Dual-band feed and base station antenna

Abstract

The present application provides a dual-band feed and a base station antenna. The dual-band feed includes: a feed horn, a circular waveguide, a waveguide transition piece, and a four-ridged feed network, wherein the feed horn is used to receive or radiate signals; one end of the circular waveguide is connected to one end of the feed horn, and the other end of the circular waveguide is connected to the first end of the waveguide transition piece, and the circular waveguide is used to transmit signals between the feed horn and the waveguide transition piece; the waveguide transition piece is configured to transition from the circular waveguide to the four-ridged waveguide along the direction from its first end to its second end, and is used to transmit signals between the circular waveguide and the four-ridged feed network; the four-ridged feed network is used to separate or synthesize signals from horizontally polarized signals and vertically polarized signals in each of two different frequency bands.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a dual-band feed source and a base station antenna. Background Art

[0002] With the rapid development of communication technology, performance requirements for microwave antenna systems are increasing, particularly in terms of data transmission rate, spectral efficiency, and system capacity. As a key component in wireless communication systems, the design of microwave antennas is directly related to the quality and reliability of the communication link. Currently, most antennas widely used in microwave communication systems operate in a single frequency band, which limits the efficient use of spectrum resources and increases system complexity.

[0003] To overcome the limitations of existing technologies, the industry is gradually moving toward dual-band and even multi-band microwave antenna systems. These antennas can operate simultaneously in two or more frequency bands on the same hardware platform, improving spectrum utilization and simplifying system design. However, existing microwave antennas that achieve dual-band operation generally suffer from complex structures, high costs, difficult processing, and high dielectric loss. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art, and proposes a dual-band feed and base station antenna, which can solve the problems of complex antenna structure, high cost, difficult processing and dielectric loss in the prior art.

[0005] To achieve the above-mentioned object, an embodiment of the present application provides a dual-band feed, comprising: a feed horn, a circular waveguide, a waveguide transition piece, and a four-ridge feed network, wherein the feed horn is used to receive or radiate signals;

[0006] One end of the circular waveguide is connected to one end of the feed horn, and the other end of the circular waveguide is connected to the first end of the waveguide transition piece, and the circular waveguide is used to transmit signals between the feed horn and the waveguide transition piece;

[0007] The waveguide transition piece is configured to transition from a circular waveguide to a quad-ridged waveguide in a direction from a first end thereof to a second end thereof for transmitting signals between the circular waveguide and the quad-ridged feed network;

[0008] The quad-ridged feed network is used to separate or combine the signal with horizontally polarized signals and vertically polarized signals in each of two different frequency bands.

[0009] In some embodiments, the waveguide transition piece includes a circular waveguide segment, a tapered quad-ridged waveguide segment, and a quad-ridged waveguide segment sequentially connected along a direction from its first end to its second end, wherein the radial cross-sectional profile size of the first end of the tapered quad-ridged waveguide segment is the same as the radial cross-sectional profile size of the circular waveguide segment; the radial cross-sectional profile size of the second end of the tapered quad-ridged waveguide segment is the same as the radial cross-sectional profile size of the quad-ridged waveguide segment; and the radial cross-sectional profile size of the tapered quad-ridged waveguide segment decreases along a direction from its first end to its second end.

[0010] In some embodiments, the waveguide transition piece includes a circular waveguide segment, at least two stepped four-ridged waveguide segments and a four-ridged waveguide segment connected in sequence along a direction from its first end to its second end, wherein one end of the stepped four-ridged waveguide segment adjacent to the circular waveguide segment has the same radial cross-sectional profile size as the circular waveguide segment, one end of the stepped four-ridged waveguide segment adjacent to the four-ridged waveguide segment has the same radial cross-sectional profile size as the four-ridged waveguide segment, and the radial cross-sectional profile sizes of the at least two stepped four-ridged waveguide segments decrease in sequence along a direction from the circular waveguide segment to the four-ridged waveguide segment.

[0011] In some embodiments, a total length of the waveguide transition piece from its first end to its second end is greater than or equal to four times the wavelength of an electromagnetic wave corresponding to the lowest frequency value in the operating frequency range in free space.

[0012] In some embodiments, the quad-ridge feed network includes a quad-ridge splitter and four ridge waveguide duplexers, wherein the quad-ridge splitter is used to separate or combine the signal and two horizontally polarized signals and two vertically polarized signals; the quad-ridge splitter has a common port, and the common port is connected to the second end of the waveguide transition piece;

[0013] Two of the ridge waveguide duplexers are used to separate or synthesize the horizontally polarized signal from the first-frequency band horizontally polarized signal and the second-frequency band horizontally polarized signal, and are synthesized with a first transmission port and a second transmission port for outputting or inputting the first-frequency band horizontally polarized signal and the second-frequency band horizontally polarized signal, respectively; the other two ridge waveguide duplexers are used to separate or synthesize the vertically polarized signal from the first-frequency band vertically polarized signal and the second-frequency band vertically polarized signal, and are synthesized with a third transmission port and a fourth transmission port for outputting or inputting the first-frequency band vertically polarized signal and the second-frequency band vertically polarized signal, respectively.

[0014] In some embodiments, the quad-ridged wave splitter has at least one frustum, and at least one frustum is disposed at the common port and coaxially with the waveguide transition piece;

[0015] When there are multiple frustums, the multiple frustums are coaxially stacked in sequence along the axial direction of the waveguide transition piece, and the diameters of the multiple frustums increase in sequence in a direction away from the waveguide transition piece.

[0016] In some embodiments, the total length of the at least one frustum along the signal propagation direction of the waveguide transition piece is greater than or equal to 0.1 to 0.2 times the wavelength of the electromagnetic wave corresponding to the lowest frequency value in the operating frequency range in free space.

