A Ka-band conical beam antenna

Abstract

The present invention discloses a Ka-band conical beam antenna, comprising a filter unit, a wave conversion unit and a circular waveguide horn, the central axes of which are located on the same straight line and are connected in sequence; the filter unit is used to filter the input electromagnetic energy to obtain an electromagnetic wave of a preset frequency after filtering; the wave conversion unit is used to convert the TE 10 The circular waveguide horn is used to respond to the electromagnetic wave of the coaxial TEM mode and stimulate the TM 01 The mode radiates and radiates a conical beam pattern in the far field of the antenna; the present invention realizes the control of the impedance bandwidth of the antenna, which can significantly improve the out-of-band suppression capability, so that the gain of the antenna is significantly attenuated outside the frequency band, and effectively improves the anti-interference ability of the antenna; by setting a wave conversion unit, the power capacity of the antenna is effectively improved, and it is ensured that the antenna has a high radiation efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a Ka-band conical beam antenna. Background Art

[0002] As a key component of wireless communication systems, antennas play the role of energy conversion between guided electromagnetic waves and radiated electromagnetic waves. Conical beam antennas are widely used in ground satellite communication terminals, indoor WLAN micro base stations, radio fuse systems and navigation systems because their maximum radiation direction is located on a cone with a preset inclination angle to the normal, and their radiation pattern and polarization are axially symmetric.

[0003] At present, most existing conical beam antennas use helical antennas or patch antennas. Among them, the helical antenna can generate radial reverse currents and thus generate a conical beam by symmetrically exciting two sets of balanced modes; the patch antenna made of a flat printed circuit board can generate a conical beam by exciting the TM n1 mode to achieve a conical beam; spiral antennas or patch antennas have the advantages of low antenna profile and easy conformity with other devices; however, existing conical beam antennas have low efficiency and small power capacity in the millimeter wave frequency band; at the same time, since the existing conical beam antennas do not integrate structural components designed for filtering, the filtering function cannot be achieved, resulting in poor anti-interference ability of the antenna. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a Ka-band conical beam antenna to solve the technical problems that the existing conical beam antenna has low efficiency, small power capacity and poor anti-interference ability in the millimeter wave frequency band.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a Ka-band conical beam antenna, comprising a filtering unit, a waveguide conversion unit and a circular waveguide horn, the central axes of which are located on the same straight line and are connected in sequence;

[0007] The filtering unit is used to filter the input electromagnetic energy to obtain an electromagnetic wave of a preset frequency after filtering;

[0008] The wave conversion unit is used to convert the TE in the electromagnetic wave of the preset frequency after filtering. 10 The mode electromagnetic wave is converted into a coaxial TEM mode electromagnetic wave;

[0009] The circular waveguide horn is used to respond to the electromagnetic wave of the coaxial TEM mode and stimulate the TM 01 mode radiates and radiates a conical beam pattern in the far field of the antenna.

[0010] Furthermore, the filtering unit comprises a waveguide flange, an input coupling structure, a first spherical resonant cavity, an inductively coupled diaphragm, a second spherical resonant cavity and an output coupling structure;

[0011] One end of the input coupling structure is connected to the waveguide flange, and the other end of the input coupling structure is connected to one end of the first spherical resonant cavity; the other end of the first spherical resonant cavity is connected to one end of the inductive coupling diaphragm, and the other end of the inductive coupling diaphragm is connected to one end of the second spherical resonant cavity, and the other end of the second spherical resonant cavity is connected to one end of the output coupling structure, and the other end of the output coupling structure is connected to the input end of the waveguide conversion unit.

