Multi-frequency array antenna

Abstract

A multi-frequency array antenna, includes a reflective metal plate, a low-frequency radiation column element which is arranged on the reflective metal plate and operating in a first frequency band range, and a high-frequency radiation column element operating in a second frequency band range. The low-frequency radiation column element comprises several low-frequency radiation units arranged at an equal first distance in the axial direction of a first reference axis. The high-frequency radiation column element comprises several high-frequency radiation units arranged at an equal second distance in the axial direction of the first reference axis. The first distance is 2.5 times the second distance. At least one of the low-frequency radiation units is nested with one high-frequency radiation unit locationally corresponding thereto, and at least one of the low-frequency radiation units is axially located between two adjacent high-frequency radiation units close to the low-frequency radiation unit.

Claims

1. A multi-frequency array antenna, comprising: a metal reflector, a low-frequency radiation column element that is arranged on the metal reflector and operates in a first frequency band range, and a high-frequency radiation column element operating in a second frequency band range, wherein the low-frequency radiation column element comprising several low-frequency radiation units arranged at an equal first distance in the axial direction of a first reference axis, and the high-frequency radiation column element comprising several high-frequency radiation units arranged at an equal second distance in the axial direction of the first reference axis, characterized in that the first distance is 2.5 times of the second distance, at least one of the low-frequency radiation units is nested with one high-frequency radiation unit locationally corresponding thereto, and separately, at least one of the low-frequency radiation units is axially located between two neighboring high-frequency radiation units adjacent to the low-frequency radiation unit; wherein for the mutually nested low-frequency radiation units and high-frequency radiation units, their own radiation arms are in a relationship of central symmetry, and when projected orthographically to the orthographical projection plane of the metal reflector, the two's symmetry centers are overlapped.

2. The multi-frequency array antenna according to claim 1, characterized in that each of the low-frequency radiation units with the axial positions on the first reference axis being an odd or even number is nested with one high-frequency radiation unit locationally corresponding thereto, and other low-frequency radiation units are scattered between two neighboring high-frequency radiation units axially adjacent to said low-frequency radiation units.

3. The multi-frequency array antenna according to claim 1, characterized in that both the low-frequency radiation units and the high-frequency radiation units comprise a radiation arm for radiating signals in their band ranges, and when projected orthographically to the orthographical projection plane of the metal reflector, there is no overlapping between all radiation arms of the low-frequency radiation units and radiation arms of the high-frequency radiation units.

4. The multi-frequency array antenna according to claim 1, characterized in that the low-frequency radiation column element comprises two types of low-frequency radiation units having different radiation arm structures, wherein the first low-frequency radiation unit and the second low-frequency radiation unit are located at the odd numbered and even numbered positions in said axial direction, respectively.

5. The multi-frequency array antenna according to claim 4, characterized in that when projected orthographically to the orthographical projection plane of the metal reflector, the radiation arm of the first low-frequency radiation unit is of any ring shape, including rectangular and circular.

6. The multi-frequency array antenna according to claim 4, characterized in that when projected orthographically to the orthographical projection plane of the metal reflector, the radiation arm of the second low-frequency radiation unit is of a crossing shape with an orthogonal relationship.

7. The multi-frequency array antenna according to claim 4, characterized in that the first low-frequency radiation unit and the high-frequency radiation unit nested therein are arranged at positions at one side of the reference axis.

8. The multi-frequency array antenna according to claim 4, characterized in that the second low-frequency radiation units are arranged at positions at one side of the reference axis.

9. The multi-frequency array antenna according to claim 1, characterized in that the first distance of the low-frequency radiation column element is 0.6-1.0 times of the wavelength corresponding to the center frequency of the first frequency band range.

10. The multi-frequency array antenna according to claim 9, characterized in that the first distance of the low-frequency radiation column element is 0.8 times of the wavelength corresponding to the center frequency of the first frequency band range.

11. The multi-frequency array antenna according to claim 1, characterized in that the second distance of the high-frequency radiation column element is 0.6-1.0 times of the wavelength corresponding to the center frequency of the second frequency band range.

12. The multi-frequency array antenna according to claim 11, characterized in that the second distance of the high-frequency radiation column element is 0.8 times of the wavelength corresponding to the center frequency of the second frequency band range.

