V3I

5I

5V

6I

6V

12L12C

13L13C

22L22C

23L23C

M2C

M3C

550mil

SIP at 2.9GHz

ency

(GH

z)

3 Uncoupled lines 3 Uncoupled lines 3 Coupling Capacitors

Coupled lines

3 Uncoupled lines 3 Uncoupled lines 3 Coupling Capacitors

Coupled lines

Effect of Tree-way Coupling (CM3 nonzero) on K-ω Diagram:• Lower order K ω branch can display a 6th order behavior

Coupling Capacitors

Freq

u

K- Bloch Wavenumber

Hz)

Higher order K-ω curve

Hz)

Higher order K-ω curve

Higher order K-ωCurve

• Lower order K-ω branch can display a 6th order behavior.• Symmetric stationary inflection points (similar to SIP in MPCs)

z)

z)

•Symmetric Stationary Inflection Points in the

p

Freq

uenc

y (G

H

Freq

uenc

y (G

H Curve

Freq

uenc

y (G

Hz

Freq

uenc

y (G

Hz Inflection Points in the

Propagation Spectrum

•Achieved without resorting

39

K – Bloch Wavenumber

K – Bloch Wavenumber

K – Bloch Wavenumber

K – Bloch WavenumberL11 = L12 = L13 = L21 = L22 = L23 = 1nH, C11 = 10pF, C12 = 5pF, C13 = 1pF, C21 = C22 = C23 = 1pF, CM1 = 2pF, CM2 = 2pF, CM3 = 2.6pF

to lossy ferromagnetic layers!

Magnetic Substrates and Realization of Magnetic Photonic Crystal Modes

N21

Z01

Z02

Z03

Z04

……

……

……

excitation

N = 64excitationDBE vs. MPC Antenna Performance

40

Tuning Non-Reciprocal K-Diagrams.

• Ferrite substrate only under the coupled sections.

H0

dielectric ferrite Provides Several Advantages:• Ferrite losses kept to a minimum (only

small ferrite substrate sections)s a e i e subs a e sec io s)• High epsilon (r ≈ 15) ferrite (r > 1)

adds to miniaturization• Radiation mechanism similar to patch

H0

ferritefringingfields

• Radiation mechanism similar to patch antennas (fringing fields on dielectric substrate)

• Ferrite inclusion allows for design• Ferrite inclusion allows for design flexibility for matching and tunability

• Standard bandwidth increase techniques can be

41

qincorporated

Specific Design with Magnetic Inserts

2”

r = 2.2, tan = 0.0009

ferrite: = 15,tan < 1.4E‐4,

H = 6Oe

Band gap

Band gap ..

2”

0.87”

0.8”

H 6Oe

H0 = 80kA/m

thickness = 100mil

•Novel MPC concept improves beneficial properties of DBE antennas:

–Close to optimal gain and bandwidth–Close to optimal gain and bandwidth–Broadside radiation pattern (suitable for phased arrays)–Smaller footprints (suitable for tightly packed arrays)

•21% footprint reduction with MPC Design (over DBE antenna)12% 14% B d id h I

42• Substrate: Rogers Duroid r = 2.2, tan = 0.0009• Ferrite inclusions: Calcium Vanadium-doped Garnet (CVG)

(4πMs = 1000G, ∆H = 6Oe).

•12%‐14% Bandwidth Improvement–For the thin substrate (d=100mil), 12% improvement–For the thick substrate (d=400mil), 14% improvement

Substrate Thickness EffectMPC, d = 100mil MPC, d = 200mil MPC, d = 300mil

MPC d = 400milMPC, d = 400mil

FBW = 0.7635%Gain = 6 2845dB

FBW = 2.2302%Gain = 6 5290dB

FBW = 3.8922%Gain = 6.4109dBGain 6.2845dB Gain 6.5290dB Gain 6.4109dB

FBW = 5.7554%Gain = 6.3185dB

DBE-2, d = 400mil

FBW = 5.0314%

43

Gain = 6.7626dB

MPC Antenna with Unbiased Ferrite Blocks

6 dB

Realized GainReflection

5.19 dB

6.23 dB

d~330 MHz shift

2.04 dB330 MHz shift

2.00 3.00 4.00Freq [GH z]2.467 3.465

2 467 3 4652 799 3 794

44

2.467 3.4652.799 3.794

Realized Gain with Biasing

5 76 dB5.76 dB

1.55 dB

‐0.03 dB

MPCresonanceat 2.35 GHz

Linearly polarized

45

Linearly polarizedBroadside radiation

Performance ComparisonsMPC

2”