[0017] In some embodiments, the first frequency band is a standard backhaul frequency band; and the second frequency band is an E-band.

[0018] In some embodiments, the inner circumferential surface of the feed horn is provided with a corrugated structure, and the corrugated structure includes a plurality of first annular grooves sequentially arranged along the axial direction of the feed horn.

[0019] As another technical solution, the present application also provides a base station antenna, comprising:

[0020] The above-mentioned dual-band feed provided by this application;

[0021] a secondary reflector, disposed on a side of the feed horn away from the circular waveguide and having a secondary reflective surface facing the circular waveguide;

[0022] A main reflector is arranged between the waveguide transition piece and the four-ridge feed network, and the waveguide transition piece passes through the main reflector and is connected to the four-ridge feed network; the main reflector has a main reflecting surface facing away from the four-ridge feed network.

[0023] In some embodiments, a central plane and multiple concentric annular surfaces surrounding the central plane are provided in the central area of ​​the secondary reflector, and the central plane and the multiple annular surfaces constitute a continuous surface; the orthographic projections of the central plane and the multiple annular surfaces on a preset cross-section constitute multiple line segments connected in series, and the preset cross-section is parallel to the central axis and radial straight line of the secondary reflector.

[0024] In some embodiments, a plurality of concentric second annular grooves are provided in the edge region of the secondary reflective surface.

[0025] In some embodiments, a plurality of concentric annular surfaces are provided in the edge area of ​​the secondary reflector, and the plurality of annular surfaces constitute a continuous surface; the orthographic projections of the plurality of annular surfaces on a preset cross section constitute a plurality of serially connected line segments, and the preset cross section is parallel to the central axis and radial straight line of the secondary reflector.

[0026] In some embodiments, a plurality of concentric second annular grooves are provided in the central area of ​​the secondary reflective surface.

[0027] Other objects and features of the present application will become clear by reading the specification, claims and drawings of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 is a structural exploded perspective view of a base station antenna provided in an embodiment of the present application;

[0030] Figure 2 This is an installation diagram of a dual-band feed and a sub-reflector provided in an embodiment of the present application;

[0031] Figure 3 is a structural diagram of a waveguide transition piece used in an embodiment of the present application;

[0032] Figure 4 is a perspective view of a four-ridge feed network and a waveguide transition piece used in an embodiment of the present application;

[0033] Figure 5 is a perspective view of a quad-ridged wave splitter used in an embodiment of the present application;

[0034] Figure 6 1 is a top view of a quad-ridged wave splitter used in an embodiment of the present application;

[0035] Figure 7 is a perspective view of a ridge waveguide duplexer used in an embodiment of the present application;

[0036] Figure 8 is a schematic diagram of a ridge waveguide duplexer used in an embodiment of the present application;

[0037] Figure 9 1 is a transmission diagram of horizontally and vertically polarized signals in two frequency bands in an embodiment of the present application;

[0038] Figure 10 is a structural diagram of the feed horn used in the embodiment of the present application;

[0039] Figure 11 is a structural diagram of the secondary reflective surface of the secondary reflector used in the embodiment of the present application;

[0040] Figure 12 1 is a graph showing the standing wave ratio of the dual-band feed used in the embodiment of the present application in the conventional return frequency band;

[0041] Figure 13 : is a standing wave ratio curve of the dual-band feed used in the embodiment of the present application in the E-BAND band;

[0042] Figure 14is the gain pattern of the base station antenna used in the embodiment of the present application in the conventional backhaul frequency band;

[0043] Figure 15 It is the gain pattern of the base station antenna used in the embodiment of the present application in the E-BAND frequency band.

[0044] Description of main component symbols:

[0045] 100, dual-band feed; 2, feed horn; 21, first annular groove; 3, fixing bracket; 4, circular waveguide; 5, waveguide transition piece; 5a, first end; 5b, second end; 51, circular waveguide segment; 52, gradient quad-ridge waveguide segment; 521, first end; 522, second end; 53, quad-ridge waveguide segment; 7, quad-ridge feed network; 71, quad-ridge splitter; 711a, common port; 711b, ridge waveguide port; 721a, common port; 7 21b, first frequency band port; 721c, second frequency band port; 72a, first ridge waveguide duplexer; 72b, second ridge waveguide duplexer; 72c, third ridge waveguide duplexer; 72d, fourth ridge waveguide duplexer; 722a, first transmission port; 722b, second transmission port; 722c, third transmission port; 722d, fourth transmission port; 723, rectangular waveguide; 724, stepped ridge transition structure; 725, metal ridge; 73, truncated cone;

[0046] 200, antenna; 1, secondary reflector; 11, annular surface; 111, line segment; 12, center plane; 13, second annular groove; 6, primary reflector; 61, primary reflective surface; 62, metal frame;

[0047] X1, first direction; X2, second direction. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0049] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0051] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0052] Throughout this specification, reference to terms such as "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0053] Please also refer to Figure 1 and Figure 2 , the embodiment of the present application provides a dual-band feed 100, which is used, for example, in Figure 1 The point-to-point microwave communication antenna shown is an antenna used in a point-to-point (PtP) microwave communication system. This antenna is designed to establish a direct wireless communication link between two fixed locations. However, the dual-band feed 100 provided in the embodiment of the present application can also be applied to 5G, 6G communications, satellite communications, and other communication scenarios with high data rates and broadband spectrum requirements. The dual-band feed 100 provided in the embodiment of the present application can be shared simultaneously, allowing one antenna to operate simultaneously in two different frequency bands (such as the conventional backhaul band and the E-BAND band), rather than using two independent antennas. This can significantly improve the utilization efficiency of spectrum resources while reducing the number of antennas and system complexity. On this basis, the dual-band feed 100 provided in the embodiment of the present application does not involve a medium, which not only avoids dielectric loss and achieves optimal transmission efficiency; moreover, compared with the coaxial nested waveguide structure adopted in the prior art (the high-frequency transmission waveguide is nested inside the low-frequency transmission waveguide), when the dual bands are shared, the dual-band feed 100 provided in the embodiment of the present application has a simpler structure, thereby reducing processing difficulty and cost while maintaining high performance.