13. The multi-frequency array antenna according to claim 1, characterized in that the first frequency band range in which the low-frequency radiation column element operates is 790-960 MHz; and the second frequency band range in which the high-frequency radiation column element operates is 1700-2700 MHz.

14. The multi-frequency array antenna according to claim 1, characterized in that the value of the first distance is in the range of 262.5-287.5 mm, and the value of the second distance is in the range of 105-115 mm, both of which are inclusive.

15. The multi-frequency array antenna according to claim 1, characterized in that the low-frequency radiation units and the high-frequency radiation units are all arranged on the first reference axis.

16. The multi-frequency array antenna according to claim 1, characterized in that at least one of the low-frequency radiation units axially arranged between two neighboring high-frequency radiation units is fixed on a second reference axis, while the two high-frequency radiation units adjacent thereto are fixed on a third reference axis, and the second reference axis and the third reference axis are symmetric with respect to and parallel to the first reference axis.

17. The multi-frequency array antenna according to claim 16, characterized in that another low-frequency radiation units axially arranged between two neighboring high-frequency radiation units is fixed on the third reference axis, while the two high-frequency radiation units adjacent thereto are fixed on the second reference axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Description of the Drawings

(1) FIG. 1 illustrates the structure of a radiation unit according to the US Patent Publication U.S. Pat. No. 4,434,425;

(2) FIG. 2 illustrates the structure of a radiation unit according to the US Patent Publication U.S. Pat. No. 6,333,720B1;

(3) FIG. 3 illustrates a dual-frequency dual-polarized array antenna according to the Chinese Patent Publication No. N101425626A;

(4) FIG. 4 illustrates a dual-frequency dual-polarized array antenna according to the Chinese Patent Publication No. CN102299398A;

(5) FIG. 5 is an arraying schematic diagram of the multi-frequency array antenna according to Example 1 of the present invention with both low-frequency radiation units and high-frequency radiation units arranged on the same reference axis;

(6) FIG. 6 and FIG. 7 are arraying schematic diagrams of the multi-frequency array antenna according to Example 2 and Example 3 of the present invention, respectively, with their low-frequency radiation units and high-frequency radiation units arranged on a plurality of reference axis, wherein FIG. 7 is an alternative based on FIG. 6;

(7) FIG. 8 is an arraying schematic diagram of the multi-frequency array antenna according to Example 3 of the present invention, which employs low-frequency radiation units of a unified shape;

(8) FIG. 9 is an arraying schematic diagram of the multi-frequency array antenna according to Example 4 of the present invention, which expands the high-frequency radiation column element based on the example disclosed in FIG. 5 such that the antenna operates in three frequency band ranges;

(9) FIG. 10 is an arraying schematic diagram of the multi-frequency array antenna according to Example 5 of the present invention, which expands the high-frequency radiation column element and the low-frequency radiation column element based on the example disclosed in FIG. 5 such that the antenna operates in four frequency band ranges;

(10) FIG. 11 is an arraying schematic diagram of the multi-frequency array antenna according to Example 6 of the present invention, which enables the antenna to operate in five frequency band ranges through more flexible expansion of the high-frequency radiation column element and the low-frequency radiation column element.

PREFERRED EMBODIMENTS TO IMPLEMENT THE PRESENT INVENTION

Preferred Embodiments of the Invention

Embodiments of the Invention

Detailed Description of Specific Embodiments

(11) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

(12) In a mobile communication antenna, radiation column elements (comprising low-frequency radiation column element and high-frequency radiation column element) are used for radiating communicating signals, which are typically formed by arranging a plurality of radiation units in a single-column matrix on a metal reflector. For high-frequency signals, the high-frequency radiation column element is formed by arranging a plurality of high-frequency radiation units at an equal distance in the axial direction of the same reference axis, and for the ease of subsequent description, the distance is defined as the second distance. Correspondingly, the low-frequency radiation column element is formed by arranging a plurality of low-frequency radiation units at an equal distance in the axial direction of the same reference axis, and similarly, the distance is defined as the second distance, wherein the part of the radiation units for performing signal transmission and receiving is the radiation arm thereof, the radiation arm is usually located at the periphery of a radiation unit and has a variety of known structures. However, they all employ the central symmetric relationship, i.e. they typically consist of two pairs of symmetric radiators in the orthogonal form, each pair of symmetric radiators comprises two of the radiation arms, and radiation arms of common radiation units mostly form a ring shape, including rectangular and circular. Of course, they may also comprise other polygonal rings; alternatively, the radiation arm may also be designed to have a shape of horizontal elongation, and the same pair of symmetric radiators is substantially elongated longitudinally, such that the radiation units after orthogonal configuration appear to be a “cross”. Generally speaking, radiation arms of different symmetric radiators do not have physical contact. Radiation units may be printed in 2 dimensions, or may have a 3-D structure. These fundamental concepts will be followed in the description of all examples of the present invention. When a radiation column element is installed on a metal reflector, it is projected orthographically to the direction of the reflector to form an orthographical projection plane. FIG. 5 to FIG. 11 of the present invention all use this orthographical projection plane for illustration so as to clearly disclose the layout relationship among different radiation column elements.

