iWAT2014: Metamaterials-based Antennas · 2014. 3. 1. · iWAT2014: Metamaterials-based Antennas 3 Professor, Department of Electrical and Computer Engineering National University

iWAT2014: Metamaterials-based Antennas

1

Metamaterials-based Antennas

Zhi Ning Chen

Professor

National University of Singapore

Advisor

Institute for Infocomm Research, Singapore

Metamaterial Antennas:

From Physics To Designs

Acknowledgements:

Dr Xianming Qing

Dr Liu Wei

Dr Lau Pui Yi

Dr Sun Mei

Dr Amir Khurrum Rashid

Mr Goh Chean Khan


3

Professor, Department of Electrical and Computer Engineering National University of Singapore Fellow, IEEE Distinguished Lecturer, IEEE AP-S Associate Editor, IEEE Trans AP Member, IEEE AP-S Fellow Committee Advisor & Principal Scientist, Institute for Infocomm Research Agency of Science, Technology and Research, Singapore Founding General Chairs, iWAT, IS 3T-in-3A, APCAP, IMWF

Current research interest: applied electromagnetic, metamaterials, and antennas for microwave, mmW, submmW, and THz systems.

140 keynotes & invited talks, 400 papers, 4 books, 31 patents, 28 licenses

CHEN Zhi Ning, PhDs 陈志宁


4

In this talk,

Background Brief History Review

Potentials & Challenges in Antenna Engineering

State-of-the-art Designs

Rethinking Strategy

Metamaterial-based Antennas

Case study

Comments


5

Background Information:

Brief Historic Review

Artificial Molecules in

NIM by Pendry in 20002

tt

ww

hh dd

Artificial dielectric

by Kock in19481

Experimental NIM

by Smith in 2001 Transmission-line based NIM

by Eleftheriades in 2002

1. The term artificial dielectric was originated by Winston E. Kock in 1948 when he was employed by Bell Laboratories.

2.J. B. Pendry, “Metamaterials and the Control of Electromagnetic Fields”

http://en.wikipedia.org/wiki/Winston_E._Kock

http://en.wikipedia.org/wiki/Winston_E._Kock


6

Background Information: Brief Historic Review

Pioneering Work: Negative Index

“Negative Refraction Makes a Perfect Lens” by JB Pendry, Phys. Rev. Lett., 85, 3966 (2000).

In 2000, Sir Pendry published a short but explosive paper in PRL

explaining the theoretical possibility of a perfect lens.


7


Working in Quadrant III

r

r

Most materials

in nature

Metals in optical bands

Ferro-magnetic

materials

0

: permittivity

: permeability

Unknown materials

(Mate-materials)

Notes: This idea proposed 40 years earlier by the Russian scientist Victor Veselago,

who suggested that a material with a negative refractive index–never seen in

nature–could produce an almost magical lens capable of creating images at a

resolution finer than the wavelength of light being used. After that, the work related

to metamaterials have been majorly focused double-negative materials.


8


Updates of Publications since 2000

21 66 213

403

689

1560

2160

3000

4250

4530

5260

6600

7700

8360

10 48 108 221

403

898

1200

1650

2070

2380

2760

3400

4060

4420

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

matematerials matematerial antenna

1 March 2014 by Google Scholar

Metamaterials: 44,812

Metamaterial Antennas: 23,628

Meta-Ant/MetaM: 53%


9


Potentials in EM Engineering

Cloaking devices

Antennas

Absorber Superlens

Frequency ranging from microwave, THz to optical:

1. Shielding,

2. Low-reflection materials (absorber),

3. Novel substrates/superstrate,

4. Antennas/sensors,

5. Electronic switches,

6. “Perfect lenses,”

7. Resonators, and

8. etc.


10


Potentials in Antenna Engineering

To improve antenna design by:

Lowering antenna profile (conformal/flexible)

Reducing antenna volume/weight/cost

Widening bandwidth (impedance/phase/gain)

Enhancing gain (efficiency/directivity)

Suppressing mutual coupling

Widening operating frequency tuning range

Achieving controllable beam (shaping/steering/lobe)


11


Potentials in Antenna Engineering: Features

Double Negative (DNG)

Material (<0 & <0)

1960’s & 2000’s

Artificial Complex Impedance Surface

Zs =jL/(1- 2LC)

1940’s, 1970’s, 1990’s & 2000’s

Left-hand/negative index of

refraction (NIR)