2” 0.87”

DBE2”

2” 1 05”

Patch2”

2” 1 2”2

0.5”

0.8”0.87 2”

0 5”

0.92”1.05” 2”

1.3”1.2

0 5”0.5 0.5

All antennas are on 2”x2” finite ground planesg p

46

G/Q Footprint Comparison

DBE4” x 4”

PATCH1.8” x 1.8”

PATCH4” x 4”

r = 2.2

P i t d MPC

DBE

PATCH2” x 2”

PATCH

PATCH2” x 2”DBE

2” x 2”MPC

2” x 2”r = 9.6

Printed MPC 2” x 2”

unbiased

2” x 2”

DBE

PATCH1.2” x 1.2”(Elliptical)OSU-ESL double loop

Max. radius 6cm

DBE1.8” x 1.8”

DBE1 5” 1 5”

1.2” x 1.2”PATCH

1.5” x 1.5”

PATCH1.2” x 1.2”(Linear)

1.5” x 1.5”Iizuka-Hall Printed Antenna

10cm x 1cm (no GP)Iizuka-Hall Wire Antenna10cm x 1cm (no GP)

47

Future Radios will Likely be on Hybrid Substrates

RadioReceiver

Interconnects

Beamformer Design

between Silicon and Polymer

48

High speed data lanes overlaid on top of standard FR4 board targeting.

A SERDES I/O signaling over a backplane utilizing OTT interconnectsIssue: Limiting Speed due to

Interconnects

Interconnected ICs

a ba bPolymer data lanes

Passives/discrete ICs

M l i

Standard/low speed interconnectFR-4 board

Multi-processors

multi-chip bus connection. chip-to-chip link 49

Printing on Polymers is Challenging

• Printing on smooth PDMS surface (no surface modifications)

• Printing on microte t red PDMS

Cracks formed on metal surface

microtextured PDMS (only evaporation)

• Printing onPrinting on microtextured PDMS(evaporation and electroplating)

Peeling from PDMS surface• Printing on microtextured

d f difi dand surface modified composite surface 50

Transfer Molding/Lift-off and ElectroplatingLift-off negative mask in acetone

Transfer Molding

PDMS-Ceramic CompositePlastic negative mask on PDMS moldStamp Mold

Transfer Molding

PDMS-Ceramic Composite1μm

10-200 μmPDMS-Ceramic CompositeThin copper seed layer (~1 um)

PDMS-Ceramic Composite

Reactive Ion EtchingStamp Mold

PDMS-Ceramic Composite

PDMS-Ceramic Composite

Electroplating PDMS-Ceramic Compositep g

Negative pattern mask

M+M+ M+

Reference electrode Flexible, thick conduction lines on composite

Evaporated thin seed layer (cathode)

Polymer composite substrate

Copper electrode (Anode)Cu+2 sulfate-sulfuric acid solution 51

Flexible Microstrip Line Via ElectrodepositionMicro textured surface:Micro-textured surface: Flexible microstrip line:

74 mm

-0.1

0

0.1Measured insertion losses (S21)

-0.1

-0.05

0S21

-0.1

-0.05

0S21

-0.5

-0.4

-0.3

-0.2

dB-0.3

-0.25

-0.2

-0.15

dB

-0.3

-0.25

-0.2

-0.15

dB

0 9

-0.8

-0.7

-0.60 degree30 degree90 degree-30 degree-90 degree

0 5

-0.45

-0.4

-0.35

Printed TLsimulated PEC TL

0 5

-0.45

-0.4

-0.35

Printed TLsimulated PEC TL

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2-0.9

frequency (GHz)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

-0.5

frequency (GHz)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

-0.5

frequency (GHz)

Conducting loss: @ 1 GHzmdBmmmmdB /35.11000

741.0

High flexibility and high conductivity.52

Carbon Nanotube Printing on Polymer-Ceramic Composites

Carbon Nanotube/Silver coated textiles for integration into polymer-ceramicCarbon Nanotube/Silver coated textiles for integration into polymer ceramic composites.