(13) In all examples disclosed by the present invention, the low-frequency radiation column element and high-frequency radiation column element thereof all operate in different frequency band ranges, and the “low-frequency” of the low-frequency radiation column element herein indicates that it is lower than the frequency of the “high-frequency” of the high-frequency radiation column element. Preferably, the low-frequency radiation column element operates in the frequency band range of 790-960 MHz, which covers current 2G and 3G mobile communication frequency bands globally, while the high-frequency radiation column element operates in the frequency band range of 1700-2700 MHz, which covers current 4G mobile communication frequency bands globally, such as the LTE standard.

(14) Please refer to FIG. 5. The multi-frequency array antenna according to Example 1 of the present invention arranges a low-frequency radiation column element and a high-frequency radiation column element coaxially along an imaginary first reference axis a on the metal reflector 1, thereby forming a set of dual frequency common antenna.

(15) The high-frequency radiation column element is formed by 12 high-frequency radiation units (4, 5, 6) arranged sequentially at an equal second distance in the axial direction of the first reference axis a, all of the high-frequency radiation units are arranged on the first reference axis a, and arranged in the position sequence from left to right. For the ease of description, the second distance between the locationally neighboring high-frequency radiation units 4, 6, 5 is defined as d.

(16) The low-frequency radiation column element is formed by 5 low-frequency radiation units (2, 3) arranged sequentially at an equal first distance in the axial direction of the first reference axis a, all of the low-frequency radiation units are arranged on the first reference axis a, and arranged in the position sequence from left to right, wherein given the above second distance d, the first distance between two axially neighboring low-frequency radiation units 2, 3 is limited to be 2.5 d.

(17) To realize the above multiple relationship between the first distance and the second distance, according to the sequence from left to right, the low-frequency radiation unit 2 with the position being an odd number is nested with a high-frequency radiation unit 4 that appears to be locationally corresponding due to the multiple relationship. For example, the axial 1.sup.st, 3.sup.rd and 5.sup.th low-frequency radiation units are nested with the axial 1.sup.st, 6.sup.th and 11.sup.th high-frequency radiation units, respectively. If physical error is not considered, the realization of such a nesting relationship means that, on the orthographical projection plane, the symmetry center of the radiation arm of the low-frequency radiation unit 2 is overlapped with the symmetry center of the radiation arm of the high-frequency radiation unit 4. On the other hand, the low-frequency radiation unit 3 with the position being an even number is located axially between two neighboring high-frequency radiation units 5 due to the multiple relationship, and if physical error is not considered, it is theoretically located at the exact middle between two neighboring high-frequency radiation units 5. For example, the axial 2.sup.nd and 4.sup.th low-frequency radiation units are exactly located at the exact middle between the axial 3.sup.rd and 4.sup.th, and 8.sup.th and 9.sup.th high-frequency radiation units 5, respectively. In such a way, if calculated according to the multiple relationship, the distance from the low-frequency radiation unit 3 with the position being an even number to any radiation unit 5 that is axially neighboring to the position of the low-frequency radiation unit 3 is 0.5 d.

