Patent Application
20230208014
The present application claims priority to Chinese Patent Application No. 202111586457.1, filed Dec. 23, 2021, the entire content of which is incorporated herein by reference as if set forth fully herein.
The present disclosure relates to a communication system, more specifically, to an integrated base station antenna, which includes a passive antenna device and an active antenna device.
With the development of wireless communication technology, an integrated base station antenna that includes both a passive antenna and an active antenna has emerged. The passive antenna may include one or more arrays of radiating elements that are configured to generate relatively static antenna beams, such as antenna beams that are configured to cover a 120 degree sector (in the azimuth plane). The arrays may include arrays that operate, for example, 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 shape of the antenna beams generated by the arrays to be changed via electromechanical means in order to change the coverage area of the antenna beams. The active antenna may include one or more arrays of radiating elements that operate 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 than the previous generations of mobile communication. These arrays typically have individual amplitude and phase control over subsets of the radiating elements therein and perform active beamforming.
In fifth generation mobile communication systems, the cross-polarization performance requirements for active antennas may be high. Moreover, since the active antenna is positioned behind the passive antenna, the passive antenna may negatively impact the cross-polarization performance of the active antenna.
In addition, the cross-polarization performance of the active antenna may differ as a function of the scanning angle of the antenna beam generated by the active antenna. For example, in some cases, at small horizontal (i.e., azimuth plane) scanning angles, e.g., around 0°, the active antenna tends to have good cross-polarization performance (e.g., good cross-polarization discrimination); however at large horizontal scanning angles, e.g., around 47°, it the active antenna may exhibit relatively poor cross-polarization performance. Therefore, it is desirable to provide different tuning elements for small horizontal scanning angles and large horizontal scanning angles respectively (e.g., small tuning elements for small horizontal scanning angles and large tuning elements for large horizontal scanning angles) in order to maintain good cross-polarization performance over a wide scanning angle range. However, the installation of tuning elements is limited by the compact available space in the active antenna. Therefore, it is also desirable to improve the available space in integrated base station antennas.
According to a first aspect of the present disclosure, an integrated base station antenna is provided, comprising: a passive antenna; and an active antenna installed behind the passive antenna, wherein the active antenna comprising a reflecting plate and an array of radiating elements extending forward from the reflecting plate, wherein an array of metal tuning elements used for the array of radiating elements is mounted in the passive antenna, the array of metal tuning elements positioned right in front of the array of radiating elements of the active antenna, and wherein a longitudinal axis of at least some of the metal tuning elements extend at an angle between 70° and 110° with respect to a plane defined by the reflecting plate.
According to a second aspect of the present disclosure, an integrated base station antenna is provided, comprising: a passive antenna; and an active antenna installed behind the passive antenna, the active antenna comprising a reflecting plate and an array of radiating elements extending forward from the reflecting plate, wherein an array of metal tuning elements for the array of radiating elements is installed in the passive antenna, the array of metal tuning elements is right in front of the array of radiating elements of the active antenna, and the array of metal tuning elements is printed on a plurality of printed circuit board (PCB) components, and at least one column of metal tuning elements is printed on each PCB component respectively.
According to a third aspect of the present disclosure, an integrated base station antenna is provided, comprising: a passive antenna; and an active antenna installed behind the passive antenna, the active antenna comprising a reflection plate and an array of radiating elements extending forward from the reflection plate, wherein an array of metal tuning elements for the array of radiating elements is installed in the passive antenna, which is right in front of the array of radiating elements of the active antenna and is configured to: provide a first projection component in the horizontal direction at a horizontal scanning angle larger than the first angle, and a second projection component in the longitudinal direction at a horizontal scanning angle smaller than the second angle, the second projection component being larger than the second projection component.
Note, in the embodiments described below, the same reference signs are sometimes jointly used between different attached drawings to denote the same parts or parts with the same functions, and repeated descriptions thereof are omitted. In some cases, similar labels and letters are used to indicate similar items. Therefore, once an item is defined in one attached drawing, it does not need to be further discussed in subsequent attached drawings.
For ease of understanding, the position, dimension, and range of each structure shown in the attached drawings and the like sometimes may not indicate the actual position, dimension, and range. Therefore, the present disclosure is not limited to the positions, dimensions, and ranges disclosed in the attached drawings and the like.
The present disclosure will be described below with reference to the attached drawings, wherein the attached drawings illustrate certain embodiments of the present disclosure. However, it should be understood that the present disclosure may be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and to fully explain the protection scope of the present disclosure to those of ordinary skill in the art. It should also be understood that the embodiments disclosed in the present disclosure may be combined in various ways so as to provide more additional embodiments.
It should be understood that the terms used herein are only used to describe specific examples, and are not intended to limit the scope of the present disclosure. All terms used herein (including technical terms and scientific terms) have meanings normally understood by those skilled in the art unless otherwise defined. For brevity and/or clarity, well-known functions or structures may not be further described in detail.
