Cross-dipole radiating element with feed handle exhibiting improved masking performance and base station antenna comprising such radiating element

Abstract

A cross-dipole radiating element includes a feed shank having a base and a distal end positioned forward of the base; a first dipole radiator mounted at the distal end of the feed handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feed handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feed shank includes a first ground line, a first signal trace at least partially overlapping the first ground line, and a transmission line segment extending from the first ground line and / or the first signal trace, and the transmission line segment includes a transmission line signal trace shorted to a ground conductor of the transmission line segment.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 414,127 filed on October 7, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0003] The present invention relates generally to radio communications and, more particularly, to base station antennas for cellular communication systems and to radiating elements for such base station antennas.

[0004] Cellular communication systems are well known in the art. In a cellular communication system, a geographic area is divided into a series of areas called "cells" served by corresponding base stations. A base station may include one or more base station antennas configured to provide two-way radio frequency ("RF") communications with mobile users within the cell served by the base station. Typically, the base station antenna is mounted on a tower or other elevated structure, where a radiation pattern (also referred to herein as an "antenna beam") is generated by the base station antenna pointing outward. In many cases, each cell is divided into a plurality of smaller areas in the horizontal or "azimuth" plane, which are referred to as "sectors". In a common configuration, a hexagonal-shaped cell is divided into three 120° sectors in the azimuth plane, and each sector is served by one or more "sector" base station antennas, which generate an antenna beam having an azimuth half-power beamwidth ("HPBW") of approximately 65° to provide good coverage of the entire 120° sector. The antenna beam is generated by a linear or planar phased array of radiating elements included in the antenna. The radiating element is typically mounted to extend forwardly from a flat metal surface called a reflector, which acts as a ground plane for the radiating element and serves to reflect rearwardly directed RF radiation emitted by the radiating element backwardly in a forward direction.

[0005] In order to accommodate the growing volume of cellular communications, cellular operators have added cellular services in various new frequency bands. Although in some cases, a single array of "wideband" radiating elements can be used to provide services in multiple frequency bands, in other cases, different arrays of radiating elements must be used to support services in different frequency bands. As a result, the number of base station antennas deployed at a typical base station has increased significantly. However, due to local zoning regulations and / or weight and wind load constraints on antenna towers, there are usually limits on the number of base station antennas that can be deployed at a given base station. In order to increase capacity without further increasing the number of base station antennas, so-called multi-band base station antennas have been introduced that include multiple arrays of radiating elements operating in different frequency bands. Unfortunately, the radiating elements in different arrays can interact with each other, which can make it challenging to implement such multi-band antennas while also meeting customer requirements related to the size (particularly width) of the base station antenna. Summary of the invention

[0006] According to an embodiment of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line, a first signal trace at least partially overlapping the first ground line, and a transmission line segment extending from the first ground line and / or the first signal trace. The transmission line segment comprises a transmission line signal trace short-circuited to a ground conductor of the transmission line segment.

[0007] In some embodiments, the transmission line segment is at least a portion of a short-circuited transmission line configured to inhibit unbalanced current from flowing onto the feed handle.

[0008] In some embodiments, the transmission line segment is at least a portion of a short-circuited transmission line having a base adjacent to a distal end of the feed handle, wherein a transmission line signal trace shorted to a ground conductor of the transmission line segment is located approximately one quarter wavelength away from the base of the short-circuited transmission line by a center frequency of an operating frequency band of the cross-dipole radiating element.

[0009] In some embodiments, the transmission line signal trace extends from the first signal trace.

[0010] In some embodiments, the ground conductor of the transmission line segment extends from the first ground line.

[0011] In some embodiments, the first ground line serves as a ground conductor for the transmission line segment.

[0012] In some embodiments, the feed handle includes a feed handle printed circuit board, and the first signal trace is a first metallization pattern on a first side of the feed handle printed circuit board, and the first ground line is a second metallization pattern on a second side of the feed handle printed circuit board. In some embodiments, the feed handle also includes a second ground line separated from the first ground line by a gap, the second ground line includes a third metallization pattern on the second side of the feed handle printed circuit board, and wherein the first signal trace and the transmission line signal trace each overlap the gap. In some embodiments, a first end of the transmission line signal trace is connected to the first ground line via a first plated through hole in the feed handle printed circuit board, and a second end of the transmission line signal trace is connected to the second ground line via a second plated through hole in the feed handle printed circuit board. In some embodiments, the distal end of the first signal trace extends forward.

[0013] In some embodiments, a width of the transmission line signal trace is smaller than a width of the first signal trace.

[0014] In some embodiments, the transmission line signal trace includes at least one serpentine section.

[0015] In some embodiments, the ground conductor of the transmission line segment has an average width that is smaller than an average width of the first ground line, and the transmission line signal trace has an average width that is smaller than an average width of the first signal trace.

[0016] In some embodiments, the first signal trace directly feeds the first dipole arm, and the first ground trace directly feeds the second dipole arm.

[0017] In some embodiments, a base of the transmission line segment is connected to the first ground line and / or the first signal trace, and the transmission line segment is shorted to a ground conductor of the transmission line segment at a distal end of the transmission line segment.

[0018] In some embodiments, a cross-dipole radiating element is provided, in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element. An open-ended line configured to act as a bandpass filter that suppresses current in the second frequency band extends from the first ground line. Additionally or alternatively, a central region of the first ground line may include an open region from which metallization is omitted, the open region being configured to act as a high-pass filter that suppresses current in the second frequency band. Additionally or alternatively, a front portion of the first ground line may include a plurality of slots from which metallization is omitted, the plurality of slots being configured to suppress current in the second frequency band.

[0019] According to another embodiment of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line extending from the base to connect to the first dipole arm, a first signal trace extending from the base to connect to the second dipole arm, and a transmission line segment having a transmission line signal trace extending from the first signal trace.

[0020] In some embodiments, the transmission line signal trace is shorted to the first ground line.

[0021] In some embodiments, the transmission line segment is a first transmission line segment, and portions of the first signal trace and the first ground line extending from the first transmission line segment to the first dipole arm form a second transmission line segment, the first transmission line segment and the second transmission line segment forming a short-circuited transmission line.

[0022] In some embodiments, the distal end of the transmission line signal trace is shorted to the first ground line so that the first transmission line segment and the second transmission line segment form a shorted transmission line. In some embodiments, the electrical length of the shorted transmission line is between 0.2 and 0.35 of the wavelength corresponding to the center frequency of the operating frequency band of the cross-dipole radiating element. In some embodiments, the shorted transmission line is configured to prevent unbalanced current from flowing to the feed handle.

[0023] In some embodiments, the first ground line forms a ground conductor of the transmission line segment.

[0024] In some embodiments, the feed handle includes a feed handle printed circuit board, and the first signal trace is a metallization pattern on a first side of the feed handle printed circuit board, and the first ground line is a second metallization pattern on a second side of the feed handle printed circuit board. In some embodiments, the transmission line signal trace is a third metallization pattern on the first side of the feed handle printed circuit board. In some embodiments, a first end of the transmission line signal trace is connected to the first ground line via a first plated through hole in the feed handle printed circuit board.

[0025] In some embodiments, the width of the transmission line signal trace is less than the width of the first signal trace. In some embodiments, the transmission line signal trace includes at least one serpentine section.

[0026] In some embodiments, a base of the transmission line segment is connected to the first ground line and / or the first signal trace, and the transmission line segment is shorted to a ground conductor of the transmission line segment at a distal end of the transmission line segment.

[0027] A cross-dipole radiating element may be provided in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element. In some embodiments, an open-ended line configured to act as a bandpass filter that suppresses current in the second frequency band extends from the first ground line. In some embodiments, a central region of the first ground line comprises an open region from which metallization is omitted, the open region being configured to act as a high-pass filter that suppresses current in the second frequency band. In some embodiments, a front portion of the first ground line comprises a plurality of slots from which metallization is omitted, the plurality of slots being configured to suppress current in the second frequency band.

[0028] According to other embodiments of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line extending from the base to connect to the first dipole arm, a second ground line separated from the first ground trace by a gap, a first signal trace across the gap, and a transmission line segment comprising a transmission line signal trace across the gap.

[0029] In some embodiments, the second ground line is connected to the second dipole arm.

[0030] In some embodiments, the first signal trace is shorted to the first ground line on a first side of the gap and is shorted to the second ground line on a second side of the gap.

[0031] In some embodiments, the transmission line segment is at least a portion of a short-circuited transmission line configured to inhibit unbalanced current from flowing onto the feed handle.

[0032] In some embodiments, the transmission line segment is at least a portion of a short-circuited transmission line having a base adjacent to a distal end of the feed handle, wherein a transmission line signal trace shorted to a ground conductor of the transmission line segment is located approximately one quarter wavelength away from the base of the short-circuited transmission line by a center frequency of an operating frequency band of the cross-dipole radiating element.

[0033] In some embodiments, the first ground line serves as a ground conductor for the transmission line segment.

[0034] In some embodiments, the distal end of the first signal trace extends forward.

[0035] According to another embodiment of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground wire and a first short post extending from the first ground wire, the first short post having an open distal end.

[0036] A cross-dipole radiating element may be provided in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element. In some embodiments, a first stub configured to act as a bandpass filter that suppresses current in the second frequency band extends from the first ground wire. In some embodiments, the feed handle further comprises a second ground wire and a second stub extending from the second ground wire, the second stub having an open circuit distal end, the second stub being configured to act as a bandpass filter that suppresses current in the second frequency band. In some embodiments, the first ground wire and the second ground wire each extend from the base of the feed handle to the distal end of the feed handle. In some embodiments, the feed handle further comprises: a third stub extending from the first ground wire, the third stub having an open circuit distal end, the third stub being configured to act as a bandpass filter that suppresses current in the second frequency band; and a fourth stub extending from the second ground wire, the fourth stub having an open circuit distal end, the fourth stub being configured to act as a bandpass filter that suppresses current in the second frequency band.

[0037] According to some other embodiments of the present invention, a base station antenna is provided, the base station antenna comprising: a first radiating element, the first radiating element being configured to operate in a first frequency band; and a second radiating element, the second radiating element being configured to operate in a second frequency band lower than the first frequency band. The second radiating element comprises a feeding handle and at least one radiator mounted at a distal end of the feeding handle, the feeding handle comprising a first grounding wire extending substantially from a base of the feeding handle to a distal end of the feeding handle, the first grounding wire comprising an internal opening completely enclosed by the first grounding wire, the internal opening forming a high pass filter that suppresses RF current in the first frequency band.

[0038] In some embodiments, the feeding handle further includes a second ground line and a signal trace, wherein at least a rear portion of the signal trace overlaps the second ground line.

[0039] In some embodiments, the interior opening is located in a rear portion of the first ground line.

[0040] In some embodiments, the interior opening is a rectangular opening.

