deber alta pdf foster
TRANSCRIPT
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Non-Foster Reactances for Electrically-Small Antennas, High-Impedance
Surfaces, and Engineered Materials
James T. Aberle
Associate Professor of Electrical Engineering
School of Electrical, Computer and Energy Engineering
Arizona State University
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Outline of Presentation What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas High-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
2IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
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Outline of Presentation
What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas High-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
3IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
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Fosters Reactance Theorem The theorem is a consequence of
conservation of energy.
The slope of the input reactance
(susceptance) of a lossless passive one-port is always positive.
All zeros and poles of the impedance
(admittance) function are simple, and azero must lie between any two poles, anda pole between any two zeros.
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Consequences of Fosters
Reactance Theorem
Impedances (admittances) of passive one-
port networks rotate clockwise on theSmith Chart as frequency increases.
There is no such thing as a negativecapacitor or a negative inductor (forpassive circuits).
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Foster NetworkC
C1
C=30 pF
L
L1
R=
L=40 nH
L
L2
R=
L=40 nH
Term
Term1
Z=50 Ohm
Num=1
R
R1
R=50 Ohm
50 100 150 200 2500 300
0
20
40
-20
60
freq, MHz
real(Zin1)
imag(Zin1)
freq (10.00MHz to 300.0MHz)
S(1,1
)
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Non-Foster NetworkL
L3
R=
L=-40 nH
L
L1
R=
L=40 nH
L
L2
R=
L=40 nH
Term
Term1
Z=50 Ohm
Num=1
R
R1
R=50 Ohm
50 100 150 200 2500 300
0
20
40
60
80
100
-20
120
f req, MHz
real(Zin1)
imag(Zin1)
f req (10.00MHz to 300.0MHz)
S(1,1
)
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Outline of Presentation What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas High-Impedance Surfaces
Artificial High-Permeability Materials Realization of Non-Foster Reactances
8IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
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VHF Whip: A Canonical ESA
Geometry of monopole
antenna as modeled inAntenna Model software.The monopole is a coppercylinder 0.6 meters in
length and 0.010 meters indiameter, mounted on aninfinite perfect groundplane.
Frequency range is 30 to90 MHz.
9IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
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Input Impedance of VHF Whip From Simulation
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Two Tools to Help With Analysis Exact two-portrepresentation of antenna
in frequency domain in terms of s-parameters.
Approximate lumped equivalent circuitmodel of antenna over frequency range ofinterest.
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ajXlR 1:N0Z
0Z
Two-Port Representation of Antenna
The quantities in this box are re-evaluatedat every frequency for which we have data.
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Two-Port Representation of Antenna
/
radiation resistance
(1 ) dissipative loss resistanceantenna reactance
a a a r l a
r cd a
cd a
a
Z R jX R R jXR e R
R e RX
= + = + += =
= ==
0Z
RN r=
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Two-Port Representation of Antenna
Antenna impedance and radiation efficiency are
used to produce a Touchstone *.s2p file for usein circuit simulation the exact two-port
representation of the antenna at each frequency
for which we have data. Allows concepts like transducer power gain and
stability measures to be applied to antennas.
The latter being particularly important forconsidering the use of non-Foster reactances in
antenna matching networks.
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Approximate Equivalent Circuit of the Antenna
To model the antenna, we assume that the real
part of the antenna impedance varies as thesquare of frequency, and the imaginary part
behaves as a series LC.
+
=
a
aaC
LjRZ
12
0
0
Impedance produced by equivalent circuit
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Approximate Equivalent Circuit of the Antenna
Evaluation of the model parameters (R0,La and
Ca):( ){ }
( ){ }
( ){ }
=
=
2
1
2
2
1
1
00
11
1
a
a
a
a
a
Z
Z
C
L
ZR
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Approximate Equivalent Circuit of the Antenna
pF69.8
nH194
30.40
=
=
=
a
a
C
L
RL
La
R=
L=194 nHZ1P_Eqn
Z1P1
Z[1,1]=4.30*(freq/52e6)**2
C
Ca
C=8.69 pF
Term
Term1
Z=50 OhmNum=1
40 50 60 70 8030 90
-500
-400
-300
-200
-100
-600
0
freq, MHz
imag
(Zin1)
imag
(VH
F_
Whip
_S2P
..Zin1)
40 50 60 70 8030 90
5
10
15
0
20
freq, MHz
rea
l(Zin1)
rea
l(VH
F_
Whip
_S2P
..Zin1)
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LZ
0Z
MatchingNetwork
Matching Network Concept
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Points to Consider A real passive matching network can only
approach and never exceed the performancepredicted by the Bode-Fano criterion.
