The present application claims priority to Chinese Patent Application Serial No. 201811263937.2, filed Oct. 29, 2018, the entire content of which is incorporated herein by reference.
The present invention relates to blocking devices for low frequency and direct current (“DC”) signals for antennas, and to antennas having such low frequency and DC signal blocking devices.
In antenna systems such as antenna systems for cellular communications systems, various signals such as RF signals, low frequency control signals and/or DC signals may be transmitted on the same transmission line. The RF signals typically are the signals transmitted and received by the antenna system. The low frequency signals typically are control signals, such as, for example, control signals for a remote electronic downtilt (RET) device. The DC signals may be power signals that are used to power components within the antenna.
In order to separate the RF signals from the low frequency signals and/or the DC signals, it may be necessary to provide a low frequency signal blocking device on a transmission line path to block the low frequency signals. Such a low frequency signal blocking device will also block DC signals. The current practice is to add a coupling layer to a transmission line that is implemented on a printed circuit board (PCB) to achieve a capacitive-coupling and accordingly low frequency and DC signal suppression. However, these methods may be complicated, and also may have high costs.
The present invention provides a low frequency and DC signal blocking device, characterized in that the low frequency and DC signal blocking device comprises: a dielectric substrate layer; a low frequency and DC signal blocking transmission line on a first surface of the substrate layer, wherein the low frequency and DC signal blocking transmission line has an input end and an output end; a metal layer on a second surface of the substrate layer, wherein there is at least one gap on the metal layer such that the metal layer is separated into at least a first sub-region and a second sub-region, wherein the gap is configured to block at least one of a low frequency signal and a DC signal; the substrate layer disposed between the low frequency and DC signal blocking transmission line and the metal layer; and a metal plate, wherein a dielectric layer is disposed between the metal plate and the metal layer.
According to the present invention, the DC signal blocking device requires less wiring space, has a simple structure, is easy to operate, and has reduced cost.
In some embodiments, the dielectric layer includes a solder mask layer and/or air.
In some embodiments, the input end is configured to be connected to a first cable upstream of the low frequency and DC signal blocking device, and the output end is configured to be connected to a second cable downstream of the low frequency and DC signal blocking device.
In some embodiments, the first and second cables are coaxial cables.
In some embodiments, the input end is connected to an inner conductor of the first cable, and the output end is connected to an inner conductor of the second cable.
In some embodiments, the first sub-region is connected to an outer conductor of the first cable, and the second sub-region is connected to an outer conductor of the second cable.
In some embodiments, the metal plate is a reflector of an antenna.
In some embodiments, the metal plate is connected to the metal layer only via the solder mask layer.
In some embodiments, the metal layer has two or more gaps such that the metal layer is divided into a first sub-region, a second sub-region, and one or more additional regions, the first sub-region being spaced apart from the second sub-region by the one or more additional regions.
In some embodiments, the low frequency and DC signal blocking transmission line is configured in a straight line shape or an L shape.
In some embodiments, the low frequency and DC signal blocking transmission line is configured in a T-shape, wherein the low frequency and DC signal blocking transmission line has one input end and two output ends.
In some embodiments, the low frequency and DC signal blocking transmission line is configured in a cross shape, wherein the low frequency and DC signal blocking transmission line has one input end and three output ends.
In some embodiments, the metal layer is a copper layer.
In some embodiments, the second sub-region is configured as a polygonal region or a region with a circular arc.
In some embodiments, the second sub-region is configured as a rectangular region, a triangular region, a hexagonal region or an octagonal region.
In some embodiments, the gap is filled with air.
In some embodiments, the gap is completely or partially filled with solid dielectric materials. For example, ceramic, glass, mica sheets, bakelite or the like may be completely or partially filled in the gap to change the dielectric constant of the gap.
In some embodiments, the substrate layer is configured as a paper substrate, a glass fiber substrate, or a composite substrate. Of course, other types of substrates such as a paper substrate (FR-1, FR-2), a composite substrate (CEM series), or a substrate of special materials (ceramic, metal base, etc.) may also be used for the substrate layer of the PCB.
In some embodiments, the area of the second sub-region, the thickness of the metal layer and/or the width of the gap are adapted to a frequency range of the radio frequency signals.
In some embodiments, the thickness of the metal layer is between 0.02 mm and 0.3 mm.
In some embodiments, the width of the gap is between 0.01 mm and 1 mm.