Much less than a wavelength

with backward propagation

Narrow bandwidth

Electromagnetic bandgap (EBG) surface with

pass/stop bands

Tunable impedance surface (TIS) with

controllable reflection phase of 0-180o

On order of one half wavelength or more

Narrow/moderate operating bandwidth

DNI lens for high directivity

Zeroth order resonant antenna

with reduced size

Series-fed array with improved

beam-squint

Shell of antenna element

Patch antenna: directivity/efficiency

Dipole with reflector: directivity/ efficiency/

low profile

Waveguide/reflector/horn antenna:

directivity

FSS

me

ta

fea

ture

s

ap

plic

ati

on

s

Left/right handed scanning leaky wave antennas


12


Challenges in Antenna Engineering: General

Electrical:

Bandwidths: performance of interest

Gain: directivity & efficiency

Others: polarization, isolation, beamwidth, etc.

Mechanical:

Size: volume/conformal/low-profile

Integration: with other circuits

Others: robustness, lightweight, etc.

Commercialization (mass production):

Cost (materials/process/fabrication & installation)


13


Challenges in Antenna Engineering: Analysis

Antennas Metamaterials

Bandwidths: impedance/gain Difficult but Possible

Gain: directivity & efficiency Yes & Difficult

Size: volume/conformal/low-profile Promising*

Integration: with other circuits Promising

Cost: mass production

(fabrication & materials)

Possible

Overall Promising

*overall size against gain and bandwidth


14


State-of-the-arts in Antenna Engineering: Example

Used as superstrate (cover/lens/radome)

dipole/monopole/inverted-L/patch antenna:

high directivity & beam control

Used as substrate (with ground plane)

dipole/monopole/inverted-L antenna:

low profile & high directivity

patch antenna:

high directivity & efficiency & low coupling

•artificial surfaces with controllable reflection phase

•artificial magnetic conductors (AMC)

•electromagnetic bandgap (EBG) surfaces


15


State-of-the-arts in Antenna Engineering

(incomplete)

Suppression of inter-element mutual coupling: MIMO

Low profile of antennas: Cellular base-stations

Miniaturization of antennas (e.g. zero/negative-order resonator):

Portable devices

High gain for antennas with planar lens: horns/patch

High gain of antennas with zero-index loading: Vivadi@60GHz

Composite Right/Left-handed TL/LW antennas: Beam-steering

arrays

Zero-phase-shift-line loop antennas: RFID

Controllable active metasurface arrays: Satellite

Notes: Many metamaterials-based technologies have been explored for antenna

design. The incomplete list shows the technologies and their applications which have

been claimed by the researchers in their publications and some startups.


16


State-of-the-arts in Antenna Engineering

Hype or Reality?

Suppression of inter-element mutual coupling: MIMO?

Low profile of antennas: Cellular base-stations ? ?

Miniaturization of antennas (e.g. zero/negative-order resonator):

Portable devices ? ?

High gain for antennas with planar lens: horns/patch

High gain of antennas with zero-index loading: Vivadi@60GHz

Composite Right/Left-handed TL/LW antennas: Beam-steering

arrays ?

Zero-phase-shift-line loop antennas: RFID

Controllable active metasurface arrays: Satellite ? ?

Notes: However, we have not had any chance to see metamaterials-based products in

market so far although we have investigated on all antenna companies we can find

out. We studied the metamaterials related patents and the description of the products

which claimed that the designs are based on metamaterials.


Rethinking

Metamaterial

Antennas: ?

17

Metamaterial

Publications: 23,628

Notes: The observation raises a critical question how many ideas published in

scientific and even engineering journals have been successfully translated into

engineering designs such as antennas which really enhance the performance of

designs in conventional ways or/and invent new methods for engineering design. In

the other words, we need the translation from the physical concepts to engineering

designs. How to bridge this gap?

http://www.iconpng.com/icon/11939


18

Rethinking:

Antenna Engineering: Case Study

Low profile of antennas: Cellular Base-stations

Key Parameters Requirements

Operating Frequency, MHz 1710-2690 (~45%) (VSWR<1.6)

Size, wavelength@1710MHz 0.8x0.8x0.10

Gain, dBi with efficiency >90% >7.0 at 1710 MHz; >11 at 2690 MHz

HP-Beamwidth >555 degree

Polarization dual-linear , 45 degree

Isolation of polarization >25 dB

Front-to-Back ratio >22 dB

Any solutions???

No way for any conventional methods.

Metamaterial-based solutions?


Rethinking

Metamaterial

Publications

Why and How?

Metamaterial

Antennas

? Inherent weakness of metamaterials (especially DNG) in terms of

bandwidth, efficiency, size, etc.