[0041] According to some other embodiments of the present invention, a base station antenna is provided, which includes: a first radiating element, which is configured to operate in a first frequency band; and a second radiating element, which is configured to operate in a second frequency band lower than the first frequency band, the second radiating element including a feeding handle and at least one radiator installed at a distal end of the feeding handle, the feeding handle including a first ground wire, the first ground wire basically extending from a base of the feeding handle to the distal end of the feeding handle, the first ground wire including a plurality of slots formed therein, the plurality of slots forming a high-pass filter for suppressing RF current in the first frequency band.

[0042] In some embodiments, the feeding handle further includes a second ground line and a signal trace, wherein at least a rear portion of the signal trace overlaps the second ground line.

[0043] In some embodiments, the second ground line includes a plurality of slots formed therein, the plurality of slots forming a high pass filter that suppresses RF currents in the first frequency band.

[0044] In some embodiments, the plurality of slots are formed in a portion of the first ground line in front of the signal trace.

[0045] In some embodiments, a first slot of the plurality of slots extends inwardly from a first side of the first ground line, and a second slot of the plurality of slots extends inwardly from a second side of the first ground line opposite the first side. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1A is a perspective view of a conventional crossed-dipole radiating element.

[0047] Figure 1B yes Figure 1A Side view of a conventional crossed-dipole radiating element.

[0048] Figure 2A is a schematic perspective view of a base station antenna according to an embodiment of the present invention.

[0049] Figure 2B yes Figure 2A Schematic front view of an antenna assembly of a base station antenna.

[0050] Figure 2C The components behind the reflector of the antenna assembly are omitted. Figure 2B Schematic cross-sectional view of an antenna assembly.

[0051] Figure 3-5 is a schematic side view of a crossed-dipole radiating element according to some embodiments of the present invention.

[0052] Figures 6A-6F yes Figure 4 Schematic shaded view of a modified form of a feed handle printed circuit board showing the manner in which short-circuited transmission lines according to embodiments of the present invention may have different lengths.

[0053] Figures 7A-7D yes Figure 4 Schematic shaded representation of the first and second main surfaces of a modified form of a feed stem showing different connection schemes for a dipole arm connected to a dipole radiator fed by the feed stem.

[0054] Figure 8 is a schematic shaded diagram of a crossed-dipole radiating element according to a further embodiment of the present invention.

[0055] Figures 9A-9D is a schematic shadow diagram of a feed handle printed circuit board including a filter structure for suppressing higher frequency band current according to another embodiment of the present invention. DETAILED DESCRIPTION

[0056] As discussed above, it can be challenging to provide a relatively narrow base station antenna with an array of radiating elements operating in several different frequency bands. The width of a multi-band base station antenna can be reduced by reducing the spacing between radiating elements of adjacent arrays. However, as the spacing between arrays decreases, the coupling between radiating elements of different arrays increases, which causes the RF signal at one frequency band to be "scattered" by radiating elements of other frequency bands. Scattering is undesirable because it can affect the shape of the antenna beam in both the azimuth plane and the elevation plane, and the effect can vary significantly with frequency, which can make it difficult to compensate for these effects. For example, scattering tends to negatively affect the beam width, beam shape, pointing angle, gain, and front-to-back ratio of the antenna beam in the azimuth plane.

[0057] Scattering occurs primarily when the conductive structure of a first frequency band radiating element has an electrical length that causes the structure to resonate in the operating band of a nearby radiating element operating in a different second frequency band. For example, most modern base station antennas include both "low-band" radiating elements that operate in the 696-960 MHz band or a portion thereof and "mid-band" radiating elements that operate in the 1427-2690 MHz band (or the 1695-2690 MHz band) or a portion thereof. If a crossed dipole radiating element is used, the low-band dipole radiator typically has a length of approximately 1 / 2 the wavelength of the center frequency of the low-band operating band or a portion thereof (e.g., a dipole radiator will have an electrical length of approximately 1 / 2 the wavelength of the 828 MHz center frequency of the 696-960 MHz operating band). In this article, the wavelength corresponding to the center frequency of the operating band of the radiating element is referred to as the "center wavelength." In this case, the electrical length of the low-band dipole arm (which is half the length of the low-band dipole radiator) will be about 1 / 2 of the wavelength of the RF signal transmitted in the lower part of the mid-band operating band, so the RF energy transmitted by the mid-band radiating element (especially when the mid-band radiating element operates in the lower part of the mid-band operating band) will tend to couple to the dipole arm of the low-band radiating element. As mentioned above, this coupling can distort the antenna pattern generated by the array of the mid-band radiating element in an undesirable manner. If the RF energy emitted by the so-called high-band radiating element (which usually operates in a part of the 3.1-5.8GHz band) is coupled to the low-band radiating element or the mid-band radiating element, similar distortion may occur. The radiating element according to an embodiment of the present invention can be designed to be substantially transparent to the nearby radiating elements operating in other frequency bands, so that scattering is eliminated to a large extent. The radiating element designed to suppress this scattering is generally referred to as a "masking" radiating element.

[0058] Masking radiating elements are known in the art. For example, U.S. Patent No. 9,570,804 discloses a low-band radiating element comprising a dipole arm formed as a series of RF chokes. The RF chokes suppress the formation of mid-band currents on the low-band dipole arms so as to make the low-band radiating element substantially transparent to mid-band RF energy. U.S. Patent No. 10,439,285 and U.S. Patent No. 10,770,803 each disclose a low-band radiating element comprising a dipole arm formed as a series of widened segments connected by narrow inductor segments, which can be implemented as small serpentine trace segments on a printed circuit board. In each case, the narrow inductor segments act as high impedance elements for RF energy in the mid-band frequency range, thereby making the low-band radiating element substantially transparent to RF energy in this frequency range. As another example, U.S. Patent No. 11,018,437 discloses a low-band radiating element including two dipole arms substantially transparent to mid-frequency RF energy and another two dipole arms substantially transparent to high-band RF energy. Additional shielded radiating element designs are disclosed in Chinese Patent No. CN 112787061A, Chinese Patent No. CN 112164869A, Chinese Patent No. CN 112290199A, Chinese Patent No. CN 111555030A, Chinese Patent No. CN 112186333A, Chinese Patent No. CN112186341A, Chinese Patent No. CN 112768895A, Chinese Patent No. CN 112821044A, Chinese Patent No. CN213304351U, Chinese Patent No. CN 112421219A, and PCT Publication WO 2021 / 042862.

[0059] The above-described shielded radiating elements are focused on ensuring that RF energy emitted by a higher frequency band radiating element does not create higher frequency band currents on the dipole arms of a nearby low frequency band radiating element. The present invention is based in part on the recognition that the feed stems of the lower frequency band radiating elements can also cause scattering. The feed stem of a cross-dipole radiating element refers to the structure that feeds RF signals to and from the dipole arms of the radiating element. In most cases, the dipole arms are mounted on the distal (front) end of the feed stem, and the base (rear) end of the feed stem is mounted on a reflector of a base station antenna or on a feed board printed circuit board, which is mounted on the reflector.

[0060] The feed stem of the radiating element typically has a length of about 1 / 4 of the center wavelength so that the RF radiation emitted backward by the dipole radiator will be reflected from the reflector and will be in phase with the RF radiation emitted by the dipole arm in the forward direction (because the phase of the RF radiation changes by 90° as it travels 1 / 4 of the center wavelength from the dipole arm to the reflector, will change by another 180° as it reflects from the reflector, and will change by another 90° as it travels 1 / 4 of the center wavelength back to the dipole radiator). The feed stem typically includes metal structures extending along the length of the feed stem, and thus these metal structures may have a length of about 1 / 4 of the center wavelength of the radiating element. Thus, these metal structures may be about 1 / 2 of the wavelength of the RF signal emitted by the nearby mid-band radiating element. Thus, mid-band currents may be formed on these metal structures, which produce mid-band RF radiation. While the emissions of mid-band RF radiation from the feed stem tend to be much lower than those from the unmasked dipole arms, the emission levels are still significant enough to distort the mid-band antenna beam.

[0061] According to embodiments of the present invention, there are provided cross-dipole radiating elements having feed handles that exhibit improved masking performance. These radiating elements may be included in multi-band base station antennas and may potentially allow arrays in such antennas to be spaced more closely, thereby advantageously reducing the width of the antenna. Base station antennas including radiating elements according to embodiments of the present invention may be used, for example, as sector antennas in the above-described cellular communication systems.

[0062] Before discussing radiating elements according to embodiments of the present invention, it is helpful to discuss the design and operation of a representative conventional low-band radiating element for a base station antenna.

[0063] Figure 1A is a perspective view of a conventional low-band crossed dipole radiating element 1. Figure 1AAs shown in , a conventional cross-dipole radiating element 1 includes a feed handle 10 and a pair of dipole radiators 70-1, 70-2. It should be noted that in this article, the same elements can be referred to individually by their full reference numerals (e.g., dipole radiator 70-2), and can be referred to collectively by the first part of their reference numerals (e.g., dipole radiator 70). The feed handle 10 includes a first printed circuit board and a second printed circuit board 20-1, 20-2. Each feed handle printed circuit board 20-1, 20-2 includes a corresponding RF transmission line structure 16-1, 16-2, which transmits RF signals between the first feed transmission line and the second feed transmission line (not shown) of the radiating element 1 and the corresponding cross-dipole radiator 70-1, 70-2. Each feed transmission line (not shown) may include, for example, a microstrip transmission line on a feed board printed circuit board on which the radiating element 1 is mounted, or a coaxial cable. The feed transmission line transmits RF signals between the radiating element 1 and other components of the base station antenna. The feeding stem 10 may extend rearward from the plane defined by the dipole radiators 70-1, 70-2. For example, the feeding stem 10 may extend substantially perpendicular to the plane defined by the dipole radiators 70-1, 70-2.

[0064] The feeding handle 10 has a base 12 and a distal end 14 (see Figure 1B ). The distal end 14 is positioned in front of the base 12. The first feeding handle printed circuit board 20-1 includes a slit 22-1 extending backward from the distal end 14 of the feeding handle 10, and the second feeding handle printed circuit board 20-2 includes a slit 22-2 extending forward from the base 12 of the feeding handle 10. The feeding handle printed circuit boards 20-1 and 20-2 are arranged perpendicular to each other, wherein the slit 22-2 in the feeding handle printed circuit board 20-2 is received within the slit 22-1 in the feeding handle printed circuit board 20-1, so that when viewed from the front, the two mating feeding handle printed circuit boards 20-1, 20-2 have a cross shape.

[0065] The rear portion of each feed handle PCB 20 may include a protrusion 24 that is inserted through a slot (not shown) in the feed board PCB. The metallized pads on the protrusion 24 may be soldered to the metallized pads on the feed board PCB to mechanically mount the radiating element 1 on the feed board PCB and electrically connect the RF transmission line structures 16-1, 16-2 on the feed handle 10 to the feed transmission lines on the feed board PCB.

