US-12627063-B2 - Base station antenna and a reflector for the base station antenna

Abstract

A reflector for a base station antenna comprises: a body; and at least one slot provided in the body, where the at least one slot is configured for forming at least one stub-type filtering structure in the body. The stub-type filtering structure is configured for at least partially inhibiting an induced current in the body within an operating frequency band of a radiating element mounted behind the reflector.

Inventors

• Qiang Liu
• Xun Zhang
• Changfu Chen
• Nengbin Liu

Assignees

• Outdoor Wireless Networks LLC

Dates

Publication Date

20260512

Application Date

20231020

Priority Date

20221024

Claims (20)

1. 1 . A reflector for a base station antenna, wherein the reflector comprises: a body; and at least one slot provided in the body, wherein the at least one slot is configured to form at least one stub filtering structure in the body, and the stub filtering structure is configured to at least partially inhibit an induced current in the body within an operating frequency band of a radiating element mounted behind the reflector.
2. 2 . The reflector for the base station antenna according to claim 1 , wherein the at least one stub filtering structure includes at least one open stub.
3. 3 . The reflector for the base station antenna according to claim 2 , wherein the longitudinal length of the at least one open stub is 0.25+n/2 times the equivalent wavelength, n being a natural number, wherein the equivalent wavelength is a wavelength at a predetermined frequency point within the operating frequency band.
4. 4 . The reflector for the base station antenna according to claim 2 , wherein the at least one slot includes an H-, L-, M-, U-, S-shaped or scalloped slot for forming the at least one open stub.
5. 5 . The reflector for the base station antenna according to claim 1 , wherein the at least one stub filtering structure includes at least one closed stub.
6. 6 . The reflector for the base station antenna according to claim 5 , wherein the longitudinal length of the at least one closed stub is N/2 times the equivalent wavelength, and N is a positive integer, wherein the equivalent wavelength is the wavelength at a predetermined frequency point within the operating frequency band.
7. 7 . The reflector for the base station antenna according to claim 5 , wherein the at least one slot comprises two slots for forming a single closed stub between the two slots.
8. 8 . The reflector for the base station antenna according to claim 1 , wherein the at least one stub filtering structure comprises multiple stub filtering structures arranged acyclically in at least one direction, and the multiple stub filtering structures include at least one open stub and at least one closed stub.
9. 9 . The reflector for the base station antenna according to claim 1 , wherein the at least one stub filtering structure comprises: a first stub filtering structure configured to at least partially inhibit a first induced current within a predetermined first frequency band; and a second stub filtering structure configured to at least partially inhibit a second induced current within a predetermined second frequency band; wherein the first frequency band is the operating frequency band and is different from the second frequency band.
10. 10 . The reflector for the base station antenna according to claim 1 , wherein the body includes a reflective strip section extending in a vertical direction, wherein the reflective strip section is configured for mounting a radiating element, and the at least one slot is at least partially provided on the reflective strip section for forming at least one of the stub filtering structures on the reflective strip section.
11. 11 . The reflector for the base station antenna according to claim 10 , wherein the body includes a first reflective strip section and a second reflective strip section at the side in a horizontal direction, and an opening is provided between the first reflective strip section and the second reflective strip section.
12. 12 . The reflector for the base station antenna according to claim 1 , wherein the reflector includes a fence extending in a vertical direction, and the fence extends forwardly from the body of the reflector, wherein the at least one additional slot is provided on the fence, wherein the at least one additional slot is configured to form at least one additional stub filtering structure in the fence, and the at least one additional stub filtering structure is configured to at least partially inhibit the induced current within the predetermined frequency band in the fence.
13. 13 . A base station antenna, wherein the base station antenna comprises the reflector for the base station antenna according to claim 1 , wherein the base station antenna includes a passive module and an active module mounted behind the passive module, wherein a reflector and a reflection compensation plate separated from the reflector are mounted inside the passive module, and the reflection compensation plate includes a frequency-selective surface composed of multiple pattern units arranged periodically.
14. 14 . The base station antenna according to claim 13 , wherein the frequency-selective surface is configured to reflect electromagnetic waves within a second frequency band and allow electromagnetic waves within a first frequency band to pass through, wherein the first frequency band corresponds to an operating frequency band of at least a portion of the radiating element inside the passive module and the second frequency band corresponds to the operating frequency band.
15. 15 . The base station antenna according to claim 13 , wherein the reflector includes a first reflective strip section and a second reflective strip section for mounting radiating elements, and that an opening is provided between the first reflective strip section and the second reflective strip section, wherein, the reflection compensation plate is mounted behind the reflector and at least partially overlaps the opening in the projection in the forward direction.
16. 16 . A reflector for a base station antenna that comprises a first array of radiating elements and a second array of radiating elements, the reflector comprising: a body having an opening therein, the body including a first reflective strip and a second reflective strip on opposed sides of the opening; a first slot provided in the first reflective strip that defines a first stub and a second slot provided in the second reflective strip that defines a second stub, wherein the first stub has a first longitudinal length that is 0.25 times a first wavelength that corresponds to a first frequency within an operating frequency band of the second array of radiating elements and the second stub has a second longitudinal length that is 0.25 times a second wavelength that corresponds to a second frequency within the operating frequency band of the second array of radiating elements.