(18) To avoid mutual interference to signals between the low-frequency radiation units and the high-frequency radiation units, it is defined that all low-frequency radiation units with the position thereof being an odd number are the first low-frequency radiation units 2, and that all low-frequency radiation units with the position thereof being an even number are the second low-frequency radiation units 3. In this example, the first low-frequency radiation units 2 and the second low-frequency radiation units 3 have different structural forms, which are specifically reflected by different forms of their radiation arms. With respect to a first low-frequency radiation unit 2 with the position thereof being an odd number, due to the nesting with the high-frequency radiation unit 4, the radial size of the radiation arm of the high-frequency radiation unit 4 is usually smaller than the radial size of the radiation arm of the low-frequency radiation unit 2 on the orthographical projection plane. Therefore, the radiation arm of the first low-frequency radiation unit 2 may use a ring-shaped structure. In such a way, the radiation arm of the high-frequency radiation unit 4 and the radiation arm of the first low-frequency radiation unit 2 do not have an overlapping relationship on the orthographical projection plane, which avoids or reduces mutual interference of the signals. With respect to a second low-frequency radiation unit 3 with the position thereof being an even number, on the other hand, if the same structure of radiation arm as that of the first low-frequency radiation unit 2 is still employed, then the ring-shaped radiation arm will easily cross above the two high-frequency radiation units 5 adjacent to the first low-frequency radiation unit 2, thereby leading to mutual interference of the two's signals. Thus, the radiation arm of the second low-frequency radiation unit 3 preferably has a crossing shape, i.e. the above “cross” form of radiation arm structure. With its longitudinally elongated design of symmetric radiators, therefore, the phenomenon of overlapping with the high-frequency radiation units 5 on the orthographical projection plane can be avoided. With this means, it can ensure that signals of the low-frequency radiation column element and high-frequency radiation column element do not interfere with each other, or at least the degree of interference is minimized.

(19) In all examples of the present invention, just like this example, the low-frequency radiation column element and high-frequency radiation column element are adapted to be within the above specified ranges of operating bands, the value of the first distance between neighboring low-frequency radiation units is limited to be in the range of 262.5-287.5 mm, and the value of the second distance between neighboring high-frequency radiation units is limited to be in the range of 105-115 mm. Alternatively, the first distance and the second distance may be determined in the following manner: the first distance of the low-frequency radiation column element is 0.6-1.0 times of the wavelength corresponding to the center frequency of the frequency band range in which the column element operates, preferably 0.8 times; similarly, the second distance of the high-frequency radiation column element is 0.6-1.0 times of the wavelength corresponding to the center frequency of the frequency band range in which the column element operates, preferably 0.8 times.

(20) Please refer to FIG. 6. The multi-frequency array antenna according to Example 2 of the present invention is similarly a set of dual frequency common antenna, which, similarly to Example 1, comprises a low-frequency radiation column element and a high-frequency radiation column element, but the difference is that a part of the low-frequency radiation column element and a corresponding part of the high-frequency radiation column element are arranged to deviate from the imaginary first reference axis a. Specifically, it means that the second low-frequency radiation unit 3 and two high-frequency radiation units 5 adjacent axially thereto are no longer located on the first reference axis a, as other radiation units do, but are arranged to deviate from the first reference axis a, respectively: the adjacent two high-frequency radiation units 5 are fixedly arranged on an imaginary second reference axis (not shown) at one side of the first reference axis a, the second low-frequency radiation unit 3 is fixedly arranged on an imaginary third reference axis (not shown) at the other side of the first reference axis a, and both the second reference axis and the third reference axis are symmetric with respect to the first reference axis a and parallel to the first reference axis a. The improvement to this structure is favorable for flexible selection of the form of the radiation arm structure of the second low-frequency radiation unit, without causing concerns of signal interference with the adjacent two radiation units. In addition, this type of signal interference may theoretically be further reduced regardless of the selected form of the radiation arm structure.

(21) It should be noted that the reason why the second reference axis and the third reference axis are imaginary but not shown is only for the purpose of description, which avoids misunderstanding by additional lines that radiation units on different reference axes are mistaken as a plurality of radiation units. The same reason applies below.

(22) Please refer to the multi-frequency array antenna in Example 3 disclosed by FIG. 7, which makes improvements to Example 2. The improvements thereof are: wherein one of the second low-frequency radiation units 3 is arranged on an imaginary third reference axis (not shown), and two high-frequency radiation units adjacent axially thereto are similarly still located on the imaginary second reference axis (not shown). However, the other second low-frequency radiation unit 3 is arranged on the imaginary second reference axis (not shown). To adapt to this change, the two high-frequency radiation units 5 adjacent axially to the second low-frequency radiation unit 3 are moved to the third reference axis. This example is substantially equivalent to Example 2, which are mutually interchangeable solutions.

