阅读说明：本技术 具有交叉偶极子辐射元件的多频带基站天线 (Multiband base station antenna with crossed dipole radiating elements ) 是由 M·V·瓦奴斯法德拉尼 胡忠浩 O·依斯克 于 2018-02-20 设计创作，主要内容包括：一种用于基站天线的双极化辐射元件包括沿第一轴延伸的第一偶极子以及沿第二轴延伸的第二偶极子,第一偶极子包括第一偶极子臂和第二偶极子臂,第二偶极子包括第三偶极子臂和第四偶极子臂,第二轴大致垂直于第一轴,其中第一偶极子臂至第四偶极子臂中的每个偶极子臂具有间隔开的第一导电段和第二导电段,该第一导电段和第二导电段一起形成大致椭圆形形状。(a dual polarized radiating element for a base station antenna comprising a th dipole extending along a axis and a second dipole extending along a second axis, the th dipole comprising a th dipole arm and a second dipole arm, the second dipole comprising a third dipole arm and a fourth dipole arm, the second axis being substantially perpendicular to a axis, wherein each of the th to fourth dipole arms has spaced apart and second conductive segments, the and second conductive segments forming a substantially elliptical shape.)

1, a dual polarized radiating element, comprising:

a th dipole extending along an th axis, the th dipole comprising a th dipole arm and a second dipole arm;

a second dipole extending along a second axis, the second dipole comprising a third dipole arm and a fourth dipole arm, and the second axis being substantially perpendicular to the axis;

wherein each of the th through fourth dipole arms has spaced and second conductive segments that together form a generally elliptical shape, the spaced and second conductive segments .

2. The dual polarized radiating element of claim 1, further comprising at least feed bars, the at least feed bars extending substantially perpendicular to a plane defined by the th dipole and the second dipole.

3. The dual polarized radiating element of claim 1, wherein distal ends of the and second conductive segments of the th dipole arm are electrically connected to each other such that the th dipole arm has a closed loop structure.

4. The dual polarized radiating element of any , wherein each of the and second conductive segments of the through fourth dipole arms comprises a widened section having an average width of , a second widened section having a second average width, and a narrowed section having a third average width between the widened section and the second widened section, wherein the third average width is less than and less than halves of the second average width of the average width.

5. The dual polarized radiating element of claim 4, wherein the narrowed section comprises a meandering conductive trace.

6. The dual polarized radiating element of claim 4, wherein the narrowed segments create a high impedance for current at a frequency that is about twice the highest frequency in the operating frequency range of the dual polarized radiating element.

7. The dual polarized radiating element of any of claims 1-6, wherein a combined surface area of the th conductive segment and the second conductive segment forming the th dipole arm is greater than a combined surface area of the th conductive segment and the second conductive segment forming the second dipole arm.

8. The dual polarized radiating element of claim 7, mounted on a base station antenna, wherein said th dipole arm is closer to a side edge of said base station antenna than said second dipole arm.

9. The dual polarized radiating element of any of claims 1-8, wherein the and second conductive segments of each dipole arm comprise conductive segments of a printed circuit board.

10. The dual polarized radiating element of any of claims 1-9, wherein at least halves of an area between the and second conductive segments of said th dipole arm comprises an open area.

11. The dual polarized radiating element of any of claims 1-10, wherein the meandering trace of the conductive segment of the th dipole arm and the second meandering trace of the second conductive segment of the th dipole arm extend into an interior section of the th dipole arm between the conductive segment and the second conductive segment of the dipole arm.

12. The dual polarized radiating element of any of claims 1-11, wherein all meander trace segments on the dipole arm extend toward an interior section of the dipole arm between the and second conductive segments of the dipole arm.

13. The dual polarized radiating element of any of claims 1-12, wherein the th dipole directly radiates Radio Frequency (RF) signals at +45 ° polarization and the second dipole directly radiates RF signals at-45 ° polarization.

14. The dual polarized radiating element of claim , wherein a distal end of the conductive segment of the dipole arm is spaced apart from a distal end of the second conductive segment of the dipole arm such that the and second conductive segments of the dipole arm are electrically connected to each other only through the proximal ends of the and second conductive segments of the dipole arm.

15. The dual polarized radiating element of any of claims 1-14, wherein a conductive plate is mounted over a central portion of the dipole and the second dipole.

16. The dual polarized radiating element of claim 15, wherein said conductive plates are located within a distance of 0.05 times an operating wavelength of said th dipole and said second dipole, wherein said operating wavelength is a wavelength corresponding to a center frequency of an operating frequency band of said dual polarized radiating element.

17, base station antenna having the th linear array of dual polarized radiating elements of claim 15 or 16 and the second linear array of dual polarized radiating elements of claim 15 or 16, wherein the conductive plates included on each dual polarized radiating element are configured to shift the frequency of common mode resonance generated on the second linear array and located within the operating frequency band of the th and second linear arrays when the th linear array is transmitting signals such that the common mode resonance falls outside the operating frequency band.

18, a dual polarized radiating element, comprising:

a th dipole extending along an th axis, the th dipole comprising a th dipole arm and a second dipole arm;

a second dipole extending along a second axis, the second dipole comprising a third dipole arm and a fourth dipole arm, and the second axis being substantially perpendicular to the th axis,

wherein each of the th through fourth dipole arms has a th and second current paths spaced apart, and

wherein a central portion of each of the spaced and second current paths of the dipole arms extends parallel to the axis and a central portion of each of the spaced and second current paths of the third and fourth dipole arms extends parallel to the second axis.

19. The dual polarized radiating element of claim 18, wherein each of the th through fourth dipole arms has a conductive segment and a second conductive segment that are spaced apart, and wherein the th current path is along the conductive segment and the second current path is along the second conductive segment.

20. The dual polarized radiating element of any of claims 18-19, wherein the spaced and second conductive segments on each of said th through fourth dipole arms together form a generally elliptical shape.

21. The dual polarized radiating element of any of claims 18-20, wherein the spaced apart and second conductive segments on each of said th through fourth dipole arms together form a substantially rectangular shape.

22. The dual polarized radiating element of any , wherein each of the and second conductive segments of the through fourth dipole arms comprises a widened section having an average width of , a second widened section having a second average width, and a narrowed section having a third average width between the widened section and the second widened section, wherein the third average width is less than and less than halves of the second average width of the average width.

23. The dual polarized radiating element of claim 22, wherein the narrowed segments create a high impedance for current at a frequency that is about twice the highest frequency in the operating frequency range of the dual polarized radiating element.

24. The dual polarized radiating element of claim 22, wherein the narrowed section comprises a meandering conductive trace.

25. The dual polarized radiating element of any of claims 18-24, wherein a combined surface area of the conductive segment and the second conductive segment forming the th dipole arm is greater than a combined surface area of the conductive segment and the second conductive segment forming the second dipole arm.

26. The dual polarized radiating element of claim 25, mounted on the base station antenna, wherein said th dipole arm is closer to a side edge of the base station antenna than said second dipole arm.