The matchable bandwidth is limited by the Qofthe load.
The matchable bandwidth can only be increasedby de-Qing the load that is by intentionalintroduction of dissipative losses into thematching network and concomitant reduction
in radiation efficiency.
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Bode-Fano Criterion
mQ
f
f
1ln
0
Maximum value of fractionalbandwidth that can be achieved withany passive, lossless matching
network.
Q of the load
Maximumallowable
reflectioncoefficient
035.03
1,9.81
0
==f
fQ m
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Single-Tuned Mid-band Match
TermTerm1
Z=4.30 Ohm
Num=1
L
Le
R=
L=884 nHCCa
C=8.69 pF
Z1P_Eqn
Z1P1Z[1,1]=4.30*(freq/52e6)**2
L
La
R=
L=194 nH
freq (30 .00MHz to 90 .00MHz)
S(1
,1)
m1
m2
m1freq=
S(1,1)=-10.409 / -73.141impedance = Z0 * (0.992 - j0.630)
51.80MHzm2freq=
S(1,1)=-10.477 / 71.883impedance = Z0 * (1.008 + j0.630)
52.20MHz
008.0
52
8.512.52
0
=
f
f
009.02
1
0
==
Qf
fAnalytical:
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Wheeler-Lopez Double-Tuned Matching
A.R. Lopez, Wheeler and Fano ImpedanceMatching, IEEE Antennas and PropagationMagazine, Vol. 49, No. 4, August 2007
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Wheeler-Lopez Double-Tuned Matching
A.R. Lopez, Wheeler and Fano ImpedanceMatching, IEEE Antennas and PropagationMagazine, Vol. 49, No. 4, August 2007
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Wheeler-Lopez Double-Tuned Matching with
Antenna De-Qing
Term
Term2
Z=50 Ohm
Num=2
R
RD
R=200 Ohm
C
C2
C=53.0 pF
TF
TF1
T=0.354
L
L2
R=
L=177 nH
L
Le
R=
L=884 nHTerm
Term1
Z=50 Ohm
Num=1
Zin
Zin1
Zin1=zin(S11,PortZ1)
Zin
N
S_Param
SP1
Step=1 MHz
Stop=90 MHz
Start=30 MHz
S-PARAMETERS
S2P
SNP1
File="VHF_whip.s2p"
21
Ref
freq (30.00MHz to 90.00MHz)
S(1
,1)
40 50 60 70 8030 90
-12
-10
-8
-14
-6
freq, MHz
dB(S(1
,1))
40 50 60 70 8030 90
-22
-20
-18
-16
-14
-24
-12
freq, MHz
dB(S(2
,1))
Decent match, poor efficiency
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Matching Network with Non-Foster Reactances
Z1P_EqnZ1P1
Z[1,1]=4.30*(freq/52e6)**2
LLa
R=
L=194 nHC
Ca
C=8.69 pF
LLa1
R=
L=-194 nH
C
Ca1C=-8.69 pF
Term
Term1
Z=50 Ohm
Num=1
LL2
R=
L=-44.9 nH
LL1
R=
L=-44.9 nH LL3
R=
L=44.9 nH
AntennaDualizer
freq (30.00MHz to 90.00MHz)
S(1,1
) m1m1freq=S(1,1)=4.843E-4 / -3.517E-5impedance = Z0 * (1.001 - j5.952E-10)
90.00MHzCancels frequency squareddependence of radiation resistance.
Van Der Pol, Proc, IRE, Feb. 1930
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0Z
0ZmL
( )ma LL +
aC
Two-port model ofantenna
Active matching network
Antenna with More Practical Matching Network
using Non-Foster Reactances.
