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Microwave Electronics Lab
New Metamaterials (MMs) based on
an Extended Transmission Line (TL) Approach
for Novel Microwave
Components, Antennas and Reflectors
Applications
Microwave Electronics Lab
Outline
I. Anisotropic RH / LH 2D Structures
II. RH/LH Surface Plasmons
III. Novel Class of Leaky-Wave Reflectors______________________________________
IV. 2D Distributed Meta-StructuresExhibiting Focusing, Frequency-Scanning Radiation, SP next time
2
Microwave Electronics Lab
Anisotropic RH / LH Structures
Γ X
MY
xk
yk
0ω
1Rω 2Rω
1Lω2Lω
2 1 0 1 2L L R Rω ω ω ω ω< < < <
(b)
RH
Rβ
LH Lβ
−2
0
2
−3−2
−10
12
3
−8
−6
−4
−2
0
2
4
6
8
xkyk
( ),x yk kω
Brillouinzone
Γ
YX
M
(a)
0 0k cω =
radiation(leakage)
cone
0ω
Microwave Electronics Lab
2D Transmission Line Unit-Cell ModelsIsotropic RH
yz
x
RC
2RL
2RL2RL
2RL
2RL2 LC
RC
LL
Anisotropicx-RH & y-LH
sZ
2RL2 LC
yz
x x-RH
y-LH
LL
Isotropic LH2 LC
2 LC
2 LC2 LC
yz
x
( )
( )
( )
( )
( )
2
2
2
2
2
2
1SHUNT IMPEDANCE: , with 1
1 1 low-freq:
(capacitive)1
1 high-freq:
1 (ind
os
os
oss os L R
R
osos s
R eq
Req R
os
osos s eq
R
oseq L
R
Z j L CC
Z j jC C
CC C
Z j j LC
L LC
ω ω
ω ω
ω ωω
ω
ω ωω ω
ω ω
ω ω
ω ωω ω ω
ω
ω ωω
−= =
−< ⇒ = − = −
= =−
−> ⇒ = =
−= = uctive)
2RL
eqC
2RL
x-RH
2 LC
eqL2 LC
y-LH
3
Microwave Electronics Lab
Dispersion Relation Computation (1)arbitrary unit-cell
x
yz
ABCD Matrix
Y
ZZ
1A1B1C1D
2A2B
2C2D
5A 5B5C 5D
3A3B3C3D
4A4B
4C4D
xI
+−
+−
+−
+−
xV
yI
yV
xjk axI e
−
xjk axV e
−
yjk ayI e
−
yjk ayV e
−
Kirchhoff&
Bloch(periodic)
0V
ZZ
5inI
Kirchhoff Equations
( )
( )
1 11 0
1 1 1 1
2 22 0
2 2 2 2
3 0 3 3
4 0 4 4
x
y
out x x
y yout
jk dinx x
jk diny y
D V B IV VA D B C
D V B IV V
A D B C
V V A V B I e
V V A V B I e
−
−
−= =
−
−= =
−
= = −
= = −
( ) ( )
( ) ( )
center52 21 1node
1 1 1 1 1 2 2 2 2
3 3 4 4
5 5
5 5 5 5
0
yx
y yx xk
kjk djk d
x x y yin
C V A IC V A II
A D B C A D B CC V D I e C V D I eA I
A D B C
=−−
− +− += +
− −− + − +
− =−
∑
0 5
6 equations / 6 unknowns:, , , , , inx x y yV I V I V I
Microwave Electronics Lab
Dispersion Relation Computation (2)
( )11 12 13 14
21 22 23 24
31 32 33 34
41 42 43 44
00
matrix system: M = det 000
x
x
y
y
m m m m Vm m m m I
v Mm m m m Vm m m m I
⋅ = ⇒ =
1 1 2 23 3 4 4
1 1 2 2
where x x y yC A C AC e D e C e D eα β γ δ= − − = − − = − − = − +∆ ∆ ∆ ∆
5 1 5 111 12 13 14
5 1 5 1
5 2 5 221 22 23 24
5 2 5 2
3 5 5 331 32 33 34
5 5
4 5 5 441 42 43 44
5 5
x x
y y
A D A Bm m m mB B
A D A Bm m m mB B
MA A e A B em m m mB B
A A e A B em m m m
B B
α β γ δ
α β γ δ
α β γ δ
α β γ δ
= − = + = = ∆ ∆
= = = − = + ∆ ∆ =
= − = − = =
= = = − = −
( )with 1, 2 and , yx jk djk dk k k k k x yA D B C k e e e e−−∆ = − = = =
4
Microwave Electronics Lab
Particular Case of Anisotropic x-RH / y-LH
( )
