A broadband wide-beam double-ridged horn antenna

Abstract

The present invention relates to a broadband wide-beam double-ridged horn antenna, which can simultaneously meet the requirements of broadband, wide beam, and low voltage standing wave ratio. It includes a horn section, a waveguide section, an upper-ridge waveguide, a lower-ridge waveguide, a short-circuit waveguide, and a radio frequency coaxial connector; the non-ridge walls of the horn section adopt a metal strip structure. At the beginning of the horn section, semi-elliptical slots are opened on both the non-ridge walls and the ridge walls, and the upper-ridge waveguide adopts an exponential and triangular hybrid gradual change structure. The present invention uses an exponential and triangular hybrid curve as the gradual change curve of the ridge, which is beneficial to obtaining good matching characteristics; at the same time, at the beginning of the horn section, semi-elliptical slots are opened on both the non-ridge walls and the ridge walls, and the non-ridge walls adopt a metal strip structure, which plays a very important role in broadening the ¾dB beam broadband of the E and H planes of the antenna. The designed antenna has a stable radiation pattern and a low voltage standing wave ratio in the 2-6GHz bandwidth range. The ¾dB beam broadband of the E and H planes is >60° in the entire frequency band range, and it has a very wide application scenario in the fields of broadband and wide beam.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a broadband wide-beam double-ridged horn antenna. Background Art

[0002] A horn antenna is a surface antenna, a microwave antenna with a circular or rectangular cross-section that gradually expands at the end of a waveguide. With the rapid development of satellite navigation, positioning, and mobile communication technologies, in order to meet the needs of specific users, broadband and wide-beam antennas have become one of the research hotspots.

[0003] Although there are currently many types of wide-beam antennas, such as microstrip antennas, rotating antennas, dipole reflector antennas, etc., the above several antennas have certain limitations, usually manifested as narrow bandwidth and low gain. The horn antenna has the advantages of simple structure, diverse functions, and good radiation performance, and is widely used in different military and civilian electronic systems. Among the methods for broadening the operating frequency band of a horn antenna, introducing a ridge structure is the most commonly used method. The feeding of a ridged horn antenna usually adopts a coaxial-ridge waveguide conversion structure. The outer conductor of the coaxial cable is connected to the waveguide side, and the inner conductor of the coaxial cable extends and penetrates deep into the relative ridge waveguide away from the waveguide wall, so as to achieve good impedance matching. Theoretically analyzed, the gain of a horn antenna depends on the size of the horn aperture surface, that is, the larger the horn aperture surface, the greater the gain of the antenna, and the narrower the antenna beam. Usually, in actual engineering applications, the size of the antenna is limited. Therefore, how to improve the antenna gain without changing the aperture surface, that is, to improve the aperture utilization efficiency of the horn antenna has become a difficult point. In a horn antenna, its gain and beam width are a pair of contradictions, and often only a compromise can be made to meet specific application scenarios. However, in some application scenarios, it is required that the antenna has a relatively wide beam width. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a broadband wide-beam double-ridged horn antenna with a semi-elliptical groove opened in the horn section and an exponential and triangular hybrid ridge curve, which effectively broadens the beam width of the E-plane without changing the horn aperture surface, keeps the input impedance basically unchanged, and the voltage standing wave ratio (VSWR) basically remains unchanged, achieving a good matching effect.

[0005] To achieve the above purpose, the technical solution of the present invention is as follows:

[0006] A broadband wide-beam double-ridged horn antenna includes a horn section, a waveguide section, an upper ridge waveguide, a lower ridge waveguide, a short-circuit waveguide, and a radio frequency coaxial connector.