[0054] Specifically, the dual-band feed 100 provided in the embodiment of the present application includes: a feed horn 2, a circular waveguide 4, a waveguide transition piece 5 and a four-ridge feed network 7, wherein the feed horn 2 is used to receive or radiate signals. Specifically, the feed horn 2 is used to receive electromagnetic wave signals in free space in a receiving mode; in a radiating mode, the signal from the circular waveguide 4 is radiated into free space. One end of the circular waveguide 4 is connected to one end of the feed horn 2, and the other end of the circular waveguide 4 is connected to the first end 5a of the waveguide transition piece 5 (such as Figure 3Circular waveguide 4 is connected to the feed horn 2 (as shown), and is used to transmit signals between the feed horn 2 and the waveguide transition piece 5. Specifically, the circular waveguide 4 has a circular radial cross-section and is used to transmit signals from the feed horn 2 to the waveguide transition piece 5 in the receiving mode, and to transmit signals from the waveguide transition piece 5 to the feed horn 2 in the radiating mode. The circular waveguide 4 is typically used to transmit specific electromagnetic wave modes, such as the TE11 mode.

[0055] See also Figure 3 The waveguide transition piece 5 is arranged in a direction from its first end 5a to its second end 5b (ie Figure 3 The waveguide transition piece 5 transitions from a circular waveguide to a quad-ridged waveguide (in the vertical direction) for signal transmission between the circular waveguide 4 and the quad-ridged feed network 7. The radial cross-section of the first end 5a of the waveguide transition piece 5 is circular, while the radial cross-section of the second end 5b is quad-ridged, i.e., a central shape (e.g., circular, quadrilateral, etc.) surrounded by four ridges (or fins). The radial cross-section of the waveguide transition piece 5 is configured to transition from a circular shape to this quad-ridged shape to facilitate smooth conversion of electromagnetic wave modes, reducing reflections and high-order mode excitation. The waveguide transition piece 5 is used to achieve effective conversion between different waveguide modes, thereby helping to optimize impedance matching, reduce signal reflections and high-order mode excitation, and thereby improve signal transmission efficiency and antenna performance. On this basis, the waveguide transition piece 5 does not involve any medium, for example, it is an all-metal structure, which not only avoids dielectric loss and achieves optimal transmission efficiency; moreover, compared with the coaxial nested waveguide structure adopted in the prior art (the high-frequency transmission waveguide is nested inside the low-frequency transmission waveguide), the structure of the waveguide transition piece 5 is simpler, thereby reducing the processing difficulty and cost while maintaining high performance.

[0056] In some embodiments, the length of the waveguide transition piece 5 should ensure good impedance matching and mode control within the desired frequency range. To achieve this, the total length of the waveguide transition piece 5 along the direction from its first end 5a to its second end 5b is preferably greater than or equal to four times the wavelength of the electromagnetic wave in free space corresponding to the lowest frequency value within the operating frequency range. By meeting this total length range, good impedance matching can be achieved within the conventional return frequency band and the E-BAND frequency band, avoiding high-order mode excitation and ensuring stable signal transmission. Of course, in actual applications, the above total length of the waveguide transition piece 5 can be obtained based on specific electromagnetic simulation and optimization processes.

[0057] The quad-ridged feed network 7 is used to separate or synthesize signals from horizontally polarized signals and vertically polarized signals in each of two different frequency bands. With the help of the quad-ridged feed network 7, dual-band (such as the conventional backhaul band and the E-BAND band) and dual-polarization (such as horizontal and vertical polarization) operations can be achieved, thereby improving spectrum efficiency and system capacity. On this basis, by combining the waveguide transition piece 5 and the quad-ridged feed network 7, the operating bandwidth of each device in the feed network can be expanded (for example, the ratio of high frequency to low frequency is approximately 2:1). Compared to the coaxial nested waveguide structure used in the prior art, which is difficult to achieve a large ratio of high frequency to low frequency (for example, 10:1), the embodiments of the present application allow each device in the feed network to operate within a wider frequency range, thereby supporting multiple modes of electromagnetic wave propagation and thus covering a wider frequency range. Moreover, both the waveguide transition piece 5 and the quad-ridged feed network 7 can be all-metal structures, which can overcome the defects of the prior art such as dielectric loss, difficulty in processing, and high cost caused by the need to use dielectrics.

[0058] The radial cross-sectional shape of the waveguide transition piece 5 is configured to transition from a circular shape to the four-ridge shape, which can be implemented in a variety of ways. In one example, Figure 3 As shown, the waveguide transition piece 5 includes a circular waveguide segment 51, a tapered quad-ridge waveguide segment 52, and a quad-ridge waveguide segment 53, which are sequentially connected along a direction from its first end 5a to its second end 5b. The radial cross-sectional profiles of the circular waveguide segment 51 at different axial positions are all circular, and the dimensions can be uniform throughout, or can decrease gradually away from the circular waveguide 4. In practical applications, this can be set according to specific needs to achieve a good impedance matching effect. The radial cross-sectional profiles of the quad-ridge waveguide segment 53 at different axial positions are all quad-ridged, and the dimensions can be uniform throughout, or can decrease gradually away from the circular waveguide 4. In practical applications, this can be set according to specific needs to achieve a good impedance matching effect. The radial cross-sectional profile dimensions of the first end 521 of the tapered quad-ridged waveguide segment 52 are identical to those of the circular waveguide segment 51 (this dimension is a fixed value or a minimum value); the radial cross-sectional profile dimensions of the second end 522 of the tapered quad-ridged waveguide segment 52 are identical to those of the quad-ridged waveguide segment 53 (this dimension is a fixed value or a maximum value); and the radial cross-sectional profile dimensions of the tapered quad-ridged waveguide segment 52 decrease gradually from its first end 521 to its second end 522. By using a gradual transition from a circular waveguide to a quad-ridged waveguide, the structure is simplified and fabricated more easily, reducing costs while maintaining high performance.