[0012] Furthermore, an input coupling window is provided at one end of the first spherical resonant cavity, and the input coupling window is used to be connected to an input coupling structure; a first resonant cavity coupling window is provided at the other end of the first spherical resonant cavity, and the first resonant cavity coupling window is used to be connected to one end of the inductive coupling diaphragm;

[0013] The side walls of the first spherical resonant cavity are respectively provided with first spherical depressions, the two first spherical depressions are located on both sides of the longitudinal center plane of the first spherical resonant cavity, and the normals of the two first spherical depressions coincide with each other; wherein, the normal of the first first spherical depression forms an angle of 45° with the upper end of the longitudinal center plane of the first spherical resonant cavity, and the normal of the second first spherical depression forms an angle of 45° with the lower end of the longitudinal center plane of the first spherical resonant cavity.

[0014] Furthermore, a second resonant cavity coupling window is provided at one end of the second spherical resonant cavity, and the second resonant cavity coupling window is used to be connected to the other end of the inductive coupling diaphragm; an output coupling window is provided at the other end of the second spherical resonant cavity, and the output coupling window is used to be connected to the output coupling structure;

[0015] Second spherical recesses are respectively provided on the side walls on both sides of the second spherical resonant cavity, and the two second spherical recesses are located on both sides of the longitudinal center plane of the second spherical resonant cavity, and the normals of the two second spherical recesses coincide with each other; wherein, the normal of the first second spherical recess forms an angle of 45° with the lower end of the longitudinal center plane of the second spherical resonant cavity, and the normal of the second second spherical recess forms an angle of 45° with the upper end of the longitudinal center plane of the second spherical resonant cavity.

[0016] Furthermore, the inductive coupling diaphragm adopts a cross-elliptical coupling diaphragm; the cross-elliptical coupling diaphragm is placed at the center connecting line of the first spherical resonant cavity and the second spherical resonant cavity;

[0017] The cross-elliptical coupling diaphragm includes a transverse elliptical coupling diaphragm and a longitudinal elliptical coupling diaphragm arranged in a cross shape; wherein the major axis of the transverse elliptical coupling diaphragm is perpendicular to the longitudinal center plane of the first spherical resonant cavity, and the major axis of the longitudinal elliptical coupling diaphragm is parallel to the longitudinal center plane of the first spherical resonant cavity.

[0018] Furthermore, the wave conversion unit includes a conversion cavity, an impedance conversion structure and a coaxial structure;

[0019] The conversion cavity is arranged between the output end of the filtering unit and the feeding end of the circular waveguide horn; a rectangular cavity is opened at the center of one end of the conversion cavity, and a coaxial mounting hole is opened at the other end of the conversion cavity; the impedance transformation structure is arranged in the rectangular cavity, and the bottom of the impedance transformation structure is connected to the bottom plate of the rectangular cavity; the coaxial structure is concentrically arranged in the coaxial mounting hole, one end of the coaxial structure is connected to the impedance transformation structure, and the other end of the coaxial structure is connected to the feeding end of the circular waveguide horn.

[0020] Furthermore, the impedance transformation structure includes a first step structure, a second step structure and a third step structure sequentially arranged along the long axis center line direction of the rectangular cavity;

[0021] The bottom surfaces of the first step structure, the second step structure and the third step structure are all connected to the bottom plate of the rectangular cavity, and the top surfaces of the first step structure, the second step structure and the third step structure extend toward the top plate of the rectangular cavity;

[0022] The first step structure, the second step structure and the third step structure are all rectangular parallelepiped structures, and their heights increase successively; a rectangular groove is provided on the top surface of the third step structure, and the rectangular groove is arranged close to one side of the coaxial mounting hole.

[0023] Furthermore, the coaxial structure includes a coaxially arranged cylindrical inner conductor and a cylindrical outer conductor, the cylindrical outer conductor is concentrically inserted into the coaxial mounting hole, and the cylindrical inner conductor is concentrically arranged in the cylindrical outer conductor; wherein air is filled between the cylindrical inner conductor and the cylindrical outer conductor.