01 1
01 1
02 2
02 2
3 3 0
3 3 0
cos( 2) sin( 2)1 2sin( 2) cos( 2)0 1
cos( 2) sin( 2)1 1 2sin( 2) cos( 2)0 1
cos( 2) sin( 2)1 2si0 1
R
L
R
kd jZ kdA B j LjY kd kdC D
kd jZ kdA B j CjY kd kdC D
A B kd jZ kdj LC D jY
ω
ω
ω
=
=
=
( )
( ) ( )
04 4
04 4
25 5
5 5
n( 2) cos( 2)
cos( 2) sin( 2) 1 1 2sin( 2) cos( 2) 0 1
1 1
0 1
L
R L R
kd kd
kd jZ kdA B j CjY kd kdC D
C L j CA BC D
ω
ω ω
=
− =
yz
x x-RH
y-LH
Anisotropicx-RH & y-LH
unit-cell
Appropriate Transmission Matrixes
2RL 2 LC
RC
LL
2RL2 LC
2d2d
2d2d
Microwave Electronics Lab
Anisotropic Dispersion Diagram
0
11
31.6
1
R L
R L
R L
R L
C C pFL L nH
L LZC C
d mm
= == =
= = = Ω
=
Components Values
Freq
uenc
y (G
Hz)
- : , 0x yX k kΓ =- : , 0y xY k kΓ =
: , x yX M k d kπ− =: , y xY M k d kπ− = : x yM k k− Γ =
ΓΓ ,X Y ,X Y M M
GAP GAPGAP
- XΓ
- XΓ
- XΓ
-YΓ
-YΓ
-YΓ
RH
LH
Brillouin Zone
Γ
M
Xxk
yk
Y
0
dπ
dπ
dπ−
dπ−
5
Microwave Electronics Lab
Effect of Transmission Lines Interconnects
ΓΓ ,X Y ,X Y M M
d = 1 mm
Freq
uenc
y (G
Hz)
d = 5 mm
ΓΓ ,X Y ,X Y M M
Freq
uenc
y (G
Hz)
ΓΓ ,X Y ,X Y M M
d = 2.5 mm
Freq
uenc
y (G
Hz)
d = 7.5 mm
ΓΓ ,X Y ,X Y M M
Freq
uenc
y (G
Hz)
Microwave Electronics Lab
Circuit Simulation Results
Freq
uenc
y (G
Hz)
Dispersion Diagram
ΓXY M MXY
RHf
LHf
2RL2 LC
RC
LLsZ
2RL2 LC
yz
x x-RH
y-LH
ΓLHf f=
voltage magnitude
voltage magnitude power
powerRHf f=
6
Microwave Electronics Lab
Sensitivity to Terminations (f=10GHz: LH => y)
0Uniform Terminations: Z mismatch cavity effectsL C= ⇒ →
voltage magnitude x-curentvoltage phase y-curent
voltage magnitude x-curentvoltage phase y-curent
Optimized Terminations (array of coupled lines)
Microwave Electronics Lab
Conventional Surface Plasmons (SPs)
SP: electromagnetic surface wave (TM) which exists at theinterface between 2 media whose ε have opposite signs
Surface Plasma Oscillation: coherent fluctuations of the electroncharges on the metal boundaryfollowed by the SP mode
Reference: Heinz Raether, “Surface Plasmons on Smoothand Rough Surfaces”, Springer-Verlag, Berlin, 1988
+++ --- +++ --- +++ ---
dielectric: ε2 >0
metal: ε1 <0
x
zEur
Huur
kr
x pk β=
zk
TM
metaltanˆsJ z H≅ ×
r r
7
Microwave Electronics Lab
Smooth Surface: Non-Radiative SPsField components:
( )0 , 1, 2ix zj k x t
i iF F e e iαω −− −= =
1 2i xkα ε ε′→∞⇒ →∞⇒ →−
1 2
1 2x x x xk k jk jk
cω ε ε
ε ε′
′ ′′ ′′= + = +′ +
22
zi x i ik j k jcωε α ′= − = −
Confined x-propagating mode SP:
( )2
21 2metal: 1 , 4p
p ne mω
ε ω ω πω
′ = − =
1 22
and 1
pSP
ωω ε ε ω ω
ε′↑⇒ →− → =
+
1 1 2metal: 0, with realxkε ε ε′ ′ ′< > ⇒
metal: 1 1 1jε ε ε′ ′′= +
dielectric: 2ε
x
z
1xk
2xk1 2x x xk k k= =
1α
2α
2xckω ε=
SPω
xk
ω
SP
lightline
0 2x pk π λ=
0ω
Dipersion diagram
( ) 3 2 21 2 1 2 1 12xk c
ω ε ε ε ε ε ε′′ ′ ′ ′′ ′ = + ⋅ 1 1 2
2
1automatic if 1 (air)
xk cε ε ε ωε
