elet2002(1)
TRANSCRIPT
-
8/9/2019 elet2002(1)
1/3
-1 o
-0.5
0
0.5
1 o
time, ns
I
I
-1.0 I I I I 1 I 1
Fig 1 Near-peak values of an incident
t)
with parameters in/2 z =
13.48 GHz and w,,/271=
18.01
GHz
100
I
.
predicted
.
.
.
.
.
.
0 0.005 0.01 0 0.015
depth,
m
Pig. 2 Normalised energies and peak powers of a pulse in
tD
and another
in
cL
overlap (centre), are e x p ( - 2 r x ) (top), and are
?
e x p ( - 2 r x )
(bottom)
O O L500
Debye
/
,+
, Lorentz
4
1 1 ' 1 1 ' ' ' 1 1 '0 60 8 100
frequency, GHz
Fig 3
Curves k,(o) or models
cD
and
cL,
with exponential decay ofpe aks
verijied by eight examples described n text regarding rectangles
Going beyond the analysis, a more sensitive measure of exponential
decay is
- I /€
= [ln (x)]/dx. This is times the x-dependent
slope (in dB/cm) of (x) when graphed in dB. Thus, - I / € is the local
exponential decay rate of . For the pulses of Figs. 1 and 2, the
computed - I/aries from 1185-1257/m (51-55 dB/cm) for the
first
60
dB
of
energy attenuation. This is in the range [ 2 y y ] f
101 1485/m (4 4 6 4 dB/cm) suggested but not yet predicted by
theory.
Fig. 3 shows ranges of local exponential decay rates
- P / / P
of peaks
P for the first 60dB of peak-power attenuation. The large, marked
rectangle, e.g. signifies that the incidentfwith spectrum 40-70 GHz has
a peak that decays in the Lorentz model
c
at an exponential rate that
varies from 709-868/m. The dashed curve shows this is within the
range
[T,r]
f
508-1247/m for
E L .
This example and the seven
others in Fig. 3 verify the 5 e x p ( - r x ) prediction for peaks. The
spectrum for the small, marked rectangle is 4-6 GHz. Linearity and
Fig. 3 thereby yield
two
four-parameter families of examples of peaks
that decay faster than ex p( -r .r ), with bandwidths over three and four
octaves.
Conclusions: In this Letter a practical model
of
pulses in far-field,
lossy materials is used to show that exponential decay is typical. This
is verified by many numerical examples, with bandwidths up to four
octaves. Two other numerical observations have not yet been
explained by analysis. First, analysis has not explained why
e x p ( - 2 y x ) is a bound in Fig. 2. Secondly, the local exponential
decay rates of energies and peaks are within bounds suggested, but not
yet predicted, by analysis. The analytical results in this Letter,
however, are all numerically verified.
A consequence of recent, practical interest is that algebraic decay no
longer seems to be a useful design principle for radar penetration of far-
field, lossy clutter. Although algebraic decay might be recovered from
exponential decay in a mathematical limit w in 0, this would not
escape the real difficulties of low radiation efficiency and low resolution
posed by near-DC signals.
Acknowledgments: The
US
Air Force Office of Scientific Research
supported this work. H. Steyskal contributed many useful conversa-
tions.
EE
2002
Electronics Letters Online No: 20020482
DOI: 10.1049/el:20020482
T.M. Roberts (Antenn a Technology Branch, Air Force Research
LaboratorylSNHA,
80
Scott Dr ive, Hanscom AFB, M A
01
731 , U SA )
E-mail:
robertst@maxwell rl plh af mil
28 February 2002
References
1 BRILLOUIN L.:
'Wave propagation and group velocity' (Academic Press,
1960)
2
OUGHSTUN K.E. and
SHERMAN,
G.c.: Electromagnetic pulse propagation
in causal dielectrics' (Springer-Verlag, 1994)
3
KELBERT
M. and SAZONOV 1.: 'Pukes and other wave processes in fluids'
(Kluwer Academic, 1996)
4 ROBERTS T.M.
and PETROPOULOS P.G.: 'Asymptotics and energy
estimates for electromagnetic
pulses in
dispersive media', Opt Soc
Am. A 1996, 13, (6), pp. 12041217
High voltage pulse generation
M. Petkovsek, J. Nastran,
I .