[0024] Furthermore, the circular waveguide horn includes a circular waveguide structure, an open circular horn and a probe structure; the circular waveguide structure is concentrically connected to the open circular horn; wherein one end of the circular waveguide structure is connected to the waveguide conversion unit, and the other end of the circular waveguide structure is connected to the open circular horn;

[0025] The probe structure is concentrically inserted in the center of the circular waveguide structure, one end of the probe structure is connected to the output end of the waveguide conversion unit, and the other end of the probe structure extends to one end of the open circular horn.

[0026] Furthermore, the manufacturing process of the Ka-band conical beam antenna is as follows:

[0027] According to the design requirements of the Ka-band conical beam antenna, the antenna substrate is obtained by using a photo-curing additive manufacturing process;

[0028] The antenna substrate is subjected to surface metallization treatment by using a chemical copper plating method to obtain the Ka-band conical beam antenna.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a Ka-band conical beam antenna, which adopts a filtering unit to filter the input electromagnetic energy to achieve impedance bandwidth control of the antenna, and can significantly improve the out-of-band suppression capability, so that the gain of the antenna is significantly attenuated outside the frequency band, and effectively improve the anti-interference ability of the antenna; by setting a wave conversion unit, the power capacity of the antenna is effectively improved, and it is ensured that the antenna has a high radiation efficiency.

[0031] Furthermore, two spherical resonant cavities are designed in the filtering unit to form a dual-mode filtering structure, and spherical depressions are symmetrically arranged on the spherical resonant cavity. The perturbation of the electromagnetic field by the spherical depression can excite a polarization degenerate mode. An inductively coupled diaphragm is arranged in the dual-mode filtering structure to form a cross-coupling effect so that the electromagnetic wave forms two propagation paths. When an electromagnetic wave of a certain frequency is transmitted from two propagation paths to modes with equal amplitudes and a phase difference of 180°, their energies just cancel each other out, thereby introducing a transmission zero point at this frequency point, enhancing out-of-band suppression, and effectively improving the anti-interference ability of the antenna.

[0032] Furthermore, a waveguide coaxial conversion structure with three-step impedance transformation is used to realize the electromagnetic wave from TE 10 mode to TEM mode; the air-filled structure ensures the high power handling performance of the antenna.

[0033] Furthermore, the antenna substrate is obtained by a photo-curing additive manufacturing process, and the surface of the antenna substrate is metallized by chemical copper plating to form a full-metal structure antenna, ensuring that the antenna has a high radiation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the overall structure of the Ka-band conical beam antenna described in this embodiment;

[0035] Figure 2 is a longitudinal cross-sectional view of the Ka-band conical beam antenna described in the embodiment;

[0036] Figure 3 is a transverse cross-sectional view of the Ka-band conical beam antenna described in the embodiment;

[0037] Figure 4 It is a left side view of the Ka-band conical beam antenna described in the embodiment;

[0038] Figure 5 is a schematic structural diagram of a filter unit in an embodiment;

[0039] Figure 6 is a topological diagram of the filter unit in the embodiment;

[0040] Figure 7 is a graph showing the relationship between the dimensions of the input coupling structure and the output coupling structure and the external quality factor in the embodiment;

[0041] Figure 8 is a curve diagram showing the relationship between the size of the elliptical diaphragm and the mode coupling coefficient between cavities in the embodiment;

[0042] Fig. 9 is a curve diagram showing the relationship between the size of the spherical recess and the mode coupling coefficient in the cavity in the embodiment;

[0043] Fig.10 is a simulation result diagram of the scattering parameters of the filter unit in the embodiment;

[0044] Fig.11 Schematic diagram of the overall structure of the wavelet conversion unit in the embodiment;

[0045] Fig.12 is a longitudinal sectional view of a wavelet conversion unit in an embodiment;

[0046] Fig.13 4 is a diagram showing a simulation result of a reflection coefficient of a Ka-band conical beam antenna described in an embodiment;

[0047] Fig.14 1 is a simulation result diagram of the gain variation of the Ka-band conical beam antenna described in the embodiment with respect to frequency;