[0066] The dipole radiators 70-1, 70-2 are located adjacent to the distal end 14 of the feed handle 10 and can be (and are typically) physically mounted on the distal end 14 of the feed handle 10. The first dipole radiator 70-1 includes a first dipole arm and a second dipole arm 80-1, 80-2, and the second dipole radiator 70-2 includes a third dipole arm and a fourth dipole arm 80-3, 80-4. Figure 1A As shown in , the dipole radiators 70-1, 70-2 can be implemented in a "crossed" arrangement to form a pair of center-fed -45° / +45° dipole radiators 70. The dipole radiators 70-1, 70-2 are shown as having an elongated "figure 8" shape, wherein each dipole arm 80 is formed as a loop. It should be understood that various dipole arms are known in the art, including dipole arms having a loop shape, a rod shape, a leaf shape, a square shape, etc. Similarly, the dipole arms can be formed in a variety of ways, including using metal plates, on a printed circuit board, using a choke structure, etc. Here, the dipole arm 80 is shown as being formed using a dipole radiator printed circuit board 82. The dipole arm 80 is shown as having a masking structure (here a series of widened metal segments 84 interconnected by narrow inductive traces 86). It should be understood that radiating elements having a feed handle design disclosed herein according to embodiments of the present invention may have any suitable dipole arm design, including dipole arms having any shape, such as formed in any manner discussed above, and may or may not have a masking dipole arm.

[0067] The first dipole radiator 70-1 extends along a first axis, and the second dipole radiator 70-2 extends along a second axis that is substantially perpendicular to the first axis. The dipole arms 80-1 and 80-2 of the first dipole radiator 70-1 are centrally fed by the first RF transmission line structure 16-1 on the first feed handle printed circuit board 20-1, and radiate together at a first polarization. In the depicted embodiment, the first dipole radiator 70-1 is designed to transmit and receive signals having a +45° polarization. The dipole arms 80-3 and 80-4 of the second dipole radiator 70-2 are centrally fed by the second RF transmission line structure 16-2 on the second feed handle printed circuit board 20-2, and radiate together at a second polarization that is orthogonal to the first polarization. The second dipole radiator 70-2 is designed to transmit and receive signals having a -45° polarization. The dipole arm 80 may be mounted in front of a reflector (not shown) of a base station antenna including the radiating element 1 at approximately 3 / 16 to 1 / 4 of the operating wavelength.

[0068] Figure 1B yes Figure 1A A shaded side view of a conventional cross-dipole radiating element 1 is shown, which shows the metallization pattern on the feed stem printed circuit board 20-1 of the feed stem 10. Figure 1BIn FIG. 1 , the solid line is the metallization pattern on the first side of the feed handle printed circuit board 20 - 1 , and the dashed line is the metallization pattern on the second (opposite) side of the feed handle printed circuit board 20 - 1 . Figure 1B In the figure, since the main surface of the feeding handle printed circuit board 20-2 is perpendicular to the viewing angle, only the side surface of the feeding handle printed circuit board 20-2 is visible.

[0069] like Figure 1B As shown in , a two-wire transmission line structure 30 is formed on the second side of the feed handle printed circuit board 20-1. The two-wire transmission line structure 30 includes a first metallized area and a second metallized area 32-1, 32-2 extending from the base 12 of the feed handle 10 to its distal end 14. Each metallized area 32-1, 32-2 is connected to a ground conductor (not shown) of the first feed transmission line for the radiating element 1. In this document, these metallized areas 32-1, 32-2 are also referred to as first and second ground lines 32-1, 32-2 to reflect this connection to the ground. The connection between the metallized areas 32-1, 32-2 and the ground conductor of the first feed transmission line can be at the base 12 of the feed handle 10. Each of the first and second ground lines 32-1, 32-2 includes a corresponding protrusion 34-1, 34-2 extending inwardly. These protrusions 34-1, 34-2 are positioned just above the slot 22-1, and a small gap 36 without metallization separates the two protrusions 34-1, 34-2. The first and second ground lines 32-1, 32-2 may each have an electrical length of about 1 / 4 of the central wavelength of the radiating element 1.

[0070] The signal trace 40 is formed on a first side of the feed handle printed circuit board 20-1. The signal trace 40 is connected to a signal conductor of a feed transmission line that feeds the feed handle printed circuit board 20-1. The signal trace 40 extends forward from the base 12 of the feed handle 10 and travels approximately two-thirds of the way toward the distal end 14 of the feed handle 10. The signal trace 40 then makes a first 90° turn to extend laterally across the first side of the feed handle printed circuit board 20-1. Finally, the signal trace 40 makes a second 90° turn to extend backward toward the base 12 of the feed handle 10.

[0071] The signal trace 40 includes a forward extending segment 42-1, a laterally extending segment 42-2, and a rearward extending segment 42-3. The forward extending segment 42-1 includes a widened pad area 44 near the base 12 of the feed handle 10 and a narrow trace 46 extending forward from the widened pad area 44. The forward extending segment 42-1 overlaps the first ground line 32-1. In this document, if an axis perpendicular to the main surface of the printed circuit board intersects with two elements on the printed circuit board (or equivalent structure), the two elements "overlap". The laterally extending segment 42-2 includes a narrow trace 48 that extends from the trace 46 to cross the gap 36 between the first and second ground lines 32-1, 32-2. The laterally extending segment 42-2 overlaps portions of both the first ground line 32-1 and the second ground line 32-2. The rearwardly extending section 42-3 includes a narrow trace 50 that extends from the end of the trace 48 rearwardly at a right angle toward the base 12 of the feeding handle 10. The rearwardly extending section 42-3 overlaps the second ground line 32-2.

[0072] Although the feed handle printed circuit board 20-2 is Figure 1B Most of it is not visible, but it is nearly identical to PCB 20-1, except for: (1) the location of slots 22-1, 22-2; and (2) on the feed handle PCB 20-2, the laterally extending segment 42-2 is closer to the base 12 of the feed handle 10 to allow the segment to span the axis defined by the slot 22-2 in the front portion of the feed handle PCB 20-2.

[0073] The first feed handle printed circuit board 20-1 can be used to feed the first dipole radiator 70-1 as follows. The first and second ground lines 32-1, 32-2 and the signal trace 40 form an RF transmission line feeding structure 16-1. When an RF signal is injected from the corresponding feed transmission line onto the feed handle printed circuit board 20-1, the RF energy travels along the microstrip transmission line segment formed by the forward extending segment 42-1 and the lateral extending segment 42-2 running above the first ground line 32-1 to the gap 36 between the first and second ground lines 32-1, 32-2. The portion of the signal trace 40 overlapping the second ground line 32-2 can, for example, have an electrical length of about 1 / 4 of the center wavelength of the radiating element 1 (typically in the range of 0.2-0.35 of the center wavelength) and is open circuit. The gap 36 acts as a balun to convert an unbalanced RF signal traveling along the microstrip transmission line formed by the forward extending segment 42-1 and the lateral extending segment 42-2 running above the first ground line 32-1 into a balanced RF signal, so that a first portion of the balanced signal is passed along the upper portion of the ground line 32-1 to the first dipole arm 80-1, and a second portion of the balanced signal is passed along the upper portion of the ground line 32-2 to the second dipole arm 80-2. In this way, the RF transmission line structure 16-1 feeds RF currents of opposite phases to the dipole arms 80-1, 80-2.

[0074] Due to the balanced nature of the current, a balanced RF signal flowing along the feed handle 10 generally does not radiate RF energy. However, if unbalanced RF currents are allowed to flow on the feed handle 10, these currents will radiate undesirable RF energy. In order to suppress such unbalanced RF currents, the dual ground wires 32-1, 32-2 are short-circuited to each other at the base 12 of the feed handle 10 (usually by galvanically coupling the two ground wires 32-1, 32-2 to the ground plane on the feed board printed circuit board). As described above, each ground wire 32-1, 32-2 may have a length of about 1 / 4 of the center wavelength. The short circuit at the base of the dual ground wires 32-1, 32-2 will appear as an open circuit a quarter of the wavelength away, which is at the distal end 14 of the feed handle 10. This effective open circuit is used to suppress the unbalanced current from flowing from the dipole arms 80-1, 80-2 to the feed handle 10, thereby suppressing the emission of RF radiation from the feed handle 10.

[0075] As explained in the discussion above, the dual ground wires 32-1, 32-2 are short-circuited at the base of the feed handle 10 to inhibit unbalanced current from flowing from the dipole arms 80-1, 80-2 onto the feed handle 10. However, the dual ground wires 32-1, 32-2 are large metal structures each having a length of approximately 1 / 4 of the center wavelength of the low-band radiating element 1. Therefore, the dual ground wires 32-1, 32-2 may each have a length of approximately 1 / 2 of the center wavelength of the RF radiation emitted by the nearby mid-band radiating element, and thus any such mid-band RF radiation may induce undesirable mid-band currents on the dual ground wires 32-1, 32-2.

[0076] According to embodiments of the present invention, cross-dipole radiating elements are provided that may have feed stems that may have less impact on the radiation pattern of nearby higher frequency band radiating elements. Feed stems used in radiating elements according to embodiments of the present invention may exhibit improved masking performance because they may have less metal, because they have fewer 1 / 4 wavelength metallized structures, because they have narrowed transmission lines that may exhibit increased inductance, which may help suppress higher frequency band currents from flowing on these structures, and / or may have filter structures that suppress higher frequency band currents. The improved masking performance may improve the peak directivity of nearby higher frequency band radiating elements (compared to the same radiating element with a conventional feed stem design).

[0077] The feed handle included in some of the cross-dipole radiating elements according to embodiments of the present invention may have an improved RF transmission line structure that does not include two full 1 / 4 wavelength dual ground wires. For example, a single 1 / 4 wavelength ground wire may be provided instead, which reduces the extent to which the mid-band current will be formed on the feed handle. In addition, the width of the remaining ground wire may be reduced to further reduce the formation of mid-band current. In addition, the feed handle included in the cross-dipole radiating element according to embodiments of the present invention may have a short-circuit transmission line that is used to suppress unbalanced current from flowing to the feed handle. At least a portion of each short-circuit transmission line may be implemented as a microstrip transmission line, which shortens the physical length and reduces the amount of metal while still suppressing unbalanced current. These short-circuit transmission lines can also be implemented using very narrow high-inductance signal traces (and narrower ground wires) to help further suppress the generation of mid-band currents on low-band feed handles. The feed handle according to embodiments of the present invention may also be a smaller, lower-cost structure than conventional feed handles.

[0078] According to some embodiments of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line, a first signal trace at least partially overlapping the first ground line, and a transmission line segment extending from the first ground line and / or the first signal trace, and the transmission line segment comprises a transmission line signal trace short-circuited to a ground conductor of the transmission line segment.

[0079] According to other embodiments of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line extending from the base to connect to the first dipole arm, a first signal trace extending from the base to connect to the second dipole arm, and a transmission line segment having a transmission line signal trace extending from the first signal trace.

[0080] According to some other embodiments of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground line extending from the base to connect to the first dipole arm, a second ground line separated from the first ground trace by a gap, a first signal trace across the gap, and a transmission line segment comprising a transmission line signal trace across the gap.