[0007] The horn section is a pyramidal horn structure, which is linearly extended along the E and H planes. Its end is connected to the waveguide section, and the two structures are an integrated structure. The non-ridge wall of the horn section adopts a metal strip structure. The upper end of the metal strip structure is flush with the horn section aperture surface. Semi-elliptical grooves are opened on the ridge wall and the non-ridge wall. The back of the upper ridge waveguide is connected to the inner side of the horn section, forming an integrated structure. Its end is connected to the upper surface of the lower ridge waveguide, forming an integrated structure. The ridge gradient starts from the interface between the upper ridge waveguide and the lower ridge waveguide, first extending to point A with an exponential function curve, and then extending from point A to the aperture of the horn section with a trigonometric function curve. The back of the lower ridge waveguide is connected to the inner side of the waveguide section, forming an integrated structure. Its lower surface is connected to the upper surface of the short-circuit waveguide to form an integrated structure. The lower ridge waveguide is a rectangular parallelepiped. The back and bottom surfaces of the short-circuit waveguide are both connected to the inner side of the waveguide section, forming an integrated structure. The short-circuit waveguide is a rectangular parallelepiped. The upper ridge waveguide, lower ridge waveguide, and short-circuit waveguide are all symmetrical along the central axis of the double ridge. The outer conductor of the RF coaxial connector is short-circuited to the outer wall of the waveguide segment via screws. The inner conductor passes through the waveguide segment and the through hole of the lower ridge waveguide, short-circuiting the symmetrical structure of the lower ridge waveguide. The cross-section of the waveguide segment is a rectangular structure.

[0008] Furthermore, the horn section is a pyramidal horn structure, extending linearly along the E and H planes. The horn aperture measures 73mm by 48mm. The non-ridged wall is a metal strip structure, with its upper end coinciding with the edge of the horn aperture parallel to the E plane, and its lower end parallel to the upper end. To effectively broaden the beamwidth of the horn antenna's E and H planes, a semi-elliptical groove is provided on both the ridged and non-ridged wall surfaces at the beginning of the horn section (at the horn aperture).

[0009] Furthermore, the upper ridge waveguide is a symmetrical structure, employing a novel horn ridge form, which improves the antenna's low-frequency VSWR and effectively expands the antenna's overall bandwidth. The ridge curve uses a modified exponential and triangular hybrid curve. The parametric equation for the exponential curve in HFSS (High Frequency Structure Simulator) is as follows:

[0010]

[0011] The parametric equation of the trigonometric curve in HFSS is as follows:

[0012]

[0013] Wherein: k1=0.75, k2=0.011, k3=0.000001, length=12mm, L1=0.25*L, L=54mm, w=2.87mm.

[0014] The lower ridge waveguide is symmetrically arranged about the central axis of the double-ridge horn antenna. Its structure is a cuboid structure, and its upper end is flush with the upper end of the waveguide section, and together with the upper ridge waveguide, it forms the radiation arm of the horn antenna.

[0015] Further, the short-circuit waveguide is symmetrically arranged about the central axis of the double-ridge horn antenna. It is a cuboid structure. Its main function is to effectively filter out the TE20 mode in the waveguide, thereby broadening the overall bandwidth of the horn antenna.

[0016] Further, the cross-section of the waveguide section of the wide-bandwidth beam double-ridge horn antenna is rectangular.

[0017] Further, the RF coaxial connector includes an SMA connector and a feeding probe. The feeding probe includes a metal inner conductor and a dielectric layer wrapped outside the metal inner conductor. Round holes for connecting with the feeding probe are opened on the lower ridge waveguide and the waveguide section, and the diameter of the round holes is the same as that of the dielectric layer of the feeding probe. The RF coaxial connector adopts the SMA specification, with a characteristic impedance of 50Ω. The outer conductor is short-circuited with the outer wall of the waveguide section, and its inner core passes through the reserved through-hole and is short-circuited with the lower ridge waveguide. The inner core diameter of the SMA connector is 0.65mm, the through-hole diameter between the waveguide section and the upper ridge waveguide is 2.3mm, and the through-hole is filled with air dielectric.