[0048] Fig.15 The Ka-band conical beam antenna described in the embodiment is at 33 GHz, Far-field radiation pattern when ;

[0049] Fig.16 The Ka-band conical beam antenna described in the embodiment is at 33 GHz, Far-field radiation pattern when ;

[0050] Fig.17 The Ka-band conical beam antenna described in the embodiment is at 34.5 GHz, Far-field radiation pattern when ;

[0051] Fig.18 The Ka-band conical beam antenna described in the embodiment is at 34.5 GHz, Far-field radiation pattern when .

[0052] Among them, 1 filtering unit, 2 wave co-conversion unit, 3 circular waveguide horn; 11 waveguide flange, 12 input coupling structure, 13 first spherical resonant cavity, 14 inductive coupling diaphragm, 15 second spherical resonant cavity, 16 output coupling structure; 131 first spherical depression; 151 second spherical depression; 21 conversion cavity, 22 impedance transformation structure, 23 coaxial structure; 211 rectangular cavity, 212 coaxial mounting hole; 221 first step structure, 222 second step structure, 223 third step structure; 231 cylindrical inner conductor, 232 cylindrical outer conductor; 31 circular waveguide structure, 32 open circular horn, 33 probe structure. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] As attached Figure 1-4 As shown, this embodiment provides a Ka-band conical beam antenna, comprising a filter unit 1, a waveguide conversion unit 2 and a circular waveguide horn 3 whose central axes are located on the same straight line and are connected in sequence; wherein the input end of the filter unit 1 is used to be connected to an electromagnetic energy source, the output end of the filter unit 1 is connected to the input end of the waveguide conversion unit 2, and the output end of the waveguide conversion unit 2 is connected to the feeding end of the circular waveguide horn 3.

[0055] In this embodiment, the filtering unit 1 is used to filter the input electromagnetic energy to obtain an electromagnetic wave of a preset frequency after filtering; the wave conversion unit 2 is used to convert the TE 10 The circular waveguide horn 3 is used to respond to the coaxial TEM mode electromagnetic wave and stimulate the TM 01 The mode radiates and has a conical beam pattern in the far field of the antenna.

[0056] As attached Figure 5As shown, in this embodiment, the filtering unit 1 includes a waveguide flange 11, an input coupling structure 12, a first spherical resonant cavity 13, an inductive coupling diaphragm 14, a second spherical resonant cavity 15 and an output coupling structure 16; one end of the input coupling structure 12 is connected to the waveguide flange 11, and the other end of the input coupling structure 12 is connected to one end of the first spherical resonant cavity 13; the other end of the first spherical resonant cavity 13 is connected to one end of the inductive coupling diaphragm 14, the other end of the inductive coupling diaphragm 14 is connected to one end of the second spherical resonant cavity 15, the other end of the second spherical resonant cavity 15 is connected to one end of the output coupling structure 16, and the other end of the output coupling structure 16 is connected to the input end of the waveguide conversion unit 2.

[0057] The Ka-band conical beam antenna adopts WR-28 standard waveguide feeding; wherein the waveguide flange 11 adopts WR-28 standard rectangular waveguide flange.

[0058] The input coupling structure 12 is a stepped structure, and the height of the input coupling structure 12 is the same as the height of the WR-28 standard rectangular waveguide flange; wherein the height b of the input coupling structure 12 is 3.56 mm; the input coupling structure 12 comprises a first input section and a second input section, one end of the first input section is connected to the waveguide flange 11, the other end of the first input section is connected to one end of the second input section, and the other end of the second input section is connected to the input coupling cavity of the first spherical resonant cavity 13; wherein the vertical cross-sections of the first input section and the second input section are both rectangular structures; wherein the width a of the vertical cross-section of the first input section is 7.12 mm, and the width a of the vertical cross-section of the second input section is 4.5 mm.