27. The dual polarized radiating element of any of claims 18-26, wherein a conductive segment of the th dipole arm comprises a th meandering trace and a second conductive segment of the th dipole arm comprises a second meandering trace, and wherein the th meandering trace and the second meandering trace extend into an interior section of the th dipole arm between the conductive segment and the second conductive segment of the th dipole arm.

28. The dual polarized radiating element of any of claims 18-27, wherein a conductive segment and a of said th dipole arm together comprise a plurality of meandering trace segments, and wherein all meandering trace segments included in a conductive segment and a second conductive segment of said th dipole arm extend toward an interior section of a th dipole arm between said conductive segment and said second conductive segment of said th dipole arm.

29. The dual polarized radiating element of any of claims 18-28 in combination with a base station antenna, wherein the base station antenna extends along a longitudinal axis, wherein the axis is angled approximately +45 degrees with respect to the longitudinal axis and the second axis is angled approximately-45 degrees with respect to the longitudinal axis.

30. The dual polarized radiating element of any , further comprising at least feed rods, the at least feed rods extending substantially perpendicular to a plane defined by the dipole and the second dipole.

31. The dual polarized radiating element of any of claims 18-30, wherein distal ends of the and second conductive segments of said th dipole arm are electrically connected to each other such that said th dipole arm has a closed loop structure.

32. The dual polarized radiating element of claim 31, wherein the distal ends of and second conductive segments of the dipole arm are electrically connected to each other by a meandering conductive trace.

33. The dual polarized radiating element of any of claims , wherein a distal end of a conductive segment of the th dipole arm is spaced apart from a distal end of a second conductive segment of the th dipole arm such that the and second conductive segments of the th dipole arm are electrically connected to each other only through a proximal end of the and second conductive segments of the th dipole arm.

34. The dual polarized radiating element of any of claims 18-33, wherein at least halves of an area between the and second conductive segments of said th dipole arm comprises an open area.

35. The dual polarized radiating element of any of claims 18-34, wherein the th dipole directly radiates Radio Frequency (RF) signals at +45 ° polarization and the second dipole directly radiates RF signals at-45 ° polarization.

36. The dual polarized radiating element of any of claims 18-35, wherein a conductive plate is mounted over a central portion of the dipole and the second dipole.

37. The dual polarized radiating element of claim 36, wherein said conductive plates are located within a distance of 0.05 times an operating wavelength of said th dipole and said second dipole, wherein said operating wavelength is a wavelength corresponding to a center frequency of an operating frequency band of said dual polarized radiating element.

38, base station antenna having the th linear array of dual polarized radiating elements of claim 36 or 37 and the second linear array of dual polarized radiating elements of claim 1836 or 37, wherein the conductive plates included on each dual polarized radiating element are configured to shift the frequency of a common mode resonance generated on the second linear array and located within an operating frequency band of the th and second linear arrays when the th linear array transmits a signal such that the common mode resonance falls outside the operating frequency band.

39, a dual polarized radiating element for a base station antenna, comprising:

a th dipole extending along an th axis, the th dipole comprising a th dipole arm and a second dipole arm;

a second dipole extending along a second axis, the second dipole comprising a third dipole arm and a fourth dipole arm, and the second axis being substantially perpendicular to the axis;

wherein each of the th through fourth dipole arms has spaced-apart and second conductive segments defining respective and second current paths, and

wherein each of the and second conductive segments of the th through fourth dipole arms comprises a plurality of widened sections and a plurality of narrowed meandering trace sections between adjacent ones of the widened sections, and

wherein a -th widened section among the widened sections of the -th dipole arm is wider than a -th widened section among the widened sections of the second dipole arm, and the -th widened section among the widened sections of the second dipole arm is the same distance from a point where the -th axis and the second axis cross as the -th widened section among the widened sections of the -th dipole arm.

40. The dual polarized radiating element of claim 39, wherein spaced apart and second conductive segments on each of the th through fourth dipole arms together form a generally elliptical shape or a generally rectangular shape.

41. The dual polarized radiating element of any of claims 39-40, wherein the widened section has a th average width and the narrowed meandering trace section has a second average width that is less than and half of the th average width.

42. The dual polarized radiating element of any of claims 39-41, mounted on a base station antenna, wherein the th dipole arm is closer to a side edge of the base station antenna than the second dipole arm.

43. The dual polarized radiating element of any of claims 39-42, wherein distal ends of the and second conductive segments of said th dipole arm are electrically connected to each other such that said th dipole arm has a closed loop structure.

44. The dual polarized radiating element of claim 43, wherein the distal ends of and second conductive segments of the dipole arm are electrically connected to each other by a meandering conductive trace.

45. The dual polarized radiating element of any of claims 39-44, wherein a conductive plate is mounted over a central portion of the dipole and the second dipole.

46. The dual polarized radiating element of claim 45, wherein said conductive plates are located within a distance of 0.05 times an operating wavelength of said th dipole and said second dipole, wherein said operating wavelength is a wavelength corresponding to a center frequency of an operating frequency band of said dual polarized radiating element.

47, base station antenna having a th linear array of dual polarized radiating elements as claimed in claim 45 or 46 and a second linear array of dual polarized radiating elements as claimed in claim 45 or 46, wherein the conductive plates included on each dual polarized radiating element are configured to shift the frequency of a common mode resonance generated on the second linear array and located within an operating frequency band of the th and second linear arrays when the th linear array is transmitting signals such that the common mode resonance falls outside the operating frequency band.

48, a method of tuning a base station antenna having a th linear array of radiating elements that transmit and receive signals within an operating frequency band and a second linear array of radiating elements that transmit and receive signals within the operating frequency band, each of the radiating elements including th to fourth dipole arms, the operating frequency band having at least a th sub-band in a th frequency range and a second sub-band in a second frequency range, the th and second sub-bands being separated by a third frequency band that is not a portion of the operating frequency band, the method comprising:

a size of a respective gap between adjacent dipole arms among th through fourth dipole arms on respective radiating elements is selected to tune a common mode resonance generated on the second linear array when the th linear array transmits a signal within the third frequency band.

49. The method of claim 48 wherein the th sub-band and the second sub-band are both within the 694-960MHz frequency band.

50. The method of claim 48 or 49 wherein the third frequency band is the 799-823MHz frequency band.

51, base station antenna, comprising:

an th linear array of radiating elements that transmit and receive signals within an operating frequency band;

a second linear array of radiating elements that transmit and receive signals within the operating frequency band,

wherein each radiating element among the th linear array of radiating elements and the radiating elements in the second linear array of radiating elements includes th and second dipoles extending in a vertical plane and a conductive plate mounted over a central portion of the th and second dipoles,

wherein the conductive plate is located within a distance of 0.05 times an operating wavelength of the th dipole and the second dipole, wherein the operating wavelength is a wavelength corresponding to a center frequency of the operating frequency band.