[0059] In another example, the waveguide transition piece 5 includes a circular waveguide segment 51, at least two stepped quad-ridged waveguide segments 53, and a quad-ridged waveguide segment 53, which are sequentially connected along the direction from the first end 5a to the second end 5b. The shapes and structures of the circular waveguide segment 51 and the quad-ridged waveguide segment 53 are the same as those in the above example and are not described in detail here. One end of the stepped quad-ridged waveguide segment 53 adjacent to the circular waveguide segment 51 has the same radial cross-sectional profile dimensions as the circular waveguide segment 51, and one end of the stepped quad-ridged waveguide segment 53 adjacent to the quad-ridged waveguide segment 53 has the same radial cross-sectional profile dimensions as the quad-ridged waveguide segment 53. The radial cross-sectional profile dimensions of at least two stepped quad-ridged waveguide segments 53 decrease sequentially along the direction from the circular waveguide segment 51 to the quad-ridged waveguide segment 53. This stepwise change in radial cross-sectional profile dimensions can also achieve a transition from a circular waveguide to a quad-ridged waveguide.

[0060] See also Figure 4 and Figure 9 The quad-ridge feed network 7 for achieving the above effect includes, for example, a quad-ridge splitter 71 and four ridge waveguide duplexers, namely a first ridge waveguide duplexer 72a, a second ridge waveguide duplexer 72b, a third ridge waveguide duplexer 72c, and a fourth ridge waveguide duplexer 72d. The quad-ridge splitter 71 is used to separate or combine a signal with two horizontally polarized signals and two vertically polarized signals. For details, please refer to Figure 5 The quad-ridge splitter 71 has a common port 711a and four ridge waveguide ports 711b, wherein, in one example, the combination Figure 3 and Figure 5 As shown, the waveguide transition piece 5 is connected to the quad-ridged wave splitter 71 through the quad-ridged waveguide section 53. That is, the quad-ridged waveguide section 53 is the common part for the waveguide transition piece 5 and the quad-ridged wave splitter 71 to achieve the connection. In this case, the quad-ridged waveguide section 53 is connected to the quad-ridged wave splitter 71. Figure 5 The upper end of the waveguide segment 53 serves as a common port 711a, which is connected to the second end 522 of the tapered quad-ridged waveguide segment 52 of the waveguide transition piece 5, so that signals can be transmitted between the waveguide transition piece 5 and the quad-ridged wave splitter 71. However, the embodiment of the present application is not limited thereto. In another example, the quad-ridged waveguide segment 53 may also adopt a split structure, that is, the quad-ridged waveguide segment 53 is composed of two sub-quad-ridged waveguide segments connected in sequence, and one of the sub-quad-ridged waveguide segments belongs to the waveguide transition piece 5, and the other sub-quad-ridged waveguide segment belongs to the quad-ridged wave splitter 71.

[0061] like Figure 6As shown, the four ridge waveguide ports 711b of the quad-ridge splitter 71 face four different directions. Two of the ridge waveguide ports 711b face two opposite directions along a first direction X1, and the other two ridge waveguide ports 711b face two opposite directions along a second direction X2. The first direction X1 and the second direction X2 are perpendicular to each other. The quad-ridge splitter 71 is used to separate the signal from the waveguide transition piece 5 into two horizontally polarized signals and two vertically polarized signals, and to combine the received horizontally polarized and vertically polarized signals for transmission to the waveguide transition piece 5. The two horizontally polarized signals can be input or output by the two ridge waveguide ports 711b facing the first direction X1, and the two vertically polarized signals can be input or output by the two ridge waveguide ports 711b facing the second direction X2.

[0062] See also Figure 7 Taking the first ridge waveguide duplexer 72a as an example, each of the first ridge waveguide duplexer 72a, the second ridge waveguide duplexer 72b, the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d has a common port 721a, a first frequency band port 721b and a second frequency band port 721c, wherein, in combination with Figure 4 The common port 721a of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b is respectively connected to the two ridge waveguide ports 711b of the quad-ridge wave splitter 71 along the first direction X1. The first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b are used to separate or synthesize horizontally polarized signals from horizontally polarized signals of the first frequency band and horizontally polarized signals of the second frequency band, and are synthesized to have a first transmission port 722a and a second transmission port 722b for outputting or inputting the horizontally polarized signals of the first frequency band and the horizontally polarized signals of the second frequency band, respectively. Figure 4As shown, the first frequency band port 721b and the second frequency band port 721c of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b are respectively combined into a first transmission port 722a and a second transmission port 722b through two rectangular waveguides 723. Specifically, the ridge waveguide ports 711b facing two opposite directions along the first direction X1 respectively transmit two horizontally polarized signals to the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b through the common port 721a of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b. The two horizontally polarized signals are respectively separated into a first frequency band horizontally polarized signal and a second frequency band horizontally polarized signal by the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b, and are respectively transmitted by the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b. The waveguide duplexer 72b outputs the first frequency band port 721b and the second frequency band port 721c. Subsequently, the first frequency band horizontally polarized signal output from the first frequency band port 721b of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b is combined through a rectangular waveguide 723 and outputted through a first transmission port 722a. The second frequency band horizontally polarized signal output from the second frequency band port 721c of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b is combined through another rectangular waveguide 723 and outputted through a second transmission port 722b. It is easy to understand that the function of each rectangular waveguide 723 is to combine the two signals output from the first frequency band port 721b or the second frequency band port 721c of the first ridge waveguide duplexer 72a and the second ridge waveguide duplexer 72b, and then output them from the first transmission port 722a or the second transmission port 722b. The first transmission port 722a and the second transmission port 722b are formed in the rectangular waveguide 723.