[0059] The first spherical resonant cavity 13 is a spherical cavity structure, and an input coupling window is provided at one end of the first spherical resonant cavity 13, and the input coupling window is connected to the second step section of the input coupling structure 12; a first resonant cavity coupling window is provided at the other end of the first spherical resonant cavity 13, and the first resonant cavity coupling window is connected to one end of the inductive coupling diaphragm 14; first spherical recesses 131 are respectively provided on both side walls of the first spherical resonant cavity 13, and the two first spherical recesses 131 are located on both sides of the longitudinal center plane of the first spherical resonant cavity 13, and the normals of the two first spherical recesses 131 coincide; wherein, the normal of the first first spherical recess 131 and the upper end of the longitudinal center plane of the first spherical resonant cavity 13 have an angle of 45°, and the normal of the second first spherical recess 131 and the lower end of the longitudinal center plane of the first spherical resonant cavity 13 have an angle of 45°.

[0060] The second spherical resonant cavity 15 is a spherical cavity structure. A second resonant cavity coupling window is provided at one end of the second spherical resonant cavity 15, and the second resonant cavity coupling window is connected to the other end of the inductive coupling diaphragm 14; an output coupling window is provided at the other end of the second spherical resonant cavity 15, and the output coupling window is connected to the output coupling structure 16; second spherical recesses 151 are respectively provided on both side walls of the second spherical resonant cavity 15, and the two second spherical recesses 151 are located on both sides of the longitudinal center plane of the second spherical resonant cavity 15, and the normals of the two second spherical recesses 151 coincide with each other; wherein, the normal of the first second spherical recess 151 forms an angle of 45° with the lower end of the longitudinal center plane of the second spherical resonant cavity 15, and the normal of the second second spherical recess 151 forms an angle of 45° with the upper end of the longitudinal center plane of the second spherical resonant cavity 15.

[0061] In this embodiment, the inner diameters of the first spherical resonant cavity 13 and the second spherical resonant cavity 15 are both r=4.23 mm; wherein, the two first spherical recesses 131 are loaded at the obliquely symmetrical 45° position along the center of the first spherical resonant cavity 13, and the two second spherical recesses 151 are loaded at the obliquely symmetrical 45° position along the center of the second spherical resonant cavity 15; the electromagnetic energy is coupled into the first resonant cavity 11 by the waveguide flange 11, and the electromagnetic energy is coupled into the first resonant cavity 13 and the second spherical resonant cavity 15 by TM 101 Mode resonance is achieved by loading two first spherical recesses 131 on both side walls of the first spherical resonant cavity 13 and two second spherical recesses 151 on both side walls of the second spherical resonant cavity 15, so as to excite two polarization degenerate electromagnetic modes in the first spherical resonant cavity and the second spherical resonant cavity. By adjusting the radius of the first spherical recess and the second spherical recess, the coupling degree of the two resonant modes in the two spherical resonant cavities is controlled.

[0062] The first resonant cavity coupling window and the second resonant cavity coupling window are both cross-shaped structures, and the inductive coupling diaphragm 14 is a cross-elliptical coupling diaphragm; the cross-elliptical coupling diaphragm is placed at the center line of the first spherical resonant cavity 13 and the second spherical resonant cavity 15, and is used to couple the electromagnetic energy between the two spherical resonant cavities; wherein one end of the cross-elliptical coupling diaphragm is connected to the first resonant cavity coupling window, and the other end of the cross-elliptical coupling diaphragm is connected to the second resonant cavity coupling window; the cross-elliptical coupling diaphragm includes a transverse elliptical coupling diaphragm and a longitudinal elliptical coupling diaphragm arranged in a cross shape; wherein the major axis of the transverse elliptical coupling diaphragm is perpendicular to the longitudinal center plane of the first spherical resonant cavity 13, and the major axis of the longitudinal elliptical coupling diaphragm is parallel to the longitudinal center plane of the first spherical resonant cavity 13; wherein the major axis of the cross-sectional ellipse of the transverse elliptical coupling diaphragm is 3.61 mm, and the minor axis is 2.17 mm; the major axis of the cross-sectional ellipse of the longitudinal elliptical coupling diaphragm is 5.52 mm, and the minor axis is 3.12 mm.