Voncina, P. Zajec, D. Miklavcic
and
G. Sersa
A new topology of a high voltage source with a variable output pulse
pattern and featuring an independent adjustment
of
the magnitude,
repetition frequency and pulse duration is presented. The power stage
of the source consists of eight individual unipolar sources that can be
arbitrarily connected in series to obtain the desired output voltage
pulse
of
several amps and with extremely high
duldt.
Introduction: Owing to the tremendous increase
of
applications in
oncology, genetics and cell biology, high voltage pulse sources
capable of delivering AC
or
DC currents of several amps are the
subject
of
intensive investigations. Several authors have reported that
the application of short high voltage pulses transiently increases the
permeability of the cell membrane
[1-31,
The so-called electropora-
tion, or electropermeabilisation, has become an effective tool for the
internalisation
of
various molecules, especially anti-cancer drugs and
gene material , into the biological cells. The efficiency of such
680 ELECTRONICS LETERS 4th July2 2 Vol 38 No 74
-
8/9/2019 elet2002(1)
2/3
-1 o
-0.5
0
0.5
1 o
time, ns
I
I
-1.0 I I I I 1 I 1
Fig 1 Near-peak values of an incident
t)
with parameters in/2 z =
13.48 GHz and w,,/271=
18.01
GHz
100
I
.
predicted
.
.
.
.
.
.
0 0.005 0.01 0 0.015
depth,
m
Pig. 2 Normalised energies and peak powers of a pulse in
tD
and another
in
cL
overlap (centre), are e x p ( - 2 r x ) (top), and are
?
e x p ( - 2 r x )
(bottom)
O O L500
Debye
/
,+
, Lorentz
4
1 1 ' 1 1 ' ' ' 1 1 '0 60 8 100
frequency, GHz
Fig 3
Curves k,(o) or models
cD
and
cL,
with exponential decay ofpe aks
verijied by eight examples described n text regarding rectangles
Going beyond the analysis, a more sensitive measure of exponential
decay is
- I /€
= [ln (x)]/dx. This is times the x-dependent
slope (in dB/cm) of (x) when graphed in dB. Thus, - I / € is the local
exponential decay rate of . For the pulses of Figs. 1 and 2, the
computed - I/aries from 1185-1257/m (51-55 dB/cm) for the
first
60
dB
of
energy attenuation. This is in the range [ 2 y y ] f
101 1485/m (4 4 6 4 dB/cm) suggested but not yet predicted by
theory.
Fig. 3 shows ranges of local exponential decay rates
- P / / P
of peaks
P for the first 60dB of peak-power attenuation. The large, marked
rectangle, e.g. signifies that the incidentfwith spectrum 40-70 GHz has
a peak that decays in the Lorentz model
c
at an exponential rate that
varies from 709-868/m. The dashed curve shows this is within the
range
[T,r]
f
508-1247/m for
E L .
This example and the seven
others in Fig. 3 verify the 5 e x p ( - r x ) prediction for peaks. The
spectrum for the small, marked rectangle is 4-6 GHz. Linearity and
Fig. 3 thereby yield
two
four-parameter families of examples of peaks
that decay faster than ex p( -r .r ), with bandwidths over three and four
octaves.
Conclusions: In this Letter a practical model
of
pulses in far-field,
lossy materials is used to show that exponential decay is typical. This
is verified by many numerical examples, with bandwidths up to four
octaves. Two other numerical observations have not yet been
explained by analysis. First, analysis has not explained why
e x p ( - 2 y x ) is a bound in Fig. 2. Secondly, the local exponential
decay rates of energies and peaks are within bounds suggested, but not
yet predicted, by analysis. The analytical results in this Letter,
however, are all numerically verified.
