Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas
The principally attainable antenna characteristics are discussed, including the ultrawideband antennas. Antenna configuration is pointed out as a principle factor for the antenna characteristics to approach the potentially attainable ones. Both the similarities and the distinctions are considered as...
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Titov, A.N. 2017-07-02T17:03:19Z 2017-07-02T17:03:19Z 2002 Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas / A.N. Titov // Радиофизика и радиоастрономия. — 2002. — Т. 7, № 4. — С. 479-482. — Бібліогр.: 12 назв. — англ. 1027-9636 https://nasplib.isofts.kiev.ua/handle/123456789/122365 The principally attainable antenna characteristics are discussed, including the ultrawideband antennas. Antenna configuration is pointed out as a principle factor for the antenna characteristics to approach the potentially attainable ones. Both the similarities and the distinctions are considered as regards the approaches to the ultrawideband and the pulse antenna designing. General recommendations are expounded as to the choice of the antenna type and structure for the transmission and reception of pulse electromagnetic signals. Рассматриваются потенциально достижимые характеристики антенн, в том числе сверхширокополосных. Подчеркивается принципиальное влияние конфигурации антенн на степень приближения характеристик антенны к потенциально достижимым. Обсуждается сходство и различие в подходах к проектированию сверхширокополосных и импульсных антенн. Излагаются общие рекомендации, связанные с выбором типов и конструкций антенн, предназначенных для излучения и приема импульсных электромагнитных сигналов. Розглянуто потенційно досяжні характеристики антен, у тому числі надширокосмугових. Підкреслено принциповий вплив конфігурації антен на ступінь наближення характеристик антени до потенційно досяжних. Обговорюється схожість та відмінність у підходах до проектування надширокосмугових та імпульсних антен. Викладено загальні рекомендації, пов’язані з вибором типів і конструкцій антен, призначених для випромінювання і прийому імпульсних електромагнітних сигналів. In conclusion, the author is deeply thankful to Prof. N. N. Kolchigin and Prof. M. B. Egorov for care and help and to Prof. C. E. Baum (USA) for fruitful discussions. en Радіоастрономічний інститут НАН України Радиофизика и радиоастрономия Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas Некоторые вопросы проектирования сверхширокополосных и импульсных антенн Деякі питання проектування надширокосмугових та імпульсних антен Article published earlier |
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Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas |
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Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas Titov, A.N. |
| title_short |
Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas |
| title_full |
Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas |
| title_fullStr |
Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas |
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Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas |
| title_sort |
some aspects concerning the designing of ultrawideband and pulse antennas |
| author |
Titov, A.N. |
| author_facet |
Titov, A.N. |
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2002 |
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English |
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Радиофизика и радиоастрономия |
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Радіоастрономічний інститут НАН України |
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Article |
| title_alt |
Некоторые вопросы проектирования сверхширокополосных и импульсных антенн Деякі питання проектування надширокосмугових та імпульсних антен |
| description |
The principally attainable antenna characteristics are discussed, including the ultrawideband antennas. Antenna configuration is pointed out as a principle factor for the antenna characteristics to approach the potentially attainable ones. Both the similarities and the distinctions are considered as regards the approaches to the ultrawideband and the pulse antenna designing. General recommendations are expounded as to the choice of the antenna type and structure for the transmission and reception of pulse electromagnetic signals.
Рассматриваются потенциально достижимые характеристики антенн, в том числе сверхширокополосных. Подчеркивается принципиальное влияние конфигурации антенн на степень приближения характеристик антенны к потенциально достижимым. Обсуждается сходство и различие в подходах к проектированию сверхширокополосных и импульсных антенн. Излагаются общие рекомендации, связанные с выбором типов и конструкций антенн, предназначенных для излучения и приема импульсных электромагнитных сигналов.
