EP2237372A1 - Dipole antenna for a CB band base station - Google Patents
Dipole antenna for a CB band base station Download PDFInfo
- Publication number
- EP2237372A1 EP2237372A1 EP10158258A EP10158258A EP2237372A1 EP 2237372 A1 EP2237372 A1 EP 2237372A1 EP 10158258 A EP10158258 A EP 10158258A EP 10158258 A EP10158258 A EP 10158258A EP 2237372 A1 EP2237372 A1 EP 2237372A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coaxial line
- dipole antenna
- coaxial
- base station
- choke coil
- 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.)
- Withdrawn
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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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
-
- 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
- H01Q9/18—Vertical disposition of the antenna
-
- 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
- H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
-
- 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
- H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
- H01Q9/32—Vertical arrangement of element
Definitions
- the present invention refers to a dipole antenna for a CB band base station.
- the invention refers to a dipole antenna for a CB band base station which makes it possible to avoid using cumbersome radials and to eliminate the tuning coils that are usually necessary, thus obtaining a useful band of impedance that is much wider than that of known antennae, with the least possible hindrance.
- the basic antennae commonly used are of the "ground plane”, "quarter-wave”, “half-wave dipole” or “five-eighths wave” type. Such antennae have a vertical pole of length that is proportional to the wavelength and, in some versions, radials.
- the "ground plane” type well known in the literature, is constituted by a vertical pole of quarter-wavelength and by a plurality of radials, also of quarter-wavelength, which form an angle at 90° from the vertical pole (see figure 1 ).
- a second version is shown in figure 2 where the radials are bent downwardly until they form an angle that is on average comprised between 120° and 140° to improve the adaptation of the impedance to the classic 50 ohm.
- the aforementioned antennae are easy to manufacture, and can be supplied with power directly to the centre, but have cumbersome radials which must be inclined in order to obtain a correct impedance.
- the "half-wave" type shown in figure 3 is substantially a dipole antenna powered at its lower end by means of an impedance transformer. Manufacturing an antenna of this type does not require the use of radials but it does imply a careful construction of the impedance transformer which in any case limits its usage band.
- the "five-eighths wave” type with a signal gain that is slightly higher than those of the previous types, is constituted by a vertical pole, of length equal to five-eighths of the wavelength, and by a plurality of radials which are essential for correct functioning and, as with the half-wave type, an adequate impedance transformer which, in this case also, limits its usage band (see figure 4 ).
- the aim of the present invention is to devise a dipole antenna of the type that makes it possible to avoid using cumbersome radials, and at the same time eliminating the tuning coils.
- an object of the present invention is to devise a dipole antenna that makes it possible to obtain a useful band of impedance that is much wider than that of known antennae, with the least possible encumbrance.
- Another object of the present invention is to devise a dipole antenna that is decoupled from the support structure, to avoid distortions in the radiation diagram.
- Another object of the present invention is to devise a dipole antenna that is highly reliable, relatively simple to provide and at competitive cost.
- a dipole antenna for a CB band base station characterized in that it is provided by means of a coaxial line comprising a first portion that is connected to a second portion which constitutes a choke coil and to a third portion which constitutes a radiating element.
- the dipole antenna according to the present invention comprises, with reference to its first embodiment shown in figure 5 , a coaxial feeder line 2, connected to a generator, not shown, such coaxial feeder line 2, with characteristic impedance of 50 ohm, continuing in a choke coil 3, made with coils that are distanced and arranged parallel to each other.
- the coaxial feeder line 2 which thus continues in the choke coil 3, finally continues in a portion of coaxial line 4 that has a length that is equal to, for example, a quarter of the wavelength and self-impedance Zc.
- the central conductor 5 of the coaxial line is electrically connected to a metal radiator 6 having a length that is equal to, for example, a quarter of the wavelength.
- the radiofrequency signal that comes from the generator travels inside the feeder line 2, continues into the coaxial cable forming the coils of the choke coil 3, and then continues into the portion of coaxial line 4 to arrive at the junction point with the radiator 6.
- the current that travels through the radiator 6 will stop at the upper end of the radiator 6, while the external current of the portion of coaxial line 4 which returns downwards will be blocked by the choke coil 3, because a choke inductance is present which is connected in series with such current.
- the choke coil 3 produces its choke effect on the currents beginning from a minimum frequency, to be identified according to necessity, and for all higher frequencies, and it is therefore intrinsically wide-band.
- the current that travels on the outside of the coaxial cable or portion of feeder line 4 is concordant with the current that travels through the radiator 6.
- Another advantage of the antenna according to the invention is that, with the varying of the frequency, the currents on the radiator are always in phase for all lengths that are shorter than an entire wave, as shown in figure 8 (as in a classic dipole antenna, powered internally). Therefore, by means of suitable systems for impedance adaptation, this structure functions correctly even when its length is other than half-wave with signal gains proportional to its length.