A consequence of recent, practical interest is that algebraic decay no
longer seems to be a useful design principle for radar penetration of far-
field, lossy clutter. Although algebraic decay might be recovered from
exponential decay in a mathematical limit w in 0, this would not
escape the real difficulties of low radiation efficiency and low resolution
posed by near-DC signals.
Acknowledgments: The
US
Air Force Office of Scientific Research
supported this work. H. Steyskal contributed many useful conversa-
tions.
EE
2002
Electronics Letters Online No: 20020482
DOI: 10.1049/el:20020482
T.M. Roberts (Antenn a Technology Branch, Air Force Research
LaboratorylSNHA,
80
Scott Dr ive, Hanscom AFB, M A
01
731 , U SA )
E-mail:
robertst@maxwell rl plh af mil
28 February 2002
References
1 BRILLOUIN L.:
'Wave propagation and group velocity' (Academic Press,
1960)
2
OUGHSTUN K.E. and
SHERMAN,
G.c.: Electromagnetic pulse propagation
in causal dielectrics' (Springer-Verlag, 1994)
3
KELBERT
M. and SAZONOV 1.: 'Pukes and other wave processes in fluids'
(Kluwer Academic, 1996)
4 ROBERTS T.M.
and PETROPOULOS P.G.: 'Asymptotics and energy
estimates for electromagnetic
pulses in
dispersive media', Opt Soc
Am. A 1996, 13, (6), pp. 12041217
High voltage pulse generation
M. Petkovsek, J. Nastran,
I .
Voncina, P. Zajec, D. Miklavcic
and
G. Sersa
A new topology of a high voltage source with a variable output pulse
pattern and featuring an independent adjustment
of
the magnitude,
repetition frequency and pulse duration is presented. The power stage
of the source consists of eight individual unipolar sources that can be
arbitrarily connected in series to obtain the desired output voltage
pulse
of
several amps and with extremely high
duldt.
Introduction: Owing to the tremendous increase
of
applications in
oncology, genetics and cell biology, high voltage pulse sources
capable of delivering AC
or
DC currents of several amps are the
subject
of
intensive investigations. Several authors have reported that
the application of short high voltage pulses transiently increases the
permeability of the cell membrane
[1-31,
The so-called electropora-
tion, or electropermeabilisation, has become an effective tool for the
internalisation
of
various molecules, especially anti-cancer drugs and
gene material , into the biological cells. The efficiency of such
680 ELECTRONICS LETERS 4th July2 2 Vol 38 No 74
-
8/9/2019 elet2002(1)
3/3
-1 o
-0.5
0
0.5
1 o
time, ns
I
I
-1.0 I I I I 1 I 1
Fig 1 Near-peak values of an incident
t)
with parameters in/2 z =
13.48 GHz and w,,/271=
18.01
GHz
100
I
.
predicted
.
.
.
.
.
.
0 0.005 0.01 0 0.015
depth,
m
Pig. 2 Normalised energies and peak powers of a pulse in
tD
and another
in
cL
overlap (centre), are e x p ( - 2 r x ) (top), and are
?
e x p ( - 2 r x )
(bottom)
O O L500
Debye
/
,+
, Lorentz
4
1 1 ' 1 1 ' ' ' 1 1 '0 60 8 100
frequency, GHz
Fig 3
Curves k,(o) or models
cD
and
cL,
with exponential decay ofpe aks
verijied by eight examples described n text regarding rectangles
Going beyond the analysis, a more sensitive measure of exponential
decay is
- I /€
= [ln (x)]/dx. This is times the x-dependent
slope (in dB/cm) of (x) when graphed in dB. Thus, - I / € is the local
exponential decay rate of . For the pulses of Figs. 1 and 2, the
computed - I/aries from 1185-1257/m (51-55 dB/cm) for the
first
60
dB
of
energy attenuation. This is in the range [ 2 y y ] f
101 1485/m (4 4 6 4 dB/cm) suggested but not yet predicted by
theory.