(not due to DNG itself but existing approaches to realize DNG, using strong

resonant structures)

? Too physical, enigmatic for engineers to understand/apply in design.

(good to describe physical phenomena using engineering languages such as

RCL, S-parameters rather than index, even permittivity or permeability etc)

? A real magic

(ought to tell engineers real success stories of metamaterials in antenna design

which have greatly enhanced performance, not potentials only.) 19

http://www.iconpng.com/icon/11939


Rethinking

Definition of Metamaterials in Electromagnetics

20

“meta”: beyond

Metamaterials are artificial materials engineered to provide

properties not readily available in nature.

These materials usually gain their properties from structures rather

than composition, using the inclusion of small inhomogeneities to

enact effective macroscopic behavior.

Notes: We may have to review the definition of Metamaterials and not limit us to

DNG only.

From the definition mentioned above, the three key words have been highlighted in

red. In the other words, all EM structures can be considered as metamaterials if they

have all three key features.


21

r

r

Transparent Dielectric

(Most materials in nature)

Electrical Plasma

(Metals in optical bands)

Negative Index Materials

(Unknown materials:

double-negative or

backward-wave, or

left-handed materials)

0

1

1

??

??

near-zero refractive index ( )

Magnetic Plasma

(Ferro-magnetic materials)

rrn

Translation from Physical Concepts to Engineering

Z. N. Chen, “Metamaterials-based Antennas: Translation from Physical Concepts to Engineering Technology,”

Comments of FERMAT, February 2014 at www.e-fermat.org

Rethinking

Why ONLY Quadrant III?

Notes: Based on this thinking, we have a chance to explore the opportunities in other

quadrants besides Quadrant III. For example, we can even look at Quadrant I for the

structures which feature the magic properties that we have yet found in nature.


Rethinking

Work on All Quadrants!

22

r

r

Transparent Dielectric

(Most materials in nature)

Electrical Plasma

(Metals in optical bands)

Negative Index Materials

(Unknown materials:

double-negative or

backward-wave, or

left-handed materials)

0

1

1

??

??

near-zero refractive index ( )

Magnetic Plasma

(Ferro-magnetic materials)

rrn

zones of interest in Q I

a. 0≤r<1;

b. 0≤ r <1;

c. either r or r >>1;

d. both r and r >>1.


Comments of FERMAT, February 2014 at www.e-fermat.org

Notes: Let us work on structures in all Quadrants not only Quadrant III, As well as

other structures featuring unique EM properties such as anisotropicity, chirality and

so on.


Rethinking

Promising Translation from Physical Concepts to

Engineering Technologies

23

Notes: The situation of metamaterials related R&D&C likes what is shown in the

photo: the sun is rising to bring hopes to us although the beach and sea is still in dark

due to the blockage of the mountains.

The photo was taken by Zhi Ning Chen in La Londe-les-Maures, Toulon, France in June 2013


Rethinking

Metamaterial-concept-based Antennas by Us

24

meta

Double Negative Material

(<0 & <0)

Artificial Complex Impedance Surface

Zs =jL/(1- 2LC)

featu

re

Left-hand/Negative index of refraction-

NIR

Zero-phase-shift lines

EBG surface with pass/stop bands

Tunable impedance surface (TIS)

Ap

plica

tio

ns

Zero-phase-shift-line antennas

•Electrically large near-field RFID antennas

•Omni-directional CP antennas

High permittivity dielectric

•Broadband low-profile dipole arrays

High impedance surface

•Thin Fabry-Perot cavity antennas

•Broadband planar antenna

Composite right/left-handed leaky wave antennas

•Consistent-gain array

•Broadband boresight radiation array

Zero-index antennas

•Gain-enhanced antipodal slot antennas

•High-gain patch antenna


Rethinking :

Metamaterial-concept-based Antennas for Industry

25

Electrically Large: Zero-phase-shift lines UHF near-field RFID reader antennas

Omni-directional CP antennas

High-gain: zero-index

Antipodal tapered slot antennas

Patch antennas

Low-profile: High-permittivity/High Capacitive Surface/AMC High-permittivity structure loaded broadband dipole array

High-capacity structure loaded broadband antenna

UHF near-field RFID AMC-loaded reader antennas


Zero-phase-shift-line-based Antennas: Electrically Large

UHF Near-field RFID Reader Antennas

26

Zero-phase-shift unit

@915 MHz Patented

Original solid loop

Qing, XM, Goh CK, and ZN Chen, A Broadband UHF Near-Field RFID Antenna, IEEE Trans. AP, vol.58, no.12, Dec 2010, pp.3829-3838



