CA1055600A - Wideband antenna - Google Patents
Wideband antennaInfo
- Publication number
- CA1055600A CA1055600A CA247,194A CA247194A CA1055600A CA 1055600 A CA1055600 A CA 1055600A CA 247194 A CA247194 A CA 247194A CA 1055600 A CA1055600 A CA 1055600A
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- bandwidth
- wide
- slots
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
- H01Q9/28—Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines
Abstract
ABSTRACT OF THE DISCLOSURE
A wide-bandwidth antenna comprises an active antenna element of generally conical surface configuration having discrete areas modified to be frequency-responsive about in-dividual ones of a geometrically progressive series of frequency maxima within the bandwidth. The dimensions of the areas are progressively scaled by a substantially constant factor cor-resonding to the multiplication factor of the series. The antenna is lightweight and inexpensive and simple in construction, but highly efficient over a wide range of frequencies.
A wide-bandwidth antenna comprises an active antenna element of generally conical surface configuration having discrete areas modified to be frequency-responsive about in-dividual ones of a geometrically progressive series of frequency maxima within the bandwidth. The dimensions of the areas are progressively scaled by a substantially constant factor cor-resonding to the multiplication factor of the series. The antenna is lightweight and inexpensive and simple in construction, but highly efficient over a wide range of frequencies.
Description
1055600 ~;
This invention relates to a novel form of a wide -bandwidth antenna. 1-Various antenna systems are commonly employed to ;
provide wide bandwidth spectra, the majority of which rely upon a plurality of physically separate, electrieally interconnected antennae, arranged to individually cover specific narrow regions of the band. Thus, each antenna is tuned to a specific region, and the total combination i5 able to cover the sum of these regions extending over the required band of frequencies.
Multiple antennae arrangements of this type sufer .. . ..
from the disadvantages of expense, bulk, and complexity, and it would clearly be advantageous to provide a single, light-weight antenna capable of e~ficiently covering a wide ranye of ~requencies.
One type of single wide bandwidth antenna was described by R. J. Wohlers ~20th USAF Antenna Symposium, 1967) in a paper entitled "The GWIA, An Extremely Wide Bandwidth Low-Dispersior Antenna". However, like other single wide bandwidth antennae which have been-proposed,~ the Wohlers design suffers from relatively high cost, complexity and bulk.
An object of the present invention is to provide a single light-weight antenna, which i9 relatively inexpensive and simple in construction, yet highly efficient over a wide . ..
range of frequencies. ;
' . . ~
Thus, according~to the present invention, there is 1-provided a~wide bandwidth~antenna comprisLng~an active antenna ;element of generally conical~surface configurat~on, said element having~discrete areas thereo~f respectL;vely modified to be frequency-responsive about individua~l ones-of algeometrically ~30~ progres~ive~series of~f~requency maxima.withln said bandwidth, ~ ;
, . . .
::
.:, , ~:', ', the dimensions of said areas being progressively scaled by a substantially constant factor corresponding to the multiplication factor of said series.
The invention will no~l be described by way of example only and with reference to the accompanying drawings, wherein~
Figure 1 is a cross-sectional view of an antenna according to one embodiment of the invention; and . Figure 2 is a cross-sectional view of an antenna .
according to yet a further embodiment of.the invention.
Considering, firstly, Figure 1, the arrangement illustrated is based upon the electromagnetic modelling or scaling log-periodic concept, which generally provides that if all the dimensions of a lossless. antenna are changed by a ~actor ~, then the antenna performance is identical at a 1.
fre~uency 1/p. Thus, in Figure 1, there 1s shown a bi-conical antenna having coaxially allgned elements lO and 11 respectively.
The elements are embedded Ln cylindrical foam block 12, which is contained within a tubul~ar membersl3.The apices of the elements : 10 and 11 are;co-ad~acent and spaced by.a smaLl amount, and ~-:20 antenna.feed..wires.14 and 15 are respectively connected thereto~
The.. arrangement thus far described is well.known in the field of ~.
.. bi-conical antenna structures.