52. The base station antenna of claim 51, wherein the conductive plate included on each radiating element is configured to shift a frequency of a common mode resonance generated on the second linear array and located within an operating frequency band of the and second linear arrays when the th linear array transmits a signal such that the common mode resonance falls outside of the operating frequency band.

Background

The present invention relates generally to radio communications and, more particularly, to base station antennas for cellular communication systems.

In cellular communication systems, the geographic area is divided into series of regions known as "cells" that are served by respective base stations, a base station may include or more base station antennas configured to provide bi-directional radio frequency ("RF") communication with mobile subscribers within the cell served by the base station in many cases, each base station is divided into "sectors". in perhaps the most common configuration, the hexagonal cell is divided into three 120 ° sectors, and each sector is served by or more base station antennas having an azimuthal Half Power Beamwidth (HPBW) of approximately 65 °.

Although it is possible to provide service in multiple frequency bands using linear arrays of so-called "wideband" or "ultra-wideband" radiating elements in cases, in other cases different linear arrays (or planar arrays) of radiating elements must be used to support service in different frequency bands.

The number of base station antennas that can be deployed at a given base station has typically increased, however, due to local area regulations such as antenna towers and/or weight and wind load constraints, there has been a limit to increasing capacity without otherwise increasing the number of base station antennas, so-called multi-band base station antennas have been introduced in recent years in which multiple linear arrays of radiating elements are included in a single antenna of the very common multi-band base station antenna design is an RVV antenna comprising linear arrays of "low band" radiating elements for providing service in or all of the 694-960MHz band (commonly referred to as the "R band") and two linear arrays of "high band" radiating elements for providing service in or all of the 1695-2690MHz band (commonly referred to as the "V band").

There is also a great interest in RRVV base station antennas, which refers to base station antennas having two linear arrays of low-band radiating elements and two (or four) linear arrays of high-band radiating elements. RRVV antennas are used in a variety of applications including 4x4 multiple-input multiple-output ("MIMO") applications, or as multi-band antennas having two different low frequency bands (e.g., 700MHz low band linear array and 800MHz low band linear array) and two different high frequency bands (e.g., 1800MHz high band linear array and 2100MHz high band linear array). However, RRVV antennas are challenging to implement in a commercially acceptable manner, because implementing a 65 ° azimuth HPBW antenna beam in the low band typically requires a low band radiating element that is at least 200mm wide. When two low band arrays are placed side by side with a high band linear array in between, this results in a base station antenna with a width of approximately 600 and 760 mm. Such large antennas may have very high wind loads, may be very heavy, and/or may be expensive to manufacture. Operators will prefer RRVV base station antennas having widths in the range of 300-.

Disclosure of Invention

According to an embodiment of the present invention, a dual polarized radiating element is provided, the dual polarized radiating element comprising a th dipole extending along a th axis and a second dipole extending along a second axis, the th dipole comprising a th dipole arm and a second dipole arm, the second dipole comprising a third dipole arm and a fourth dipole arm, the second axis being substantially perpendicular to the th axis, each of the th to fourth dipole arms having spaced-apart and second conductive segments, the and second conductive segments together forming a substantially elliptical shape.

The dual polarized radiating element may further comprise at least feed bars, the at least feed bars extending substantially perpendicular to a plane defined by the th dipole and the second dipole.

In embodiments, the distal ends of the 0 th and second conductive segments of the dipole arm are electrically connected to each other such that the th dipole arm has a closed loop structure in other embodiments, the distal end of the th conductive segment of the th dipole arm is spaced apart from the distal end of the second conductive segment of the th dipole arm such that the th and second conductive segments of the th dipole arm are electrically connected to each other only through the th and proximal ends of the second conductive segments of the th dipole arm.

In embodiments, each of the and second conductive segments of the -fourth dipole arms includes a widened section having an average width of , a second widened section having a second average width, and a narrowed section having a third average width between the widened section and the second widened section.

In embodiments, the combined surface area of the th and second conductive segments forming the th dipole arm is greater than the combined surface area of the th and second conductive segments forming the second dipole arm in such embodiments, a dual polarized radiating element may be mounted on the base station antenna with the th dipole arm being closer to a side edge of the base station antenna than the second dipole arm.

In embodiments, the th and second conductive segments of each dipole arm can comprise conductive segments of a printed circuit board.

In embodiments, at least half of the area between the th and second conductive segments of the th dipole arm can be an open area.

In embodiments, the 1 th meandering trace of the 0 th conductive segment of the th dipole arm and the second meandering trace of the second conductive segment of the 2 th dipole arm extend into an interior section of the th dipole arm between the th and second conductive segments of the th dipole arm in embodiments, all meandering trace segments on the th dipole arm extend toward the interior section of the th dipole arm between the th and second conductive segments of the th dipole arm.

In embodiments, the dipole directly radiates radio frequency ("RF") signals with +45 polarization and the second dipole directly radiates radio frequency signals with-45 polarization.

In some embodiments, the conductive plates are mounted above the center portions of the and second dipoles in some embodiments, the conductive plates may be located within a distance of 0.05 times an operating wavelength of the and second dipoles, where the operating wavelength is a wavelength corresponding to a center frequency of an operating band of the dual-polarized radiating element.

According to a further embodiment of the present invention, a dual polarized radiating element is provided, the dual polarized radiating element comprising a th dipole extending along an th axis and a second dipole extending along a second axis, the 0 th dipole comprising a th dipole arm and a second dipole arm, the second dipole comprising a third dipole arm and a fourth dipole arm, and the second axis being substantially perpendicular to the th axis each of the th through fourth dipole arms has spaced-apart and second current paths, and a central portion of each of the th and spaced-apart and second current paths of the second dipole arm extends parallel to the th axis, and a central portion of each of the spaced-apart th and second current paths of the third and fourth dipole arms extends parallel to the second axis.

In embodiments, each of the through fourth dipole arms has and a second conductive segment spaced apart, and the current path is along the conductive segment and the second current path is along the second conductive segment.

In embodiments, the spaced th and second conductive segments on each of the th through fourth dipole arms together form a generally elliptical shape in other embodiments, the spaced th and second conductive segments on each of the th through fourth dipole arms together form a generally rectangular shape.

In embodiments, each of the and second conductive segments of the -fourth dipole arms includes a widened section having an average width of , a second widened section having a second average width, and a narrowed section having a third average width between the widened section and the second widened section.

In embodiments, the combined surface area of the th and second conductive segments forming the th dipole arm is greater than the combined surface area of the th and second conductive segments forming the second dipole arm in such embodiments, a dual polarized radiating element may be mounted on the base station antenna, and the th dipole arm may be closer to a side edge of the base station antenna than the second dipole arm.