- Figure 6 shows the dipole antenna according to the invention in a second embodiment and in such figure the same reference numerals refer to identical elements.
- radiator 6 located at the end of the portion of coaxial line 4
- radiator 6 is replaced by another coaxial line 7, arranged in such a way that the central conductor 5 of the portion of coaxial line 4 is connected with the outer part of the coaxial line 7, while the outside of the portion of coaxial line 4 is connected with the internal conductor 8 of the portion of coaxial line 7.
- the central or internal conductor 8 of the portion of coaxial line 7 and the outer shielding of such portion 7 are electrically connected to each other.
- the outer shielding of the portion 7 of coaxial line performs such function of the radiator 6, while its internal conductor 8 defines a path and ensures the presence of a direct current short-circuit to protect the transmission apparatus from electrical discharges generated by atmospheric disturbances.
- the impedance of the portion of coaxial line 7 is conveniently a self-impedance Ze.
- the sections of coaxial cable can conveniently be contained inside a dielectric tube, such as for example a fibreglass tube, which carries out the function both of mechanical support and of protection from atmospheric agents.
- Figure 7 shows the dipole antenna according to the present invention in a third embodiment.
- the difference between the third embodiment shown in figure 7 and the second embodiment shown in figure 6 consists in that a radiating element 9 is connected to the upper end of the coaxial line 7, at the internal conductor 8 of the coaxial line 7.
- the radiating element 9 can be compared to the radiator 6 in the first embodiment.
- the third embodiment of the invention is a combination of the first and second embodiments described previously.
- the overall radiating part of the third embodiment of the invention is therefore composed of the internal conductor 8 and the radiator 9 and their overall lengths are, for example, quarter-wave, thus functioning like the upper portions of the embodiments in figures 5 and 6 .
- the length of the coaxial line formed by the coaxial line 7 and by the internal conductor 8 becomes usable as a new parameter for regulating and optimising the global impedance.
- the dipole antenna according to the present invention fully achieves the intended aim and objects.
Landscapes
- Mobile Radio Communication Systems (AREA)
- Details Of Aerials (AREA)
Abstract
A dipole antenna (1) for a base station provided by means of a coaxial line that comprising a first portion (2) that is connected to a second portion which constitutes a choke coil (3) and to a third portion which constitutes a radiating element (6, 9).
Description
- The present invention refers to a dipole antenna for a CB band base station.
- More specifically, the invention refers to a dipole antenna for a CB band base station which makes it possible to avoid using cumbersome radials and to eliminate the tuning coils that are usually necessary, thus obtaining a useful band of impedance that is much wider than that of known antennae, with the least possible hindrance.
- The basic antennae commonly used are of the "ground plane", "quarter-wave", "half-wave dipole" or "five-eighths wave" type. Such antennae have a vertical pole of length that is proportional to the wavelength and, in some versions, radials. In particular, the "ground plane" type, well known in the literature, is constituted by a vertical pole of quarter-wavelength and by a plurality of radials, also of quarter-wavelength, which form an angle at 90° from the vertical pole (see
figure 1 ). A second version is shown infigure 2 where the radials are bent downwardly until they form an angle that is on average comprised between 120° and 140° to improve the adaptation of the impedance to the classic 50 ohm. The aforementioned antennae are easy to manufacture, and can be supplied with power directly to the centre, but have cumbersome radials which must be inclined in order to obtain a correct impedance. The "half-wave" type shown infigure 3 is substantially a dipole antenna powered at its lower end by means of an impedance transformer. Manufacturing an antenna of this type does not require the use of radials but it does imply a careful construction of the impedance transformer which in any case limits its usage band. - The "five-eighths wave" type, with a signal gain that is slightly higher than those of the previous types, is constituted by a vertical pole, of length equal to five-eighths of the wavelength, and by a plurality of radials which are essential for correct functioning and, as with the half-wave type, an adequate impedance transformer which, in this case also, limits its usage band (see
figure 4 ). - The aim of the present invention is to devise a dipole antenna of the type that makes it possible to avoid using cumbersome radials, and at the same time eliminating the tuning coils.
- Within this aim, an object of the present invention is to devise a dipole antenna that makes it possible to obtain a useful band of impedance that is much wider than that of known antennae, with the least possible encumbrance.
- Another object of the present invention is to devise a dipole antenna that is decoupled from the support structure, to avoid distortions in the radiation diagram.
- Another object of the present invention is to devise a dipole antenna that is highly reliable, relatively simple to provide and at competitive cost.
- This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a dipole antenna for a CB band base station, characterized in that it is provided by means of a coaxial line comprising a first portion that is connected to a second portion which constitutes a choke coil and to a third portion which constitutes a radiating element.