The surfaces of the~conical elements lO;and 11 are .stepped,~ as~at lOa, lOb,:lOc,;...etc.~and lla, llb,~ llc,~ ...etc., ~ l respectively. ~As will~be~ appreciated~from a;consideration of ~ - .
the~drawing,~:the respectivel:surface~po~tions of t.he elements~
~ 10 ànd 1l between successive~steps are o:f-frusto-conical ~
:~ configuration and each~such portlon will be responsive to~a ~ ~ ¦
eaific~:narrow bandwidth.~ofsfrequenciea. It will~-further be 30~ ~seen that~.the surface portions bet~een successive steps are . ; :
::
'' ' ~ . ' ~ ' '. ;'"
'.' .' ',.:' ; ,,,,.' : .
lOSS600 ..
formed with a constant angle.of taper, and thus, the mean radii .. ;.:
of the portions vary by a constant factor. Since the surface area and dimensions of each portion are directly proportional to the mean radius thereof, the antenna structure may be considered to be a series of antennae whose dimensions are changed by a constant factor ~, Therefore, the performance of . .
each of these individually considered"antennae"is identical at -a frequency of l/p times the frequency of the adjacent "antenna".
Referring specifically,:again, to Figure 1, if the .lO antenna portion between the innermost step lOf and the apex of .
the element lO is responsive to a frequency F, then having regard to the foregoing, the antenna portions between successive ~ .
steps lOf and lOe; lOe and lOd ... lOb and lOa will have identical performances at frequencies Fj~p, Fjp2 ,,,.,F/p6, respectively. ~earing in mind that the foreg~ing are centre fre~uencies about which the respective conicaI surface "antennae"
, have optimum perormance,~.it occurs.in.practice that there ... . ,:
is sufficient overlap between the effective frequency response :~
. maxima and mlnima of adjacent suxfaces to provide a substantially 20- flat.overall response~.or the complete antenna of from F to F/p6. . ~ .
. Figure 2 shows an alternative embod.5i.ment of the invention~.using slots instead of steps to prov.ide the necessary .. re~uency scaling. The antenna Lllustrated in Figure 2 again comprises conical elements 20~and ~1 embedded with~a generally cylindrical foam.rubber block 22.. ~r~he.block 22 ls:contained ~ :
within~a tubular membar 23~and antenna~feed~wires 24 and 25 are `. :
pro~ided~.for the elements.:20 and 2L,:respectively. ~Slots~26 are -.
.arranged.circularly.around the surfaces.of.the~elements~20 and . 21, the slot~dimensions~being scaled~in accordance-:with~the , . :
~3~ respectLve radLi of the~cLrcular slot arrays, the soale faotor !
:~, :
': :
- 10556~0 again being p. Thus, if -there are seven slot arrays - as in the specific embodiment of Figure 2 - then, by analogy with the discussion set forth above, the frequency response of the antenna will be substantially flat from F to F/p7.
It will be appreciated that the slots or steps need not be circularly arrayed around the conical surface. For example, a spiral array may effectively be employed, if desired, or indeed any other type of array which will give the required constant-ratio gradation of the effective antenna elements.
Furthermore, the invention is not restricted to bi-conical antennae of th~ type specifically described. The invention is equally applicable to other types o conical-, element antennae - for example, cross bi-conicals which utilize ;
two bi-conical arrays mutually oriented at 90. The invention is also applicable to discone antennae, which comprises a conical element in~conjunction wlth~a di~sc-shaped element pro~
vided at the apex of the conical element and located coaxial therewith. ~ ~
. ~
With respect to the materials employed, it may be - ;
noted that the cylindrical ~oam block shown in each of Figures 1 and 2 is ~or mechanical support only and has no influence upon the electrical properties of the antenna. It will be ; appreciated that any~sultable~electrlcally ~insulating mate~rial may~b~e utillzed for thls~purpose and that a similar electrlc~
ally~insu~lation reinforcément;materlal~may be~placed inside~
the~conical~ elements,~if desirèd.
. .
` 30~
~ 4 ~
, ,,,, ~ ; , . . .
This invention relates to a novel form of a wide -bandwidth antenna. 1-Various antenna systems are commonly employed to ;
provide wide bandwidth spectra, the majority of which rely upon a plurality of physically separate, electrieally interconnected antennae, arranged to individually cover specific narrow regions of the band. Thus, each antenna is tuned to a specific region, and the total combination i5 able to cover the sum of these regions extending over the required band of frequencies.
Multiple antennae arrangements of this type sufer .. . ..
from the disadvantages of expense, bulk, and complexity, and it would clearly be advantageous to provide a single, light-weight antenna capable of e~ficiently covering a wide ranye of ~requencies.