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Optimized Non-Foster Matching Network
VAR
VAR1
Cneg=8.72637 {o}
Lneg=226.588 {o}
Lm=49.5959 {o}
EqnVar
C
Ca1
C=-Cneg pF
L
L2
R=
L=-Lneg nHL
L3
R=
L=Lm nH
Term
Term1
Z=50 OhmNum=1
Term
Term2
Z=50 Ohm
Num=2S2P
SNP1File="VHF_whip.s2p"
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Ref
freq (30.00MHz to 90.00MHz)
S(1,1
)
40 50 60 70 8030 90
-26
-24
-22
-20
-18
-28
-16
freq, MHz
dB(S(1
,1))
40 50 60 70 8030 90
-0.4
-0.3
-0.2
-0.1
-0.5
0.0
freq, MHz
dB(S(2,1
))
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Outline of Presentation What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small AntennasHigh-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
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High-Impedance Ground Plane
Sievenpiper, et. al, IEEE Trans. MTT, Nov. 1999
Capacitive
FSS
Low
Permittivity
Spacer
Metal BackplaneMetal Vias
10
Coaxial Feed
Bent Wire
Element
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EM Properties of the Sievenpiper
High-Impedance Ground Plane
Surface impedance is (ideally) an open-circuit(emulating a PMC rather than a PEC like a
conventional ground plane).
Propagation of TM and TE surface waves is notsupported (thus can be called an
electromagnetic bandgap structure).
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Model for Surface Impedance of Sievenpiper HIS
For plane waves at normal incidence, the substrate may be understood as an electrically short length of
shorted transmission line in parallel with a shunt capacitance at the reference plane of the outer surface.
Open
Short
Zstub
Zin
Shunt Capacitance
2d
PhaseAngle,
Frequency
180o
90o
0o
-90o
-180o
fo
BW ~ 10% to 20% of fo.
Co Zo, Short
Zstub
Zind
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Reflection Phase Bandwidth of
Sievenpiper HIS
00 2
h
r=
hr
Spacer layer
FSS layer
Ground plane
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Electrically-Thin Broadband High-
Impedance Surface In principle, one could realize an electrically-thin
broadband HIS by using a high-permeabilityspacer layer.
A high-permeability meta-material can be
realized using artificial magnetic molecules(AMMs) implement with negative inductance
circuits.
Unfortunately, AMM performance is verysensitive to component tolerances.
But, there is a better way
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Electrically-Thin Broadband
High-Impedance Surface
Kern, Werner, Wilhelm, APS 2003
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Electrically-Thin Conventional HIS
Term
Term1
Z=377 Ohm
Num=1
C
C1
C=2.17 pF
TLINP
TL1
Sigma=0
TanM=0
Mur=1
TanD=0.0009
F=1 GHz
A=0.0K=2.2
L=1.6 mm
Z=377/sqrt(2.2) Ohm
m1
freq=phase(S(1,1))=90.015
2.308GHz
m2
freq=phase(S(1,1))=-90.204
2.502GHz
m3freq=phase(S(1,1))=-0.139
2.403GHz
1.5 2.0 2.5 3.0 3.51.0 4.0
-100
0
100
-200
200
freq, GHz
phase(S(1,1))
m1
m2
m3
m1
freq=phase(S(1,1))=90.015
2.308GHz
m2
freq=phase(S(1,1))=-90.204
2.502GHz
m3freq=phase(S(1,1))=-0.139
2.403GHz
%80
=
f
f
0.062 in RogersDuroid 5880
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Electrically-Thin HIS with Negative Inductance
L
Lneg
R=
L=-2.02 nH
TLINP
TL1
Sigma=0TanM=0
Mur=1
TanD=0.0009
F=1 GHz
A=0.0K=2.2
L=1.6 mm
Z=377/sqrt(2.2) Ohm
Term
Term1
Z=377 Ohm
Num=1
1.5 2.0 2.5 3.0 3.51.0 4.0
-5
0
5
10
-10
15
freq, GHz
phase
(S(1
,1))
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Unit Cell of Sievenpiper HIGP
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Reflection Phase Response of
Sievenpiper HIGP
12 13 14 15 16 17 18-140
-120
-100
-80
-60
-40
-20
0
20
40
Frequency (GHz)
Re
flec
tion
Coeffic
ien
tPhase
(deg
)
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Unit Cell of Sievenpiper HIGP with Reactive Loading
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Equivalent Circuit of Loaded HIGP for
Normally Incident Plane Wave
E
Zload
Zload
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Reflection Phase of Capacitively
Loaded HIGP
0.5 1 1.5 2 2.5 3 3.5 4-200
-150
-100
-50
0
50
100
150
200
Frequency (GHz)
Re
flec
tion
Coef
fic
ien
tPhase
(deg
)
41IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
R fl i Ph f N i I d
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Reflection Phase of Negative-Inductor
Loaded HIGP
0.5 1 1.5 2 2.5 3 3.5 4-40
-30
-20
-10
0
10
20
30
40