[0081] According to another embodiment of the present invention, a cross-dipole radiating element is provided, the cross-dipole radiating element comprising: a feeding handle, the feeding handle having a base and a distal end positioned in front of the base; a first dipole radiator mounted at the distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; and a second dipole radiator mounted at the distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm. The feeding handle comprises a first ground wire and a first short post extending from the first ground wire, the first short post having an open distal end.

[0082] According to some other embodiments of the present invention, a base station antenna is provided, the base station antenna comprising a first radiating element configured to operate in a first frequency band and a second radiating element configured to operate in a second frequency band lower than the first frequency band. The second radiating element comprises a feeding handle and at least one radiator mounted at a distal end of the feeding handle, the feeding handle comprising a first grounding wire extending substantially from a base of the feeding handle to a distal end of the feeding handle, the first grounding wire comprising an internal opening completely enclosed by the first grounding wire, the internal opening forming a high pass filter that suppresses RF current in the first frequency band.

[0083] According to some other embodiments of the present invention, a base station antenna is provided, the base station antenna comprising a first radiating element configured to operate in a first frequency band and a second radiating element configured to operate in a second frequency band lower than the first frequency band. The second radiating element comprises a feeding handle and at least one radiator mounted at a distal end of the feeding handle, the feeding handle comprising a first grounding wire extending substantially from a base of the feeding handle to a distal end of the feeding handle, the first grounding wire comprising a plurality of slots formed therein, the plurality of slots forming a high pass filter that suppresses RF current in the first frequency band.

[0084] As described above, a cross-dipole radiating element according to an embodiment of the present invention can have a shielded feed handle that is more transparent to RF radiation emitted by a nearby higher frequency band radiating element. The following discussion of a cross-dipole radiating element according to an embodiment of the present invention will focus on a low frequency band radiating element that is designed to be shielded relative to, for example, a nearby mid-frequency band radiating element. However, it should be understood that the technology disclosed herein can be used, for example, to provide a mid-frequency band radiating element that is shielded relative to a nearby high frequency band radiating element or in any other suitable application.

[0085] Now refer to Figure 2A-9D Embodiments of the present invention are described in more detail.

[0086] Figures 2A-2CA base station antenna 100 is shown which may include a cross-dipole radiating element according to an embodiment of the present invention. In particular, Figure 2A is a perspective view of the antenna 100, and Figure 2B 1 is a front view of the antenna 100 with its radome removed to show the antenna assembly 200 housed inside the radome. Figure 2C yes Figure 2B A schematic cross-sectional view of an antenna assembly 200 is shown. Figure 2C The parts of the antenna installed behind the reflector 210 are omitted.

[0087] In the following description, the antenna 100 and the radiating elements included therein will be described using the following terms assuming that the antenna 100 is mounted on a tower for normal use, wherein the longitudinal axis of the antenna 100 extends along the vertical axis and the front surface of the antenna 100 is mounted opposite the tower pointing toward the coverage area of ​​the antenna 100.

[0088] like Figures 2A-2C As shown in , 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 with a generally rectangular cross-section. The antenna 100 includes a radome 110 and a top cover 120. The antenna 100 also includes a bottom cover 130, which includes a plurality of connectors 140, such as RF ports, mounted therein. When the antenna 100 is mounted for normal operation, the antenna 100 is typically mounted in a vertical configuration (i.e., the longitudinal axis L may be substantially perpendicular to a plane defined by a horizon). The radome 110, the top cover 120, and the bottom cover 130 may form an outer housing for the antenna 100. The antenna assembly 200 is contained within the outer housing. The antenna assembly 200 ( Figure 2B-2C ) may be slidably inserted into the radome 110 from the top or bottom before the top cover 120 or the bottom cover 130 is attached to the radome 110 .

[0089] Reference now Figure 2B and 2C , the antenna assembly 200 includes a ground plane structure 210 having a sidewall 212 and a reflector surface or “reflector” 214. Various mechanical and electronic components (not shown) of the antenna, such as phase shifters, remote electronic tilt units, mechanical linkages, controllers, duplexers, etc., may be mounted in a cavity defined between the sidewall 212 and the back side of the reflector 214. The reflector 214 of the ground plane structure 210 may include or comprise a metal surface (e.g., a sheet of aluminum) that acts as a reflector and ground plane for the radiating elements of the antenna 100.

[0090] A plurality of dual polarized radiating elements are mounted to extend forward from the reflector 214. The radiating elements include a low-band radiating element 224, an intermediate-band radiating element 234, and a high-band radiating element 244. The low-band radiating element 224 is mounted in two columns to form two linear arrays 220-1, 220-2 of the low-band radiating element 224. The intermediate-band radiating element 234 can also be mounted in two columns to form two linear arrays 230-1, 230-2 of the intermediate-band radiating element 234. Two planar arrays of high-band radiating elements 244 are included in the base station antenna 100, each planar array having four columns 242 of high-band radiating elements 244. Each planar array 240-1, 240-2 can be coupled to a corresponding beamforming radio (not shown) so that the planar array 240 can perform active beamforming to generate a higher gain antenna beam. Herein, the linear arrays 220-1, 220-2 of low-band radiating elements 224 may also be referred to as low-band linear arrays 220-1, 220-2, the linear arrays 230-1, 230-2 of mid-band radiating elements 234 may also be referred to as mid-band linear arrays 230-1, 230-2, and the planar array 240 of high-band radiating elements 244 may be referred to as high-band array 240. It should also be appreciated that the number of arrays of low-band, mid-band, and / or high-band radiating elements may vary. Figure 2B and 2C The number of columns and / or the number of radiating elements in each array and the relative positions of the arrays may also be different than shown in . For example, in another exemplary embodiment, the planar array 240 of high-band radiating elements 244 may be omitted or replaced by an additional mid-band linear array 230. Radiating elements according to embodiments of the present invention may be used in arrays having any suitable configuration.

[0091] The low-band radiating element 224 may be configured to transmit and receive signals in a frequency range of 617-960 MHz or a portion thereof (e.g., a 617-896 MHz band, a 696-960 MHz band, etc.). The mid-band radiating element 234 may be configured to transmit and receive signals in a frequency range of 1427-2690 MHz or a portion thereof (e.g., a 1710-2200 MHz band, a 2300-2690 MHz band, etc.). The high-band radiating element 244 may be configured to transmit and receive signals in a frequency range of 3100-5800 MHz or a portion thereof. The radiating elements 224, 234, 244 may be dual-polarized radiating elements (e.g., -45° / +45° cross-dipole radiating elements), and thus each array 220, 230, 240 may be used to form a pair of antenna beams, i.e., antenna beams for each of the two polarizations of the dual-polarized radiating elements designed to transmit and receive RF signals.

[0092] Although not shown in the figure, the radiating elements 224, 234, 244 may be mounted on a feed board printed circuit board that couples RF signals to and from each radiating element 224, 234, 244. One or more radiating elements 224, 234, 244 may be mounted on each feed board printed circuit board. Cables may be used to connect each feed board printed circuit board to other components of the antenna, such as a duplexer, phase shifter, etc.

[0093] The low-band radiating elements 224 may have dipole arms that are designed to be substantially transparent to the RF energy emitted by the mid-band radiating element 234. For example, the low-band radiating elements 224 may each have the same configuration as described above with reference to Figure 1A The shielded dipole radiator 70-1, 70-2 discussed above, but any shielding design can be used. In addition, the low-band radiating element 224 can have a feeding handle, and the feeding handle is designed to have improved transparency relative to the RF energy emitted by the intermediate-band radiating element 234. Therefore, even if the intermediate-band radiating element 234 is very close to the low-band radiating element 224, the undesirable coupling of the intermediate-band RF energy discussed above to the low-band radiating element 224 can be significantly reduced. In the following discussion, an exemplary low-band radiating element with such shielding feeding handle will be discussed. It will be recognized that any radiating element in these radiating elements can be used to realize the low-band radiating element 224 included in the base station antenna 100. It will also be recognized that these radiating elements can have any shielded dipole radiator design, or even have unshielded dipole arms. Therefore, the following discussion will focus on the feeding handle design of these radiating elements. For purposes of the following discussion, it will be assumed that each of the radiating elements is implemented using the dipole radiators 70-1, 70-2 discussed above.

[0094] Figure 3 FIG. 2 is a side view of a low-band radiating element 300 that can be used to implement the low-band radiating element 224 of the base station antenna 100 according to an embodiment of the present invention. The low-band radiating element 300 includes a feed handle 310 and a pair of dipole radiators 70-1, 70-2 having dipole arms 80-1 to 80-4 (see FIG. 2 ). Figure 1B and 2B ). The dipole radiators 70 - 1 , 70 - 2 have been discussed in detail above, so the discussion of the low-band radiating element 300 will focus on the feed handle 310 .

[0095] The feeding handle 310 has a base 312 and a distal end 314. The distal end 314 is located in front of the base 312. The feeding handle 310 includes a first printed circuit board and a second printed circuit board 320-1 and 320-2. Since the main surface of the feeding handle printed circuit board 320-2 is perpendicular to the viewing angle, Figure 3 Only the side surface of the feed handle printed circuit board is visible. The feed handle printed circuit board 320-1 includes an RF transmission line structure 316-1, which transmits RF signals between a feed transmission line (not shown) of the feed handle printed circuit board 320-1 and the cross-dipole radiator 70-1. The feed transmission line (not shown) may include, for example, a microstrip transmission line on the feed board printed circuit board on which the radiating element 300 is mounted, or a coaxial cable.

[0096] The first feed handle PCB 320-1 includes a slit 322-1 extending forward from the base 312 of the feed handle 310, and the second feed handle PCB 320-2 includes a slit 322-2 extending backward from the distal end 314 of the feed handle 310. The feed handle PCBs 320-1 and 320-2 are arranged perpendicular to each other, wherein the slit 322-2 in the feed handle PCB 320-2 is received within the slit 322-1 in the feed handle PCB 320-1, so that when viewed from the front, the two mating PCBs 310-1, 310-2 have a cross shape. The dipole radiator of the radiating element 300 (see Figure 1B and 2B ) is positioned adjacent to the distal end 314 of the feeding handle 310 and can be (and typically is) physically mounted on the distal end of the feeding handle 310.

[0097] The base 312 of the feed handle PCB 320-1 includes a protrusion 324 that is inserted through a slot (not shown) in the feed board PCB. A metallized pad on one of the protrusions 324 can be soldered to a metallized pad on the feed board PCB to mechanically mount the radiating element 300 on the feed board PCB and electrically connect the RF transmission line structure 316-1 on the feed handle PCB 320-1 to the feed transmission line on the feed board PCB.

[0098] The feed handle printed circuit board 320-1 includes a metallization pattern on each major surface thereof. Figure 3 In FIG. 3 , the solid line shows the metallization pattern on the first side of the feed handle printed circuit board 320 - 1 , and the dashed line shows the metallization pattern on the second side of the feed handle printed circuit board 320 - 1 .