Near-field UHF RFID Reader Antennas

27 Maximum area up to 280×280mm (500x500 mm)

Zero-phase-shift unit

x

y

RF in

250

250

Via to top layer

Bottom layer

Top layer

Parallel line

matching stubs

1.3

1.3

20.5

Unit: mm

2

2

2

22

2

2

22

2

10

73.3

6

6

6

30.7 30.730.730.7 30.6 31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.3

31.332.3

26.326.326.326.3

41.85 34.35

33.133.133.133.1 33.1

33.133.133.133.1 33.1

33.133.1

33.3 24.9

33.433.1

74.1

68.3

L1=230.6

L2=103.6

o

L3=5

Distributed

capacitor

Straight line

Current

Current

-125 -100 -75 -50 -25 0 25 50 75 100 125-50

-40

-30

-20

-10

0

|HZ|, A

/m (

dB

)

X, mm

L2=60.5 mm

L2=103.6 mm

L2=146.7 mm

-125 -100 -75 -50 -25 0 25 50 75 100 125-50

-40

-30

-20

-10

0

|HZ|, A

/m (

dB

)

Y, mm

L2=60.5 mm

L2=103.6 mm

L2=146.7 mm

Patented



Omni-directional Circularly Polarized Antennas

28

44 mm

35.25 mm

Feeding network

Feed point

44 mm

Segmented loop

Dipole

27.1 mm

Feed point

Segmented loop

Feed pointSubstrate

II

II

x

y

0

17.7

3 m

m Feeding 1

Feeding 2

Segmented

Loop Dipole

r1∠0°1∠0°

E1

(0°)

P

E2

(90°)

Patented

-50

-40

-30

-20

-10

0

0

30

60

90

120

150

180

210

240

270

300

330

-50

-40

-30

-20

-10

0

2.45 GHz

-50

-40

-30

-20

-10

0

0

30

60

90

120

150

180

210

240

270

300

330

-50

-40

-30

-20

-10

0

2.45 GHz

xy-plane yz-plane

2.40 2.42 2.44 2.46 2.48 2.50-10

-5

0

5

10

Gain

(dB

ic)

Frequency(GHz)

WLAN (2.4-2.5 GHz)


30

Zero-Index Antennas: High Gain

Antipodal Tapered Slot Antenna

@60-GHz

Substrate

y

x

z

Ws

L

S

g

ay

ax

L1

z = 0

z = h

Metal

Proposed ZIM unit cell on a dielectric substrate.

40 50 60 70 80 90 100-45

-40

-35

-30

-25

-20

-15

-10

-5

0

S p

ara

mete

r (d

B)

Frequency (GHz)

|S11

|

|S21

|

40 50 60 70 80 90 100-10

-5

0

5

10

eff

Frequency (GHz)

Re(eff

)

Im(eff

)

Characteristics of the ZIM unit

cell: (a) S-parameter data and (b)

retrieved effective permittivity.

x

y z

Wr

Wg

a1

a2

S b1 b2

L1

af1 af2

Wp

Ws

bf

L

top metal bottom metal

10 mm

16

.7 m

m

M. Sun, Z. N. Chen and X. Qing, “Gain Enhancement of 60-GHz Antipodal Tapered Slot Antenna Using Zero-Index Metamaterial”,

IEEE Trans. AP, vol.61, no.4, Apr 2013, pp. 1741 - 1746


31

Field distribution of the antenna at 60 GHz (xy plane, z = h/2):

(a) withoutZIM cells and (b) with ZIM cells.

50 52 54 56 58 60 62 64 66 68 70-45

-40

-35

-30

-25

-20

-15

-10

-5

0

|S1

1| (d

B)

Frequency (GHz)

with ZIM

original

50 52 54 56 58 60 62 64 66 68 700

3

6

9

12

15

Pea

k G

ain

(d

Bi)

Frequency (GHz)

with ZIM (silver)

original

with ZIM (PEC)

50 52 54 56 58 60 62 64 66 68 700

3

6

9

12

15

Gai

n i

n x

-dir

ecti

on

(d

Bi)

Frequency (GHz)

with ZIM

original

Rethinking: Case study

Gain-enhanced Antipodal Tapered Slot Antenna


32


High & Anisotropic Permittivity Structure Loaded

Low profile Broadband MIMO Antenna

No. Parameters Specifications

1. Operating Frequency 1.71-2.65GHz (43%) for VSWR<1.5

2. Antenna size: mm 200x300x38 ([email protected])

3. Gain >12dBi

4. Cross-Polarization >25dB in all direction

5. Sidelobe Level >15dB

6. Backlobe Level -25dB

7 H-Plane Beamwidth 20°~25° (10dB)


33




>30

>6

high permittivity >30 and high reflective index >6

Permittivity is also anisotropic along x, y, z directions!