As used herein, when an element is said to be “on” another element, “attached” to another element, “connected” to another element, “coupled” to another element, or “in contact with” another element, etc., the element may be directly on another element, attached to another element, connected to another element, coupled to another element, or in contact with another element, or an intermediate element may be present. In contrast, if an element is described as “directly” “on” another element, “directly attached” to another element, “directly connected” to another element, “directly coupled” to another element or “directly in contact with” another element, there will be no intermediate elements. As used herein, when one feature is arranged “adjacent” to another feature, it may mean that one feature has a part overlapping with the adjacent feature or a part located above or below the adjacent feature.
In this Specification, elements, nodes or features that are “connected” together may be mentioned. Unless explicitly stated otherwise, “connected” means that one element/node/feature can be mechanically, electrically, logically or otherwise connected with another element/node/feature in a direct or indirect manner to allow interaction, even though the two features may not be directly connected. That is, “connected” means direct and indirect connection of components or other features, including connection using one or a plurality of intermediate components.
As used herein, spatial relationship terms such as “upper”, “lower”, “left”, “right”, “front”, “back”, “high” and “low” can explain the relationship between one feature and another in the drawings. It should be understood that, in addition to the orientations shown in the attached drawings, the terms expressing spatial relations also comprise different orientations of a device in use or operation. For example, when a device in the attached drawings rotates reversely, the features originally described as being “below” other features now can be described as being “above” the other features”. The device may also be oriented by other means (rotated by 90 degrees or at other locations), and at this time, a relative spatial relation will be explained accordingly.
As used herein, the term “A or B” comprises “A and B” and “A or B”, not exclusively “A” or “B”, unless otherwise specified.
As used herein, the term “exemplary” means “serving as an example, instance or explanation”, not as a “model” to be accurately copied”. Any realization method described exemplarily herein may not be necessarily interpreted as being preferable or advantageous over other realization methods. Furthermore, the present disclosure is not limited by any expressed or implied theory given in the above technical field, background art, published contents or embodiments.
As used herein, the word “basically” means including any minor changes caused by design or manufacturing defects, device or component tolerances, environmental influences, and/or other factors. The word “basically” also allows for the divergence from the perfect or ideal situation due to parasitic effects, noise, and other practical considerations that may be present in the actual realization.
In addition, for reference purposes only, “first”, “second” and similar terms may also be used herein, and thus are not intended to be limitative. For example, unless the context clearly indicates, the words “first”, “second” and other such numerical words involving structures or elements do not imply a sequence or order.
It should also be understood that when the term “comprise/include” is used herein, it indicates the presence of the specified feature, entirety, step, operation, unit and/or component, but does not exclude the presence or addition of one or a plurality of other features, steps, operations, units and/or components and/or combinations thereof.
The base station antenna is an elongated structure that extends along a longitudinal axis. The base station antenna may include a front radome, a rear radome, a top end cap and a bottom end cap which includes a plurality of connectors mounted therein. The base station antenna is typically mounted in a basic vertical configuration (i.e., the longitudinal axis L (see
Refer to
The passive antenna 110 may include a front radome 111, a rear radome 112 and one or more arrays (not shown in
The active antenna 120 may include its own front radome 121, rear radome and one or more arrays 123 of radiating elements located between the front radome and the rear radome. These arrays are mounted to extend forwardly from a reflector 122 of the active antenna 120 and these arrays may include arrays that operate under fifth generation or next generation (5G or 6G) 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)..
Dielectric materials that form the radome (such as front radome and/or rear radome) of the passive antenna 110 typically have frequency selectivity to electromagnetic waves. Typically, the higher the frequency of the electromagnetic waves, the greater the effect that the dielectric materials may have on the electromagnetic waves. In particular, as the reflectivity of the dielectric materials tends to increase with increasing frequency of the electromagnetic waves, and hence the transmittance of the electromagnetic waves through the dielectric materials decreases. Decreased transmittance reduces the signal strength of the electromagnetic waves, thereby causing the gain of the base station antenna to decrease. The higher the reflectivity, the more the electromagnetic waves are reflected by the radome and these reflected waves superimpose with electromagnetic waves radiated by the radiating elements, which cause jitters and ripples in the radiation pattern.