In embodiments, the 0 th conductive segment of the dipole arm comprises a 1 th meandering trace and the 2 th conductive segment of the th dipole arm comprises a second meandering trace, and the 3 th and second meandering traces extend into an interior section of the 4 th dipole arm between the 6 th and second conductive segments of the 5 th dipole arm in 7 embodiments, the th and second conductive segments of the th dipole arm together comprise a plurality of meandering trace segments, and all of the meandering trace segments included in the th and second conductive segments of the th dipole arm extend toward the interior section of the th dipole arm between the th and second conductive segments of the th dipole arm.

In embodiments, the 0 th and distal ends of the second conductive segments of the th dipole arm are electrically connected to each other such that the 1 th dipole arm has a closed loop structure the th and distal ends of the second conductive segments of the 2 th dipole arm are electrically connected to each other by a meandering conductive trace, in other embodiments, the distal end of the th conductive segment of the th dipole arm is spaced apart from the distal end of the second conductive segment of the th dipole arm such that the th and second conductive segments of the th dipole arm are electrically connected to each other only through the th and proximal ends of the second conductive segment of the th dipole arm.

According to yet further embodiments of the present invention, there is provided a dual polarized radiating element for a base station antenna comprising a th dipole extending along a th axis and a second dipole extending along a second axis, the th dipole comprising a st dipole arm and a second dipole arm, the second dipole comprising a third dipole arm and a fourth dipole arm, and the second axis being substantially perpendicular to a th axis, each of the 3 to fourth dipole arms having spaced-apart th and second conductive segments defining respective th and second current paths, and each of the conductive segments of the th to fourth dipole arms and second conductive segments comprising a plurality of widened sections and a plurality of widened meandering trace sections between adjacent ones of the widened sections, a widened section of the widened dipole section of the dipole arm intersecting the second widened dipole section of the second dipole arm at a same distance as the second axis 3637 and a second widened dipole section of the second dipole arm 3638.

According to yet further embodiments of the present invention, there is provided a method of tuning a base station antenna, the base station antenna may include a th linear array of radiating elements to transmit and receive signals within an operating frequency band and a second linear array of radiating elements to transmit and receive signals within the operating frequency band, each radiating element including to fourth dipole arms, the operating frequency band having at least a th sub-band within a th frequency range and a second sub-band within the second frequency range, the th and second sub-bands being separated by a third frequency band that is not part of of the operating frequency band.

In embodiments, both the and second sub-bands are within the 694-960MHz band, in embodiments, the third band is the 799-823MHz band.

In still further embodiments of the present invention, base station antennas are provided that include an th linear array of radiating elements to transmit and receive signals within an operating frequency band and a second linear array of radiating elements to transmit and receive signals within the operating frequency band, each radiating element of the and second linear arrays of radiating elements includes a th dipole and a second dipole extending in a vertical plane, and a conductive plate is mounted over a center portion of the th and second dipoles, the conductive plate being located within a distance of 0.05 times an operating wavelength of the th and second dipoles, wherein the operating wavelength is a wavelength corresponding to a center frequency of the operating frequency band.

In embodiments, the conductive plate is configured to shift a frequency of a common mode resonance generated on the second linear array and within an operating frequency band of the and second linear array when the linear array transmits a signal such that the common mode resonance falls outside of the operating frequency band.

Drawings

Fig. 1 is a side perspective view of a base station antenna according to an embodiment of the present invention.

Fig. 2 is a perspective view of the base station antenna of fig. 1 with the radome removed.

Fig. 3 is a front view of the base station antenna of fig. 1 with the radome removed.

Fig. 4 is a side view of the base station antenna of fig. 1 with the radome removed.

Fig. 5 and 6 are enlarged perspective views of portions of the base station antenna of fig. 1-4.

Fig. 7 is an enlarged perspective view of of the low band radiating element component of the base station antenna of fig. 1-6.

Fig. 8 is a top view of the low band radiating element assembly of fig. 7.

Fig. 9 is a side view of the low band radiating element assembly of fig. 7.

Fig. 10 is a top view of a dipole illustrating of low band radiating elements included in the low band radiating element assemblies of fig. 7-9.

Fig. 11 is a top view of a dipole illustrating a low-band radiating element according to further embodiments of the present invention.

Fig. 12 is an enlarged perspective view of of the high-band radiating element assembly of the base station antenna of fig. 1-6.

Fig. 13A-13C are schematic diagrams illustrating example implementations of a common-mode filter that may be included on a feed stalk of a radiating element of the base station antenna of fig. 1-6.

Fig. 14 is a schematic diagram illustrating an example implementation of a common-mode filter that may be integrated into the dipole arms of the low-band radiating elements of the base station antennas of fig. 1-6.

Figure 15 is a perspective view of a low band radiating element assembly including a respective conductive plate mounted over a central section of a dipole arm of each low band radiating element in accordance with an embodiment of the present invention.

Detailed Description

Embodiments of the present invention generally relate to dual polarized low band radiating elements for dual band base station antennas and related base station antennas and methods such dual band antennas may be capable of supporting two or more major air interface standards in two or more cellular frequency bands and allow wireless operators to reduce the number of antennas deployed at the base station, thereby reducing tower rental costs while increasing speed to market.

In addition, at least in the azimuth plane, scattering tends to affect beam width, beam shape, pointing angle, gain, and front-to-back ratio (front-to-back ratio) in an undesirable manner.

In accordance with an embodiment of the present invention, there is provided a base station antenna having a cross-dipole dual polarized radiating element including a and a second dipole extending along respective th and second vertical axes, each dipole may include pairs of dipole arms, each dipole arm having spaced and second conductive segments, the and second conductive segments together forming a generally elliptical shape or a generally elongated rectangular shape, the spaced and second conductive segments of each dipole arm may include a central portion extending parallel to the axis of their respective dipole, the dipole may directly radiate RF signals with a +45 ° polarization, and the second dipole may directly radiate RF signals with a-45 ° polarization.

In embodiments, the distal ends of the and second conductive segments of each dipole arm can be electrically connected to each other such that each dipole arm each has a closed loop structure the and second conductive segments each can include a plurality of widened sections and a narrowed meandering conductive trace section connecting adjacent ones of the widened sections.

In embodiments, the dipole may be unbalanced such that the combined surface area of the th and second conductive segments forming the th dipole arm is greater than the combined surface area of the th and second conductive segments forming the second dipole arm.

The dipole arms may be implemented, for example, on a printed circuit board or other substantially planar substrate, the cross-dipole dual-polarized radiating element according to embodiments of the invention may also include a feed stalk that may be implemented, for example, on a printed circuit board, in embodiments, the feed stalk may support the dipole arms above a ground plane, such as a reflector.

in some embodiments, dual polarized radiating elements may be included in the base station antenna and used to form a th and second linear arrays, each dual polarized radiating element including a conductive plate that may be located within 0.15 times the operating wavelength of the dipole and may be substantially parallel to the dipole, in other embodiments, the conductive plate may be located within 0.1 times the operating wavelength of the dipole or within 0.05 times the operating wavelength of the dipole, the conductive plate may be configured to shift a frequency of a common mode resonance generated on the second linear array and within an operating frequency band of the and second linear array when the th linear array transmits a signal.