One type of single wide bandwidth antenna was described by R. J. Wohlers ~20th USAF Antenna Symposium, 1967) in a paper entitled "The GWIA, An Extremely Wide Bandwidth Low-Dispersior Antenna". However, like other single wide bandwidth antennae which have been-proposed,~ the Wohlers design suffers from relatively high cost, complexity and bulk.
An object of the present invention is to provide a single light-weight antenna, which i9 relatively inexpensive and simple in construction, yet highly efficient over a wide . ..
range of frequencies. ;
' . . ~
Thus, according~to the present invention, there is 1-provided a~wide bandwidth~antenna comprisLng~an active antenna ;element of generally conical~surface configurat~on, said element having~discrete areas thereo~f respectL;vely modified to be frequency-responsive about individua~l ones-of algeometrically ~30~ progres~ive~series of~f~requency maxima.withln said bandwidth, ~ ;
, . . .
::
.:, , ~:', ', the dimensions of said areas being progressively scaled by a substantially constant factor corresponding to the multiplication factor of said series.
The invention will no~l be described by way of example only and with reference to the accompanying drawings, wherein~
Figure 1 is a cross-sectional view of an antenna according to one embodiment of the invention; and . Figure 2 is a cross-sectional view of an antenna .
according to yet a further embodiment of.the invention.
Considering, firstly, Figure 1, the arrangement illustrated is based upon the electromagnetic modelling or scaling log-periodic concept, which generally provides that if all the dimensions of a lossless. antenna are changed by a ~actor ~, then the antenna performance is identical at a 1.
fre~uency 1/p. Thus, in Figure 1, there 1s shown a bi-conical antenna having coaxially allgned elements lO and 11 respectively.
The elements are embedded Ln cylindrical foam block 12, which is contained within a tubul~ar membersl3.The apices of the elements : 10 and 11 are;co-ad~acent and spaced by.a smaLl amount, and ~-:20 antenna.feed..wires.14 and 15 are respectively connected thereto~
The.. arrangement thus far described is well.known in the field of ~.
.. bi-conical antenna structures.
The surfaces of the~conical elements lO;and 11 are .stepped,~ as~at lOa, lOb,:lOc,;...etc.~and lla, llb,~ llc,~ ...etc., ~ l respectively. ~As will~be~ appreciated~from a;consideration of ~ - .
the~drawing,~:the respectivel:surface~po~tions of t.he elements~
~ 10 ànd 1l between successive~steps are o:f-frusto-conical ~
:~ configuration and each~such portlon will be responsive to~a ~ ~ ¦
eaific~:narrow bandwidth.~ofsfrequenciea. It will~-further be 30~ ~seen that~.the surface portions bet~een successive steps are . ; :
::
'' ' ~ . ' ~ ' '. ;'"
'.' .' ',.:' ; ,,,,.' : .
lOSS600 ..
formed with a constant angle.of taper, and thus, the mean radii .. ;.:
of the portions vary by a constant factor. Since the surface area and dimensions of each portion are directly proportional to the mean radius thereof, the antenna structure may be considered to be a series of antennae whose dimensions are changed by a constant factor ~, Therefore, the performance of . .
each of these individually considered"antennae"is identical at -a frequency of l/p times the frequency of the adjacent "antenna".
Referring specifically,:again, to Figure 1, if the .lO antenna portion between the innermost step lOf and the apex of .
the element lO is responsive to a frequency F, then having regard to the foregoing, the antenna portions between successive ~ .
steps lOf and lOe; lOe and lOd ... lOb and lOa will have identical performances at frequencies Fj~p, Fjp2 ,,,.,F/p6, respectively. ~earing in mind that the foreg~ing are centre fre~uencies about which the respective conicaI surface "antennae"
, have optimum perormance,~.it occurs.in.practice that there ... . ,:
is sufficient overlap between the effective frequency response :~
. maxima and mlnima of adjacent suxfaces to provide a substantially 20- flat.overall response~.or the complete antenna of from F to F/p6. . ~ .
. Figure 2 shows an alternative embod.5i.ment of the invention~.using slots instead of steps to prov.ide the necessary .. re~uency scaling. The antenna Lllustrated in Figure 2 again comprises conical elements 20~and ~1 embedded with~a generally cylindrical foam.rubber block 22.. ~r~he.block 22 ls:contained ~ :
within~a tubular membar 23~and antenna~feed~wires 24 and 25 are `. :
pro~ided~.for the elements.:20 and 2L,:respectively. ~Slots~26 are -.
