The present invention relates to a base station antenna used in a mobile communication system and, more particularly, relates to a base station antenna having a beam-width expanding apparatus for expanding the beam width of a radiating element included in an antenna.
Antennas used in base stations as well as repeaters in mobile communication systems may have various shapes and structures, and in recent years, base station antennas have generally used a dual-band dual-polarized antenna structure by applying a polarization diversity method.
The dual-band dual-polarized antenna generally has a structure in which first radiating elements in a low frequency band (e.g., a band of 700 MHz) and second radiating elements in a high frequency band (e.g., a band of 1.9 GHz) are properly arranged on at least one reflection plate that stands erect in the longitudinal direction. The first and second radiating elements are used to transmit (or receive) two orthogonal linear polarizations that are arranged at +45° and −45° to the vertical (or the horizontal).
An example of such a dual-band dual polarized antenna is disclosed in KR Patent Application No. 2000-7010785 first filed by Kathrein-Verke AG (entitled ‘Dual polarized multi-range antenna’).
Meanwhile, the horizontal beam width of radiation beams generated by each radiating element (and a combination of radiating elements) of a base station antenna is one of the very important characteristics of the corresponding antenna. Constant studies on the design of a radiating element and an antenna have been conducted to satisfy a beam width required for service conditions and environments. The studies have been conducted in a direction of increasing the beam width where possible in order to allow the corresponding antenna to have a wider coverage range.
An aspect of the present invention is to provide a mobile communication base station antenna including a beam-width expanding apparatus that can expand the beam width of a radiating element with a comparatively simple structure and the minimum addition of equipment without affecting the radiation characteristic of the antenna where possible.
In accordance with one aspect of the present invention, a mobile communication base station antenna including a beam-width expanding apparatus is provided. The mobile communication base station antenna includes: a reflection plate; a radiating element mounted on the reflection plate; and a beam-width expanding apparatus that is fixedly mounted to be separated a preset distance upward from the radiating element and constituted by a thin metal body.
Hereinafter, an exemplary embodiment according to the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings and the descriptions relating thereto, identical elements are indicated by identical reference numerals where possible.
Referring to
The beam-width expanding apparatus 10 may be constituted by, for example, a circular thin metal body. The beam-width expanding apparatus 10 may be constituted by a thin metal body made of a conductive material. For example, the beam-width expanding apparatus 10 may be constituted in a structure in which a copper or aluminum thin metal body is plated with silver.
The beam-width expanding apparatus 10 is disposed above the radiating element 2 based on the center of beams radiated from the radiating element 2 (i.e., for example, disposed such that the beam-width expanding apparatus 10 shares the same central axis with the radiating element 2). The beam-width expanding apparatus 10 is disposed to be included within the beam width of beams radiated in an initial stage from the radiating element 2 to have a direct influence on the pattern of the radiated beams. In this case, the total size and the shape of the beam-width expanding apparatus 10 as well as the mounting position thereof are designed in comprehensive consideration of the pattern of the initially radiated beams from the radiating element 2, a change in the radiation pattern according to the mounting of the beam-width expanding apparatus 10, radiation loss, and the like.
The expansion of the beam width due to the beam-width expanding apparatus 10 is based on the principle that the radiation pattern of beams changes when an object having permittivity is placed near a portion of the radiating element 2 that radiates beams.
Of course, in this case, the beam-width expanding apparatus 10 placed near the portion of the radiating element 2 that radiates beams causes a loss in terms of a radiation gain, and therefore the beam-width expanding apparatus 10 is constituted to be as thin as possible in order to reduce such a loss. In cases where the beam-width expanding apparatus 10 is constituted to be thin enough, even though a loss is caused due to this, it is possible to sufficiently satisfy a radiation characteristic required for the corresponding radiating element 2.
The beam-width expanding apparatus 10 may have a planar circular ring shape as illustrated in
The detailed structure of the beam-width expanding apparatus 10 including the plurality of branch portions 140 has an influence on the pattern of beams, radiated from the radiating element 2, in the same way. Since a comparatively small structural difference also causes a considerable variation in the beam pattern, particularly, the beam width, the optimum structure is obtained by experimentally identifying the corresponding radiation characteristic when a detailed structure is added or modified.
In cases where the beam-width expanding apparatus 10 having such a configuration is disposed above the radiating element 2, the beam-width expanding apparatus 10 is secured to a reflection plate 1 through the separate support parts 12 as clearly illustrated in
Of course, even in this case, the pattern of beams radiated from the radiating element 2 is affected by the support parts 12 that support the beam-width expanding apparatus 10. Therefore, additionally considering this, the detailed structure and the mounting position of the support parts 12 and the beam-width expanding apparatus 10 are designed.
Referring to
In addition, as illustrated in
In order to expand the beam width of the second radiating element 2, it may be additionally considered to increase the height of the second radiating element 2. However, increasing the height of the second radiating element 2 to a proper value or more may degrade a Voltage Standing Wave Ratio (VSWR) characteristic and affect the radiation characteristic of the first radiating element 3 disposed near the second radiating element 2.
Furthermore, a method may be considered for expanding the beam width of the radiating element by decreasing the width of the reflection plate 1. However, when the width of the reflection plate 1 is decreased to a proper value or smaller, the Front-to-Back Ratio (FBR) of the antenna is degraded due to a deficiency in a ground contact area.
Accordingly, in order to expand the beam width of the second radiating elements 2, the auxiliary side walls 4, the height of the second radiating element 2, and the width of the reflection plate 1 are appropriately designed. This helps the beam width of the second radiating element 2 to be formed as wide as possible in a range satisfying the radiation characteristic required for the entire antenna. In addition, the beam-width expanding apparatus 10, according to the present invention, may be additionally provided, thereby doubling the beam-width expansion effect.
Moreover, the beam-width expanding apparatus, according to the present invention, may be additionally mounted in a comparatively simple manner without any change in the radiating element structure of an existing antenna, thereby expanding the beam width of radiating elements of the corresponding antenna.
The configuration and operation of the mobile communication base station antenna including the beam-width expanding apparatus according to the embodiment of the present invention may be made as described above, and although the specific embodiment of the present invention has been described above, various modifications can be made without departing from the scope of the present invention.
In the above-described embodiment, it has been illustrated that the beam-width expanding apparatus has a circular interconnected ring shape with a plurality of branch portions extending inward. However, the beam-width expanding apparatus may have a non-interconnected structure, or may have a rectangular shape or include branch portions extending outward rather than inward.
In the above-described embodiment, it has been illustrated that the support parts fix the beam-width expanding apparatus using the through holes formed in the beam-width expanding apparatus. However, the support parts may have various structures such as fixing the beam-width expanding apparatus in such a manner of holding a portion of the beam-width expanding apparatus using a clip structure.
In the above-described embodiment, it has been illustrated that the first radiating element and the second radiating elements are arranged in a particular structure as illustrated in
As described above, a mobile communication base station antenna including a beam-width expanding apparatus, according to the present invention, can expand the beam width of a radiating element with a comparatively simple structure and the minimum addition of equipment without affecting the radiation characteristic of the antenna where possible.
Number | Date | Country | Kind |
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10-2012-0137901 | Nov 2012 | KR | national |
This application is a continuation of International Application No. PCT/KR2013/010998 filed on Nov. 29, 2013, which claims priority to Korean Applications No. 10-2012-0137901 filed on Nov. 30, 2012, which applications are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/KR2013/010998 | Nov 2013 | US |
Child | 14727061 | US |