[0099] The second side of the feed handle printed circuit board 320-1 includes a metallized area 332-1 extending from the base 312 of the feed handle 310 to the distal end 314 thereof. The metallized area 332-1 is similar to Figure 1BThe metallized area 32-1 of the feed handle printed circuit board 20-1 is similar to the metallized area 32-1 of the feed handle printed circuit board 20-1, but has a smaller width to reduce the total amount of metal. The feed handle printed circuit board 320-1 also includes a metallized area 332-2, which extends from a protrusion 324-1 (discussed below) adjacent to the metallized area 332-1 to the distal end 314 of the feed handle 310. The metallized areas 332-1, 332-2 are also referred to as first and second ground lines 332-1, 332-2. The metallized area 332-1 is connected to a ground conductor (not shown) of the first feed transmission line for the radiating element 300 at the base 312 of the feed handle 310.

[0100] Each of the first and second ground lines 332-1, 332-2 includes a corresponding inwardly extending protrusion 334-1, 334-2. These protrusions 334-1, 334-2 are positioned just in front of the slit 322-1. A gap 336 without metallization separates the protrusions 334-1, 334-2. The first ground line 332-1 may have a length of about 1 / 4 of the central wavelength of the radiating element 300.

[0101] The signal trace 340 is formed on a first side of the feed handle printed circuit board 320-1. The signal trace 340 is connected to a signal conductor of a feed transmission line, which feeds the feed handle printed circuit board 320-1. The signal trace 340 extends forward from the base 312 of the feed handle 310 and travels approximately two-thirds of the way toward the distal end 314 of the feed handle 310. The signal trace 340 then makes a first 90° turn to extend laterally across the first side of the feed handle printed circuit board 320-1. Finally, the signal trace 340 makes a second 90° turn to extend forward toward the distal end 314 of the feed handle 310.

[0102] The signal trace 340 includes a first forward extending segment 342-1, a lateral extending segment 342-2, and a rearward extending segment 342-3. The first forward extending segment 342-1 includes a widened pad area 344 near the base 312 of the feeding handle 310 and a narrow trace 346 extending forward from the widened pad area 344. The first forward extending segment 342-1 overlaps with the first ground line 332-1. The lateral extending segment 342-2 includes a narrow trace 348, which extends from the trace 346 to cross the gap 336 between the first ground line and the second ground line 332-1, 332-2. The lateral extending segment 342-2 overlaps with portions of both the first ground line 332-1 and the second ground line 332-2. The second forward extending segment 342-3 includes a narrow trace 350 extending at right angles from the end of the trace 348 toward the distal end 314 of the feeding handle 310. The second forward extending segment 342 - 3 overlaps the second ground line 332 - 2 .

[0103] Although the feed handle printed circuit board 320-2 is Figure 3 Most of it is not visible, but it is nearly identical to PCB 320-1, except for: (1) the location of slots 322-1, 322-2; and (2) on the feed handle PCB 320-2, the laterally extending segment 342-2 is closer to the base 312 of the feed handle 310 to allow the segment to span the axis defined by the slot 322-2 in the front portion of the feed handle PCB 320-2.

[0104] The feed handle printed circuit board 320-2 also includes a transmission line segment 362. The transmission line segment 362 includes a narrow transmission line signal trace 364 having a first end overlapping the protrusion 334-2 of the second ground line 332-2 and a second end overlapping the first ground line 332-2. The first plated through hole 338-1 connects the first end of the transmission line signal trace 364 to the second ground line 332-2, and the second plated through hole 338-2 connects the second end of the transmission line signal trace 364 to the first ground line 332-1. The transmission line signal trace 364 spans the gap 336 between the first and second ground lines 332-1, 332-2 (overlapping the gap).

[0105] The feed handle printed circuit board 320-1 can be used to feed the first and second dipole arms 80-1, 80-2 of the cross-dipole radiating element 300 as follows. The first and second ground lines 332-1, 332-2 and the signal trace 340 form an RF transmission line structure 316-1. When an RF signal is injected from its associated feed transmission line onto the feed handle printed circuit board 320-1, the RF energy travels along the microstrip transmission line segment formed by the forward extending segment 342-1 and the lateral extending segment 342-2 of the signal trace 340 and the first ground line 332-1 to the gap 336 between the first ground line 332-1 and the second ground line 332-2. The distal end of the signal trace 340 is open circuit, and the portion of the signal trace 340 located to the right of the gap 336 can have an electrical length of about 1 / 4 of the center wavelength (typically in the range of 0.2-0.35 of the center wavelength). The open circuit at the end of the signal trace 340 creates an effective short circuit at the gap 336, which acts as a balun to convert an unbalanced RF signal traveling along the microstrip transmission line formed by the forward extending segment 342-1 and the lateral extending segment 342-2 running above the first ground line 332-1 into a balanced RF signal, so that a first portion of the balanced signal is passed along the upper portion of the ground line 332-1 to the first dipole arm 80-1, and a second portion of the balanced signal is passed along the upper portion of the ground line 332-2 to the second dipole arm 80-2. In this way, the RF transmission line structure 316-1 feeds the center of the dipole arms 80-1, 80-2 with RF currents of opposite phases.

[0106] The feed handle 310 includes only a single ground wire 332-1 that extends the full length of the feed handle 310. Therefore, it is not possible to short the two ground wires together at the base 312 of the feed handle 310 to create an open circuit at the distal end of the feed handle that inhibits unbalanced current from flowing onto the feed handle 310, as in the conventional radiating element 1. As discussed above, if unbalanced RF currents are allowed to flow on the feed handle 310, then these currents will radiate undesirable RF energy. Therefore, the feed handle 310 includes a short-circuit transmission line 360 ​​that extends from the distal end 314 of the feed handle 310 and can have an electrical length of about 1 / 4 of the center wavelength of the low-band radiating element 300. This short-circuit transmission line 360 ​​can be used to inhibit unbalanced current from flowing from the dipole arms 80-1, 80-2 onto the feed handle 310.

[0107] The short-circuit transmission line 360 ​​includes the short-circuit transmission line segment 362 discussed above and the upper portion of the second ground line 332-2 extending forward from the laterally extending segment 342-2 of the signal trace 340. In some embodiments, the electrical length of the short-circuit transmission line 360 ​​may be about 1 / 4 of the central wavelength of the radiating element 300 (i.e., the electrical distance from the plated through hole 338-2 that shorts the transmission line signal trace 364 to the first ground line 332-1 to the distal end of the ground line 332-2 may be about 1 / 4 of the central wavelength of the radiating element 300). Therefore, the short-circuit transmission line 360 ​​may appear as an open circuit at the distal end 314 of the feeding handle 310, which inhibits the unbalanced current from flowing from the dipole arms 80-1, 80-2 to the feeding handle 310, thereby inhibiting the emission of RF radiation from the feeding handle 310. It should also be understood that, in practice, the short-circuit transmission line 360 ​​does not need to have an electrical length of exactly 1 / 4 of the center wavelength to adequately suppress unbalanced current from flowing to the feed stem 310. Therefore, in practice, the length of the short-circuit transmission line 360 ​​may be selected based on a number of factors, such as suppressing unbalanced current and optimizing impedance matching of the feed stem 310 with the dipole arms 80-1, 80-2.

[0108] As is known in the art, the electrical length of a microstrip transmission line is shorter than its physical length. Therefore, since a portion of the short-circuit transmission line 360 ​​is implemented as a microstrip transmission line, the physical length of the short-circuit transmission line can be reduced compared to the physical length of the dual grounding lines 32-1, 32-2 included in the conventional feeding handle 10 that perform the same function as the short-circuit transmission line 360.

[0109] Although the short-circuit transmission line segment 362 extends from the second ground line 332-2 across the gap 336 and then extends backward, it should be understood that the embodiments of the present invention are not limited thereto. For example, in other embodiments, the short-circuit transmission line 362 can extend from the second ground line 332-2 across the gap 336 and then can extend forward toward the dipole arm 80.

[0110] As described above, the width "w" of the full-length ground line 332-1 is reduced in the feed handle 310 compared to the conventional feed handle 10. This reduced width can improve the masking performance. However, the ground line 332-1 can be maintained to have a width greater than the width of the signal trace 340 (e.g., at least 2-3 times wider), so that the microstrip feed line formed by the ground line 332-1 and the signal trace 340 can have good transmission characteristics.

[0111] Figure 4 FIG. 4 is a side view of a low-band radiating element 400 that can be used to implement the low-band radiating element 224 of the base station antenna 100 according to another embodiment of the present invention. The low-band radiating element 400 includes a feeding handle 410 and a pair of dipole radiators, which can be implemented as described above with reference to FIG. Figure 1A The dipole radiators 70-1, 70-2 are discussed in detail.

[0112] The feed handle 410 has a base 412 and a distal end 414 positioned forward of the base 412. The feed handle 410 includes a single feed handle printed circuit board 420 on which a pair of RF transmission line structures 416-1, 416-2 are formed, which transmit RF signals between a feed transmission line (not shown) of the radiating element 400 and its crossed dipole radiators 70-1, 70-2. Both dipole radiators 70-1, 70-2 can be physically mounted on the distal end of the feed handle printed circuit board 420. The base 412 of the feed handle printed circuit board 420 includes a protrusion 424, which is inserted through a slot (not shown) in the feed board printed circuit board. The metallized pads on the protrusion 424 can be soldered to metallized pads on the feed board PCB to mechanically mount the radiating element 400 on the feed board PCB and electrically connect the RF transmission line structures 416-1, 416-2 to corresponding feed transmission lines on the feed board PCB.

[0113] The feed handle printed circuit board 420 includes a metallization pattern on each major surface thereof. Figure 4 In FIG. 4 , the solid line shows the metallization pattern on the first side of the feed handle printed circuit board 410 , and the dashed line shows the metallization pattern on the second side of the feed handle printed circuit board 420 .

[0114] The feed stem printed circuit board 420 includes first and second metallized ground lines 432-1, 432-2 extending from the base 412 of the feed stem 410 to the distal end 414 thereof. The ground line 432-1 is coupled to a ground conductor (not shown) of a first feed transmission line for the radiating element 400, and the ground line 432-2 is coupled to a ground conductor (not shown) of a second feed transmission line for the radiating element 400. Each of the ground lines 432-1, 432-2 may have a length of about ¼ of the central wavelength of the radiating element 400.

