Antenna, in particular mobile radio antenna

• US 20030011529A1
• Filed: 08/19/2002
• Published: 01/16/2003
• Est. Priority Date: 12/21/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Kathrein-Werke KG. (Kathrein SE)
• Inventors: Göttl, Maximilian
• Granted Patent: US 6,831,615 B2
• Time in Patent Office: Days
• US Class Current: 343/795
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 19/028 for reducing the cross polarisation
• CPC Class Codes: H01Q 19/06 using refracting or diffracting devices, e.g. lens radome H01Q1/42
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407

Abstract

An improved antenna, in particular a mobile radio antenna, is distinguished by the following features:

at least one additional dielectric body (21) is provided, and

the at least one dielectric body (21) is arranged such that it is entirely arranged underneath the radiating elements (4a, 13) or more than 40% of its volume and/or of its weight, and in particular more than 50% or 60% of its volume and/or of its weight, are/is arranged underneath the radiating elements (4a, 13), for the lower frequency band on the one hand and/or on the other hand, such that it is arranged entirely, or at least 40%, 50% or 60% of its volume and/or of its weight are/is arranged, viewed from the reflector (11), above the radiating elements (4b, 15) which are provided for an upper frequency band.

Claims

1. An antenna, in particular a mobile radio antenna, for operation in at least two frequency bands, having the following features:

the antenna is provided with a protective shroud composed of nonconductive material,

the radiating elements of the antenna are arranged underneath the protective shroud and in front of the reflector (11),

the radiating elements (4a, 13) for a lower frequency band are arranged at a first distance, or in a first distance range, in front of the reflector (11),

the radiating elements (4b, 15) for the higher frequency band are, in contrast, arranged at a second distance, or in a second distance range, in front of the reflector (11), but closer to it,

characterized by the following further features;

at least one dielectric body (21) which does not form the protective shroud is provided,

more than 40% of the volume, and/or more than 40% of the weight, of the at least one dielectric body (21) is arranged in the region between the reflector (11) and the first distance or the first distance range of the radiating elements (4a, 13) for the lower frequency band, and

more than 40% of the volume and/or more than 40% of the weight of the at least one dielectric body (21) is arranged, as seen from the reflector (11), at more than the second distance or the second distance range for the radiating elements (4b, 15) which are provided for the upper frequency band.

2. The antenna as claimed in the precharacterizing clause of claim 1 or claim 1, having the following features:

the antenna is provided with a protective shroud composed of nonconductive material,

the radiating elements of the antenna are arranged underneath the protective shroud and in front of the reflector (11),

the radiating elements (4a, 13) for a lower frequency band are arranged at a first distance, or in a first distance range, in front of the reflector (11),

the radiating elements (4b, 15) for the higher frequency band are, in contrast, arranged at a second distance, or in a second distance range, in front of the reflector (11), but closer to it,

characterized by the following further features;

at least one dielectric body (21) which does not form the protective shroud is provided, and

at least part of the dielectric body (21) is arranged in the distance area which extends parallel to the reflector (11) and is provided by the radiating elements (4a, 13) for the lower frequency band and by the radiating elements (4b, 15) for the upper frequency band, and

the dielectric body (21) also has an extent component (22) which runs toward the plane of the reflector (11) and is longer than its extent direction which runs at right angles to the plane of the reflector (11), and/or than its distance from the plane of the reflector (11).

3. The antenna as claimed in the precharacterizing clause of claim 1 or claim 1 or 2, having the following features:

the antenna is provided with a protective shroud composed of nonconductive material,

the radiating elements of the antenna are arranged underneath the protective shroud and in front of the reflector (11),

the radiating elements (4a, 13) for a lower frequency band are arranged at a first distance, or in a first distance range, in front of the reflector (11),

the radiating elements (4b, 15) for the higher frequency band are, in contrast, arranged at a second distance, or in a second distance range, in front of the reflector (11), but closer to it,

characterized by the following further features;

a) at least one dielectric body (21) which does not form the protective shroud is provided, and

b) in a vertical plan view of the reflector (11), the dielectric body (21) is arranged such

that the dielectric body (21) is located at the same level as a dipole square (13, 17) or as a radiating element arrangement which is similar to a dipole square and, in this case, is arranged within the dipole square (13, 17) or within the radiating element arrangement which is similar to a dipole square, and/or

that the dielectric body (21) is arranged above a dipole radiating element and/or above a cruciform radiating element (15) or patch radiating element (17), and is thus arranged further away from the reflector (11) than these radiating elements,

c) the entire surface area of the dielectric body (21) or at least the size of the surface area of the dielectric body (21) which is produced by a right-angle projection onto the plane of the reflector (11), is larger than the square of the linear distance which is obtained from the distance between the plane of the reflector (11)

and

the dielectric body (21), or

from the distance between the plane of the reflector (11) and a center plane which runs through the dielectric body (21) or

from the distance between the plane of the reflector (11) and the outer boundary surface, facing away from the reflector plane (11) of the dielectric body (21).