Розглянуто потенційно досяжні характеристики антен, у тому числі надширокосмугових. Підкреслено принциповий вплив конфігурації антен на ступінь наближення характеристик антени до потенційно досяжних. Обговорюється схожість та відмінність у підходах до проектування надширокосмугових та імпульсних антен. Викладено загальні рекомендації, пов’язані з вибором типів і конструкцій антен, призначених для випромінювання і прийому імпульсних електромагнітних сигналів.
|
| issn |
1027-9636 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/122365 |
| citation_txt |
Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas / A.N. Titov // Радиофизика и радиоастрономия. — 2002. — Т. 7, № 4. — С. 479-482. — Бібліогр.: 12 назв. — англ. |
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2025-11-25T22:33:25Z |
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| fulltext |
Radio Physics and Radio Astronomy, 2002, v. 7, No. 4, pp. 479-482
SOME ASPECTS CONCERNING THE DESIGNING
OF ULTRAWIDEBAND AND PULSE ANTENNAS
A.N. Titov
Scientific Research Institute of Instrument Design
Zhukovsky ,140180, Moscow region, Russia
The principally attainable antenna characteristics are discussed, including the ultrawideband antennas. An-
tenna configuration is pointed out as a principle factor for the antenna characteristics to approach the potentially
attainable ones. Both the similarities and the distinctions are considered as regards the approaches to the ul-
trawideband and the pulse antenna designing. General recommendations are expounded as to the choice of the
antenna type and structure for the transmission and reception of pulse electromagnetic signals.
1. Introduction
Out of the most significant successive stages in the
development of the antenna technology during the
last 50 years, one can point out these.
1. The definition of ways in order to essentially in-
crease the antenna work band. If in the 1950s the
antenna with a 10 % work band was a wideband
one, nowadays the work band maximal to minimal
frequency ratio may be up to 30…50 [1,2]. In
most applications this amount exceeds the capac-
ity limits of the antenna-employing devices (trans-
mitters/receivers).
2. The development of the antenna array theory and
practice, including the phased and adaptive arrays.
The successes and achievements in this field are
widely known and related to bands from tens of
MHz to the optical one.
3. The search of ways in order to create the ultra-
short pulse signal transmission and reception de-
vices. In this case are washed away the differences
between the usual in radio techniques notions of
the carrier frequency and the mode of modulation
of radio signal. Nowadays the attempts are made at
the creation for various purposes of radio technical
devices employing the ultrashort pulses. Despite
the long-term and numerous investigations by nu-
merical methods on powerful computers for calcu-
lating the time-pulse electromagnetic processes, se-
rious difficulties are encountered in practice in the
design of effective antennas in this regard.
2. Ultrawideband Antennas
and Their Features
The ultrawideband antennas are often called fre-
quency independent [3]. Wherein the independence
of the antenna parameters on frequency is meant.
However even a comparatively simple antenna avails
of about 20 parameters of a quite different behavior
each as signal frequency varies. The examples in
Fig. 1 are to prove this statement. For a linear an-
tenna with its size much less than the radiation wave-
length (Fig. 1(a)), the spatial pattern in the band, the
directivity factor and the radiation field polarization
structure are invariant for a wide band. Whereas, for
example, the input complex impedance of the an-
tenna varies essentially.
Fig. 1.
rS
f
R
f
∆Θ
f
G
f
c)
G
∆Θ
f
rS
fb)
∆Θ
azimuth
elevation
f
X
f
a)
A.N. Titov
480 Radio Physics and Radio Astronomy, 2002, v. 7, No. 4
Fig. 1(b) concerns the antennas made as the
logo-periodic structures [3]. In such antennas the gain
and the directivity pattern width remain constant in
the band. At the same time such important character-
istics as the effective height and the receiving area of
the antenna do experience a sharp decrease as fre-
quency increases. A principal feature of these anten-
nas is that at any frequency in the band only one reso-
nant part of the antenna is excited and the rest ones
are a useless ballast. Evidently, the wider is the work-
ing band of a suchlike antenna, the slighter are the
relative coefficients characterizing its overall dimen-
sions, the cost, the material capacity, upon the higher
frequencies in the band.