[0115] The first and second signal traces 440-1, 440-2 are formed on the feed handle 420 and are connected to the signal conductors (not shown) of the corresponding first and second feed transmission lines for the radiating element 400. Each signal trace 440-1, 440-2 extends substantially the entire length of the feed handle printed circuit board 420. The first signal trace 440-1 can overlap the first ground line 432-1 substantially over its entire length. The distal end of the first signal trace 440-1 is connected to the first dipole arm 80-1, and the distal end of the first ground line 432-1 is connected to the second dipole arm 80-2, so that the first signal trace 440-1 and the first ground line 432-1 form a first RF transmission line structure 416-1 that is directly fed by the first dipole radiator 70-1. The second signal trace 440-2 that overlaps the second ground line 432-2 over its entire length is also provided on the feed handle printed circuit board 420. The distal end of the second signal trace 440-2 is coupled to the third dipole arm 80-3 and the distal end of the second ground line 432-2 is coupled to the fourth dipole arm 80-4 such that the second signal trace 440-2 and the second ground line 432-2 form a second RF transmission line structure 416-2 that directly feeds the second dipole radiator 70-2.

[0116] The feed handle printed circuit board 420 can be used to feed the first dipole radiator 70-1 as follows. The first signal trace 440-1 connects the signal conductor of the first feed transmission line directly to the first dipole arm 80-1. The first ground line 432-1 connects the ground conductor of the first feed transmission line directly to the second dipole arm 80-2. Similarly, the second signal trace 440-2 connects the signal conductor of the second feed transmission line directly to the third dipole arm 80-3. The second ground line 432-2 connects the ground conductor of the second feed transmission line directly to the fourth dipole arm 80-4. Here, a single feed handle printed circuit board 420 is used to feed two dipole radiators 70-1, 70-2.

[0117] The feed handle printed circuit board 420 also includes a first transmission line segment and a second transmission line segment 462-1, 462-2. The transmission line segment 462-1 includes a microstrip transmission line having a narrow transmission line signal trace 464-1 extending from a central portion of the first signal trace 440-1 and overlapping the first ground line 432-1. The end of the transmission line signal trace 464-1 adjacent to the base 412 of the feed handle 410 is short-circuited to the first ground line 432-1. The transmission line segment 462-1 together with the signal trace 440-1 and the first ground line 432-1 includes a short-circuited transmission line 460-1, which extends from the distal end 414 of the feed handle 410 and can have an electrical length of about 1 / 4 of the central wavelength of the low-band radiating element 400. This short-circuited transmission line 460-1 can be used to suppress unbalanced current from the dipole arms 80-1, 80-2 to the feed stem 410. The width of the transmission line signal trace 464-1 is kept very narrow to increase its inductance in order to further suppress mid-band currents on the feed stem 410.

[0118] Similarly, the transmission line segment 462-2 includes a microstrip transmission line having a narrow transmission line signal trace 464-2 extending from a central portion of the second signal trace 440-2 and overlapping the second ground line 432-2. The end of the transmission line signal trace 464-2 adjacent to the base 412 of the feed handle 410 is short-circuited to the second ground line 432-2. The transmission line segment 462-2, together with portions of the signal trace 440-2 and the second ground line 432-2, includes a short-circuited transmission line 460-2 that extends from the distal end 414 of the feed handle 410 and can have an electrical length of approximately 1 / 4 of the central wavelength of the low-band radiating element 400. This short-circuited transmission line 460-2 can be used to suppress unbalanced currents from the dipole arms 80-3, 80-4 from flowing to the feed handle 410.

[0119] Figure 5 1 is a side view of a low-band radiating element 500 that can be used to implement the low-band radiating element 224 of the base station antenna 100 according to some other embodiments of the present invention. The low-band radiating element 500 includes a feeding handle 510 and a pair of dipole radiators, which can be implemented as, for example, the dipole radiators 70-1 and 70-2 discussed above.

[0120] The feeding handle 510 has a base 512 and a distal end 514 located in front of the base 512. The feeding handle 510 includes a first printed circuit board and a second printed circuit board 520-1 and 520-2. Since the main surface of the feeding handle printed circuit board 520-2 is perpendicular to the viewing angle, Figure 5Only the side surface of the feed handle printed circuit board is visible. Each feed handle printed circuit board 520-1, 520-2 includes a corresponding RF transmission line structure 516-1, 516-2, which transmits RF signals between the feed transmission line (not shown) of the radiating element 500 and its cross-dipole radiators 70-1, 70-2. The first feed handle printed circuit board and the second feed handle printed circuit board 520-1, 520-1 are mated together in the same manner as the feed handle printed circuit boards 320-1 and 320-2 discussed above. The dipole radiators 70-1, 70-2 can be physically mounted on the distal end of the feed handle 510.

[0121] The feed handle printed circuit board 520-1 includes a metallization pattern on each major surface thereof. Figure 5 In FIG. 5 , the solid line shows the metallization pattern on the second side of the feed handle printed circuit board 520 - 1 , and the dashed line shows the metallization pattern on the first side of the feed handle printed circuit board 520 - 1 .

[0122] As shown, the first side of the feed stem printed circuit board 520-1 includes a metallized ground trace 532-1 extending from the base 512 of the feed stem 510 to its distal end 514. The ground trace 532-1 is coupled to a ground conductor (not shown) of the first feed transmission line for the radiating element 500. The metallized area 532-1 is similar to Figure 1B The metallized area 32-1 of the feed handle printed circuit board 20-1 is similar to the metallized area 32-1 of the feed handle printed circuit board 20-1, but has a smaller width to reduce the total amount of metal. The second side of the feed handle printed circuit board 520-1 includes a signal trace 540-1, which also extends from the base 512 of the feed handle 510 to its distal end 514. The signal trace 540-1 is connected to the signal conductor of the feed transmission line, which feeds the feed handle printed circuit board 520-1.

[0123] The signal trace 540-1 includes a first forward extending segment 542-1, a lateral extending segment 542-2, and a second forward extending segment 542-3. The first forward extending segment 542-1 includes a widened pad area 544 near the base 512 of the feeding handle 510 and a narrow trace 546 extending forward from the widened pad area 544. The first forward extending segment 542-1 overlaps with the first ground line 532-1. The lateral extending segment 542-2 includes a narrow trace 548 extending from the trace 546. The second forward extending segment 542-3 includes a narrow trace 550 extending at a right angle from the end of the trace 548 toward the distal end 514 of the feeding handle 510. The distal end of the first signal trace 540-1 is coupled to the first dipole arm 80-1, and the distal end of the first ground line 532-1 is coupled to the second dipole arm 80-2, such that the first signal trace 540-1 and the first ground line 532-1 form a first RF transmission line structure 516-1 that directly feeds the first dipole radiator 70-1.

[0124] Although the feed handle printed circuit board 520-2 is Figure 5 Most of it is not visible, but it is almost identical to the feed handle PCB 520 - 1 , except for: (1) the location of the slots 522 - 1 , 522 - 2 ; and (2) on the feed handle PCB 520 - 2 , the laterally extending segment 542 - 2 is closer to the base 512 of the feed handle 510 .

[0125] The feed handle printed circuit board 520-1 can be used to feed the first dipole radiator 70-1 as follows. The first signal trace 540-1 directly connects the signal conductor of the first feed transmission line to the first dipole arm 80-1. The first ground line 532-1 directly connects the ground conductor of the first feed transmission line to the second dipole arm 80-2. Therefore, the RF transmission line structure 516-1 directly feeds the first dipole radiator 70-1.

[0126] The feed handle printed circuit board 520-1 also includes a transmission line segment 562. The transmission line segment 562-1 includes a microstrip transmission line having a narrow transmission line signal trace 564-1 extending from a central portion of the first signal trace 540-1. The transmission line segment 562-1 also includes a narrow ground trace 566-1 extending from a central portion of the first ground line 532-1. The transmission line signal trace 564-1 overlaps the narrow ground trace 566-1. The end of the transmission line signal trace 564-1 adjacent to the base 512 of the feed handle 510 is shorted to the narrow ground trace 566-1 via a plated through hole 538-1 in the feed handle printed circuit board 520-1. The transmission line segment 562 may include, together with the signal trace 540-1 and portions of the first ground line 532-1, a short-circuit transmission line 560-1 extending from the distal end 514 of the feed stem 510 and may have an electrical length of about 1 / 4 of the center wavelength of the low-band radiating element 500. This short-circuit transmission line 560-1 may be used to suppress unbalanced currents from flowing from the dipole arms 80-1, 80-2 onto the feed stem 510. The width of the transmission line signal trace 564-1 is kept very narrow to increase its inductance in order to further suppress mid-band currents on the feed stem 510.

[0127] Figures 6A-6F yes Figure 4 A schematic shaded view of a first main surface and a second main surface of a modified form of a feed handle printed circuit board 420-1, which illustrates the manner in which the short-circuited transmission lines according to an embodiment of the present invention can have different lengths. Figures 6A-6F In the description, only the first short-circuited transmission line 460-1 is discussed, but it should be understood that Figures 6A-6F The feeding handles shown in FIG. 4 each include a second short-circuit transmission line 460 - 2 having the same design as the first short-circuit transmission line 460 - 1 on each respective feeding handle.

[0128] like Fig. 6A As shown in FIG. , in some embodiments, a feed handle 410A may be provided, wherein a transmission line segment 462-1 may be provided from Figure 4 As described above, the electrical length of the short-circuited transmission line 460-1 may involve a compromise between impedance matching the RF transmission line structure 416-1 to the dipole arms 80-1, 80-2 and providing a short-circuited quarter-wavelength transmission line stub that helps suppress unbalanced current from flowing from the dipole arms 80-1, 80-2 to the feed handle 410. Fig. 6A It is shown that in some cases, impedance matching problems may cause the shorted transmission line 460-1 to have an electrical length less than 1 / 4 of the center wavelength. In contrast, Figure 6B-6FA feed handle is depicted in which the transmission line 460-1 is short-circuited by bending one or more sections of the transmission line 460-1. Figure 4 The length shown in is longer. Figure 6B In FIG. 4 , the transmission line 460 - 1 is lengthened by providing a feed handle 410B having a transmission line segment 462 - 1 including a serpentine segment 466 . Figure 6C In FIG. 4 , the transmission line 460 - 1 is lengthened by providing a feeding handle 410C having a serpentine section 466 in a front portion of the signal trace 440 - 1 . Fig.6D and 6E Depicted are feed handles 410D, 410E, wherein the short-circuited transmission line 460-1 is provided from the upper portion of the signal trace 440-1 and the transmission line segment 462-1 by including a plurality of serpentine segments 466 disposed in the upper portion of the signal trace 440-1 and the transmission line segment 462-1. Figure 4 Finally, Fig. 6F A feed handle 410F is depicted in which the portion of the shorting transmission line 460 - 1 extending forwardly from the signal trace 440 - 1 is bent by including a plurality of serpentine segments 466 therein.

[0129] Figures 7A-7D yes Figure 4 Schematic shaded views of first and second major surfaces of a modified form of a feed stem 410 showing different connection schemes for connecting a feed stem printed circuit board 420 to a dipole arm 80 (not shown).

[0130] like Fig. 7A As shown in FIG. 4 , the feed handle 410G has a similar design to the feed handle 410, but the connection 468 between the feed handle 410G and the dipole arm 80 is smaller than that of the feed handle 410G. Figure 4 This can make it easier to form the solder joints connecting the dipole arms 80 to the feed stem 410G. Figures 7B-7D Feed handles 410H, 4101, 410J are each shown having a slightly different connection 468 configuration.