′ ′ ′> − ⇒ >=
Microwave Electronics Lab
RH/LH Interface Plasmon (IP)
0cR cL R L L RZ Z Z L C L C LC= = ⇒ = =Matched interface :( )int 0Γ =
220 1 2
1
1 SP condition !!!L RL R
L CL CLC
ε ω ε εε
′ ′′ ′⇒ = − = − = − ≡ → −
Same EM densities in RH & LH :matched
0 04
1 1
R R L LL C L C LCω ω ω= = ⇒ =( )L Rn n= −
Under matched condition, the equi-density frequency ω0corresponds an surface plasmon (IP) frequency:
IP0 1 LCω ω= =
RH LH
RC
2RL
2RL2RL
2RLR
cRR
LZC
=
LL
2 LC2 LC
2 LC2 LC
LcL
L
LZC
=
2
2
R R
R R
CL
ε εµ µ
′= =′= =
( )( )
1 2
1 2
1 i.e. 1
1 i.e. 1
eL p L
Lm
L p LL
LL
CC
ε ε ωω
µ µ ωω
′= = − =′
′= = − =′
: plasma: dielectricintΓ intΓ
R R Rn L C′ ′=
2LL L
cnL Cω
= −′ ′x
z
[ ][ ] [ ] [ ][ ] [ ]NB: and R L R L L R L RL C L C L C L CH m F m H F H m F m H F
′ ′ ′ ′= =⋅ ⋅ ⋅ ⋅
2
1
NB: also 1R LL CLC
µµ
′ ′= − = −
8
Microwave Electronics Lab
Difference Conventional SP and RH/LH-SP
RH/LHRH LHx
z
( )
( )
( )( )
2
1 1 1 12
2 2
TM 1 2
1 2
2TM TM TM2
TM1 2
2
0 and 0 : 1 and 1
cste 0 and cste 0
small : 0 , or
large (SP) : 1
p
x
x x x
px SP
kc
k k ckc
k
ωε µ ε µ
ωε µ
ω ε εε ε
ω εω ω ε
ωε ε ω ω
ε
∗
∗
> = − =
= > = >
=+
→ = =
→ − ⇒ = =+
<
conventionaldielectric metalx
z
2xckω ε=
SPω
xk
ω
SP
lightline
loosely bound
tightly bound
pω
non-radiativeSP
radiativeSP
SP gap
Rexk
RexkImxk
( ) ( )
( )
( )
( )
( )
1 1 1 12 2
2 2
1 2 1 2 2 1TM2 22 1
TM TM
TM1 2
1 10 and 0 : and
and
small : 0
1 1 large (SP) :
L L
R R
x
R Rx x L R
L L
x SPR L
L CC L
kc
C Lk k j L CC L
kL C LC
ε µ ε µω ω
ε µ
ε ε µ ε µ εωε ε
ω
ε ε ω ω
∗ ∗∗
∗
= − = −′ ′
′ ′= =
−=
−
′ ′′ ′→ = + ′ ′
→ ± ⇒ = = =′
<
′
<
SPω
xk
ω
SP
lightline
2xckω ε=
Rexk
Imxk
tightly bound
loosely bound
non-radiativeSP
radiativeSP
Microwave Electronics Lab
Dispersion Diagram of a RH/LH SP
case 1: perfect matching @ ω0
( )
1 2 1 2
B.H.1 2 1 2 2 1
1 12 22 1
and
1x
L L
kc c L C
ε ε µ µ
ε ε µ ε µ εω ω ε µε ε ω
= − = −
⇓
−= → = −
− ′ ′
case 2: small mismatch @ ω0 ( Γ = -30 dB)
case 2: larger mismatch @ ω0 ( Γ = -15 dB) case 2: very large mismatch @ ω0 ( Γ = -3 dB)
SPω
xk
ω
SPω
xk
ω
SPω
xk
ω
( )1 2 1 2 2 12 22 1
xk cε ε µ ε µ εω
ε ε−
=−
Dispersion of LH only !SP radiative and non-radiative
SP essentially non-radiative SP non-radiative
9
Microwave Electronics Lab
Interface Plasmon at a RH/LH 2D-TL Interface
mag
nitu
deph
ase
Voltage distribution @ f = f0 = f IP = 2.826 GHz
RH LH
zRk zLk
xk
xkz
x
RH LH
zRk zLk
xk
xk LR φφ ∆=∆z
x
( )0 : L R L Rn nω ω β β= = − = −
0ω
β
ω
RβLβ
LH RH
R R RL Cβ ω ′ ′=
1L
L LL Cβ
ω= −
′ ′
plasmon frequencyRH LH
RC
2RL
2RL2RL
2RL
LL
2 LC2 LC
2 LC2 LC
zx
zRk zLk
xk
xk
1SP LC
ω =
xk
ωlightline
2xckω ε=
Rexk
Imxk
non-radiativeSP
radiativeSP
Dispersion Diagram
L Rβ β≅ −
Microwave Electronics Lab
Power Distributions of Interface Plasmon
Source(much smallerthan plasmon)