34




Comparisons of impedance matching and gain for single dipole antenna

(Air, high permittivity material, HAPS)

2.0 2.5 3.0 3.5 4.0 4.5 5.0-40

-30

-20

-10

0

|S1

1|, d

B

Frequency, GHz

Dipole printed on PCB with r=4.4

Dipole loaded with dielectric r=36

Dipole loaded with HPS

10%

40%70%

2.0 2.5 3.0 3.5 4.0 4.5 5.0-6

-3

0

3

6

9

12

Dipole printed on PCB with r=4.4

Dipole loaded with dielectric r=36

Dipole loaded with HPS An

ten

na G

ain

, d

Bi

Frequency, GHz

9.3 dBi


35




No. Parameters Specifications

1. Operating Frequency 1.71-2.65GHz (43%) for VSWR<1.5

2. Antenna size: mm 200x300x38 ([email protected])

3. Gain >12dBi

4. Cross-Polarization >25dB in all direction

5. Sidelobe Level >15dB

6. Backlobe Level -25dB

7 H-Plane Beamwidth 20°~25° (10dB)

Patented


Rethinking: Case Study

High-capacity-loaded Low-profile Broadband WLAN Antenna

Boresight realized gain and |S11| of mushroom antenna and conventional patch array

Antenna Impedance bandwidth

(|S11| < −10 dB)

Realized gain

(dBi)

SLL

(dB)

F/B

(dB)

mushroom

antenna 4.61-6.29 GHz, 30% 8.1 ~ 11.0 −6 ~ −11.2 7.5 ~ 14.6

Patch array 5.43-5.87 GHz, 8% 10.3 ~ 11.2 −12 ~ −12.3 12 ~ 12.3

Slot-fed patch array

Slot-fed wideband

mushroom antenna

3 4 5 6 7 8-10

-5

0

5

10

15

|S11

|, proposed antenna

|S11

|, patch array

gain, proposed antenna

gain, patch array

Bo

resi

gh

t re

ali

zed

gain

(d

Bi)

Frequency (GHz)

-50

-40

-30

-20

-10

0

|S1

1| (d

B)

36 W Liu, Z. N. Chen and X. Qing, “Metamaterial-Based Low-Profile Broadband Mushroom Antenna”, IEEE Trans. AP, vol.62, no.3,

Mar 2014, pp. 1165 - 1172


Rethinking: Case Study

AMC-loaded Low-profile Near-Field RFID Antennas

37

Pending for patent

Impinj Antenna

Cavity-backed dual-loop antenna

67 mm

55 mm

30 mm

AMC-loaded cavity backed antenna


38

Fast development of wireless applications strong increasing

demand for high-performance antennas.

Metamaterial, as a concept, has opened a new window

for innovative antenna design!

Hot topics:

New methods to invent DNG structures for engineering

Translate the physical concepts to technology for applications

Miniaturization / compact

Broadband / multiband

Diversity / co-existence

Tunable / switchable

Super gain

Low cost / cost effective

My Comments


Debate Session@iWAT2014:

My Opinion

39



FERMAT, February 2014, www.fermat.org

2.metamaterial: possibility but aspirant

•Medicine to solve all “headache” (existing

technical challenges)??

•Unique features for specific challenges

1.metamaterial: a concept not technology but

possibility:

•Everything possible (Q I,II& IV to Quadrant III)

•Thinking out-of-the-box

•Why limited to Quadrant III

http://www.fermat.org/






Debate Session@iWAT2014:

My Opinion

40



FERMAT, February 2014, www.fermat.org

3.metamaterial: opportunity-suggestion

•Scientists: exploring physical issues for crazy

ideas

•Engineers: understand and translate the ideas

for tech

4. My views

•Scientists: opportunity when things

unclear/unknown

•Engineers: opportunity when things clear/well-

known







http://2.bp.blogspot.com/_sWjJs4tp6O8/TGL_Y6TuLwI/AAAAAAAADHA/akodxtd-8wI/s1600/malaysian_girls.jpg

Documents

iWAT2014: Metamaterials-based Antennas · 2014. 3. 1. · iWAT2014: Metamaterials-based Antennas 3 Professor, Department of Electrical and Computer Engineering National University