Fig. 3 shows ranges of local exponential decay rates
- P / / P
of peaks
P for the first 60dB of peak-power attenuation. The large, marked
rectangle, e.g. signifies that the incidentfwith spectrum 40-70 GHz has
a peak that decays in the Lorentz model
c
at an exponential rate that
varies from 709-868/m. The dashed curve shows this is within the
range
[T,r]
f
508-1247/m for
E L .
This example and the seven
others in Fig. 3 verify the 5 e x p ( - r x ) prediction for peaks. The
spectrum for the small, marked rectangle is 4-6 GHz. Linearity and
Fig. 3 thereby yield
two
four-parameter families of examples of peaks
that decay faster than ex p( -r .r ), with bandwidths over three and four
octaves.
Conclusions: In this Letter a practical model
of
pulses in far-field,
lossy materials is used to show that exponential decay is typical. This
is verified by many numerical examples, with bandwidths up to four
octaves. Two other numerical observations have not yet been
explained by analysis. First, analysis has not explained why
e x p ( - 2 y x ) is a bound in Fig. 2. Secondly, the local exponential
decay rates of energies and peaks are within bounds suggested, but not
yet predicted, by analysis. The analytical results in this Letter,
however, are all numerically verified.
A consequence of recent, practical interest is that algebraic decay no
longer seems to be a useful design principle for radar penetration of far-
field, lossy clutter. Although algebraic decay might be recovered from
exponential decay in a mathematical limit w in 0, this would not
escape the real difficulties of low radiation efficiency and low resolution
posed by near-DC signals.
Acknowledgments: The
US
Air Force Office of Scientific Research
supported this work. H. Steyskal contributed many useful conversa-
tions.
EE
2002
Electronics Letters Online No: 20020482
DOI: 10.1049/el:20020482
T.M. Roberts (Antenn a Technology Branch, Air Force Research
LaboratorylSNHA,
80
Scott Dr ive, Hanscom AFB, M A
01
731 , U SA )
E-mail:
robertst@maxwell rl plh af mil
28 February 2002
References
1 BRILLOUIN L.:
'Wave propagation and group velocity' (Academic Press,
1960)
2
OUGHSTUN K.E. and
SHERMAN,
G.c.: Electromagnetic pulse propagation
in causal dielectrics' (Springer-Verlag, 1994)
3
KELBERT
M. and SAZONOV 1.: 'Pukes and other wave processes in fluids'
(Kluwer Academic, 1996)
4 ROBERTS T.M.
and PETROPOULOS P.G.: 'Asymptotics and energy
estimates for electromagnetic
pulses in
dispersive media', Opt Soc
Am. A 1996, 13, (6), pp. 12041217
High voltage pulse generation
M. Petkovsek, J. Nastran,
I .
Voncina, P. Zajec, D. Miklavcic
and
G. Sersa
A new topology of a high voltage source with a variable output pulse
pattern and featuring an independent adjustment
of
the magnitude,
repetition frequency and pulse duration is presented. The power stage
of the source consists of eight individual unipolar sources that can be
arbitrarily connected in series to obtain the desired output voltage
pulse
of
several amps and with extremely high
duldt.
Introduction: Owing to the tremendous increase
of
applications in
oncology, genetics and cell biology, high voltage pulse sources
capable of delivering AC
or
DC currents of several amps are the
subject
of
intensive investigations. Several authors have reported that
the application of short high voltage pulses transiently increases the
permeability of the cell membrane
[1-31,
The so-called electropora-
tion, or electropermeabilisation, has become an effective tool for the
internalisation
of
various molecules, especially anti-cancer drugs and
gene material , into the biological cells. The efficiency of such
680 ELECTRONICS LETERS 4th July2 2 Vol 38 No 74
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