[0063] Similarly, the common port 721a of the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d is respectively connected to the two ridge waveguide ports 711b of the quad-ridge wave splitter 71 along the second direction X2. The third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d are used to separate or synthesize the vertical polarization signal from the first frequency band vertical polarization signal and the second frequency band vertical polarization signal, and are synthesized with a third transmission port 722c and a fourth transmission port 722d for outputting or inputting the first frequency band vertical polarization signal and the second frequency band vertical polarization signal, respectively. Figure 4As shown, the first frequency band port 721b and the second frequency band port 721c of the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d are respectively combined into a third transmission port 722c and a fourth transmission port 722d through two rectangular waveguides 723. Specifically, the ridge waveguide ports 711b facing two opposite directions along the second direction X2 respectively transmit two vertically polarized signals to the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d via the common port 721a of the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d. The two vertically polarized signals are respectively separated into a first frequency band vertically polarized signal and a second frequency band vertically polarized signal by the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d, and are respectively transmitted by the third ridge waveguide duplexer 72c and the fourth ridge waveguide duplexer 72d. The first frequency band port 721b and the second frequency band port 721c of the waveguide duplexer 72d are output. Subsequently, the first frequency band vertically polarized signal output from the first frequency band port 721b of the third and fourth ridged waveguide duplexers 72c, 72d is output through a third transmission port 722c, which is synthesized by a rectangular waveguide 723. The second frequency band vertically polarized signal output from the second frequency band port 721c of the third and fourth ridged waveguide duplexers 72c, 72d is output through a fourth transmission port 722d, which is synthesized by another rectangular waveguide 723. It is easy to understand that the function of each rectangular waveguide 723 is to synthesize the two signals output from the first frequency band port 721b or the second frequency band port 721c of the third and fourth ridged waveguide duplexers 72c, 72d, and then output them from the corresponding third transmission port 722c or fourth transmission port 722d. The third transmission port 722c and the fourth transmission port 722d are formed in the rectangular waveguide 723.

[0064] The ridge waveguide duplexer adopts a multi-stage coupling structure, for example, to separate the horizontal or vertical polarization signal into a horizontal or vertical polarization signal of a first frequency band and a horizontal or vertical polarization signal of a second frequency band.

[0065] In some embodiments, the first frequency band is, for example, a standard backhaul frequency band; and the second frequency band is an E-band (ie, an E-BAND frequency band).

[0066] In some embodiments, as Figure 8 As shown, the ridge waveguide duplexer is composed of two independently designed frequency band filters (i.e., a high-pass filter and a low-pass filter) and connected through a T-junction. The impedance of the ridge waveguide duplexer at the common port, the first frequency band port, and the second frequency band port is Z0. In other words, the ridge waveguide duplexer can be integrated with a filtering structure for efficiently separating the signals of the two frequency bands. Figure 7As shown, a high-pass filter is implemented by varying the dimensions of the ridge waveguide, leveraging its low-frequency cutoff characteristics. Its matching characteristics are achieved through the stepped ridge transition structure 724. The low-pass filter's metal ridges 725 maintain a constant width while varying their height. The combination of metal ridges of varying heights creates high and low impedance, resulting in a low-pass characteristic. The low-pass filter's metal ridges 725 typically have 6 to 10 groups of grooves and teeth, for example, 8 groups.

[0067] This is achieved by loading ridges of the same width but different heights as the ridges at the common end of the ridge waveguide duplexer. Specifically, by adjusting the height of the ridges inside the ridge waveguide, the impedance characteristics can be changed, thereby affecting the propagation characteristics of the electromagnetic wave. Based on this, the ridge waveguide duplexer achieves matching with the low-pass filter by loading ridges of different heights at its common end. In this way, the influence of the change in ridge height on the impedance characteristics can be utilized to achieve good impedance matching within the operating frequency band of the low-pass filter, thereby not only improving the signal transmission efficiency and reducing signal reflection and loss, but also achieving effective frequency separation by selectively passing low-frequency signals while suppressing high-frequency signals, meeting the needs of specific communication systems and improving the performance and efficiency of the overall system. Of course, in practical applications, the ridge width of the ridge waveguide duplexer can also be variable. Figure 7 The specific structure of the ridge waveguide duplexer is shown. According to simulation results, the reflection coefficient in both frequency bands (i.e., the first and second frequency bands mentioned above) is less than -18dB, the transmission coefficient is approximately -0.1dB, and the isolation is better than -40dB, ensuring that the two frequency band signals are output from the common port of the two ridge waveguide duplexers and synthesized without intermodulation interference.

[0068] In some embodiments, to adjust the impedance matching, as Figure 5 and Figure 6 As shown, the quad-ridged wave splitter 71 has at least one frustum 73, which is disposed at the common port 711a of the quad-ridged wave splitter 71 and coaxially with the waveguide transition piece 5. Furthermore, in some embodiments, when there are multiple frustums 73, they are coaxially stacked in sequence along the axial direction of the waveguide transition piece 5, and the diameters of the multiple frustums 73 increase in a direction away from the waveguide transition piece 5. In practical applications, the number of frustums 73 can be one or more, depending on the impedance matching characteristics adapted to the specific situation. For example, simulations using two frustums 73 can produce the following impedance matching results: the reflection coefficient in both frequency bands (e.g., the standard return band and the E-BAND band) is less than -29dB, the transmission coefficient is close to 0dB, and the high-order modulus level is less than -50dB in the E-BAND band.