The present invention also provides a DC-blocking antenna having at least one low frequency and DC signal blocking device according to the present invention.
Embodiments of the present invention will be described below with reference to the drawings, in which several embodiments of the present invention are shown. It should be understood, however, that the present invention may be implemented in many different ways, and is not limited to the example embodiments described below. In fact, the embodiments described hereinafter are intended to make a more complete disclosure of the present invention and to adequately explain the protection scope of the present invention to a person skilled in the art. It should also be understood that, the embodiments disclosed herein can be combined in various ways to provide many additional embodiments.
It should be understood that, the wording in the specification is only used for describing particular embodiments and is not intended to limit the present invention. All the terms used in the specification (including technical and scientific terms) have the meanings as normally understood by a person skilled in the art, unless otherwise defined. For the sake of conciseness and/or clarity, well-known functions or constructions may not be described in detail.
The singular forms “a/an” and “the” as used in the specification, unless clearly indicated, all contain the plural forms. The words “comprising”, “containing” and “including” used in the specification indicate the presence of the claimed features, but do not preclude the presence of one or more additional features. The wording “and/or” as used in the specification includes any and all combinations of one or more of the listed items.
In the specification, words describing spatial relationships such as “up”, “down”, “left”, “right”, “forth”, “back”, “high”, “low” and the like may describe a relation of one feature to another feature in the drawings. It should be understood that these terms also encompass different orientations of the apparatus in use or operation, in addition to encompassing the orientations shown in the drawings. For example, when the apparatus in the drawings is turned over, the features previously described as being “below” other features may be described to be “above” other features at this time. The apparatus may also be otherwise oriented (rotated 90 degrees or at other orientations) and the relative spatial relationships will be correspondingly altered.
It should be understood that, in all the drawings, the same reference signs present the same elements. In the drawings, for the sake of clarity, the sizes of certain features may be modified.
In antenna systems, various signals such as RF signals, low frequency control signals and/or DC power signals may be transmitted on the same transmission line. The RF signals may be signals that are transmitted or received by the antenna system, and can include signals in multiple different RF frequency bands. The low frequency signals typically are control signals such as signals that control a RET device. The frequency range of the low frequency signals (such as Antenna Interface Signal Group signals) may be between 1 MHz to 5 MHz. In other embodiments, the frequency range of the low frequency signals may be smaller than 1 MHz or larger than 5 MHz. The DC signals are typically DC power signals that power electronic and/or electromechanical elements within the antenna. Since the RF signals and the low frequency and/or DC signals have different functions, it is necessary to process them separately.
Referring now to
Referring now to
Placing the low frequency and DC signal blocking device in
Referring now to
As can be seen from
Further, it can be seen that the copper layer 300 has a gap 600 therein, which divides the copper layer 300 into a first sub-region 700 and a second sub-region 800 that is surrounded by the first sub-region. The second sub-region 800 is located at the edge of the copper layer 300 and is configured to be rectangular. The second sub-region 800 and the first sub-region 700 are spaced apart from one another by the gap 600, thereby forming a capacitor. Further, the first sub-region 700 and the second sub-region 800 may be spaced apart from the metal plate 500 by the solder mask layer 400. The first sub-region 700 and the second sub-region 800 may be separated from the metal plate 500 via only the solder mask layer 400, thereby forming capacitors with the metal plate 500. Thus, the coupling between the copper layer 300 and the metal plate 500 may be improved in a simple manner. In other embodiments, it is also possible that the first sub-region 700 and the second sub-region 800 are spaced apart from the metal plate 500 by the solder mask layer 400 and/or air. This multi-coupling design is advantageous in that it can maintain good RF-passing performance and low frequency and DC signal blocking function in a limited space.
In the present embodiment, the first sub-region 700 and the second sub-region 800 form the two electrodes of a capacitor, and the gap 600 acts as the dielectric of the capacitor. The three edges of the metal layer that forms the second sub-region 800 that are adjacent the gap 600 are equivalent to the effective overlap area of the capacitor, and the width of the gap 600 is equivalent to the distance between the two electrodes of the capacitor. In order to adjust the capacitance of the capacitor, a thickness of the copper layer 300 may be increased or decreased, and alternatively, an area of the second sub-region 800 may be increased/decreased to thereby increase/decrease the effective overlap area. In addition, a solid dielectric material may also be filled or partially filled in the gap 600.