Frequency (GHz)
Re
flec
tion
Coe
fficien
tPhase
(deg
) Lneg = -2.2nH
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Outline of Presentation What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas High-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
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What is an Artificial Material? An artificial material is a large-scale emulation of an actualmaterial, obtained by embedding a large number of electricallysmall inclusions (artificial molecules) within a host medium.
Like natural molecules, the electrically small inclusions exhibitelectric and/or magnetic dipole moments.
As a result of these dipole moments, the macroscopic
electromagnetic constitutive parameters (r and r) are altered
with respect to the host medium.
HB
ED
0
0
==
44IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Why Create an Artificial
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Why Create an Artificial
Magnetic Material? Naturally occurring magnetic materials
(ferrites) are heavy, fragile and expensive, andthey also exhibit relatively high magnetic losses
and dielectric constant.
Available ferrite materials provide a limitedselection of relative permeabilities.
The permeability tensor of the ferrite is
controlled by applying a static magnetic field permanent magnets and/or electromagnets are
required.
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Artificial Magnetic Metamaterial
A 3-dimensional lattice of artificialmolecules.
Electrically small loop with a loadimpedance
dx
dy
dz
dz
dy
a
W
ZL
y
z
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Simple Circuit Model for Artificial Magnetic Molecule (AMM)
Llooploss
xx
ZLjR
aj
H
m
N
++==
+=
40
1
VH
Rrad
Lloop
+
-ZL
I
Relative
permeabilityNumber ofAMMs per
unit volume
Magneticpolarizability of
each AMM
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Broadband, High Permeability Requires Negative Inductance
0 1 2 3 4 5 6 7 8 9 10
0
2
4
6
8
10
12
14
16
18
Frequency, GHz
RelativePermeability
imag
real
a
W
ZL= -j Ld
0 1 2 3 4 5 6 7 8 9 10
0
2
4
6
8
10
12
14
16
18
Frequency, GHz
RelativePermeability
imag
real
a
W
ZL= -j Ld
Circuit Theory Model
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H t E t t M t i l P ti
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How to Extract Material Properties(TEM waveguide containing material sample)
wave port 1wave port 2
material sample
PMC walls
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How to Extract Material
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How to Extract Material
Properties HFSS
-Two port S parameters calculation of TEM
waveguide containing material sample.
MATLAB
-Shifting of the reference planes.
-Conversion of S-parameters to ABCDparameters.
-Calculation of propagation constant and
characteristic impedance of equivalenttransmission line.
-Evaluation of the material properties.
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How to Extract Material Properties
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How to Extract Material Properties(Loop Configuration)
lumped element
copper loop
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N i I d i M d l d F D d
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Negative Inductance is Modeled as a Frequency-Dependent
Capacitance
( ) negequiv
Lf
C2
2
1
=
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Cancellation of Parasitic
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Cancellation of Parasitic
Capacitance Using NIC
To remove the resonance, the parasitic capacitance of the loop should be
compensated by a negative capacitance.
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Remedy for Snoek-Like Phenomenon: Add Negative Capacitance in
Shunt with Negative Inductance
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Outline of Presentation What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas
High-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
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N ti I d C t (NIC)
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Negative Impedance Converter (NIC)
An ideal NIC is a two-port network such that when aload impedance is attached to the output terminal, the
input impedance is the (possibly scaled) negativevalue of the load impedance.