[0063] The output coupling structure 16 is a stepped structure, and the height of the output coupling structure 16 is the same as the height of the WR-28 standard rectangular waveguide flange; wherein, the height b of the output coupling structure 16 is 3.56 mm; the output coupling structure 16 comprises a first output section and a second output section, one end of the first output section is connected to the output coupling window of the second spherical resonant cavity 15, the other end of the first output section is connected to one end of the second output section, and the other end of the second output section is connected to the wave conversion unit 2; wherein, the vertical cross-section of the first output section and the vertical cross-section of the second output section are rectangular structures; wherein, the width a of the vertical cross-section of the first output section is 4.5 mm, and the width a of the vertical cross-section of the second input section is 7.12 mm.

[0064] In this embodiment, the filtering structure is realized by using a fourth-order filtering structure formed by two dual-mode resonant cavities; wherein the first spherical resonant cavity 13 and the second spherical resonant cavity 15 are basic resonant units; the spherical resonant cavity is a center frequency resonant cavity at TM 101spherical resonant cavity; there are two polarization degenerate modes in the cavity of each spherical resonant cavity, and the tuning between the modes is achieved by shortening or extending the diameter of the spherical resonant cavity in the vertical direction and the horizontal direction, and the above two directions are perpendicular to the direction of energy transmission; the mode coupling in the spherical resonant cavity is achieved by using two spherical depressions; since the tuning and coupling structures are very insensitive to the process and there is no sudden change in the structure; therefore, it can effectively reduce the problems of deterioration of filtering performance caused by processing errors and high-order modes introduced by sudden changes in the structure; the two spherical resonant cavities are coupled by a cross-elliptical coupling diaphragm to achieve mode coupling between the two spherical resonant cavities, the filtering structure controls the bandwidth of the overall conical beam antenna, and the fourth-order filtering effect is achieved with only two spherical resonant cavities, which is beneficial to the miniaturization of the system while improving the selectivity of the antenna.

[0065] As attached Figure 6 As shown, the filter mode 1 and the filter mode 2 of the filter unit 1 are polarization degenerate modes, resonating in the first spherical resonant cavity 13; the filter mode 3 and the filter mode 4 are polarization degenerate modes, resonating in the second spherical resonant cavity 15; in the spherical resonant cavity, the two spherical depressions perturb the electromagnetic wave to achieve the mode of exciting the polarization degenerate mode; in this embodiment, the dual-mode filtering structure formed by the first spherical resonant cavity and the second spherical resonant cavity has a cross coupling; this is mainly because the electromagnetic wave has two propagation paths; among which the first propagation path is filter mode 1→filter mode 2→filter mode 3→filter mode 4, and the other is filter mode 1→filter mode 4; when the amplitude of an electromagnetic wave of a certain frequency is equal and the phase difference is 180° when transmitted to the filter mode 4 by the two propagation paths, the energy will just cancel each other out, thereby introducing a transmission zero at this frequency point, strengthening the out-of-band suppression, and improving the antenna's anti-interference ability.

[0066] As attached Figure 7-9 As shown, attached Figure 7 The relationship between the input coupling structure and the output coupling structure size and the external quality factor is given in the figure; Figure 7 It can be seen that as the scaling ratio increases, the external quality factor decreases; Figure 8 The relationship between the size of the elliptical diaphragm and the coupling coefficient between cavities is given in the figure. Figure 8 It can be seen that the larger the diaphragm spacing, the larger the coupling coefficient, and the relationship is basically linear. Fig. 9 The relationship between the spherical depression size and the coupling coefficient in the cavity is given in the figure; Fig. 9 It can be seen that the larger the radius of the concave sphere, the larger the coupling coefficient.