In order to compensate the adverse effects of the radome of the passive antenna 110, such as the front radome 111, on the electromagnetic waves emitted by the active antenna 120, a matching dielectric layer 113 may be provided in the passive antenna 110, where the matching dielectric layer 113 may be arranged between the array of radiating elements 123 of the active antenna 120 and the front radome 111 of the passive antenna 110. The matching dielectric layer 113 may have a certain thickness and dielectric constant, and the dielectric constant of the matching dielectric layer 113 is larger than the dielectric constant of air. Design personnel may adjust the reflection of the electromagnetic waves from the active antenna 120 by designing the thickness and dielectric constant of the matching dielectric layer 113 such that these reflected waves superimpose out of phase and even anti-phase to reduce the reflectivity of the entire radome (the front and back radomes of the passive antenna, thereby allowing the reflectivity and transmittance of the entire radome to meet the design goals. Specific design parameters of the matching dielectric layer 113 are not limited herein. It should be understood that in some embodiments, the matching dielectric layer 113 may also not be provided.
The present disclosure also recognizes that the cross-polarization performance of the active antenna 120 may be negatively influenced by the array layout of the active antenna 120 with respect to the passive antenna 110 positioned in front of the active antenna 120. In order to reduce this negative influence, the present disclosure provides an array of metal tuning elements 200 for the active antenna 120 that may maintain good cross-polarization performance for the active antenna 120 over a wide scanning angle range.
In the traditional design for an integrated base station antenna, the passive antenna typically includes a concave rear radome 112 so that the active antenna 120 may extend forwardly into the space defined by the concave rear radome of the the passive antenna 110. in contrast, certain embodiments of the integrated antennas disclosed herein may have rear radomes 112 that are substantially flat or that even protrude backwardly. In this way, the available space within the passive antenna 110 can be increased.
Advantageously, in order to further reduce the adverse reflection of electromagnetic waves emitted by the active antenna 120 by the passive antenna 110, designers may adjust the reflection of electromagnetic waves from the active antenna 120 by designing the distance between the front radome 121 of the active antenna 120, the rear radome 112 of the passive antenna 110, the optional matching dielectric layer 113 and the front radome 111 of the passive antenna 110, so that these reflected waves are superposed out of phase or even have opposite phases to reduce the reflectivity of the whole passive antenna 110, enabling the reflectivity and transmittance of the passive antenna 110 on the electromagnetic waves emitted by the active antenna 120 to meet the design goals.
Specifically, this disclosure provides as follows: for the portion of the passive antenna that overlaps the active antenna 120 when viewed from the forward direction, the distance between the rear radome of the passive antenna 110 and the matching dielectric layer 113 is up to a first distance D1, and the distance between the active antenna 120, such as the front radome thereof, and the rear radome of the passive antenna 110 is up to a second distance D2. The first distance may be selected as 0.25 + n / 2 times that of the equivalent wavelength, where n is a positive integer (such as 1, 2, 3, 4, ...) and the second distance may be selected as 0.25 + N / 2 times of the equivalent wavelength, where N is a natural number (such as 0, 1, 2, ... ). The equivalent wavelength refers to a wavelength corresponding to the center frequency of the operating frequency band of the radiating elements in the active antenna 120, such as the theoretical wavelength in an air medium or in vacuum. In other words, the selection of the first distance D1 and the second distance D2 in the passive antenna 110 is related to the operating frequency band of the radiating elements in the active antenna 120. By selecting an appropriate distance, the reflection of the electromagnetic waves from the active antenna 120 by the passive antenna 110 may be effectively reduced.
Advantageously, the distance between the matching dielectric layer 113 and the front radome of the passive antenna 110 may be up to a third distance D3, which may be selected as 0.25 + M / 2 times the equivalent wavelength, where M is a natural number (such as 0, 1, 2, ...).
In some embodiments, the equivalent wavelength may be within the range of 0.8 to 1.2 times the wavelength corresponding to the center frequency. In some embodiments, the equivalent wavelength may be within the range of 0.9 to 1.1 times the wavelength corresponding to the center frequency. In some embodiments, the equivalent wavelength may be equivalent to the wavelength corresponding to the center frequency.
As an example, where the operating frequency band of the radiating elements in the active antenna 120 is 2.2 - 4.2 GHz, the center frequency may be selected as 3.2 GHz. The wavelength corresponding to the center frequency may be approximately 90 mm. When the equivalent wavelength is equivalent to the wavelength corresponding to the center frequency, the first distance D1 may be 67.5 mm (n = 1), 112.5 mm (n = 2), 157.5 mm (n = 3)... 67.5 + (n-1) * 45 mm, and the specific size may be determined based on actual needs. At the same time, the second distance D2 may be selected as 22.5 + N * 45 mm, and the third distance D3 may be selected as 22.5 + M * 45 mm. Typically, in order to reduce the size of the base station antenna, N and M may be selected as 0.
It should be understood that as the front radomes 111 and 121, rear radome 112 and matching dielectric layer 113 may not be flat throughout, only the distance within a partial area may be considered (such as the range corresponding to the active antenna 120), for example, the average distance.