IdealNIC
ZL
Zin=-kZL (k>0)
IdealNIC
ZL
Zin=-kZL (k>0)
C i l NIC
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Canonical NIC
R
RZ
+
-ZZin =
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Simple Op Amp Test Circuit
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S_Param
SP1
Step=1 MHz
Stop=4000 MHz
Start=1 MHz
S-PARAMETERS
OpAmp
AMP2
BW=500 MHz
Gain=100 dB
R
R4
R=100 OhmTerm
Term1
Z=50 Ohm
Num=1
RR3
R=50 Ohm
R
R2
R=1 kOhm
R
R1R=1 kOhm
Simple Op-Amp Test Circuit
Can specify DC
gain and unity gainBW.FOM: RL > 15 dB
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Unity-gain BW = 500 MHz
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1E7 1E8 1E91E6 4E9
-30
-20
-10
-40
0
freq, Hz
dB(S(1,1
)) m1
m1freq=dB(S(1,1))=-14.883
7.000MHz
y g
59IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
NIC R t L BW O A U it G i BW
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NIC Return Loss BW vs. Op-Amp Unity Gain BW
500 1000 1500 20005
10
15
20
25
30
Op-Amp Unity-Gain BW (MHz)
NICRe
turnL
oss
BW
(MHz)
Op-amp based NICscontra-indicated for
applications above 30 MHz
60IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Fabricated OPA690 NIC Evaluation
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Board
61IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Circuit for evaluating the performance
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NIC ZL
Rin
SignalGenerator
Vin Vneg
Iin
-ZL
Vg
Rg
Zin
g p
of a grounded negative impedance
Lin ZR >
Stability requires that
62IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Schematic captured from Agilent ADS of the circuit
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V g V in V n e g
V t S i n e
V g
P h a s e = 0
D a m p i n g = 0
D e l a y = 0 n s e c
F r eq = 0 . 5 M H z
A m p lit u d e = 1 0 0 m V
V d c = 0 m V
Tran
T ran1
M a x Ti m e S te p = 0 . 5 n s e c
S t o p Tim e = 5 u s e c
T R A N S I E N T
R
R in
R = 1 0 0 O h m
RR 7
R = R s c a l e
O P A 6 9 0 _ p o r t
X 1
R
R 1 0
R = 5 0 O h m
R
R 3
R = R s c a l e 2
V A R
V A R 1
R s c a l e 2 = 2 5 0
R s c a l e = 2 5 0
E q nVa r
R
R g
R = 5 0 O h m
p g
for evaluating the performance of the OPA690 NIC
63IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Simulated and measured return loss for
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2 4 6 8 10 12 14 16 180 20
-40
-30
-20
-10
-50
0
freq, MHz
dB(Return_
Loss_
Simulate
d)
dB(Return_
Loss_
Measure
d)
the OPA690 NIC evaluation circuit
64IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Ground Negative Impedance Versus
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Canonical NIC and most other NIC circuits in the literature producegrounded negative impedance
But for the applications we are considering here, we need floatingnegative impedance
Floating Negative Impedance
-Z
-Z
65
IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Floating NIC Realized Using Two Op-Amps
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Floating NIC Realized Using Two Op-Amps
66
IEEE Waves and Devices 19 Feb 2010
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Op-Amp FNIC Test Circuit
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S_ParamSP1
Step=0.1 MHzStop=100 MHzStart=0.1 MHz
S-PARAMETERS
MuPrime
MuPrime1MuPrime1=mu_prime(S)
MuPrime
Mu
Mu1Mu1=mu(S)
Mu
TermTerm2
Z=50 OhmNum=2
TermTerm1
Z=50 OhmNum=1
RR2R=1k Ohm
RR1R=1k Ohm
RR4R=1k Ohm
RR3R=1k Ohm