According to yet further embodiments of the present invention, a method of tuning a base station antenna may be provided, the base station antenna may have a th linear array of radiating elements to transmit and receive signals within an operating frequency band and a second linear array of radiating elements to transmit and receive signals within the operating frequency band, each radiating element may include through fourth dipole arms, and the operating frequency band may have at least a th sub-band within a frequency range and a second sub-band within a second frequency range, and the and the second sub-band may be separated by a third frequency band that is not part of of the operating frequency band.

Embodiments of the present invention will now be described in further detail at step with reference to the accompanying drawings.

Fig. 1-6 illustrate a base station antenna 100 according to some embodiments of the present invention, in particular, fig. 1 is a front perspective view of the antenna 100, fig. 2-4 are perspective, front and side views, respectively, of the antenna 100 with its radome removed to illustrate internal components of the antenna, fig. 5 and 6 are enlarged partial perspective views of the base station antenna 100, fig. 7-9 are perspective, front and side views, respectively, of a low band radiating element assembly included in the base station antenna 100, fig. 10 is a top view of a dipole illustrating a low band radiating element included in the low band radiating element assembly of fig. 7-9, finally, fig. 12 is a top view of the dipole illustrating a high band radiating element assembly included in the base station antenna 100, fig. 11 is a top view of an alternative design of the dipole illustrating a low band radiating element.

As shown in fig. 1-6, the base station antenna 100 is an elongated structure extending along a longitudinal axis L. the base station antenna 100 may have a tubular shape that is generally rectangular in cross-section.a radome 110 and a top end cap 120. in embodiments, the radome 110 and top end cap 120 may comprise a single, integral unit, which may help to waterproof the antenna 100. or more mounting brackets 150 are provided on the rear side of the radome 110. the mounting brackets 150 may be used to mount the antenna 100 to an antenna mount (not shown), such as on an antenna tower.

Fig. 2-4 are perspective, front and side views, respectively, of the base station antenna 100 with the radome 110 removed.

As shown in fig. 2-4, the base station antenna 100 includes an antenna assembly 200, which antenna assembly 200 may be slidably inserted into the radome 110 from the top or bottom before the top cover 120 or bottom cover 130 is attached to the radome 110.

The antenna assembly 200 includes a ground plane structure 210 having a sidewall 212 and a reflector surface 214. Various mechanical and electrical components of the antenna may be mounted within a cavity defined between the sidewall 212 and the back of the reflector surface 214, such as, for example, phase shifters, remote electronic tilt ("RET") units, mechanical linkages, controllers, duplexers, and the like. The ground plane structure 210 may not include a back wall to expose these electrical and mechanical components. The reflector surface 214 of the ground plane structure 210 may contain or include a metal surface that serves as a reflector and ground plane for the radiating elements of the antenna 100. Here, the reflector surface 214 may also be referred to as a reflector 214.

The plurality of radiating elements 300, 400 are mounted on the reflector surface 214 of the ground plane structure 210 the radiating elements include low band radiating elements 300 and high band radiating elements 400 as best shown in fig. 3, the low band radiating elements 300 are mounted in two vertical columns to form two vertically arranged linear arrays 220-1, 220-2 of radiating elements 300 in embodiments each linear array 220 may extend substantially along the entire length of the antenna 100 the high band radiating elements 400 may be similarly mounted in two vertical columns to form two vertically arranged linear arrays 230-1, 230-2 of high band radiating elements 400 in embodiments the high band radiating elements 400 may be mounted in a plurality of rows and columns to form two or more linear arrays 230 the linear array 230 of high band radiating elements 400 may be located between the linear arrays 220 of the low band radiating elements 300 the linear arrays 230 of the high band radiating elements 400 may or may not extend the entire length of the antenna 100 the high band radiating elements 300 may be configured to transmit signals in the and receive signals in the second 3970 MHz range or the high band radiating elements 400 may be configured to receive signals in the 3695 MHz range 2695 MHz and the high band 34, 2695 and the high band radiating elements 34.

Fig. 5-6 are enlarged perspective views of the portion of the base station antenna 100 with the radome 110 removed, more particularly illustrating a number of low-band radiating elements 300 and a number of high-band radiating elements 400 as can be seen in fig. 5-6, many of the low-band radiating elements 300 are in close proximity to a number of the high-band radiating elements 400 among the high-band radiating elements 400 the low-band radiating elements 300 are taller (above the reflector 214) than the high-band radiating elements 400 and may extend over at least of the high-band radiating elements 400.

Note that the antenna 100 and antenna assembly 200 are described using terms that assume that the antenna 100 is mounted for use on a tower and that the longitudinal axis of the antenna 100 extends along a vertical axis and that the front surface of the antenna 100 mounted opposite the tower is directed toward the coverage area of the antenna 100. In contrast, the terms assuming that the antenna assembly 200 is mounted on a horizontal surface and the radiating elements 300, 400 extend upward may be used to describe various components of the antenna 100 (such as the radiating elements 300, 400 and various other components). Thus, although the dipole arm 330 of the low band radiating element 300 is described, for example, as being the top portion of the radiating element 300 and above the reflector 214, it will be understood that when the antenna 100 is mounted for use, the dipole arm 330 will be directed forward from the ground plane structure 210 rather than upward.

The low-band radiating element 300 and the high-band radiating element 400 are mounted on the ground plane structure 210. The reflector surface 214 of the ground plane structure 210 may comprise a metal sheet, which, as described above, acts as a reflector and as a ground plane for the radiating elements 300, 400.

As described above, the low-band and high- band radiating elements 300, 400 are arranged as two low-band arrays 220 and two high-band arrays 230 of radiating elements, each array 220, 230 may be used to form a separate antenna beam each radiating element 300 in the low-band array 220-1 may be horizontally aligned with a respective radiating element 300 in the second low-band array 220-2 similarly, each radiating element 400 in the high-band array 230-1 may be horizontally aligned with a respective radiating element 400 in the second high-band array 230-2 each low-band linear array 220 may include a plurality of low-band radiating element feed assemblies 250, each low-band radiating element feed assembly 250 including two low-band radiating elements 300, each high-band linear array 230 may include a plurality of high-band radiating element feed assemblies 260, each high-band radiating element feed assembly 260 including to three high-band radiating elements 400.

Referring now to fig. 7-9, of the low band radiating element feed assemblies 250 will be described in greater detail, the low band radiating element feed assemblies 250 include a printed circuit board 252, the printed circuit board 252 having a th and second low band radiating elements 300-1, 300-2 extending upwardly from either end thereof the printed circuit board 252 includes an RF transmission line feed 254, the RF transmission line feed 254 providing RF signals to and receiving RF signals from the respective low band radiating elements 300-1, 300-2, each low band radiating element 300 includes a pair of feed bars 310 and a th and second dipoles 320-1, 320-2, a dipole 320-1 includes a th and second dipole arms 330-1, 330-2, and the second dipole 320-2 includes third and fourth dipole arms 330-3, 330-4.