Similarly, the first sub-region 700 and the metal plate 500, as well as the second sub-region 800 and the metal plate 500 form the electrodes of respective second capacitors. Thus, in order to adjust the size of the second capacitors, an area of the first sub-region 700 and the second sub-region 800 may be increased/decreased so as to increase/decrease the effective overlap area. In addition, solid dielectric materials may also be filled or partially filled between the first sub-region 700 and the metal plate 500 and/or between the second sub-region 800 and the metal plate 500.
In this embodiment, the thickness of the copper layer 300 may be between 0.02 mm and 0.3 mm. Of course, it may also be less than 0.02 mm or more than 0.3 mm in other embodiments, and the thickness of the copper layer 302 may be selected according to the characteristics of the RF signals and processing technology. Also, in this embodiment, the width of the gap 600 is between 0.02 mm and 0.1 mm. Of course, it may also be less than 0.02 mm or more than 0.1 mm in other embodiments, and the width of the gap 600 may be selected according to the characteristics of the RF signals and processing technology.
In order to achieve the function of blocking low frequency and DC signals, the first cable 6 upstream of the low frequency and DC signal blocking device 3 may be connected to the input end 1001 of the low frequency and DC signal blocking transmission line 100. The output end 1002 of the low frequency and DC signal blocking transmission line 100 may be connected to the second cable 7 downstream of the low frequency signal blocking device 3. Specifically, the inner conductor of the first cable 6 may be connected to the input end 1001, and the outer conductor of the first cable 6 may be connected to the first sub-region 700. The output end 1002 may be connected to the inner conductor of the second cable 7, and the outer conductor of the second cable 7 may be connected to the second sub-region 800, thereby breaking a transmission path of the low frequency and DC signals.
Thus, in the low frequency and DC signal blocking device according to embodiments of the present invention, the RF signals can pass from the first sub-region 700 through the gap 600 to the second sub-region 800 on the copper layer 300. At the same time, the RF signals can also pass from the first sub-region 700 to the metal plate 600 via the solder mask layer and/or air, and then from the metal plate 600 to the second sub-region 800 via the solder mask layer and/or air. Thus, the RF signals can reach the output end 1002 from the input end 1001 on the low frequency and DC signal blocking transmission line 100.
In contrast, the low frequency and DC signals are unable to pass through the gap 600 in the copper layer 300. As a result, the low frequency and DC signals are unable to be transmitted from the input end 1001 to the output end 1002 of the low frequency and DC signal blocking transmission line 100.
The low frequency and DC signal blocking devices according to embodiments of the present invention may have a number of advantages. First, the low frequency and DC signal blocking device may require less wiring space. Second, the low frequency and DC signal blocking device has a wider bandwidth, since its characteristics is not designed for a specific frequency point. In addition, the low frequency and DC signal blocking device has simple structure, is easy to operate, and has controllable costs. Furthermore, the low frequency and DC signal blocking device according to embodiments of the present invention adopts a multi-coupling design, thereby maintaining good RF-passing performance and low frequency and DC signal-blocking function in a limited space.
In other embodiments, the second sub-region may be configured as a polygonal region or a region with a circular arc. For example, the second sub-region may be configured as a triangular region, a hexagonal region or an octagonal region.
In other embodiments, more gaps may be provided to divide the copper layer into more sub-regions. For example, other sub-regions may also be provided between the second sub-region and the first sub-region.
In other embodiments, the low frequency and DC signal blocking transmission line may be configured arbitrarily, for example, it may be configured in an L shape, a T shape, or a cross shape. For example,
In other embodiments, the low frequency and DC signal blocking transmission line may have multiple input ends and multiple output ends. For example, a T-shaped low frequency and DC signal blocking transmission line may have one input end and two output ends. As such, a cross-shaped low frequency and DC signal blocking transmission line may have one input end and three output ends. Of course, a low frequency and DC signal blocking transmission line of any other form may also be envisaged.
Although the exemplary embodiments of the present invention have been described, a person skilled in the art should understand that, multiple changes and modifications may be made to the exemplary embodiments without substantively departing from the spirit and scope of the present invention. Accordingly, all the changes and modifications are encompassed within the protection scope of the present invention as defined by the claims. The present invention is defined by the appended claims, and the equivalents of these claims are also contained therein.
Number | Date | Country | Kind |
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201811263937.2 | Oct 2018 | CN | national |
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