[0131] Figure 8 According to another embodiment of the present invention, Figure 5 A schematic shaded diagram of a cross-dipole radiating element 500A which is a modified form of the radiating element 500. Figure 5 and Figure 8It can be seen that the radiating element 500A is very similar to the radiating element 500, but includes a transmission line segment 562-1 that is bent to have an increased electrical length. As described above, the transmission line segment 562-1 can be lengthened to improve the impedance matching between the feed stem 510A and the dipole arms 80-1, 80-2. In addition, the signal trace 540-1 and the first ground line 532-1 on the feed stem printed circuit board 520A-1 of the radiating element 500A each include a corresponding pointed foot that forms an auxiliary microstrip stub 533-1. This auxiliary microstrip stub 533-1 acts as a low-pass filter to suppress higher frequency currents.

[0132] According to further embodiments of the present invention, radiating elements are provided having feed stems that include features designed to suppress higher frequency band currents (e.g., currents that would otherwise be induced in the ground line in response to radiation emitted by a nearby higher frequency band radiating element). Exemplary embodiments of such radiating elements 600A-600D are respectively Figures 9A-9D Shown in. Figures 9A-9D The radiating element shown in may, for example, include the low-band radiating element 224 of the base station antenna 100, and its feed handle may be configured to suppress current in the operating frequency band of the mid-band radiating element 234 and / or the high-band radiating element 244. As another example, Figures 9A-9D The radiating element shown in the figure may include the mid-band radiating element 234 of the base station antenna 100, and its feed handle may be configured to suppress current in the operating band of the high-band radiating element 244. Each of the radiating elements 600A-600D includes a dipole radiator printed circuit board 72, which includes a first dipole radiator 70-1 having dipole arms 80-1, 80-2 and a second dipole radiator 70-2 having dipole arms 80-3, 80-4. As described above with reference to Figure 1A-1B The dipole radiator printed circuit board 72 is discussed, so the following description will be made of Figures 9A-9D Further discussion of the dipole radiator printed circuit board 72 will be omitted in the discussion of FIG.

[0133] First reference Fig. 9A, shows a radiating element 600A including a feeding handle 610A and a dipole radiator printed circuit board 72. The feeding handle 610A can be very similar to the feeding handle 10 of the conventional radiating element 1, but includes ground wires 632-1, 632-2, which have a forward portion that is narrower than the corresponding portion of the ground wires 32-1, 32-2 included on the conventional feeding handle 10. In addition, a plurality of narrowed short posts 690 extend from each ground wire 632-1, 632-2, each narrowed short post having an open-circuited distal end. The electrical length of the short posts 690 can be selected so that the short posts act as a band-stop filter. In an exemplary embodiment, the electrical length of each short post can be between 0.2 and 0.3 of the central wavelength of a nearby radiating element so as to form a current on the feeding handle 610A in response to suppressing the RF radiation emitted by such radiating elements. Although in the depicted embodiment, two short posts 690 extend from each ground wire 632, embodiments of the present invention are not limited thereto. In other embodiments, fewer (1) or more (3, 4, 5 or more) stubs 690 may extend from each ground line 632. It should also be understood that the number of stubs 690 extending from each ground line 632 need not be the same. Although the stubs 690 are shown as being formed on the same side of the feed handle PCB 620 as the ground lines 632, it should also be understood that some or all of the stubs 690 may be formed on the other side of the feed handle PCB 620, or some or all of the stubs 690 may have portions on both sides of the feed handle PCB 620.

[0134] It should also be appreciated that stub 690 may be added to any of the feed handles according to the embodiments of the invention discussed herein to further inhibit current from forming thereon in response to RF radiation emitted by nearby radiating elements. For example, ground line 332 on feed handle 310, ground line 432 on feed handle 410, and / or ground line 532 on feed handle 510 may all include one or more of stub 690. Furthermore, in some embodiments, the signal traces on these feed handles may alternatively or similarly include stub 690.

[0135] Next reference Fig. 9B and 9C, shows radiating elements 600B and 600C each including a corresponding feed handle 610B, 610C and a dipole radiator printed circuit board 72. The feed handles 610B, 610C can be very similar to the feed handle 10 of the conventional radiating element 1, but include ground wires 632-1, 632-2 having slots 692 (e.g., transversely extending slots 692) formed therein, wherein the metal of the ground wire 632 is removed or omitted. The slots 632 can be formed in the front portion of the ground wire 632 in front of the signal trace 640. The number of slots 692 can vary (e.g., 2, 3, 4, 5 or more slots per ground wire 632). The slots 692 can effectively form one or more series inductors along the ground wire 632, and the one or more series inductors suppress the formation of current on the ground wire 632 in response to RF radiation emitted by a nearby higher frequency band radiating element.

[0136] The length and / or width of the slots 692 may be selected so that the slots act as low pass filters. The length of each slot 692 may represent a compromise between better suppression of high-band currents from forming on the feed stems 610B, 610C in response to RF radiation emitted by such radiating elements and poorer impedance matching in lower frequency bands. Fig. 9B In the embodiment of the present invention, three short posts 692 extend from each ground line 632, and a slot 692 extends from each side of each ground line 632. The embodiments of the present invention are not limited thereto. Fig. 9C In the embodiment of FIG. 6 , two studs 692 extend from each ground wire 632, and a slot 692 extends from the inside of each ground wire 632. Many other configurations are possible with different numbers of slots, different slot arrangements, different numbers of slots per ground wire, etc.

[0137] It should also be appreciated that slots 696 may be added to any of the feed handles according to embodiments of the invention discussed herein to further inhibit current from forming thereon in response to RF radiation emitted by nearby radiating elements. For example, ground line 332 on feed handle 310, ground line 432 on feed handle 410, and / or ground line 532 on feed handle 510 may all include one or more of slots 692.

[0138] refer to Fig.9D, shows a radiating element 600D including a feed stem 610D and a dipole radiator printed circuit board 72. The feed stem 610D can be very similar to the feed stem 10 of the conventional radiating element 1, but the second ground line 632-2 has an internal opening 638 that is completely enclosed by the second ground line 632-2, and the internal opening 638 forms a high-pass filter that suppresses RF current in the operating band of a nearby higher-band radiating element (e.g., the high-band radiating element 244 of the base station antenna 100). The electrical length of the perimeter of the internal opening 638 can be selected so that the internal opening 638 acts as a low-pass filter that will suppress RF current in the operating band of the nearby higher-band radiating element. In an exemplary embodiment, the electrical length of the opening can be about 0.2-0.3 of the center wavelength of the nearby radiating element so as to suppress the formation of current on the feed stem 610D in response to RF radiation emitted by such radiating element.

[0139] In some embodiments, the internal opening 638 may be located in the rear portion of the second ground line 632-2. For example, the internal opening 638 may be located behind a laterally extending segment of a signal trace 640 formed on the same feed handle printed circuit board 620-1 as the second ground line 632-1. However, it should be understood that the internal opening may be located at other locations. In some embodiments, the internal opening 638 may be a rectangular opening, but embodiments of the present invention are not limited thereto.

[0140] It should also be appreciated that internal openings 638 may be added to any of the feed handles according to the embodiments of the invention discussed herein to further inhibit current from forming thereon in response to RF radiation emitted by nearby radiating elements. For example, ground wire 332 on feed handle 310, ground wire 432 on feed handle 410, and / or ground wire 532 on feed handle 510 may all include internal openings 638.

[0141] Radiating elements according to embodiments of the present invention may provide a number of advantages. First, as discussed above, the feed stem of the radiating element may exhibit better shielding performance relative to nearby higher frequency band radiating elements. Additionally, reduced metallization on the feed stem allows for the use of a smaller feed stem printed circuit board, which reduces the cost of the radiating element.

[0142] Although the dipole arms of the low-frequency band radiating element described above are implemented on a dipole radiator printed circuit board, it should be understood that the embodiments of the present invention are not limited thereto. For example, in other embodiments, the dipole arms may be implemented as metal sheet dipole arms or may be implemented using other metal structures.

[0143] Although the feed handle of the radiating element according to the embodiment of the present invention is shown as being implemented using a feed handle printed circuit board, it should be understood that the embodiments of the present invention are not limited thereto. In other embodiments, a metal plate feed handle may be used instead (i.e., the same or similar structure as shown herein may be implemented using a metal plate (or other metal component, such as a die-cast metal component)).

[0144] Embodiments of the present invention have been described above with reference to the accompanying drawings, in which embodiments of the present invention are shown. However, the present invention may be embodied in many different forms and should not be interpreted as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and these embodiments will fully convey the scope of the present invention to those skilled in the art. Throughout the text, the same reference numerals represent the same elements.

[0145] 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. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present invention, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0146] It will be understood that when an element is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element. Conversely, when an element is described as being "directly on" another element, there are no intermediate elements. It will also be understood that when an element is described as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or there may be an intermediate element. Conversely, when an element is described as being "directly connected" or "directly coupled" to another element, there are no intermediate elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (i.e., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.).

[0147] Relative terms, such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer or region to another element, layer or region as illustrated in the accompanying drawings. It is to be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the accompanying drawings.

[0148] In this context, the term "substantially" means within + / - 10%.

[0149] The terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include plural forms unless the context clearly indicates otherwise. It will also be understood that the terms "including", "comprising" and / or "having" when used in this article refer to the presence of the described features, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, operations, elements, parts and / or their groupings.

[0150] Aspects and elements of all of the embodiments disclosed above may be combined in any manner and / or combined with aspects or elements of other embodiments to provide multiple additional embodiments.

Claims

1. A crossed dipole radiating element, comprising: a feeding handle having a base and a distal end positioned forward of the base; a first dipole radiator mounted at a distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; as well as a second dipole radiator mounted at a distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm, wherein the feeding handle comprises a first ground line, a first signal trace at least partially overlapping the first ground line, and a transmission line segment extending from the first ground line and / or the first signal trace, Wherein the transmission line segment includes a transmission line signal trace shorted to a ground conductor of the transmission line segment.

2. The crossed-dipole radiating element of claim 1, wherein the transmission line segment is at least a portion of a short-circuited transmission line configured to suppress unbalanced current from flowing onto the feed handle.

3. The cross-dipole radiating element of claim 1 , wherein the transmission line segment is at least a portion of a short-circuited transmission line having a base adjacent to a distal end of the feed handle, wherein a transmission line signal trace shorted to a ground conductor of the transmission line segment is distal from the base of the short-circuited transmission line by approximately one quarter wavelength of a center frequency of an operating frequency band of the cross-dipole radiating element.

4. A crossed-dipole radiating element according to any one of claims 1-3, wherein the transmission line signal trace extends from the first signal trace.

5. The crossed-dipole radiating element according to any one of claims 1-3, wherein the ground conductor of the transmission line segment extends from the first ground line.

6. The crossed-dipole radiating element of claim 5, wherein the first ground line serves as a ground conductor for the transmission line segment.