4. The antenna as claimed in the precharacterizing clause of claim 1 or at least one of claims 1 to 3, having the following features:

the antenna is provided with a protective shroud composed of nonconductive material,

the radiating elements of the antenna are arranged underneath the protective shroud and in front of the reflector (11),

the radiating elements (4a, 13) for a lower frequency band are arranged at a first distance, or in a first distance range, in front of the reflector (11),

the radiating elements (4b, 15) for the higher frequency band are, in contrast, arranged at a second distance, or in a second distance range, in front of the reflector (11), but closer to it,

characterized by the following further features;

at least one dielectric body (21) which does not form the protective shroud is provided, and

at least part of the dielectric body (21) extends above parts of the radiating element arrangements (4a, 13;

4b, 15) at a distance in front of the reflector (11),

the dielectric body (21) extends parallel to the reflector (11), and

when viewed in a vertical plan view of the reflector, the dielectric body (21) has a flat extent which is greater than the flat extent, which results parallel to the plane of the reflector (11), of possible spacers, feet or other attachment elements which are part of the dielectric body (21) or are connected to it and run toward the reflector (11).

5. The antenna as claimed in at least one of claims 1 to 4, characterized in that, when viewed in a projection at right angles to the reflector (11), the at least one dielectric body (21) is smaller than the reflector (11) which is located underneath it.

6. The antenna as claimed in at least one of claims 1 to 4, characterized in that, when viewed in a projection at right angles to the reflector (11), the at least one dielectric body (21) is is of precisely the same size as the reflector (11) which is located underneath it.

7. The antenna as claimed in one of claims 1 to 6, characterized in that the dielectric body (21) is mechanically attached to the radiating elements (4a, 13;

4b, 15).

8. The antenna as claimed in one of claims 1 to 7, characterized in that, in a plan view, the at least one dielectric body (21) is in the form of an n-sided polygon.

9. The antenna as claimed in one of claims 1 to 8, characterized in that the at least one dielectric body (21) is at least essentially in the form of a plate.

10. The antenna as claimed in one of claims 1 to 9, characterized in that the dielectric body (21), or at least parts of it, is or are symmetrical with respect to a predetermined radiating element (4a, 4b).

11. The antenna as claimed in one of claims 1 to 10, characterized in that the dielectric body (21) is arranged such that more than 50% of it is at a distance of less than λ

/2 from the plane of the reflector (11) with respect to the higher frequency band or the mid-frequency band.

12. The antenna as claimed in one of claims 1 to 11, characterized in that at least the major parts of the dielectric body (21) extend in a region which is located above the radiating element arrangement for the highest frequency band.

13. The antenna as claimed in at least one of claims 1 to 12, characterized in that the dielectric body (21) is composed of plastic, of polystyrene, of ABS or of glass fiber reinforced plastic.

14. The antenna as claimed in one of claims 1 to 13, characterized in that the material for the dielectric body (21) is chosen such that it has a low dielectric loss factor, preferably in the order of magnitude of 10⁻

3 or less, and in particular less than 10<sup>−

4</sup> and especially 10<sup>−

5</sup>.

15. The antenna as claimed in one of claims 1 to 10, characterized in that the dielectric body (21) is used in particular for mobile radio antennas for the 900 MHz, the 1800 MHz and/or the 2000 MHz band.

16. The antenna as claimed in one of claims 1 to 15, characterized by the following further features:

more than 50% of the volume, and/or more than 50% of the weight, of the at least one dielectric body (21) is arranged in the region between the reflector (11) and the first distance or the first distance range of the radiating elements (4a, 13) for the lower frequency band, and

more than 50% of the volume and/or more than 50% of the weight of the at least one dielectric body (21) is arranged, as seen from the reflector (11), at more than the second distance or the second distance range for the radiating elements (4b, 15) which are provided for the upper frequency band.

17. The antenna as claimed in one of claims 1 to 16, characterized by the following further features:

more than 70% of the volume, and/or more than 70% of the weight, of the at least one dielectric body (21) is arranged in the region between the reflector (11) and the first distance or the first distance range of the radiating elements (4a, 13) for the lower frequency band, and

more than 70% of the volume and/or more than 70% of the weight of the at least one dielectric body (21) is arranged, as seen from the reflector (11), at more than the second distance or the second distance range for the radiating elements (4b, 15) which are provided for the upper frequency band.