However, when the logo-periodic antennas are
employed as the irradiators of the compound anten-
nas (Fig. 1(c)), the situation changes. The receiving
area of the antenna remains the same, and sufficiently
efficient, in the band. Likewise is non-varied the an-
tenna input impedance. The gain goes up by the pro-
portionality law 2λ− , acquiring at any frequency the
value close to the maximal possible one for the given
overall dimensions of the antenna. Correspondingly,
the antenna beam gets contracted proportionally to
the wavelength.
Thus, designing any particular ultrawideband
antenna it is necessary to ensure the frequency inde-
pendence primarily of those antenna parameters
which mostly affect the quality of the radio technique
system considered.
It is of much practical importance to find out
principal relations between the minimal possible
overall dimensions of the antenna and such its pa-
rameters as the amplification coefficient, the degree
of the matching in the band, and the efficiency. The
ideas in this regard have been proposed and advanced
by Chu [4], Harrington [5], Fano [6], Hansen [7]. Of
the recent researches in the field, one should point
out [8] where the relationships are obtained relating
the antenna overall dimensions to the achievable
level of its matching in a given band.
The expansion of the radiator fields in terms of
the spherical harmonics has turned out to be very
fruitful. Each harmonic is expressed in terms of Leg-
endre functions and spherical Bessel functions. For-
mally the infinite number of harmonics can be trun-
cated via the ratio N of the radius of a sphere cir-
cumscribing the antenna to 1(2 )π λ− . Then, in accor-
dance with [5], the lossless antenna gain may be up
to values 2 2N N+ . Solid line in Fig. 2 is for the
antenna gain dependence on /D λ ratio. Dotted line
is for the attainable gain of the antenna with a plain
aperture obtained by the known formula
2
4
aperG Sπ
λ
= , where aperS is taken equal the sphere
section passed through the diameter. It is seen that
the volume antenna, especially a small one, is the
energy advantageous over the plain one. Also, in this
figure there is the gain of a half-wave vibrator. By
gain the latter is inferior to the plain and, especially,
to the volume antenna conditioning that all the three
are circumscribed with the sphere of half-wavelength
diameter.
In Fig. 3 there are the curves concerning the
principal relation between the reflection coefficient
at the antenna input, the diameter of a sphere cir-
cumscribing the antenna, the maximal wavelength
and the degree of the antenna widebandness. As an
indicator of the widebandness is taken the ratio
maxf to minf , i.e. the work band maximal to mini-
mal frequency.
The curves in the figure correspond to the an-
tenna efficiency equaling 1. The similar curve fami-
lies can be plotted for the lesser efficiencies. At that
the curves will shift towards lesser max/D λ .
With these figures one can have indicated the
achieved quality of any particular worked-out an-
tenna. The analysis from this point of view of a good
many antennas in scientific publications demon-
strates that a vast majority of the antennas possess
characteristics very much worse than the potentially
achievable ones. In Fig. 3 there are the best antennas'
design results. These are the wideband plane spiral
antenna [1] and the symmetric vibrator antenna the
arms of which are spherical cones with vertex an-
Fig. 2.
G100
50
20
10
5
2
1
0.1 0.2 0.3 0.5 1.0 2.0
2
4 aperS
S
π
λ
=
D
λ
Some Aspects Concerning the Designing of Ultrawideband and Pulse Antennas
Radio Physics and Radio Astronomy, 2002, v. 7, No. 4 481
gle 100°. Also in this figure there are the characteris-
tics of the symmetric half-wave vibrator supposed to
have the bandwidth corresponding to max min/f f at
the reflection coefficient level of –10 dB.
Besides, some certain hypothetical antenna with
the reflection coefficient –25 dB in the band
max min/ 1.5f f = circumscribed with the sphere of
max0.55 λ diameter is denoted with an encircled
cross in this figure. Evidently, the optimization of
this antenna while the band is kept the same could
have potentially led to either its overall dimensions 3
times lessening or its overall dimensions 2 times
lessening and its bandwidth expanding up to
max min/ 10f f = simultaneously. The optimization
of this antenna could have been directed as well to its
reflection coefficient lessening at a simultaneous
lessening of the dimensions and expansion of the
work band.