- Further characteristics and advantages of the invention will become better apparent from the description of preferred, but not exclusive, embodiments of the dipole antenna according to the present invention, illustrated by way of a non-limiting example in the accompanying drawings wherein:
-
figures 1 to 4 show embodiments of conventional dipole antennae; -
figure 5 shows a dipole antenna according to the invention in a first embodiment; -
figure 6 shows the dipole antenna according to the present invention in a second embodiment; -
figure 7 shows the dipole antenna according to the present invention in a third embodiment; -
figure 8 shows the distribution of the currents on the radiator as a function of the electrical lengths as the frequency is varied. - With reference to the figures, the dipole antenna according to the present invention, globally indicated by the
reference numeral 1, comprises, with reference to its first embodiment shown infigure 5 , acoaxial feeder line 2, connected to a generator, not shown, suchcoaxial feeder line 2, with characteristic impedance of 50 ohm, continuing in achoke coil 3, made with coils that are distanced and arranged parallel to each other. - The
coaxial feeder line 2, which thus continues in thechoke coil 3, finally continues in a portion ofcoaxial line 4 that has a length that is equal to, for example, a quarter of the wavelength and self-impedance Zc. At the upper end of theportion 4 of coaxial line, thecentral conductor 5 of the coaxial line is electrically connected to ametal radiator 6 having a length that is equal to, for example, a quarter of the wavelength. - Therefore, the radiofrequency signal that comes from the generator travels inside the
feeder line 2, continues into the coaxial cable forming the coils of thechoke coil 3, and then continues into the portion ofcoaxial line 4 to arrive at the junction point with theradiator 6. - In this position, the current present in the central or
internal conductor 5 continues along theradiator 6 while the current that was travelling on the inside of the shielding of the portion ofcoaxial line 4 is forced to continue on the outside of such shielding and to return downwards in the direction of thechoke coil 3. - The current that travels through the
radiator 6 will stop at the upper end of theradiator 6, while the external current of the portion ofcoaxial line 4 which returns downwards will be blocked by thechoke coil 3, because a choke inductance is present which is connected in series with such current. - The
choke coil 3 produces its choke effect on the currents beginning from a minimum frequency, to be identified according to necessity, and for all higher frequencies, and it is therefore intrinsically wide-band. - From the point of view of the antenna, the current that travels on the outside of the coaxial cable or portion of
feeder line 4 is concordant with the current that travels through theradiator 6. We therefore have two parts radiating in phase, which overall form a single long radiating part, for example, half-wave. Another advantage of the antenna according to the invention is that, with the varying of the frequency, the currents on the radiator are always in phase for all lengths that are shorter than an entire wave, as shown infigure 8 (as in a classic dipole antenna, powered internally). Therefore, by means of suitable systems for impedance adaptation, this structure functions correctly even when its length is other than half-wave with signal gains proportional to its length. -
Figure 6 shows the dipole antenna according to the invention in a second embodiment and in such figure the same reference numerals refer to identical elements. - The difference between the embodiment shown in
figure 5 and the embodiment shown infigure 6 consists in that instead of having aradiator 6 located at the end of the portion ofcoaxial line 4,such radiator 6 is replaced by anothercoaxial line 7, arranged in such a way that thecentral conductor 5 of the portion ofcoaxial line 4 is connected with the outer part of thecoaxial line 7, while the outside of the portion ofcoaxial line 4 is connected with theinternal conductor 8 of the portion ofcoaxial line 7. - At the upper end, the central or
internal conductor 8 of the portion ofcoaxial line 7 and the outer shielding ofsuch portion 7 are electrically connected to each other. In this way, the outer shielding of theportion 7 of coaxial line performs such function of theradiator 6, while itsinternal conductor 8 defines a path and ensures the presence of a direct current short-circuit to protect the transmission apparatus from electrical discharges generated by atmospheric disturbances. - The impedance of the portion of
coaxial line 7 is conveniently a self-impedance Ze. - Moreover it is possible to use the global impedance of the antenna by suitably regulating the self-impedances Zc and Ze of the coaxial conductors.
- In this way it is possible to obtain an antenna that has reduced encumbrance, since it is free from radials, as well as being decoupled from the support structure which in some cases could distort the radiation diagram, and which in addition is characterised in that it has a band that is wider by 250%-350% than those of conventional antennae, such as those shown in
figures 1 to 4 . - The sections of coaxial cable can conveniently be contained inside a dielectric tube, such as for example a fibreglass tube, which carries out the function both of mechanical support and of protection from atmospheric agents.
-
Figure 7 shows the dipole antenna according to the present invention in a third embodiment. - The difference between the third embodiment shown in
figure 7 and the second embodiment shown infigure 6 consists in that aradiating element 9 is connected to the upper end of thecoaxial line 7, at theinternal conductor 8 of thecoaxial line 7. Theradiating element 9 can be compared to theradiator 6 in the first embodiment. - Therefore, substantially, the third embodiment of the invention is a combination of the first and second embodiments described previously.