[0018] The thicknesses of the upper ridge waveguide, the lower ridge waveguide, and the short-circuit waveguide are all ridge thickness w = 2.87mm.

[0019] Both the lower ridge waveguide and the short-circuit waveguide are cuboid structures, and their respective length, width, and height dimensions are: 8.90mm * 2.87mm * 6.53mm, 6.2mm * 2.87mm * 5.22mm.

[0020] The cross-section of the waveguide section is a rectangle, and the length, width, and height dimensions of the waveguide section are: 24.48mm * 18.28mm * 12mm.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention proposes a wide-bandwidth beam double-ridge horn antenna with a semi-elliptical groove opened at the horn section and an exponential and triangular hybrid ridge curve. The improved ridge curve (exponential and triangular hybrid curve) is very effective in improving the low-frequency voltage standing wave ratio and expanding the working bandwidth of the entire antenna. By opening a semi-elliptical groove at the beginning of the horn section, the 3dB beam bandwidth of the E-plane and H-plane can be significantly improved, so that the 3dB beam width of the E-plane and H-plane is > 60° throughout the working frequency band. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0024] Figure 1 It is a three-dimensional view of a broadband wide-beam dual-ridge horn antenna of the present invention;

[0025] Figure 2 It is a front view of a broadband wide-beam dual-ridge horn antenna of the present invention;

[0026] Figure 3 It is a top view of a broadband wide-beam dual-ridge horn antenna of the present invention;

[0027] Figure 4 It is a VSWR diagram of the entire operating frequency band of a broadband wide-beam dual-ridge horn antenna of the present invention;

[0028] Figure 5 It is the E-plane and H-plane radiation patterns of a broadband wide-beam dual-ridge horn antenna of the present invention at 2 GHz;

[0029] Figure 6 It is the E-plane and H-plane radiation patterns of a broadband wide-beam dual-ridge horn antenna of the present invention at 4 GHz;

[0030] Figure 7 It is the E-plane and H-plane radiation patterns of a broadband wide-beam dual-ridge horn antenna of the present invention at 6 GHz. Detailed implementation manners

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] The following will explain each step in detail one by one.

[0033] The present invention provides a broadband wide-beam dual-ridge horn antenna (hereinafter referred to as the antenna, such as Figure 1 、 Figure 2 ), which includes a horn section 1, a waveguide section 2, an upper ridge waveguide 3, a lower ridge waveguide 4, a short-circuit waveguide 5, and a radio frequency coaxial connector 6. The horn section 1 is a pyramidal horn structure, linearly expanded along the E-plane and H-plane. The total height of the horn section 1 is L = 54 mm, as shown in Figure 1The narrow side of the shown aperture plane is parallel to the E-plane, and the wide side is parallel to the H-plane. The size of the horn aperture plane is 73mm * 48mm. The non-ridge wall adopts a metal strip structure. The upper end of the metal strip structure coincides with the narrow side of the horn aperture plane, the lower end is parallel to the upper end, and the length of the lower end is 38mm. A semi-elliptical groove is opened on the ridged wall surface. The center of the ellipse and the short axis are located on the wide side of the aperture plane. The length of the short axis is 6.8mm, and the ratio of the short axis to the long axis is 0.375. A semi-elliptical groove is also opened on the non-ridged wall surface. The center of the ellipse and the short axis are located on the narrow side of the aperture plane. The length of the short axis is 5.2mm, and the ratio of the short axis to the long axis is 0.225. The wall thickness of the entire horn section 1 is 1mm. The use of a semi-elliptical groove at the beginning of the horn section 1 and a metal strip on the non-ridged wall effectively broadens the beam widths of the E and H planes of the horn antenna, making the 3dB beam widths of the E and H planes of the antenna > 60° throughout the frequency band.