It should be understood that the aforementioned matching dielectric layer 113 does not necessarily have to be provided. In some embodiments, the integrated base station antenna 100 does not include the matching dielectric layer 113 and in this case, the layout parameters may be set as follows: for the portion of the passive antenna that overlaps the active antenna 120 when viewed from the forward direction, the distance between the rear radome 111 of the passive antenna 110 and the front radome 112 of the passive antenna 110 is up to the first distance, and the distance between the active antenna 120, such as the front radome 121 thereof, and the rear radome 112 of the passive antenna 110 is up to the second distance, in which, the first distance is selected as 0.25 + n / 2 times of the equivalent wavelength, where n is a positive integer and the second distance is selected as 0.25 + N / 2 times of the equivalent wavelength, where N is a natural number.
Next, referring to
As shown in
In some embodiments, the array of metal tuning elements 200 may be configured to: improve the peak cross-polarization discrimination rate of the antenna beams generated by the active antenna 120 at a horizontal scanning angle larger than a first angle and/or to improve the peak cross-polarization discrimination rate of the antenna beams generated by the active antenna 120 at a horizontal scanning angle smaller than a second angle.
In some embodiments, the array of metal tuning elements 200 may be configured to: improve the peak cross-polarization discrimination rate by at least 2 dB at a horizontal scanning angle greater than the first angle (e.g., 41°~53°), and/or to improve the peak cross-polarization discrimination rate by at least 2 dB at a horizontal scanning angle smaller than the second angle ( e.g., 0°-12°).
Each metal tuning element can be constructed as an elongated metal element. The longitudinal axis M of each metal tuning element may extend at an angle of 70° -110°, 80° ~ 100° or basically 90° with respect to a plane defined by the reflecting plate 122 of the active antenna 120. In the present disclosure, the extension size of the tuning element on its longitudinal axis M is different from its lateral extension size, Different extension ratios may be set according to the actual needs of the active antenna 120. Through simulation and experimental verification, it is found that stronger resonance compensation is required in the longitudinal direction in the current embodiment. That is to say, the extension size of the tuning element on its longitudinal axis M may be larger than its lateral extension size, for example, 2 times, 3 times or even 5 times larger than its lateral extension size. Based on the (e.g., smaller) lateral extension size of the tuning element, the tuning element can provide a (e.g., smaller) projection component along the longitudinal direction V (see
In the embodiment shown in
In order not to hinder the high-frequency electromagnetic waves emitted by the active antenna 120, the reflector in the passive antenna 110 may include a large opening. The active antenna 120 may be installed at a position corresponding to the opening so that the high-frequency electromagnetic waves emitted by the active antenna 120 pass through the opening. Radiating elements of the passive antenna 110 may be mounted on the first reflective strip 218 and second reflective strip 220. For example, as shown in
The support frame 210 according to the present disclosure may further include a support structure 222 at the rear end of the support beam 212, which extends from the first support leg 214 to the second support leg 216 along the horizontal direction H. The support structure 222 may be configured to mount a printed circuit board (PCB) component 300 that includes a plurality of printed tuning elements. In some embodiments, the PCB component 300 may be constructed as an elongated PCB component 300 on which a column of tuning elements in the array of metal tuning elements 200 may be printed. As shown in
In some embodiments, the extension size on the longitudinal axis M of the tuning element is in the range of 0.1 ~ 0.5, 0.15 ~ 0.4 or about 0.25 wavelength length, which is the wavelength corresponding to the center frequency wavelength of the operating band of the radiating element 123 in the active antenna 120.
With continued reference to
In some embodiments, in order to fix the corresponding PCB component 300, the support structure 222 may include a first support sheet 224 and a second support sheet 226 which are in front-rear superimposition and spaced apart by a distance, and the PCB component 300 is installed between the first support sheet 224 and the second support sheet 226. The PCB component 300 may be installed between the first support sheet 224 and the second support sheet 226 by any feasible fixing means such as screw connection, clamping, embedding or bonding.
It should be understood that the specific configurations of the support structures 222 for fixing the corresponding PCB components 300 can be varied, as long as the corresponding tuning elements can be fixed, which should not be understood in a limited way here.
Different from the embodiments described above, a plurality of metal tuning element arrays 200 used for the active antenna 120 are installed in the passive antenna 110, which are in front-rear superimposition and spaced apart by a distance, so as to adjust at least the projection component of the tuning element at large horizontal scanning angles, thereby further improving the cross-polarization performance of the active antenna 120.
As shown in
In other embodiments, in order to form the plurality of metal tuning element arrays 200, a plurality of columns of metal tuning elements superimposed in an upper-lower way and spaced apart by a distance can be printed on each PCB component 300. Thus, the plurality of metal tuning element arrays 200 are formed by a plurality of PCB components 300 arranged side by side with each other in the horizontal direction.
Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration rather than for limiting the scope of the present disclosure. The embodiments disclosed herein can be combined arbitrarily without departing from the spirit and scope of the present disclosure. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021115864571 | Dec 2021 | CN | national |