[0069] Furthermore, in some embodiments, in order to achieve good impedance matching, the total length of at least one frustum 73 along the signal propagation direction of the waveguide transition piece 5 is greater than or equal to 0.1 to 0.2 times the wavelength of the electromagnetic wave in free space corresponding to the lowest frequency value within the operating frequency range.

[0070] In some embodiments, as Figure 10 As shown, the inner circumference of the feed horn 2 is provided with a corrugated structure comprising a plurality of first annular grooves 21 arranged sequentially along the axial direction of the feed horn 2. The diameter of the inner circumference of the feed horn 2 gradually decreases as it approaches the circular waveguide 4. In this case, the inner diameters of the plurality of first annular grooves 21 decrease one by one as they approach the circular waveguide 4. Adjacent first annular grooves 21 are radially spaced apart. The first annular grooves 21 are used to control the radiation pattern, reducing unwanted radiation (such as sidelobes), while ensuring good rotational symmetry and a stable phase center within the dual-band main radiation region, improving the uniformity of electromagnetic radiation in all directions, and thereby enhancing antenna performance. For example, there are three to five first annular grooves 21. In one specific embodiment, there are four first annular grooves 21, each having a radial width of approximately 0.9 mm. Adjacent first annular grooves 21 are spaced apart by approximately 0.6 mm.

[0071] As another technical solution, see Figure 1 The present invention also provides an antenna 200, comprising a dual-band feed 100, a sub-reflector 1, and a main reflector 6. The dual-band feed 100 utilizes the antenna described above. The sub-reflector 1 is mounted on a side of the feed horn 2, away from the circular waveguide 4, via a fixing bracket 3. The sub-reflector 1 has a sub-reflecting surface facing the circular waveguide 4. The main reflector 6 is disposed between a waveguide transition piece 5 and a four-ridge feed network 7. The waveguide transition piece 5 extends through the main reflector 6 and connects to the four-ridge feed network 7. The main reflector 6 has a main reflector 61 facing away from the four-ridge feed network 7.

[0072] The secondary reflector 1 has a smaller secondary reflector surface than the primary reflector. It is located in front of the primary reflector 61 and faces the circular waveguide 4. The secondary reflector's primary function is to help focus electromagnetic waves emitted by the feed source onto the primary reflector 61, thereby improving the antenna's directivity and gain. The secondary reflector 1 can be secured to the feed horn 2 via a mounting bracket 3 (e.g., comprising multiple support rods).

[0073] The main reflector 61, for example, employs a ring-focus parabolic structure to effectively focus the electromagnetic waves radiated by the feed source, forming plane waves. This ensures high gain and low sidelobe performance in two frequency bands (e.g., the conventional return band and the E-BAND band). The main reflector 61 has an aperture of approximately 0.6 m. A metal frame 62 may be provided around the main reflector to enhance structural stability and anti-interference performance.

[0074] The existing antennas that can cover two frequency bands do not consider the sidelobe envelope problem of the antenna pattern, that is, they do not optimize the performance of the sidelobe envelope. The sidelobe envelope refers to the maximum radiation intensity distribution of the sidelobe in the antenna pattern. If the sidelobe level is too high, it may cause the antenna to interfere with signals in other directions or receive interference signals in other directions, resulting in the antenna failing to meet the requirements of the ETSI standard and being difficult to use in point-to-point microwave communication systems that have strict requirements for high directivity and low interference. In order to solve this problem, Figure 11 As shown, the central region of the secondary reflector employed in the embodiment of the present application comprises a central plane 12 and multiple concentric annular surfaces 11 surrounding the central plane 12. The central plane 12 and the multiple annular surfaces 11 form a continuous surface. The orthographic projections of the central plane 12 and the multiple annular surfaces 11 on a predetermined cross-section form a plurality of serially connected line segments 111. The predetermined cross-section is parallel to the central axis and radial lines of the secondary reflector. That is, the line segments 111 extend radially along the annular surfaces 11. In one specific embodiment, the orthographic projections of the central plane 12 and the multiple annular surfaces 11 on the predetermined cross-section form eight line segments. The endpoints of two adjacent line segments 111 are connected to form nodes, for a total of seven nodes. The positions of the seven nodes (e.g., their axial coordinate positions) are adjustable to control the reflection path of the electromagnetic wave, thereby controlling the distribution of the aperture field of the primary reflector.

[0075] According to the principles of geometric optics, when the shape of the secondary reflector changes, the energy scattered from the feed source after hitting the secondary reflector also changes accordingly, forming a different aperture field distribution after hitting the main reflector 61, thereby changing the antenna radiation pattern. Based on this, by adjusting the number of concentric annular surfaces 11 and the shape and length of the line segments 111, the shape of the secondary reflector can be controlled, and thus the distribution of the aperture field (i.e., the distribution of electromagnetic waves on the main reflector) of the primary reflector can be controlled, thereby optimizing the antenna's radiation pattern, reducing the level of sidelobes, and increasing the gain of the main lobe. This allows for flexible adjustment of antenna performance to meet different communication requirements and standards. It is easy to understand that adjusting the shape and length of the line segments 111, for example, includes adjusting the position of the node connecting two adjacent line segments 111 (i.e., the endpoints of each line segment 111) to change the geometric structure of the entire multi-segment shape. Compared to the primary or secondary reflectors of traditional annular or Cassegrain paraboloids, the secondary reflectors of this application utilize multiple concentric annular surfaces 11. By adjusting the number of concentric annular surfaces 11, as well as the shape and length of the line segments, the antenna 200's directivity pattern can be optimized, for example, to reduce sidelobe levels, improve the mainlobe shape, or adjust beam pointing. In practical applications, the optimal locations of these nodes can be determined based on the antenna 200's operating frequency band, desired radiation characteristics, and the communication standards to be met (such as ETSI standards). Furthermore, these line segments 111 can be straight, curved, or have other shapes to achieve specific electromagnetic wave reflection and radiation characteristics.