[0034] In the antenna, such as Figure 1 and Figure 2 the horn section 1, waveguide section 2, upper ridged waveguide 3, lower ridged waveguide 4, and short-circuit waveguide 5 are all symmetric along the double-ridge central axis. The single-sided radiation arm of the antenna is composed of Figure 2 the combination of 3 and 4 in Figure 2 The thickness of the radiation wall is w = 2.87mm. Figure 2 As shown in

[0035]

[0036] the ridge curve of the upper ridged waveguide 3 is a mixture of exponential and triangular curves. The parametric equations of the exponential curve in HFSS are as follows:

[0037]

[0038] where: k1 = 0.75, k2 = 0.011, k3 = 0.000001, length = 12mm, L1 = 0.25 * L, L = 54mm, w = 2.87mm.

[0039] The use of this improved curve for the upper ridged waveguide 3 effectively improves the low-frequency VSWR of the antenna, which plays a very important role in expanding the low-frequency bandwidth. By using the improved curve, the short-circuit backplane structure in the traditional double-ridge horn antenna can be removed. In the traditional double-ridge horn antenna, the short-circuit backplane structure is generally related to Figure 2The short-circuit waveguide 5 shown forms the rear cavity, and the bandwidth is extended by adjusting the distance between the RF coaxial connector 6 and the short-circuit plate and the height of the half-way plate. However, the short-circuit plate is very troublesome and time-consuming in actual processing and assembly. Therefore, using the upper-ridge waveguide 3 with this improved curve can make the actual assembly simpler.

[0040] As Figure 2 shown, the short-circuit waveguide 5 has a cuboid structure, and its length, width and height dimensions are 6.2mm * 2.87mm * 5.22mm. The short-circuit waveguide effectively filters out the TE20 mode in the waveguide and plays a great role in expanding the bandwidth.

[0041] Figure 3 is the top view of the entire antenna. From Figure 3 it can be seen that the cross-section of the waveguide section 2 is a rectangle, and the length, width and height dimensions of the waveguide section 2 are: 24.48mm * 18.28mm * 12mm.

[0042] Figure 3 As shown, 6 is the RF coaxial connector. The RF coaxial connector 6 adopts the SMA standard with a characteristic impedance of 50Ω. The outer conductor is short-circuited with the outer wall of the waveguide section 2, and its inner core passes through the reserved through-hole and is short-circuited with the lower-ridge waveguide 4. The inner core diameter of the SMA connector is 0.65mm, and the through-hole diameter of the waveguide section 2 and the upper-ridge waveguide 3 is 2.3mm, and the through-hole is filled with air medium.

[0043] Figure 1 A broadband beam double-ridge horn antenna provided by the shown embodiment can operate in the fL~fH frequency band (where fL and fH respectively represent the lowest and highest operating frequencies, and fH / fL = 3). In the broadband operating frequency band, the voltage standing wave ratio of 97% of the frequency band is less than 2, and the voltage standing wave ratio of the remaining frequency band is less than 2.2; the 3dB beam widths of the E and H planes of the antenna are both > 60° throughout the frequency band, the radiation pattern is stable, and there is no obvious splitting of the main lobe beam.

[0044] Referring to Figure 4 is the simulation curve graph of the voltage standing wave ratio of the Figure 1 structure. It can be seen that in the frequency band of 2 - 6GHz, the voltage standing wave ratio of 97% of the frequency band is less than 2, and only in the 3% frequency band at low frequencies, the voltage standing wave ratio is less than 2.2. This shows that the present invention has good impedance characteristics in the 2 - 6GHz frequency band.

[0045] Referring to Figure 5 、 Figure 6 and Figure 7 is the simulation radiation pattern of the E and H planes of the Figure 1 structure at 2GHz, 4GHz, and 6GHz. It can be seen that the main lobe of the radiation pattern of the antenna is stable at each frequency point, and there is no cracking of the main lobe.