7. A cross-dipole radiating element according to any one of claims 1-3, wherein the feed handle includes a feed handle printed circuit board, and the first signal trace is a first metallization pattern on a first side of the feed handle printed circuit board, and the first ground line is a second metallization pattern on a second side of the feed handle printed circuit board.

8. The cross-dipole radiating element of claim 7 , wherein the feed handle further comprises a second ground line separated from the first ground line by a gap, the second ground line comprising a third metallization pattern on a second side of the feed handle printed circuit board, and wherein the first signal trace and the transmission line signal trace each overlap the gap.

9. The cross-dipole radiating element of claim 8, wherein a first end of the transmission line signal trace is connected to the first ground line via a first plated through hole in the feed handle printed circuit board, and a second end of the transmission line signal trace is connected to the second ground line via a second plated through hole in the feed handle printed circuit board.

10. The crossed-dipole radiating element of any one of claims 1-3, wherein a width of the transmission line signal trace is smaller than a width of the first signal trace.

11. The crossed-dipole radiating element of any one of claims 1-3, wherein the transmission line signal trace comprises at least one serpentine section.

12. The cross-dipole radiating element of claim 8, wherein a distal end of the first signal trace extends forward.

13. The crossed-dipole radiating element of any one of claims 1-3, wherein the ground conductor of the transmission line segment has an average width that is smaller than an average width of the first ground line, and the transmission line signal trace has an average width that is smaller than an average width of the first signal trace.

14. The cross-dipole radiating element according to any one of claims 1-13, wherein the first signal trace directly feeds the first dipole arm, and the first ground line directly feeds the second dipole arm.

15. The crossed-dipole radiating element according to any one of claims 1-14, wherein a base of the transmission line segment is connected to the first ground line and / or the first signal trace, and the transmission line segment is short-circuited to the ground conductor of the transmission line segment at a distal end of the transmission line segment.

16. A cross-dipole radiating element according to any one of claims 1-16 in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element.

17. The crossed-dipole radiating element of claim 16, wherein an open-ended line configured to act as a bandpass filter to suppress current in the second frequency band extends from the first ground line.

18. The cross-dipole radiating element of claim 16, wherein a central region of the first ground line comprises an open area from which metallization is omitted, the open area being configured to function as a high pass filter to suppress current in the second frequency band.

19. The cross-dipole radiating element of claim 16, wherein a front portion of the first ground line comprises a plurality of slots from which metallization is omitted, the plurality of slots being configured to suppress current in the second frequency band.

20. A crossed dipole radiating element, comprising: a feeding handle having a base and a distal end positioned forward of the base; a first dipole radiator mounted at a distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; as well as a second dipole radiator mounted at a distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm, The feeding handle includes a first ground line extending from the base to connect to the first dipole arm, a first signal trace extending from the base to connect to the second dipole arm, and a transmission line segment having a transmission line signal trace extending from the first signal trace.

21. The crossed-dipole radiating element of claim 20, wherein the transmission line signal trace is shorted to the first ground line.

22. The cross-dipole radiating element of claim 21 , wherein the transmission line segment is a first transmission line segment, and portions of the first signal trace and the first ground line extending from the first transmission line segment to the first dipole arm form a second transmission line segment, the first transmission line segment and the second transmission line segment forming a short-circuited transmission line.

23. The crossed-dipole radiating element of claim 22, wherein a distal end of the transmission line signal trace is shorted to the first ground line such that the first transmission line segment and the second transmission line segment form a shorted transmission line.

24. The cross-dipole radiating element of claim 23, wherein the electrical length of the short-circuit transmission line is between 0.2 and 0.35 of the wavelength corresponding to the center frequency of the operating frequency band of the cross-dipole radiating element.

25. The crossed-dipole radiating element of claim 23, wherein the short-circuit transmission line is configured to prevent unbalanced current from flowing to the feed handle.

26. A crossed-dipole radiating element according to any of claims 20-25, wherein the first ground line forms a ground conductor of the transmission line segment.

27. A cross-dipole radiating element according to any one of claims 20-25, wherein the feed handle includes a feed handle printed circuit board, and the first signal trace is a metallization pattern on a first side of the feed handle printed circuit board, and the first ground line is a second metallization pattern on a second side of the feed handle printed circuit board.

28. The crossed-dipole radiating element of claim 27, wherein the transmission line signal trace is a third metallization pattern on the first side of the feed handle printed circuit board.

29. The crossed-dipole radiating element of claim 28, wherein a first end of the transmission line signal trace is connected to the first ground line via a first plated through hole in the feed handle printed circuit board.

30. The crossed-dipole radiating element of any one of claims 20-25, wherein a width of the transmission line signal trace is less than a width of the first signal trace.

31. A crossed-dipole radiating element according to any one of claims 20-25, wherein the transmission line signal trace comprises at least one serpentine section.

32. A crossed-dipole radiating element according to any one of claims 20-25, wherein the base of the transmission line segment is connected to the first ground line and / or the first signal trace, and the transmission line segment is short-circuited to the ground conductor of the transmission line segment at the distal end of the transmission line segment.

33. A cross-dipole radiating element according to any one of claims 20-25 in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element.

34. The crossed-dipole radiating element of claim 33, wherein an open-ended line configured to act as a bandpass filter to suppress current in the second frequency band extends from the first ground line.

35. The cross-dipole radiating element of claim 33, wherein a central region of the first ground line comprises an open area from which metallization is omitted, the open area being configured to function as a high pass filter to suppress current in the second frequency band.

36. The cross-dipole radiating element of claim 33, wherein a front portion of the first ground line comprises a plurality of slots from which metallization is omitted, the plurality of slots being configured to suppress current in the second frequency band.

37. A crossed dipole radiating element, comprising: a feeding handle having a base and a distal end positioned forward of the base; a first dipole radiator mounted at a distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; as well as a second dipole radiator mounted at a distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm, The feed handle includes a first ground line extending from the base to connect to the first dipole arm, a second ground line separated from the first ground trace by a gap, a first signal trace crossing the gap, and a transmission line segment including a transmission line signal trace crossing the gap.

38. The crossed-dipole radiating element of claim 37, wherein the second ground line is connected to the second dipole arm.

39. The crossed-dipole radiating element of any one of claims 37-38, wherein the first signal trace is shorted to the first ground line on a first side of the gap and is shorted to the second ground line on a second side of the gap.

40. The crossed-dipole radiating element of any one of claims 37-39, wherein the transmission line segment is at least a portion of a short-circuited transmission line configured to suppress unbalanced current from flowing onto the feed handle.

41. A cross-dipole radiating element according to any one of claims 37-40, wherein the transmission line segment is at least a portion of a short-circuited transmission line having a base adjacent to the distal end of the feed handle, wherein a transmission line signal trace shorted to a ground conductor of the transmission line segment is approximately one-quarter wavelength away from the base of the short-circuited transmission line by a center frequency of an operating frequency band of the cross-dipole radiating element.

42. The crossed-dipole radiating element of any one of claims 37-41, wherein the first ground line serves as a ground conductor for the transmission line segment.

43. A cross-dipole radiating element as claimed in any one of claims 37-42, wherein the distal end of the first signal trace extends forwardly.

44. A crossed dipole radiating element, comprising: a feeding handle having a base and a distal end positioned forward of the base; a first dipole radiator mounted at a distal end of the feeding handle, the first dipole radiator comprising a first dipole arm and a second dipole arm; as well as a second dipole radiator mounted at a distal end of the feeding handle, the second dipole radiator comprising a third dipole arm and a fourth dipole arm, The feeding handle includes a first grounding wire and a first short column extending from the first grounding wire, wherein the first short column has an open-circuited distal end.

45. A cross-dipole radiating element according to claim 44 in combination with a base station antenna, the base station antenna comprising a second radiating element, the second radiating element being configured to operate in a second frequency band higher than the operating frequency band of the cross-dipole radiating element.

46. ​​The cross-dipole radiating element of claim 45, wherein a first stub configured to act as a bandpass filter to suppress currents in the second frequency band extends from the first ground line.

47. The cross-dipole radiating element of claim 46, wherein the feed handle further comprises a second ground line and a second stub extending from the second ground line, the second stub having an open-circuited distal end, the second stub being configured to act as a bandpass filter that suppresses current in the second frequency band.

48. The cross-dipole radiating element of claim 47, wherein the first ground wire and the second ground wire each extend from a base of the feed stem to a distal end of the feed stem.

49. The cross-dipole radiating element of claim 48, wherein the feed handle further comprises: a third stub extending from the first ground line, the third stub having an open-circuited distal end, the third stub being configured to act as a bandpass filter that suppresses current in the second frequency band; and a fourth stub extending from the second ground line, the fourth stub having an open-circuited distal end, the fourth stub being configured to act as a bandpass filter that suppresses current in the second frequency band.

50. A base station antenna, comprising: a first radiating element configured to operate in a first frequency band; as well as A second radiating element, the second radiating element is configured to operate in a second frequency band lower than the first frequency band, the second radiating element includes a feed handle and at least one radiator mounted at a distal end of the feed handle, the feed handle includes a first ground wire, the first ground wire extends substantially from a base of the feed handle to the distal end of the feed handle, the first ground wire includes an internal opening completely enclosed by the first ground wire, the internal opening forms a high pass filter that suppresses radio frequency ("RF") currents in the first frequency band.

51. The cross-dipole radiating element of claim 50, wherein the feed stem further comprises a second ground line and a signal trace, wherein at least a rear portion of the signal trace overlaps the second ground line.

52. A crossed-dipole radiating element according to claim 50 or 51, wherein the internal opening is located in a rear portion of the first ground line.

53. A crossed-dipole radiating element according to any one of claims 50-52, wherein the inner opening is a rectangular opening.

54. A base station antenna, comprising: a first radiating element configured to operate in a first frequency band; as well as a second radiating element configured to operate in a second frequency band lower than the first frequency band, the second radiating element comprising a feed handle and at least one radiator mounted at a distal end of the feed handle, the feed handle comprising a first ground wire extending substantially from a base of the feed handle to the distal end of the feed handle, the first ground wire comprising a plurality of slots formed therein, the plurality of slots forming a high pass filter that suppresses radio frequency ("RF") currents in the first frequency band.

55. The cross-dipole radiating element of claim 54, wherein the feed stem further comprises a second ground line and a signal trace, wherein at least a rear portion of the signal trace overlaps the second ground line.

56. The cross-dipole radiating element of claim 55, wherein the second ground line includes a plurality of slots formed therein, the plurality of slots forming a high pass filter that suppresses RF currents in the first frequency band.

57. The cross-dipole radiating element of claim 56, wherein the plurality of slots are formed in a portion of the first ground line in front of the signal trace.

58. The cross-dipole radiating element of claim 54, wherein a first slot of the plurality of slots extends inwardly from a first side of the first ground line, and a second slot of the plurality of slots extends inwardly from a second side of the first ground line opposite the first side.

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