Key features:• Mechanically very flexible & strong• Mechanically very flexible & strong• Strong adhesion with polymer-ceramic composites• Scalable production process•Comparable performance compared to traditional•Comparable performance compared to traditional antennas

•Developed E-textile patch gain was within 90% of the ideal PEC patch gain)--- Measured gain was 6dB at 2GHz (viz. 53

Direct CNT Printing on Polymer

Step 1: Grow Aligned CNTs on a Glass Substrate

Key Critical Parameters:• CNT Length• CNT Density• CNT Vertical Uniformity

Step 2: Spin Coating with Polymer Solution

Key Critical Parameters:• Spin Coating Rate• Polymer type (higher shrinkage rate

h d)when cured)

Step 3: Transfer to Larger Polymer SubstrateLarger Polymer Substrate

54

Step 1: Growing Aligned CNTsThis process involves using a quartz tubeThis process involves using a quartz tube.

1. Prepare the platform for the CNT (Si, SiO2 or Quartz)

Si, SiO2, Quartz etc.

Key Observations:

Length of CNTs are very criticalto achieving high conductivity.

b i id b

2. Deposit Catalyst (Fe)-Optionalto achieving high conductivity.We have found out that CNTswith about 100um length has the best conductivity characteristics.

Density of CNTs are very criticalto higher conductivity3. Grow Nanotubes inside Quartz Tube to higher conductivityWe found that the grow-process is very vitalto achieving denser aligned nanotubes. We developed our own process to achieve the best performance

Uniformity of CNTs in vertical C2H2CH Uniformity of CNTs in vertical

directionWe found out that CNTs tend to pull each other at the tips. Therefore, they have highercontact area. This leads to higher conductivity.In other words, we are using aligned CNT

t hi li d ti f hi h

Quartz Tube Furnace 79400 (1000 ºF)

CH4

process to achieve non-aligned tips for highercontact area.

55

Step 2: Spin Coating With Polymer

Take off the silicon wafer by Hydrofluoric (HF) acid

PDMS

Or peel it off

(Before Curing: Resistance is R0)

(After Curing: Resistance is R0/2)(After Curing: Resistance is R0/2)

Key Observations:

Curing leads to shrinkage in polymer, which in turn improves conductivity.

Higher shrinkage ratio is critical to achieving higher Higher shrinkage ratio is critical to achieving higher conductivity. For PDMS, it has about 2% shrinkage. For instance rubber has 4% which leads to 100% improvement in conductivity.

56

Step 3: Transfer to Larger Polymer Substrate

57

Carbon Nanotube Printing on Polymers for Layered Packaged Electronics?

• Over 6 dB Gain

10E-plane patternantenna layer:

microstrip patches,

antenna layer:

microstrip patches,

Within 1dB of the Perfectly Conducting Patch

5

0

5dipoles, bowties and etc.

feeding layer:

feeding networks, impedance tuning stubs

dipoles, bowties and etc.

feeding layer:

feeding networks, impedance tuning stubs

-15

-10

-5dB

circuits layer:

filters, mixers, LNAs and etc.

circuits layer:

filters, mixers, LNAs and etc.

-200 -150 -100 -50 0 50 100 150 200-25

-20

(degree)

58

Packaging Trends – A Bigger Challenge?

*Photo from StratEdge data sheet

• Low Cost IC’s Still Need Viable Packagingg g

• Likely bigger challenge than the chipset for MMW/THz

• Commercial Packaging extends toCommercial Packaging extends to MMW frequencies

– DC to 50+ GHz– Progress continues up in frequency

• Plastic Packages in use to ~30 GHz

59

Multi-physics, multi-domain co-simulation of system-in-package (SiP)

Working withProf Jin-Fa LeeProf. Jin-Fa Lee

60

Many Thanks to my Students & Collaborators at ElectroScience

61