RRLR=50 Ohm
RRnegR=50 Ohm
OpAmpAMP2
BW=500 MHzGain=100 dB
OpAmpAMP1
BW=500 MHz
Gain=100 dB
67IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Unity-gain BW = 500 MHz
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m1freq=dB(S(1,1))=-15.048
3.600MHz
1E6 1E71E5 1E8
-40
-30
-20
-10
-50
0
freq, Hz
dB(S
(1,1
))m1
m1freq=dB(S(1,1))=-15.048
3.600MHz
1E6 1E71E5 1E8
-10
-5
-15
0
freq, Hz
dB(S(
2,1
))
20 40 60 800 100
1.000
1.002
1.004
1.006
1.008
0.998
1.010
freq, MHz
Mu1
MuPrime1
68IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
NIC Return Loss BW vs. Op-Amp Unity Gain BW
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Op Amp BW 15 dB RL NIC BW
500 MHz 3.6 MHz
1000 MHz 7.2 MHz
2000 MHz 14.5 MHz
C etu oss s Op p U ty Ga
69IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Floating NIC Circuit Using Two Transistors
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1i
1v
+
-
LZ
2i
2v
+
-
1Q 2Q
3v 3v
Floating NIC Circuit Using Two Transistors
70IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
NIC All-Pass Test Circuit
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NIC All Pass Test Circuit
0Z
LZ0Z L
Z
71IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
High-Frequency BJT Device Model
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High Frequency BJT Device Model
VAR
VAR1
Cpi=gm/(2*pi*fT)
Cc=Cpi/10
Rb=7
gm=900
fT=32
Rpi=110
EqnVar
Port
P3
Num=3
Port
P2
Num=2
Port
P1
Num=1
C
Cc
C=Cc pF
R
Rb
R=Rb Ohm
CCpi
C=Cpi pF
VCCS
SRC1
R2=1e100 Ohm
R1=Rpi Ohm
G=gm mS
72IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Test Circuit Results (f = 32 GHz)
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Test Circuit Results (fT
32 GHz)
0.2 0.4 0.6 0.80.0 1.0
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.9
-0.2
freq, GHz
dB(S(2
,1))
0.2 0.4 0.6 0.80.0 1.0
-25
-20
-30
-15
freq, GHz
dB(S(1
,1))
m1
m1freq=dB(S(1,1))=-19.995
502.0MHz
0.2 0.4 0.6 0.80.0 1.0
1.0000000
1.0000000
1.0000000
1.0000000
1.0000000
freq, GHz
Mu
1
Mu
Prime
1
73IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
All-Pass -20 dB RL BW v. fT
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All Pass 20 dB RL BW v. fT
0 5 10 15 20 25 30 350
100
200
300
400
500
600
Transistor fT in GHz
All-passb
an
dw
idthinMHz
74IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Fabricated Two Transistor Floating
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NIC Using 2N2222 Devices
75IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Measured Results for Two Transistor FNIC
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76IEEE Waves and Devices 19 Feb 2010Copyright 2010James T. Aberle
Summary of NIC Developments
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y p
Weve had some successes in fabricating NICs
that work up to about 50 MHz.
We have had many more failures.
The main issue concerns stability small and
large signal stability. We are making progress, albeit very slowly
Someday, someone will make a reliable FNIC
that works into the 100s of MHz range.
77IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
How Best to Use a NIC to Make
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a Non-Foster Reactance?
Direct negation:
ZZ NIC
78IEEE Waves and Devices 19 Feb 2010
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How Best to Use a NIC to Make
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a Non-Foster Reactance?