(23) FIG. 8 further discloses the arraying solution of the multi-frequency array antenna according to Example 4 of the present invention, which performs transformation based on Example 1, and the only transformation is that all of the low-frequency radiation units employed by the low-frequency radiation column element thereof are the above second low-frequency radiation units, i.e. the form of the radiation arm structure is a “cross” shape. The unified structure form of the low-frequency radiation units is favorable for the standard execution in the production process, making the assembly more convenient and thereby improving the production efficiency.

(24) Please refer to FIG. 9, FIG. 10 and FIG. 11, which disclose the multi-frequency array antenna according to Example 5, Example 6 and Example 7, respectively, and disclose the implementation form to apply the multi-frequency array antenna in 3, 4 and 5 frequency bands, respectively. Among them, the 3-frequency band common antenna shown in FIG. 9 is implemented based on the arraying solution in Example 1 and by providing another imaginary reference axis a2 parallel to the first reference axis a1 on the metal reflector, and arranging another high-frequency radiation column element on the reference axis a2 for processing signals in a third frequency band range; the 4-frequency band common antenna shown in FIG. 10 is implemented by providing two imaginary reference axes a1 and a2 on the metal reflector, and arranging a dual-frequency common antenna structure similar to Example 1 and operating in different frequency bands on the two reference axes a1 and a2, respectively; the 5-frequency band common antenna shown in FIG. 11 is implemented by providing three imaginary reference axes a1, a2 and a3 on the metal reflector, wherein the reference axis a1 is arranged with only one high-frequency radiation column element, while an arraying structure that is completely the same as Example 4 is employed on the other two reference axes a2 and a3 that are arranged symmetrically with respect to a1. It can be seen from the examples in FIG. 9 through FIG. 11 that the multi-frequency array antenna according to the present invention may achieve an antenna with two or more common frequency bands by flexibly adding a plurality of low-frequency radiation column elements and/or high-frequency radiation column elements and assigning identical or different ranges of operating frequency bands thereto.

(25) The second distance arranged in the axial direction of the first reference axis a for the distance between high-frequency radiation units in the above examples may also be fine-tuned according to specific implementation situations and arranged to be close to an equal distance. Similarly, the first distance 2.5 d arranged in the axial direction of the first reference axis a for the distance between low-frequency radiation units may also be fine-tuned according to specific implementation situations and arranged to be close to an equal distance. All of those skilled in the art are aware of such variations. As a result, any solutions that achieve the same or similar technical effect as the present invention by fine-tuning values of the first distance and the second distance shall be deemed not departing from the spirit and essence of the present invention.

(26) It should be noted that when the distance between high-frequency radiation units in the present invention is not an equal distance, the axial distance between low-frequency radiation units is not strictly 2.5 times, but changes to an equivalent relative position close to 2.5 times. Namely, the physical center of the low-frequency radiation unit that is not nested with high-frequency is located between two high-frequency radiation units locationally corresponding thereto. Those skilled in the art should be aware that according to their understanding of antenna technologies, such a variation is an equivalent alternative to the present invention, which similarly does not depart from the spirit and essence of the present invention.

(27) All examples of the present invention achieve unanticipated effect and can realize compatibility with 2G, 3G and 4G signals. According to the current mobile communication systems 2G/3G/LTE, the frequency band range in which the low-frequency radiation column element operates may be 790-960 MHz and the frequency band range in which the high-frequency radiation column element operates may be 1700-2700 MHz, based on which the center frequencies of the high-frequency radiation column element and the low-frequency radiation column element are calculated to be f1=2200 MHz and f2=875 MHz, respectively. It can be seen that it exactly satisfies the relationship of f1/f2˜2.5 times.

(28) In summary, the according to the present invention optimally meets the current arraying need by super wide frequency common antennas, greatly improves the electrical performance of the antennas, and at the same time, realizes overall miniaturization of the antennas.

(29) It should be noted that the above examples are only used to describe the present invention, rather than limit the technical solution described by the present invention; although the Specification has provided a detailed description of the present invention with reference to the above examples, therefore, those skilled in the art should understand that modifications or equivalent substitutions may still be made to the present invention; all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention shall be encompassed by the claims of the present invention.