The feed bars 310 may each include a printed circuit board having RF transmission lines 314 formed thereon, the RF transmission lines 314 carrying RF signals between the printed circuit board 252 and the dipoles 320, each feed bar 310 may also include a hook balun (hook base). The -th feed bar 310-1 of the feed bars may include a lower vertical slot, and the second feed bar 310-2 of the feed bars may include an upper vertical slot, the vertical slots allowing two feed bars 310 to be assembled to form a vertically extending column having a generally x-shaped horizontal cross-section.A lower portion of each printed circuit board may include plated bumps 316, the plated bumps 316 are inserted through the slots in the printed circuit board 252. the plated bumps 316 may be soldered to plated portions of the printed circuit board 252 adjacent to the slots on the printed circuit board to electrically connect the feed bars 310 to the printed circuit board 252. the RF transmission lines 314 on the respective feed bars 310 may center-ohmic feed the dipoles 320-1, 320-2 via a direct connection between the dipole lines 314 and the sub-arms 330.

A dipole support 318 may also be provided to hold the th and second dipoles 320-1, 320-2 in their proper positions and to reduce the force applied to the soldered coupling that electrically connects the dipoles 320 to their feed stalk 310.

The azimuth half-power beamwidth of each low-band radiating element 300 may be in the range of 55 degrees to 85 degrees in the embodiments, the azimuth half-power beamwidth of each low-band radiating element 300 may be about 65 degrees.

Each dipole 320 may include, for example, two dipole arms 330, the length of dipole arms 330 being between about 0.2 and 0.35 times the operating wavelength, where "operating wavelength" refers to a wavelength corresponding to the center frequency of the operating band of radiating element 300. For example, if the low band radiating element 300 were designed as a broadband radiating element that is used to transmit and receive signals across the entire 694-960MHz frequency band, the center frequency of the operating band would be 827MHz and the corresponding operating wavelength would be 36.25 cm.

As shown in FIG. 8, dipole 320-1 extends along a th axis 322-1 and second dipole 320-2 extends along a second axis 322-2, second axis 322-2 is substantially perpendicular to a th axis 322-1. therefore, a th and second dipoles 320-1, 320-2 are arranged in the general shape of a cross dipole 320-1 dipole arms 330-1 and 330-2 are center-fed by a common RF transmission line 314 and radiate with a th polarization . in the depicted embodiment, dipole 320-1 is designed to transmit a signal with a +45 degree polarization.second dipole 320-2 dipole arms 330-3 and 330-4 are similarly center-fed by a common RF transmission line 314 and radiate with a second polarization orthogonal to a th polarization.second dipole 320-2 is designed to transmit a signal with a-45 degree polarization.310 dipole arm 330 may be mounted above reflector 214 by approximately 3/16 times the operating wavelength 1/4 and may be printed next to circuit board 214.

As best seen in fig. 8 and 10, each dipole arm 330 includes spaced apart and second conductive segments 334-1, 334-2, the and second conductive segments 334-1, 334-2 0 together forming generally elliptical shapes in fig. 10, a thick dashed ellipse is superimposed on the dipole arm 330-3 to illustrate the generally elliptical nature of the combination of conductive segments 334-1 and 334-2 in fig. 10, a and second dashed ellipse are also superimposed on the dipole arm 330-2, the dashed ellipses generally enclosing respective first and second 334-1, 334-2 in embodiments, the spaced apart conductive segments 334-1, 334-2 may be implemented, for example, in a printed circuit board 332, and may lie in a plane, which is generally parallel to a plane defined by the bottom layer reflector 214, all four dipole arms 330 may lie in this plane, all four dipole arms may extend in a direction generally perpendicular to the feeding rod plane.

Each conductive segment 334-1, 334-2 may include a metal pattern having a plurality of widened segments 336 and at least narrowed trace sections 338. the th conductive segment 334-1 may form the half of a substantially oval shape and the second conductive segment 334-2 may form the other half of the substantially oval shape.

As shown in FIG. 10, each widened section 336 of conductive segments 334-1, 334-2 may have a respective width W in a th plane₁Wherein, the width W₁Measured in a direction substantially perpendicular to the direction of current flow along the respective widened section 336. Width W of each widened section 336₁Not necessarily constant, and thus in cases reference will be made to the average width of each widened section 336. the narrowed trace section 338 may similarly have a corresponding width W in the plane₂Wherein the width W₂Measured in a direction substantially perpendicular to the direction of the instantaneous current along the narrowed trace segment 338. Width W of each narrowed trace segment 338₂Nor need it be, and thus in some cases reference will be made to the average width of each narrowed trace segment 338.

The use of meandering conductive trace segments 338 provides convenient ways to extend the length of the meandering trace segments 338 while still providing a relatively compact conductive trace segment 334.

In embodiments, the average width of each widened section 336 may be at least twice the average width of each narrowed trace section 338, for example, in other embodiments, the average width of each widened section 336 may be at least three times the average width of each narrowed trace section 338, in yet other embodiments , the average width of each widened section 336 may be at least four times the average width of each narrowed trace section 338, in yet other embodiments, the average width of each widened section 336 may be at least five times the average width of each narrowed trace section 338.

The narrowed trace section 338 may serve as a high impedance portion designed to interrupt current in a high band frequency range that might otherwise be induced on the dipole arms 330, in particular, when the high band radiating element 400 is transmitting and receiving signals, high band RF signals may tend to induce current on the dipole arms 330 of the low band radiating element 300, this is particularly true when the low and high band radiating elements 300, 400 are designed to operate in frequency bands having center frequencies spaced approximately twice apart, since a low band dipole arm 330 having a length of wavelengths that is a quarter of the low band operating frequency will in this case have a length that is approximately half the length of the high band operating frequency.

The narrowed trace section 338 may be designed to act as a high impedance portion designed to interrupt high band currents that may otherwise be induced on the low band dipole arms 330. in this way, the narrowed trace section 338 may be designed to create this high impedance for high band currents without significantly affecting the ability of the low band currents to flow on the dipole arms 330. in this way, the narrowed trace section 338 may reduce the induced high band currents on the low band radiating element 300 and thus reduce interference with the antenna pattern of the high band linear array 230. in embodiments, the narrowed trace section 338 may make the low band radiating element 300 nearly invisible to the high band radiating element 400, and thus the low band radiating element 300 may not distort the high band antenna pattern.