Using a certain transformation:
Verman, Proc. IRE, Apr. 1931
79IEEE Waves and Devices 19 Feb 2010
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Negative Impedance Transformation
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R R
-R ZL(s)
Zin(s)
( )( ) 2( )( )
( ) ( )
L
in
L L
R Z s R RZ s R
Z s Z s
+ = + =
ZL(s)
R/2 R/2
R/2 R/2
-R
Can develop an NIC thatneeds to work for only one
value of real impedance Also suggests the possibilityof using negative resistancediodes (Tunnel, Gunn, etc.) forNIC realization
Grounded
Floating
80IEEE Waves and Devices 19 Feb 2010
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Negative Impedance Transformation
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( )( )
1
1
1 11
1 11
L in
neg
neg
neg
neg
neg
neg
Z s Z s
sL
sC
sLsC
sLsC
sCsL
sLsC
sCsL
+
+
2
2
neg
neg
L R C
LCR
=
=
81IEEE Waves and Devices 19 Feb 2010
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Schematic captured from Agilent ADS of
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Optim
Optim1
SaveCurrentEF=no
UseAllGoals=yes
UseAllOptVars=yes
SaveAllIterations=no
SaveNominal=no
UpdateDataset=yes
SaveOptimVars=noSaveGoals=yes
SaveSolns=yes
SetBestValues=yes
NormalizeGoals=noFinalAnalys is="None"
StatusLevel=4
DesiredError=0.0
MaxIters=250
OptimTy pe=Gradient
OPTIM
VAR
VAR1
Cneg=7.6146 {o}
Lneg=291.922 {o}Lm=55.1849 {o}
EqnVar
Goal
OptimGoal2
RangeMax[1]=RangeMin[1]=
RangeVar[1]=
Weight=
Max=10
Min=
SimInstanceName="SP1"
Expr="abs(real(Zin1)-50)"
GOAL
Goal
OptimGoal1
RangeMax[1]=
RangeMin[1]=
RangeVar[1]=
Weight=
Max=20
Min=
SimInstanceName="SP1"
Expr="abs(imag(Zin1))"
GOAL
sp_nec_NE85630_7_19940401
SNP3
Frequency ="{0.05 - 3.60} GHz"
Bias="Bjt: Vce=10V Ic=30mA"sp_nec_NE85630_7_19940401
SNP2
Frequency ="{0.05 - 3.60} GHz"
Bias="Bjt: Vce=10V Ic=30mA"
CAPQ
Cneg
Mode=proportional to f req
F=60.0 MHz
Q=100.0
C=Cneg pF
INDQ
Lm
Rdc=0.0 Ohm
Mode=proportional to f req
F=60.0 MHz
Q=100.0
L=Lm nH
INDQ
Lneg
Rdc=0.0 Ohm
Mode=proportional to f reqF=60.0 MHz
Q=100.0
L=Lneg nH
MuPrime
MuPrime1
MuPrime1=mu_prime(S)
MuPrime
Mu
Mu1
Mu1=mu(S)
Mu
Zin
Zin1
Zin1=zin(S11,PortZ1)
Zin
N
S2P
SNP1
21
Ref
Term
Term2
Z=50 Ohm
Num=2
Term
Term1
Z=50 Ohm
Num=1
S_Param
SP1
Step=1 MHz
Stop=90 MHz
Start=30 MHz
S-PARAMETERS
VHF monopole with active matching network
82IEEE Waves and Devices 19 Feb 2010
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Simulated return loss at input of optimized active
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40 50 60 70 8030 90
-25
-20
-15
-30
-10
freq, MHz
dB(S(1
,1))
Return Loss (dB)
matching network and antenna
83IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Overall efficiency (in percent) of optimized active matchingnetwork and antenna
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40 50 60 70 8030 90
75
80
85
90
70
95
freq, MHz
mag(S(2,1
))*100
Overall Efficiency (%)
84IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Small-signal geometrically-derived stability factor for theoptimized active matching network and antenna
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40 50 60 70 8030 90
0.98
0.99
1.00
0.97
1.01
freq, MHz
Mu1
Mu
Prime1
85IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle
Outline of Presentation
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What Does Non-Foster Mean?
Possible Applications of Non-FosterReactances
Electrically Small Antennas
High-Impedance Surfaces
Artificial High-Permeability Materials
Realization of Non-Foster Reactances
86IEEE Waves and Devices 19 Feb 2010
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Summary
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The use of non-Foster reactances could improve
the performance of ESAs and HIGPs
dramatically. Some hard-won successes have been achieved
in the development of the requisite NICs.
But an interdisciplinary team with expertise incircuits as well as field theory and sufficient
funding is needed to realize reliable high
frequency non-Foster reactances and tointegrate them into electromagnetic devices.
87IEEE Waves and Devices 19 Feb 2010
Copyright 2010James T. Aberle