[0046] The present invention uses an exponential and triangular hybrid curve as the gradual change curve of the ridge, which is beneficial to obtaining good matching characteristics; at the same time, at the beginning of the horn section, semi-elliptical grooves are opened on both the non-ridge wall and the ridge wall, and the non-ridge wall adopts a metal strip structure, which plays a very important role in broadening the 3dB beam bandwidth of the E and H planes of the antenna. The designed antenna has stable directivity and low voltage standing wave ratio within the bandwidth range of 2-6 GHz, and the 3dB beam bandwidth of the E and H planes is >60° throughout the frequency band range, and has a very wide application scenario in the fields of wideband and wide beam.

[0047] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions and variations of these embodiments still fall within the protection scope of the present invention.

Claims

1. A broadband wide-beam double-ridge horn antenna, characterized in that: It includes a horn section, a waveguide section, an upper ridged waveguide, a lower ridged waveguide, a short-circuit waveguide, and a radio frequency coaxial connector; the horn section is a pyramidal horn structure, linearly expanded along the E-plane and H-plane, with its bottom end connected to the waveguide section. The back of the upper ridged waveguide is connected to the inner side of the horn section to form an integral body, and its bottom end is short-circuited to the upper end of the lower ridged waveguide. The ridge curve of the upper ridged waveguide adopts a mixed curve of exponential and triangular curves. The bottom end of the lower ridged waveguide is short-circuited to the upper end of the short-circuit waveguide, and the back of the lower ridged waveguide is connected to the inner side of the waveguide section. The back and bottom of the short-circuit waveguide are both connected to the waveguide section. The cross-section of the waveguide section is rectangular. The radio frequency coaxial connector includes an SMA connector and a feeding probe. The feeding probe includes a metal inner conductor and a dielectric layer wrapped around the metal inner conductor. Round holes for facilitating connection with the feeding probe are provided on the lower ridged waveguide and the waveguide section. The diameter of the round holes is the same as that of the dielectric layer of the feeding probe. The non-ridge walls of the horn section adopt a metal strip structure, parallel to the probe direction of the radio frequency coaxial connector. The upper end of the metal strip structure coincides with the narrow side of the horn aperture surface. Semi-elliptical grooves are provided on both the ridged wall surface and the non-ridged wall surface at the starting end of the horn section. The upper ridged waveguide is a symmetric structure and adopts a new horn ridge form. The ridge curve is a mixture of exponential and triangular curves. The parametric equation of the exponential curve in HFSS is as follows: The parametric equation of the triangular curve in HFSS is as follows: Where: k1 = 0.75, k2 = 0.011, k3 = 0.000001, length = 12mm, L1 = 0.25*L, L = 54mm, w = 2.87mm.

2. The broadband wide-beam double-ridge horn antenna according to claim 1, characterized in that: The thicknesses of the upper ridged waveguide, the lower ridged waveguide, and the short-circuit waveguide are all the ridge thickness w = 2.87mm.

3. The broadband wide-beam double-ridge horn antenna according to claim 1, characterized in that: The lower ridged waveguide and the short-circuit waveguide are both cuboid structures, and the lower ridged waveguide and the short-circuit waveguide are symmetrically arranged about the central axis of the double-ridged horn antenna.

4. A broadband wide-beam double-ridge horn antenna according to claim 1, characterized in that: The cross-section of the waveguide section is a rectangle, and the dimensions of the length, width, and height of the waveguide section are: 24.48mm * 18.28mm * 12mm.

5. A broadband wide-beam double-ridged horn antenna according to claim 1, characterized in that: The radio frequency coaxial connector adopts the SMA specification, with a characteristic impedance of 50Ω. The outer conductor is short-circuited to the outer wall of the waveguide section, and its inner core passes through the reserved through-hole and is short-circuited to the lower ridged waveguide. The diameter of the inner core of the SMA connector is 0.65mm, and the diameter of the through-hole between the waveguide section and the upper ridged waveguide is 2.3mm. The through-hole is filled with air dielectric.

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