As also seen in fig. 7-10, in some embodiments , the distal ends of conductive segments 334-1, 334-2 may be electrically connected to one another such that conductive segments 334-1, 334-2 form a closed loop structure in some embodiments depicted of conductive segments 334-1, 334-2 are electrically connected to one another by narrowed trace sections 338, while in other embodiments widened sections 336-2 at the distal ends of conductive segments 334-1, 334-2 may be merged at in yet other embodiments, different electrical connections may be used in other embodiments, the distal ends of conductive segments 334-1, 334-2 may not be electrically connected to one another in some embodiments, it is further seen that the interior of the loop defined by conductive segments 334-1, 334-2 (which may or may not be a closed loop) may generally be free of conductive material, in some embodiments, at least 5 of a dielectric mounting substrate (e.g., a dielectric layer of a printed circuit board) on which conductive segments 334 are mounted may be a conductive material, in addition, at least two thirds of the dielectric mounting substrate area 340 of the dielectric mounting substrate may be formed by open loops 340, and in some embodiments, the inner portions of conductive segments 340 may be formed by open loops 340, stabilized by printed circuit board 340, including at least two thirds of open loop regions 340, preferably printed circuit board 340, stabilized by open loop regions 340, 310, 26, 310, 26, 310, 26.

7-10, the and second conductive segments 334-1, 334-2 may include meandering trace segments 338 that are in opposing positions about the axis of the dipole 320 in embodiments in such embodiments, these opposing meandering trace segments 338 may extend toward the interior of the generally elliptical structure defined by the conductive segment 334-1 and the second conductive segment 334-2, and thus may also extend toward each other in embodiments, all of the meandering trace segments 338 on each dipole arm 330 may extend toward the interior segments of the dipole arm 330 between the th and second conductive segments 334-1, 334-2 of the dipole arm 330 in embodiments .

In embodiments, capacitors may be formed between adjacent dipole arms 330 of different dipoles 320, for example, a th capacitor may be formed between dipole arms 330-1 and 330-3, and a second capacitor may be formed between dipole arms 330-2 and 330-4.

In addition, by using a ring structure, the overall length of the dipole arms 330 may be advantageously reduced, allowing for greater spacing between each dipole arm 330 and the high-band radiating elements 400 and between each dipole arm 330 and the low-band radiating elements 300 in the other low-band arrays 220.

As described above, the th dipole 320-1 is configured to transmit and receive RF signals with a +45 degree tilted polarization and the second dipole 320-2 is configured to transmit and receive RF signals with a-45 degree tilted polarization, thus, when the base station antenna 100 is installed for normal operation, the th axis 322-1 of the th dipole 320-1 may be at an angle of about +45 degrees with respect to the longitudinal (vertical) axis of the antenna 100 and the second axis 322-2 of the second dipole 320-2 may be at an angle of about-45 degrees with respect to the longitudinal axis L of the antenna 100.

As best seen in FIG. 10, the central portion 344 of each of the th and second dipole arms 330 extends parallel to the th axis 322-1, and the central portion 344 of each of the third and fourth dipole arms 330 extends parallel to the second axis 322-2. furthermore, the dipole arms 330 as a whole extend generally along the or another of the and second axes 322-1, 322-2. thus, each dipole 320 will radiate directly at either a +45 or-45 polarization.

It will be appreciated that in other embodiments, the dipole arms 330 may have shapes other than the generally elliptical shape shown in fig. 7-10, for example, in another embodiments, each dipole arm 330 may have a generally elongated rectangular shape (where elongated rectangle refers to a rectangle that is not square or nearly square), in another embodiment, the elliptical and rectangular shapes may be combined such that the inner portion of the dipole arm 330 has a generally elliptical shape and the outer portion of the dipole arm 330 has a generally elongated rectangular shape.

In embodiments, so-called "unbalanced" dipole arms 330 may be used to form the and second dipoles 320-1, 320-2. here, if the two dipole arms 330 have different conductive shapes or sizes, the dipole arms 330 of the dipoles 320 are unbalanced.

Perhaps the most common dual band antenna is the RVV antenna, which typically includes a linear array of low band radiating elements having a linear array of high band radiating elements on each of its sides, for a total of three linear arrays, in which low band radiating elements typically extend down the center of the antenna, so the portion of the reflector below the left two dipole arms of the low band radiating element typically appears the same as the portion of the reflector below the right two dipole arms of the low band radiating element, however, as shown in fig. 2-3, in the base station antenna 100, the linear array 230 of low band radiating elements 300 is on the outer edge of the antenna 100, and, because the RRVV antenna is necessarily large (due to the number of linear arrays and the inclusion of two low band linear arrays with large radiating elements), it is typically endeavoured to reduce the width of the antenna, which means that the low band radiating elements 300 are typically positioned close to the side edge of the reflector 214, when the low band radiating elements 300 are positioned close to the side edge of the reflector 214, the inner radiating elements 300 may affect the dipole arms 330 more negatively than the outer dipole arms 330' beam may see.

In order to correct for this imbalance, the dipole arms 330 may be unbalanced, for example, this may be accomplished by modifying the length and/or width (and thus surface area) of or more of the widened sections 336 of the conductive segments 334-1, 334-2. in the particular embodiment of fig. 7-10, it can be seen that the more distal widened sections 336 on the conductive segments 334-1, 334-2 of dipole arms 330-1 and 330-3 have an increased width compared to the corresponding widened sections of dipole arms 330-2 and 330-4. modifying the length and/or width of these sections 336 effectively changes the length of dipole arms 330-1 and 330-3 compared to dipole arms 330-2 and 330-4.

In some cases , the low-band radiating element 300 may also create resonance at frequencies within the operating band of the high-band radiating element 400. if this occurs, it has been found that the length of or more of the narrow meander traces 338 may be modified to move the resonance lower or higher out of the high-band linear array 230 until the resonance is out of the high-band. in embodiments, the length of the distal narrow meander traces 338 connecting the conductive segments 334-1 and 334-2 on the dipole arms 330-2 and 330-4 may be varied because varying the length of these narrow meander traces 338 may tend to have the greatest effect on the high-band radiation pattern and, because the magnitude of the current through these distal narrow meander traces 338 is relatively small, the variation in length tends to have the least effect on the radiation pattern of the low-band radiating element 300. the narrowed meander traces 338 operate as inductive segments with increased inductance.

Thus, in accordance with embodiments of the invention, methods are provided for shifting the frequency of resonance in a low-band radiating element in which the length of the sense trace section included in the low-band radiating element is adjusted to shift the resonance outside of the operating band of the closely positioned high-band radiating element embodiments in which the length-adjusted sense trace section is the furthest sense trace section from where the four dipole arms meet (which is where the -th and second axes 322-1, 322-2 intersect).

Fig. 12 is a perspective view of of the high-band feed plate assembly 260 included in the antenna 100, as shown in fig. 12, the high-band feed plate assembly 260 includes a printed circuit board 262 having three high-band radiating elements 400-1, 400-2, 400-3 extending upwardly from the printed circuit board 262. the printed circuit board 262 includes an RF transmission line feed 264, the RF transmission line feed 264 providing RF signals to and receiving RF signals from the respective high-band radiating elements 400-1 through 400-3. each high-band radiating element 400 includes a pair of feed posts 410 and a th and second dipoles 420-1, 420-2.