The analysis of the structures and characteristics
of the ultrawideband antennas in publications permits
also to arrive at the conclusion that their characteris-
tics approach the potentially achievable ones closer
so far as the better the antenna configuration can be
circumscribed with a sphere. In order to illustrate this
thesis, in Fig. 4 there are different antenna configura-
tions in their growth of preference order. There are
successively the following antenna types in the fig-
ure: 1 − linear antenna, 2 − plain symmetrical vibra-
tor antenna (“butterfly”), 3 − plain spiral antenna, 4 −
symmetrical vibrator with spherical-cone arms, 5 −
TEM-horn.
In this way, the following practically useful
conclusions can be drawn up:
1. Any arbitrarily electrically small antenna can be
well matched in a certain band without losses.
2. Any arbitrarily electrically small antenna can be
well matched in some fairly wide band at the ex-
pense of diminishing its efficiency.
3. The overall antenna dimensions should be re-
garded as a resource permitting to enlarge its
widebandness and quality of the matching.
4. If the overall dimensions are kept up, the antenna
dimensionality (linear, plain, volume) can also be
considered a resource allowing to enlarge the
widebandness, the quality of the matching and the
antenna amplification coefficient.
5. The transition, at the kept-up maximal wave-
length, from a wideband antenna to an ultrawide-
band one requires in fact only an insignificant
enlargement of its dimensions.
As a consequence: if a radio technical system
has several work bands at a uniform radiation polari-
zation, it does make sense testing the possibility of
using a common antenna. In this case the functions of
signals separation should be given over to such
feeder line elements as the commutators and filters.
3. Some General Aspects of the Pulse
Antenna Design
The principal distinction of the pulse antennas from
the wideband ones resides in the following. As re-
gards the ultrawideband antennas, it is supposed first
that frequency spectrums of the signals exciting the
antenna and of the fields formed by it are identical
and second that these signals spectrums are much
narrower than the work band of the antenna. As re-
gards their pulse counterparts, those spectrums differ
and practically fill up the whole antenna bandwidth.
Moreover, they are generally distance-and-direction-
dependent related to the pulse radiator. The next
peculiarity resides in that the radio technique sys-
tems employing the ultrashort electromagnetic sig-
nals are essentially short-ranged. These short ranges
may not only fall inside the Fresnel zone, but may be
less than the wavelength of the signal spectrum cen-
tral frequency.
The arising problems are also concerned with
that all of the antenna parameters have been intro-
duced for the antenna excitation by a continuous si-
nusoidal signal of a certain frequency. The pulse an-
tennas do require other, more effective, parameters
enabling a comparison between different pulse an-
tennas and also to analyze and design the radio tech-
nique system as a whole. Such parameters as the
Fig. 3.
max
D
λ
max
min
f
f
= ∞
, dBΓ
SWR
∞1.951.221.061.02
50− 40− 30− 20− 10− 0
0.1
0.2
0.3
0.4
1.5
1.2
50
5010
1.5
1.1
1.01
1 2 3 4 5
Fig. 4.
A.N. Titov
482 Radio Physics and Radio Astronomy, 2002, v. 7, No. 4
complex gain, the pulse and transient responses of
the four-poles, so much effective in the linear elec-
tronic circuit analysis, are evidently unsatisfactory in
this case. Correspondingly, serious methodological
and hardware problems are available as regards the
pulse antenna design. Therefore the empirical meth-
ods based on the experimental investigation of the
system as a whole prevail in the pulse antenna design
for any particular system. The experience accumu-
lated by now due to a good many researchers’ labour
permits to put down the following recommendations
to be made use of in the pulse antenna design.
1. From the view-point of providing the required
bandwidth, the previous-section statements con-
cerning the ultrawideband antennas can be a basis.
As the energy condition in the systems employing
ultrawideband pulse signals is not, as a rule,
strained and, first of all, it is necessary to produce
a compact pulse without “tails”, one can recom-
mend an enlargement of losses in the antenna as a
way to expand the bandwidth. For this purpose
various absorbents of electromagnetic energy can
be used; such as the ballast resistors, conductors
made of poor conductivity materials, radio absorb-
ing materials round the antenna elements, includ-
ing the ferrite one. There are certain examples that
the antenna efficiency reduction only to 0.5 can
expand essentially the antenna bandwidth [10, 11].