.arranged.circularly.around the surfaces.of.the~elements~20 and . 21, the slot~dimensions~being scaled~in accordance-:with~the , . :
~3~ respectLve radLi of the~cLrcular slot arrays, the soale faotor !
:~, :
': :
- 10556~0 again being p. Thus, if -there are seven slot arrays - as in the specific embodiment of Figure 2 - then, by analogy with the discussion set forth above, the frequency response of the antenna will be substantially flat from F to F/p7.
It will be appreciated that the slots or steps need not be circularly arrayed around the conical surface. For example, a spiral array may effectively be employed, if desired, or indeed any other type of array which will give the required constant-ratio gradation of the effective antenna elements.
Furthermore, the invention is not restricted to bi-conical antennae of th~ type specifically described. The invention is equally applicable to other types o conical-, element antennae - for example, cross bi-conicals which utilize ;
two bi-conical arrays mutually oriented at 90. The invention is also applicable to discone antennae, which comprises a conical element in~conjunction wlth~a di~sc-shaped element pro~
vided at the apex of the conical element and located coaxial therewith. ~ ~
. ~
With respect to the materials employed, it may be - ;
noted that the cylindrical ~oam block shown in each of Figures 1 and 2 is ~or mechanical support only and has no influence upon the electrical properties of the antenna. It will be ; appreciated that any~sultable~electrlcally ~insulating mate~rial may~b~e utillzed for thls~purpose and that a similar electrlc~
ally~insu~lation reinforcément;materlal~may be~placed inside~
the~conical~ elements,~if desirèd.
. .
` 30~
~ 4 ~
, ,,,, ~ ; , . . .
Claims (4)
1. A wide-bandwidth antenna, comprising:
an active antenna element of generally conical surface configuration;
a plurality of sets of slots formed in said active antenna element and frequency-responsive about individual ones of a geometrically progressive series of frequency maxima within said bandwidth;
the dimensions of the slots being scaled in accordance with the respective radii of said slots from the axis of said active antenna element and said radii varying by a substantially constant factor corresponding to the multiplication factor of said series.
an active antenna element of generally conical surface configuration;
a plurality of sets of slots formed in said active antenna element and frequency-responsive about individual ones of a geometrically progressive series of frequency maxima within said bandwidth;
the dimensions of the slots being scaled in accordance with the respective radii of said slots from the axis of said active antenna element and said radii varying by a substantially constant factor corresponding to the multiplication factor of said series.
2. A wide-bandwidth antenna claimed in claim 1, wherein said slots are circularly arrayed within said conical surface about the axis thereof.
3. A wide-bandwidth antenna as claimed in claim 1, wherein said slots are spirally arrayed within said conical surface.
4. A wide-bandwidth antenna as claimed in claim 1, 2 or 3, wherein said antenna is of bi-conical configuration, wherein each of the active elements thereof is modified as aforesaid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA247,194A CA1055600A (en) | 1976-03-05 | 1976-03-05 | Wideband antenna |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA247,194A CA1055600A (en) | 1976-03-05 | 1976-03-05 | Wideband antenna |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1055600A true CA1055600A (en) | 1979-05-29 |
Family
ID=4105389
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA247,194A Expired CA1055600A (en) | 1976-03-05 | 1976-03-05 | Wideband antenna |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1055600A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2406220A (en) * | 2003-09-22 | 2005-03-23 | Thales Uk Plc | Ultra wide band antenna for pulse transmission and reception |
| EP2001083A2 (en) | 2002-10-23 | 2008-12-10 | Sony Corporation | Wideband antenna |
-
1976
- 1976-03-05 CA CA247,194A patent/CA1055600A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2001083A2 (en) | 2002-10-23 | 2008-12-10 | Sony Corporation | Wideband antenna |
| EP2001082A3 (en) * | 2002-10-23 | 2008-12-24 | Sony Corporation | Wideband antenna |
| EP2001083A3 (en) * | 2002-10-23 | 2008-12-24 | Sony Corporation | Wideband antenna |
| US7626558B2 (en) | 2002-10-23 | 2009-12-01 | Sony Corporation | Wideband antenna |
| GB2406220A (en) * | 2003-09-22 | 2005-03-23 | Thales Uk Plc | Ultra wide band antenna for pulse transmission and reception |
| GB2406220B (en) * | 2003-09-22 | 2006-10-18 | Thales Uk Plc | An antenna |
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