17. 17 . The reflector according to claim 16 , wherein the base station antenna comprises an integrated base station antenna that includes a passive module and an active module, and the reflector and the first array of radiating elements are part of the passive module and the second array of radiating elements is part of the active module.
18. 18 . The reflector according to claim 17 , wherein the active module is mounted rearwardly of the opening in the body of the reflector.
19. 19 . The reflector according to claim 16 , wherein the first slot is configured to form at a first stub filtering structure that is configured to at least partially inhibit an induced current in the body within an operating frequency band of the second array of radiating elements.
20. 20 . A reflector for a base station antenna, the reflector comprising: a body; a first stub filtering structure that includes at least one first slot in the body and a second stub filtering structure that includes at least one second slot in the body, wherein the first stub filtering structure is configured to at least partially inhibit a first induced current within a first frequency band and the second stub filtering structure is configured to at least partially inhibit a second induced current within a second frequency band that is different than the first frequency band.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority to Chinese Patent Application No. 202211301204.X, filed Oct. 24, 2022, the entire content of which is incorporated herein by reference as if set forth fully herein. FIELD The present disclosure relates to the field of radio communication, and more particularly, to a base station antenna and a reflector for the base station antenna. BACKGROUND With the development of wireless communication technology, an integrated base station antenna including a passive module and an active module has emerged. The passive module may include one or more arrays of the radiating element configured to generate relatively static antenna beams, such as antenna beams that are configured to cover a 120-degree sector (in the azimuth plane) of the integrated base station antenna. The arrays may include arrays that operate under second generation (2G), third generation (3G) or fourth generation (4G) cellular network standards. These arrays are not configured to perform active beamforming operations, although they typically have remote electronic tilt (RET) capabilities which allow the pointing direction of the antenna beam in the elevation plane to be changed via electromechanical means in order to change the coverage area of the antenna beam. The active module may include one or more arrays of the radiating element operating under fifth generation (5G or higher version) cellular network standards. In 5G mobile communication, the frequency range of communication includes a main frequency band (specific portion of the range 450 MHz-6 GHz) and an extended frequency band (24 GHz-73 GHz, i.e. millimeter wave frequency band, mainly 28 GHz, 39 GHz, 60 GHz and 73 GHz). The frequency range used in 5G mobile communication includes frequency bands that use higher frequencies in the previous generations of mobile communication. These arrays typically have individual amplitude and phase control over subsets of the radiating element therein and perform active beamforming. As shown in FIG. 1 and FIG. 2, the integrated base station antenna 10 may include a passive module 11 and an active module 12 mounted on the back of or behind the passive module 11. The passive module 11 includes one or more arrays of the radiating element 115 mounted to extend forwardly from the reflector 13 of the passive module 11 (as shown in FIG. 3). The reflector 13 acts to reflect electromagnetic waves that are emitted backwardly by the radiating element 115 in the forward direction, and the reflector 13 also serves as a ground plane for the radiating element 115 of the arrays. The active module 12 is capable of emitting high-frequency electromagnetic waves (such as, high-frequency electromagnetic waves in the 2.3-4.2 GHz frequency band or a portion thereof). At least a portion of the active module 12 is typically mounted behind the passive module 11. Since the reflector 13 in the passive module 11 is configured forwardly of the active module 12, when the electromagnetic wave from the active module 12 is radiated forwardly through the passive module 11, an induced current, such as an induced current within the operating frequency band of the active module 12, may be formed or otherwise induced on the reflector 13 of the passive module 11. Such an induced current may lead to poor radiation performance of the integrated base station antenna 10, such as distortion of the radiation pattern or “antenna beams” of the active module 12 and/or reduced cross-polar discrimination, etc. Current countermeasures generally include reducing the size of the reflector 13. However, the effect of the countermeasures is limited because the size of the reflector 13 can only be reduced to a limited extent, and there is still an induced current on the reflector 13. In addition, as the size of the reflector 13 decreases, the radiation pattern of the passive module 11 will also deteriorate. SUMMARY According to a first aspect of the present disclosure, a reflector for the base station antenna is provided, wherein the reflector comprises: a body; and at least one slot provided in the body, wherein the at least one slot is configured for forming at least one stub-type filtering structure in the body, and the stub-type filtering structure is configured for at least partially inhibiting an induced current in the body within an operating frequency band of a radiating element mounted behind the reflector. In some embodiments, the at least one stub-type filtering structure may include at least one open stub. In some embodiments, the longitudinal length of the at least one open stub may be 0.25+n/2 times the equivalent wavelength, n being the natural number, wherein the equivalent wavelength is the wavelength at the predetermined frequency point within the operating frequency band. In some embodiments, the longitudinal length of the at least one open stub may be configured as 0.25 times the equivalent wavelength. In some embodi