2. The basic type of oscillations in the pulse antenna
must be TEM wave as a wave without dispersion.
3. The pulse antenna bandwidth has to exceed sig-
nificantly the spectrum width of the signal excit-
ing the antenna. It appears that the thin temporal
structure of any electromagnetic pulse radiated by
antenna, the 'tails' of this response are dependent
on the antenna characteristics outside the given
band [1].
4. In the antenna one should avoid to use the dense-
dielectric elements longitudinal related to a propa-
gating signal. This is a protective measure against
transformations of the TEM-wave into types with
dispersion [12].
5. In the antenna one should avoid the cross-wise
dielectric plates of the width over min /20λ ε .
This measure is to diminish the risk of undesirable
resonance phenomena to emerge in the work band.
Acknowledgment
In conclusion, the author is deeply thankful to
Prof. N. N. Kolchigin and Prof. M. B. Egorov for
care and help and to Prof. C. E. Baum (USA) for
fruitful discussions.
References
1. I.L. Volakis et al. IEEE Ant. and Prop. Mag. 43,
No. 6, pp. 15-26, Dec. 2001.
2. S.S. Sandler, R.W.P. King. IEEE Trans. on Ant. and
Prop. 42, No. 3, pp. 436-439, March 1994.
3. V. Rumsey. Frequency Independent Antennas. AP, N-
J. 1996.
4. L.I. Chu. Journ. of Appl. Phys. Vol. 19, No. 12, 1948.
5. R.F. Harrington. Journ. Res. Nat. Bur. St. Vol. 64D,
No. 1, 1960.
6. R. Fano. Electromagnetic Energy Transmission and
Radiation, N-J, 1960.
7. R. Hansen. PIEEE Vol. 69, No. 2, pp. 170-182, 1981.
8. G.S. Ohmarov, A.Kh. Kharmush. Radiotechnika,
2001, No. 11, pp. 31-34 (in Russian).
9. T.T. Wu, R.W.P. King. IEEE Trans. on Ant. and Prop.
Vol. AP-13, May 1965, pp. 369-379.
10. 10. L.C.Shen, R.W.P.King IEEE Trans. on Ant. and
Prop. Vol. AP-13, Nov 1965, p. 998.
11. C. Bennett, G.F. Ross. PIEEE, Vol. 66, No. 3, March
1978, pp. 299-318.
12. M.A.P. Gunston. Microwave Transmission-Line Im-
pedance Data. Van Nostrand, N-J-Melbourne, 1972.
НЕКОТОРЫЕ ВОПРОСЫ
ПРОЕКТИРОВАНИЯ
СВЕРХШИРОКОПОЛОСНЫХ И
ИМПУЛЬСНЫХ АНТЕНН
А.Н. Титов
Рассматриваются потенциально достижимые ха-
рактеристики антенн, в том числе сверхширокополос-
ных. Подчеркивается принципиальное влияние конфи-
гурации антенн на степень приближения характеристик
антенны к потенциально достижимым. Обсуждается
сходство и различие в подходах к проектированию
сверхширокополосных и импульсных антенн. Излага-
ются общие рекомендации, связанные с выбором типов
и конструкций антенн, предназначенных для излучения
и приема импульсных электромагнитных сигналов.
ДЕЯКІ ПИТАННЯ ПРОЕКТУВАННЯ
НАДШИРОКОСМУГОВИХ ТА
ІМПУЛЬСНИХ АНТЕН
А.М. Титов
Розглянуто потенційно досяжні характеристики
антен, у тому числі надширокосмугових. Підкреслено
принциповий вплив конфігурації антен на ступінь на-
ближення характеристик антени до потенційно досяж-
них. Обговорюється схожість та відмінність у підходах
до проектування надширокосмугових та імпульсних
антен. Викладено загальні рекомендації, пов’язані з
вибором типів і конструкцій антен, призначених для
випромінювання і прийому імпульсних електромагніт-
них сигналів.
|