[0067] As attached Fig.10 As shown, attached Fig.10 The simulation results of the scattering parameters of the filter unit are given in the figure; Fig.10It can be seen that the center frequency of the filter structure 1 is 33.5 GHz, the relative bandwidth is 5.9%, and the in-band return loss is better than 15 dB; and there is a pair of zero points outside the band, which further improves the out-of-band suppression capability of the filter structure 1 and enhances the selectivity of the filter structure 1.

[0068] As attached Figure 11-12 As shown, the wave conversion unit 2 includes a conversion cavity 21, an impedance transformation structure 22 and a coaxial structure 23; the conversion cavity 21 is arranged between the output end of the filter unit 1 and the feeding end of the circular waveguide horn 3; a rectangular cavity 211 is opened at the center of one end of the conversion cavity 21, and a coaxial mounting hole 212 is opened at the other end of the conversion cavity 21; the impedance transformation structure 22 is arranged in the rectangular cavity 211, and the bottom of the impedance transformation structure 22 is connected to the bottom plate of the rectangular cavity 211; the coaxial structure 23 is concentrically arranged in the coaxial mounting hole 212, one end of the coaxial structure 23 is connected to the impedance transformation structure 22, and the other end of the coaxial structure 23 is connected to the feeding end of the circular waveguide horn 3.

[0069] The impedance transformation structure 22 includes a first step structure 221, a second step structure 222 and a third step structure 223 which are sequentially arranged along the long axis center line direction of the rectangular cavity 211; the bottom surfaces of the first step structure 221, the second step structure 222 and the third step structure 223 are all connected to the bottom plate of the rectangular cavity 211, and the top surfaces of the first step structure 221, the second step structure 222 and the third step structure 223 extend toward the top plate direction of the rectangular cavity 211; the first step structure 221, the second step structure 222 and the third step structure 223 are all rectangular parallelepiped structures, and their heights increase sequentially; a rectangular groove is opened on the top surface of the third step structure, and the rectangular groove is arranged close to one side of the coaxial mounting hole 212.

[0070] In this embodiment 1, the size characteristics of the rectangular cavity 211 are: length a×height b=7.12mm×3.56mm; the size characteristics of the first step structure 221 are: length L1×width S×height H1=2.08mm×1.46mm×0.61mm; the size characteristics of the second step structure 222 are: length L2×width S×height H2=1.71mm×1.46mm×1.40mm; the size characteristics of the third step structure 223 are: length L3×width S×height H3=0.85mm×1.46mm×1.11mm; wherein the height H2 is the distance between the top surface of the first step structure 221 and the top surface of the second step structure 222, and the height H3 is the distance between the top surface of the second step structure 222 and the top surface of the third step structure 223; the size characteristics of the rectangular groove are: Lt=0.55mm.

[0071] The coaxial structure 23 is connected to the third stepped structure 223 and is placed at the end center of the third stepped structure 223; the coaxial structure 23 includes a coaxially arranged cylindrical inner conductor 231 and a cylindrical outer conductor 232; the cylindrical outer conductor 232 is coaxially inserted into the coaxial mounting hole 212, and the cylindrical inner conductor 232 is coaxially arranged in the cylindrical outer conductor 232; wherein the space between the cylindrical inner conductor 231 and the cylindrical outer conductor 232 is filled with air; wherein the cylindrical inner conductor 231 and the cylindrical outer conductor 232 both adopt a metal conductor structure, and the diameter of the cylindrical inner conductor 231 is D in =0.8mm, the diameter D of the cylindrical outer conductor 232 out =2mm.