[0076] It should be noted that the above-mentioned line segment 111 is a virtual line used to represent the characteristics or structure of the annular surface 11 during the design process of the annular surface 11. In actual applications, the secondary reflector is composed of a continuous metal surface, which is composed of multiple concentric annular surfaces 11. The orthographic projections of these annular surfaces 11 on the preset cross-section include the line segment 111.

[0077] Furthermore, in some embodiments, to increase structural strength and control the reflection characteristics of electromagnetic waves, multiple concentric second annular grooves 13 are provided in the edge region of the secondary reflector. Sidelobes are radiated lobes other than the main lobe in the antenna pattern, which can cause signal interference and reduce spectral efficiency. The second annular grooves 13 (for example, by adjusting their depth) can influence the formation of sidelobes, reducing the intensity of sidelobes by changing the reflection and propagation mode of electromagnetic waves on the secondary reflector, thereby improving the antenna's pattern characteristics. Furthermore, the second annular grooves 13 enhance the structural rigidity of the secondary reflector, making it more robust and able to withstand various forces that may be encountered during installation, transportation, or use, such as wind and deadweight. Furthermore, the design of the second annular grooves 13 helps control the propagation path of electromagnetic waves, reduce diffraction, and more concentratedly propagate electromagnetic energy in the predetermined direction. To achieve this effect, the depth of the second annular grooves 13 is, for example, one-quarter of the wavelength of the electromagnetic wave in free space corresponding to the lowest frequency value within the operating frequency range.

[0078] These second annular grooves 13 are distributed around the above-mentioned multiple annular surfaces 11, but the embodiments of the present application are not limited to this. In other embodiments, the above-mentioned multiple annular surfaces 11 can also be distributed around these second annular grooves 13. That is, multiple concentric annular surfaces are provided in the edge area of ​​the secondary reflector, and the multiple annular surfaces constitute a continuous surface; the orthographic projections of the multiple annular surfaces on the preset cross-section constitute multiple line segments connected in series, and the preset cross-section is parallel to the central axis and radial straight line of the secondary reflector. Multiple concentric second annular grooves 13 are provided in the central area of ​​the secondary reflector. Of course, in actual applications, the second annular grooves 13 can also be omitted, and multiple concentric annular surfaces can be provided only in the central area and / or edge area of ​​the secondary reflector.

[0079] The antenna provided in the present embodiment is assembled as follows: the secondary reflector is connected to the feed horn 2 via multiple support rods. One end of the circular waveguide 4 is connected to one end of the feed horn 2. The two ends of the waveguide transition piece 5 (i.e., the first end 5a and the second end 5b) are respectively connected to the other end of the circular waveguide 4 and the four-ridged feed network 7. The four-ridged feed network 7 utilizes a metal laminate structure that can be further assembled with the primary reflector. After installation, the antenna's gain and coverage can be further optimized by fine-tuning the angles of the support rods.

[0080] like Figure 12 and Figure 13 As shown in the two figures, the vertical axis represents the voltage standing wave ratio (VSWR), and the horizontal axis represents the frequency (in GHz). The black curve and the gray curve in the two figures correspond to horizontal polarization and vertical polarization respectively. The dual-band feed 100 in the embodiment of the present application achieves a standing wave ratio of less than 1.65 in the conventional return frequency band f1 (such as Figure 12 As shown), the VSWR achieved in E-BAND is less than 1.52 (as shown Figure 13 The smaller standing wave ratio indicates that the feed source of the present application and its feeding system have achieved good impedance matching and high transmission efficiency.

[0081] like Figure 14 and Figure 15 As shown in the two figures, the vertical axis represents the gain (Gain, unit is dBi), the horizontal axis represents the angle (unit is deg), and the black curve and the gray curve in the two figures correspond to horizontal polarization and vertical polarization respectively. Figure 14 as shown) and E-BAND (as Figure 15 The gain pattern test results shown in the figure basically meet the ETSI antenna radiation characteristic standard requirements.

[0082] In summary, the antenna 200 provided in the embodiment of the present application, by employing the dual-band feed 100 provided in the embodiment of the present application, can be constructed entirely of metal and operate in dual bands (e.g., the conventional return band / E-BAND). The absence of a dielectric not only avoids dielectric loss but also achieves optimal transmission efficiency. Furthermore, compared to the prior art use of a coaxial nested waveguide structure (a high-frequency transmission waveguide nested within a low-frequency transmission waveguide), the dual-band feed 100 provided in the embodiment of the present application has a simpler structure, thereby reducing manufacturing difficulty and cost while maintaining high performance. By adjusting the number of concentric annular surfaces, the shape and length of the radial segments, and the depth of the second annular groove 13, the secondary reflector can improve the sidelobe characteristics of the antenna system's radiation pattern to meet ETSI requirements.

[0083] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present application, and such modifications and improvements are also considered to be within the scope of protection of the present application.

Claims

1. A dual-band feed, characterized in that: include: A feed horn, a circular waveguide, a waveguide transition piece, and a four-ridge feed network, wherein the feed horn is used to receive or radiate signals; One end of the circular waveguide is connected to one end of the feed horn, and the other end of the circular waveguide is connected to the first end of the waveguide transition piece, and the circular waveguide is used to transmit signals between the feed horn and the waveguide transition piece; The waveguide transition piece is configured to transition from a circular waveguide to a quad-ridged waveguide in a direction from a first end thereof to a second end thereof for transmitting signals between the circular waveguide and the quad-ridged feed network; The quad-ridge feed network is used to separate or combine the signal with horizontally polarized signals and vertically polarized signals in each of two different frequency bands; The four-ridge feed network includes a ridge waveguide duplexer for separating horizontally or vertically polarized signals into horizontally or vertically polarized signals of a first frequency band and horizontally or vertically polarized signals of a second frequency band; The ridge waveguide duplexer includes a T-junction and a low-pass filter and a high-pass filter integrated inside the T-junction, wherein the low-pass filter includes a plurality of metal ridges arranged along a second direction, the plurality of metal ridges have the same width and different heights, and a groove is provided between two adjacent metal ridges, and the high-pass filter includes a transition structure of stepped ridges extending along a first direction, wherein the first direction is perpendicular to the second direction.