- The overall radiating part of the third embodiment of the invention is therefore composed of the
internal conductor 8 and theradiator 9 and their overall lengths are, for example, quarter-wave, thus functioning like the upper portions of the embodiments infigures 5 and 6 . - The length of the coaxial line formed by the
coaxial line 7 and by theinternal conductor 8 becomes usable as a new parameter for regulating and optimising the global impedance. - In practice it has been found that the dipole antenna according to the present invention fully achieves the intended aim and objects.
- The antenna, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.
- In practice the materials employed, so long as they are compatible with the specific use, as well as the dimensions and the contingent shapes, may be any according to requirements and to the state of the art.
- The disclosures in Italian Patent Application No.
MI2009A000540 - Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.
Claims (6)
- A dipole antenna (1) for a base station, characterized in that it is provided by means of a coaxial line comprising a first portion (2) that is connected to a second portion that constitutes a choke coil (3) and to a third portion that constitutes a radiating element (6, 9).
- The dipole antenna (1) according to claim 1, characterized in that said second portion that constitutes said first coaxial coil (3) is formed by a plurality of turns arranged parallel to each other so as to form said choke coil.
- The dipole antenna (1) according to claim 1, characterized in that said third portion of coaxial line comprises a portion (4, 7) of coaxial line that is connected to a radiator (6, 9).
- The dipole antenna (1) according to one or more of the preceding claims, characterized in that said third portion of coaxial line comprises a portion (4) of coaxial line that is connected to said choke coil (3) and in turn is connected to an additional portion (7) of coaxial line, said additional portion (7) of coaxial line being connected by means of its outer shielding to the central conductor (5) of said coaxial line and by means of its internal conductor (8) to the outer shielding of said portion (4) of coaxial line that is connected to said choke coil (3).
- The dipole antenna (1) according to one or more of the preceding claims, characterized in that it comprises a radiating element (6, 9) that is connected to said third portion of coaxial line, at said internal conductor of said third portion of coaxial line.
- The dipole antenna (1) according to one or more of the preceding claims, characterized in that said coaxial line is inserted within a containment and protection tube.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT000540A ITMI20090540A1 (en) | 2009-04-03 | 2009-04-03 | ANTENNA DIPOLO FOR BASE STATION IN BANDA CB. |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2237372A1 true EP2237372A1 (en) | 2010-10-06 |
Family
ID=41228724
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP10158258A Withdrawn EP2237372A1 (en) | 2009-04-03 | 2010-03-29 | Dipole antenna for a CB band base station |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2237372A1 (en) |
IT (1) | ITMI20090540A1 (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2485457A (en) * | 1944-10-20 | 1949-10-18 | Bell Telephone Labor Inc | Antenna system |
US3031668A (en) * | 1960-11-21 | 1962-04-24 | Comm Products Company Inc | Dielectric loaded colinear vertical dipole antenna |
US3656167A (en) * | 1969-11-25 | 1972-04-11 | Plessey Co Ltd | Dipole radio antennae |
US4217589A (en) * | 1976-01-12 | 1980-08-12 | Stahler Alfred F | Ground and/or feedline independent resonant feed device for coupling antennas and the like |
US4937588A (en) * | 1986-08-14 | 1990-06-26 | Austin Richard A | Array of collinear dipoles |
US20050040991A1 (en) * | 2003-07-19 | 2005-02-24 | Crystal Bonnie A. | Coaxial antenna system |
-
2009
- 2009-04-03 IT IT000540A patent/ITMI20090540A1/en unknown
-
2010
- 2010-03-29 EP EP10158258A patent/EP2237372A1/en not_active Withdrawn
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2485457A (en) * | 1944-10-20 | 1949-10-18 | Bell Telephone Labor Inc | Antenna system |
US3031668A (en) * | 1960-11-21 | 1962-04-24 | Comm Products Company Inc | Dielectric loaded colinear vertical dipole antenna |
US3656167A (en) * | 1969-11-25 | 1972-04-11 | Plessey Co Ltd | Dipole radio antennae |
US4217589A (en) * | 1976-01-12 | 1980-08-12 | Stahler Alfred F | Ground and/or feedline independent resonant feed device for coupling antennas and the like |
US4937588A (en) * | 1986-08-14 | 1990-06-26 | Austin Richard A | Array of collinear dipoles |
US20050040991A1 (en) * | 2003-07-19 | 2005-02-24 | Crystal Bonnie A. | Coaxial antenna system |
Also Published As
Publication number | Publication date |
---|---|
ITMI20090540A1 (en) | 2010-10-04 |
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