The feed rods 410 may each include a printed circuit board with an RF transmission line feed formed thereon, the feed 410 may be assembled together to form a vertically extending column having a generally x-shaped horizontal cross-section, each dipole radiating element 420 includes a printed circuit board having four plated sections (only three of which are visible in the view of FIG. 12) formed thereon that form four dipole arms 430, the four dipole arms 430 are arranged in a generally cruciform shape, two of the opposing dipole arms 430 together form a radiating element 420-1, the radiating element 420-1 is designed to transmit signals having a polarization of +45 degrees, and the other two opposing dipole arms 430 together form a second radiating element 420-2, the second radiating element 420-2 is designed to transmit signals having a polarization of-45 degrees, the and second radiating elements 420-1, 420-2 may be mounted above the reflector 214 by the feed rods 410 at about 0.16 to 0.25 times the operating band width of approximately half the high frequency radiation beam at approximately 65 degrees.

Radiating element 400 shown in fig. 12 also includes a director 440, which director 440 is mounted on a director support 450 above dipole 420 the director 440 may comprise a metal plate that may be used to improve the pattern of the high-band antenna beam as shown in various other figures, director 440 may be omitted in embodiments.

Referring again to fig. 2-6, the base station antenna 100 may include a plurality of isolation structures and/or tuning parasitic elements that may be used to reduce coupling between the linear arrays 220, 230 and/or to shape or more antenna beams.

Fig. 11 shows dipoles 320-1, 320-2 of a low-band radiating element 300' according to a further embodiment of the invention, the low-band radiating element 300' being similar to the low-band radiating element 300 described above, but in the low-band radiating element 300', the distal ends of the conductive segments 334-1, 334-2 on all four dipole arms 330 are connected together by a meandering trace section 338, whereas in the low-band radiating element 300, only two of the dipole arms 330 have conductive segments 334-1, 334-2 connected together by respective meandering trace sections 338, and the conductive segments 334-1, 334-2 on the other two dipole arms 330 are connected together by merging a distal end widening section 336 on each conductive segment 334-1, 334-2 at .

In order to reduce the width as much as possible, it may be necessary to move the two linear arrays 220 of low band radiating elements 300 close to . unfortunately, when doing so, due to the close proximity of the two linear arrays 220, when driving the low band array 220-1, this may result in the generation of common mode resonances in the radiating elements 300 of the second low band array 220-2, and vice versa, these common mode resonances may distort the antenna of the narrow frequency range around, for example, 800MHz, so that the same common mode resonances may be present as these common mode resonances may be suppressed in the same frequency range as these common mode resonances, 539, in accordance with the present invention, by multiple common mode dipole elements 330 or multiple common mode dipole antenna elements 35.

In the th technique, a common mode filter may be built into the feed stalk 310 of the dipoles 320-1, 320-2 of each low band radiating element 300. it has been shown through simulations that including a common mode filter on the feed stalk 310 may be sufficient to filter out any common mode resonances generated in the feed stalk 310. the common mode filter may be implemented, for example, as a pair induced meander line coupled at along the RF transmission line 314.

13A-13C are schematic diagrams showing example implementations of such a common mode filter 360 on a feed stalk 310. in particular, FIG. 13A shows an embodiment of a feed stalk printed circuit board 310 with an integrated common mode filter, FIG. 13B shows a top layer metal layout of the feed stalk printed circuit board 310, and FIG. 13C shows a bottom layer metal layout of the feed stalk printed circuit board 310. the substrate material of the feed stalk printed circuit board 310 is omitted in FIGS. 13A-13C to better illustrate the structure of the common mode filter 360. as shown in FIGS. 13A and 13B, a lower left portion of the RF transmission line is connected to an upper right portion of the RF transmission line via a narrowed meander line. as shown in FIGS. 13A and 13C, a lower right portion of the RF transmission line is connected to an upper left portion of the RF transmission line via another narrowed meander line and plated through holes.

However, it will be appreciated that common mode resonance is more likely to occur in the dipole arms 330 than in the feed stalk 310 of the two low band low arrays 220 because the dipole arms 330 of the two low band arrays 220 are closer to each other than in the feed stalk 310 FIG. 14 shows a common mode filter 370 according to further embodiments of the invention FIG. 14 common mode filters 360 and/or 370 may be implemented on any low band radiating element 300 according to embodiments of the invention (and may also be implemented on high band radiating element 400 in embodiments).

As shown in fig. 14, the common mode filter 370 may be implemented near the center of the radiating element 300 the same concepts explained above with reference to fig. 13A-13C for the common mode filter implemented on the feed bar printed circuit board 310 may be applied on the dipole arms 330 to prevent in-phase current from flowing on either side of the capacitor 342.

In a second approach, common mode resonance can be reduced or potentially eliminated by reducing the gap 350 between adjacent dipole arms 330 in the center of the radiating element 300. Specifically, the frequency at which common mode resonance occurs may be a function of the gap size, with common mode resonance occurring at higher frequencies as the width of the gap 350 increases. At certain gap widths, common mode resonances may fall within the operating frequency band of the low band radiating element 300. Unfortunately, however, reducing the width of these gaps 350 may make it more difficult to impedance match the dipole arms 330 to the RF transmission lines 314 on the feed stalk 310. The return loss of the low-band radiating element 300 increases if the impedance matching of the dipole arm 330 and the feed rod 310 deteriorates.

As shown in FIG. 15, a conductive plate 380 that is capacitively coupled to the dipole arm 330 may be placed on the center of the radiating element 300 according to embodiments of the present invention the conductive plate 380 may be similar to the director 440 shown in FIGS. 5A-5D, such as, for example, U.S. patent application Ser. No. 62/312,701 (the '701 application), filed 24/3/2016, except that the conductive plate 380 may be smaller and/or closer to the dipole 320 than the director disclosed in the' 701 application, the conductive plate 380 may shift the frequency of the common mode resonance lower and may be used to shift the resonant frequency out of the lower band, the size of the gap 350 may be adjusted to some extent to further tune where the common mode resonance falls.

Unfortunately, the adjustment to the width of the gap 350 required to move the common mode resonance out of band may be large enough to make it difficult to impedance match the dipole arms 330 to the feed stalk 310, which may result in degraded return performance, when the common mode resonance occurs near the middle of the low band, however, at least in jurisdictions, a small portion of of the spectrum in the low band may not be used.

Embodiments of the present invention have been described above with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

It will be understood that, although the terms first , second, etc. may be used herein to describe various elements, these elements should not be limited by these terms.

It will be understood that when an element is referred to as being "on" another elements, it can be directly on the other elements, or intervening elements may also be present.

Relative terms such as "below" or "above", "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of elements, layers or regions to another element, layer or region, as illustrated in the figures.

As used herein, the singular forms "," "," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, it will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of or more other features, operations, elements, components, and/or groups thereof.

The aspects and elements of all embodiments disclosed above may be combined in any manner and/or in combination with aspects or elements of other embodiments to provide multiple additional embodiments.