Power along x-direction
Power along z-direction
x
z
x
z
10
Microwave Electronics Lab
Plasmons in Waveguides ConfigurationsFull-Wave FEM (Ansoft-HFSS) simulations of the
WR-650 rectangular waveguide (6.5 3.25’, fc= 0.908GHz)loaded by an ideal LH material,
below cutoff operation: f = 0.85GHz (f< fc)
RH
LH
RH
E-field
z
RH
LH
RH
H-field
z
RH: 1LH: 1
r r
r r
ε µε µ
= = += = −
z
surface plasmons in super-lens
0 a+a− 2a+2a−
Microwave Electronics Lab
Backfire-to-Endfire Leaky-Wave Antenna: ResultsAntenna
Configuration
x
z
ysource
bwd
fwd
broadside
θ
-30
-20
-10
0
0
30
6090
120
150
180
210
240270
300
330
-30
-20
-10
0
f<f0 f=f0 f>f0
RadiationPatterns
ωω
2 3 4 5 6 7-90
-60
-30
0
30
60
90
Scan
ning
Ang
le (d
eg)
Frequency (GHz)
II.LW-LH
III.LW-RH
0f0 2c β π maxf
x y
z
θ
θ versus ω
I.Guided
-LH
2 3 4 5 6 7-4
-3
-2
-1
0
1
2
β / k0 α / k0
Frequency (GHz)
β / k
0
0.00
0.02
0.04
0.06
0.08
0.10
0.12α
/ k0
II.LW-LH
III. LW-RH
0f0 2c β π maxfα / β diagram
I. Guided
-LH
11
Microwave Electronics Lab
Single-Element Purely Passive Retro-Reflector
z
x
y
0θ >
RH range 0ω θ∈ ⇒ >
0Z
1Γ = −
incPreflP
incβreflβ
incSreflS0Z
z
x
y
0θ <
LH range 0ω θ∈ ⇒ <
0Z
incP reflP
1Γ = −
incβ reflβ
reflSincS0Z
θ θ
θ θ
short-circuit
matchedload
Microwave Electronics Lab
Arbitrary Reflective Angle LW Reflecto-Director
LOf
Mixer
1f 12 LOff f−=BPFBPF
RF Oscillator
LW Antenna
( )1 1f θ ( )2 2f θ
1β 1β
principle
practical implementationSchottky
diodemixer CRLH antenna
Mixer1
inf ,2
,2 ,1
22
LO m
L
out
LinO O
f fff f
f = +
= + −BPFBPF
Oscillator 1
Mixer2
Oscillator2,2LOf,1LOf
,1inm LOff f= −
IF-Amp.
LW Antenna
( )in inf θ ( )out outf θ
inβ outβ
,1
,1,2
if is fixed, then
2ou
L
t
O
OL
i LO
n
ff
fff
⇓
− +=
12
Microwave Electronics Lab
Reflector Array of CRLH-TLs Terminated by Shorts
Array Alternating Stub CRLH-TLs
-25
-20
-15
-10
-5
0
0
30
60
90
120
150
180-25
-20
-15
-10
-5
0
3.3 GHz 3.5 GHz 3.7 GHz 4.3 GHz
Mono-Static RCS
Frequency-Scanning observedBackward retrodirectivity observedSpecular reflection (GP) can be removedby using a reference PEC reflectorSpecular reflection may be minimized byetching appropriate slots in the GP
ω θ
Motivations• Larger RCS than single-element reflector• Real surface, possibly conformal to any geometry• Simple and cheap with conv. photolithography• Can include cheap/simple passive mixers for arbitrary angle
Microwave Electronics Lab
Potential Future Applications of Focus / LW / SPLeaky-Wave Full-ScanningSurface Antenna/Reflector
Surface Plasmon Antennas
Pre-Focus Radiation
RH LH
virtual focus
radiationaperture
aperture size (directivity) can be modulated by varying focal length
2D-LW structure
EndfireDispersion Diagram
1SP LC
ω =
xk
ωlightline
2xckω ε=
Rexk
Imxk
non-radiativeSP
radiativeSP
L Rβ β≅ −
Broadside
RH
LH
RH
LH