2. The dual-band feed according to claim 1, characterized in that: The waveguide transition piece includes a circular waveguide segment, a tapered four-ridged waveguide segment, and a four-ridged waveguide segment connected in sequence along a direction from a first end to a second end thereof, wherein the radial cross-sectional profile size of the first end of the tapered four-ridged waveguide segment is the same as the radial cross-sectional profile size of the circular waveguide segment; the radial cross-sectional profile size of the second end of the tapered four-ridged waveguide segment is the same as the radial cross-sectional profile size of the four-ridged waveguide segment; and the radial cross-sectional profile size of the tapered four-ridged waveguide segment decreases along a direction from the first end to the second end thereof.

3. The dual-band feed according to claim 1, wherein: The waveguide transition piece includes a circular waveguide segment, at least two stepped four-ridged waveguide segments and a four-ridged waveguide segment connected in sequence along a direction from a first end to a second end thereof, wherein one end of the stepped four-ridged waveguide segment adjacent to the circular waveguide segment has the same radial cross-sectional profile size as the circular waveguide segment, one end of the stepped four-ridged waveguide segment adjacent to the four-ridged waveguide segment has the same radial cross-sectional profile size as the four-ridged waveguide segment, and the radial cross-sectional profile sizes of the at least two stepped four-ridged waveguide segments decrease in sequence along a direction from the circular waveguide segment to the four-ridged waveguide segment.

4. The dual-band feed according to any one of claims 1 to 3, wherein: The total length of the waveguide transition piece along the direction from the first end to the second end is greater than or equal to four times the wavelength of the electromagnetic wave corresponding to the lowest frequency value in the operating frequency range in free space.

5. The dual-band feed according to claim 1, wherein: The quad-ridge feed network includes a quad-ridge splitter and four ridge waveguide duplexers, wherein the quad-ridge splitter is used to separate or combine the signal from two horizontally polarized signals and two vertically polarized signals; the quad-ridge splitter has a common port, and the common port is connected to the second end of the waveguide transition piece; Two of the ridge waveguide duplexers are used to separate or synthesize the horizontally polarized signal from the first-frequency band horizontally polarized signal and the second-frequency band horizontally polarized signal, and the synthesis has two first transmission ports for outputting or inputting the first-frequency band horizontally polarized signal and the second-frequency band horizontally polarized signal, respectively; the other two ridge waveguide duplexers are used to separate or synthesize the vertically polarized signal from the first-frequency band vertically polarized signal and the second-frequency band vertically polarized signal, and the synthesis has two second transmission ports for outputting or inputting the first-frequency band vertically polarized signal and the second-frequency band vertically polarized signal, respectively.

6. The dual-band feed according to claim 5, characterized in that: The quad-ridge wave splitter has at least one frustum, and the at least one frustum is arranged at the common port and coaxially arranged with the waveguide transition piece; When there are multiple frustums, the multiple frustums are coaxially stacked in sequence along the axial direction of the waveguide transition piece, and the diameters of the multiple frustums increase in sequence in a direction away from the waveguide transition piece.

7. The dual-band feed according to claim 6, characterized in that: The total length of the at least one frustum along the signal propagation direction of the waveguide transition piece is greater than or equal to 0.1 to 0.2 times the wavelength of the electromagnetic wave corresponding to the lowest frequency value in the operating frequency range in free space.

8. The dual-band feed according to claim 5, characterized in that: The first frequency band is a standard backhaul frequency band; the second frequency band is an E-band.

9. The dual-band feed according to claim 1, wherein: The inner circumferential surface of the feed horn is provided with a corrugated structure, and the corrugated structure includes a plurality of annular grooves sequentially arranged along the axial direction of the feed horn.

10. A base station antenna, characterized in that: include: The dual-band feed according to any one of claims 1 to 9; a secondary reflector, disposed on a side of the feed horn away from the circular waveguide and having a secondary reflective surface facing the circular waveguide; A main reflector is arranged between the waveguide transition piece and the four-ridge feed network, and the waveguide transition piece passes through the main reflector and is connected to the four-ridge feed network; the main reflector has a main reflecting surface facing away from the four-ridge feed network.

11. The base station antenna according to claim 10, characterized in that: A central plane and multiple concentric annular surfaces surrounding the central plane are provided in the central area of ​​the secondary reflector, and the central plane and the multiple annular surfaces constitute a continuous surface; the orthographic projections of the central plane and the multiple annular surfaces on a preset cross-section constitute multiple connected line segments, and the preset cross-section is parallel to the central axis and radial straight line of the secondary reflector.

12. The base station antenna according to claim 11, wherein: A plurality of concentric annular grooves are provided in the edge region of the secondary reflective surface.

13. The base station antenna according to claim 10, wherein: A plurality of concentric annular surfaces are arranged in the edge area of ​​the secondary reflector, and the plurality of annular surfaces constitute a continuous surface; the orthographic projections of the plurality of annular surfaces on a preset cross section constitute a plurality of serially connected line segments, and the preset cross section is parallel to the central axis and radial straight line of the secondary reflector.

14. The base station antenna according to claim 13, wherein: A plurality of concentric annular grooves are provided in the central area of ​​the secondary reflective surface.

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