[0072] In this embodiment, the circular waveguide speaker 3 includes a circular waveguide structure 31, an open circular speaker 32 and a probe structure 33. In the circular waveguide speaker 3, the probe structure 33 is used to feed electricity to excite the TM in the circular waveguide structure 31. 01 The electric field of the mode is adjusted by adjusting the size structure of the open circular horn 32 to adjust the gain and beam tilt of the cone beam in the far field of the antenna.

[0073] The circular waveguide structure 31 is concentrically connected to the open circular horn 32; wherein, one end of the circular waveguide structure 31 is connected to the waveguide conversion unit 2, and the other end of the circular waveguide structure 31 is connected to the open circular horn 32; the probe structure 33 is concentrically inserted in the center of the circular waveguide structure 31, one end of the probe structure 33 is connected to the output end of the waveguide conversion unit 2, and the other end of the probe structure 33 extends to one end of the open circular horn 32; wherein, the probe structure 33 is connected to the coaxial structure 23 and extends into the circular waveguide structure 31; wherein the extension distance of the probe structure 33 is 2mm; the inner diameter of the circular waveguide structure is 8.16mm, and the height is 4mm; the inner diameter of the open circular horn gradually increases from 8.16mm to 10.9mm, and the height is 9.22mm.

[0074] Production process:

[0075] The manufacturing process of the Ka-band cone-beam antenna described in this embodiment is as follows:

[0076] According to the design requirements of the antenna, the antenna substrate is processed by using the photo-curing additive manufacturing process;

[0077] The antenna substrate is subjected to surface metallization treatment by using a chemical copper plating method to obtain the Ka-band conical beam antenna.

[0078] In this embodiment, stereolithography (SLA) additive manufacturing technology is used for processing, and after stereolithography, surface metallization is achieved by chemical copper plating, so that the antenna has the electromagnetic properties of a full metal antenna. The advantage of the antenna using the processing method is that it is light in weight and reduces the mechanical burden of the system. Compared with the traditional CNC mechanical milling method, the processing cost is significantly reduced.

[0079] As attached Fig.13 As shown, attached Fig.13 The reflection coefficient simulation result diagram of the Ka-band conical beam antenna is given in the figure; Fig.13 It can be seen that the Ka-band conical beam antenna can achieve a return loss better than 10 dB in the frequency range of 32.70 GHz-34.95 GHz; and due to the design of the filter unit 1, four resonance poles can be clearly observed in the reflection coefficient curve.

[0080] As attached Fig.14 As shown, attached Fig.14 The simulation results of the gain variation of the Ka-band conical beam antenna with frequency are given in FIG. Fig.13 It can be seen that within the impedance bandwidth, the maximum gain of the Ka-band conical beam antenna is 6.3dBi, the gain variation within the operating frequency band is less than 0.5dB, and the out-of-band gain attenuation exceeds 35dB / GHz.

[0081] As attached Figure 15-16 As shown, attached Fig.15 The Ka-band conical beam antenna at 33 GHz is given in The far-field radiation pattern when Fig.16 The Ka-band conical beam antenna at 33 GHz is given in Far-field radiation pattern when Figure 15-16 It can be seen that the far-field gain radiation pattern of the Ka-band conical beam antenna at 33 GHz; the gain of the Ka-band conical beam antenna is 6.2 dBi, the beam tilt angle is 34°, the 3dB beam width is 38°, and the cross-polarization is better than 20 dB.

[0082] As attached Figure 17-18 As shown, attached Fig.17 The Ka-band conical beam antenna at 34.5 GHz is given in The far-field radiation pattern when Fig.18 The Ka-band conical beam antenna at 34.5 GHz is given in Far-field radiation pattern when Figure 17-18It can be seen that the Ka-band conical beam antenna gain is 6.1dBi, the beam tilt angle is 37°, the 3dB beam width is 41°, and the cross polarization is better than 20dB.

[0083] The Ka waveguide conical beam antenna described in this embodiment uses a fourth-order dual-mode spherical filter structure formed by two spherical resonant cavities to control the working bandwidth of the conical beam antenna, improve the antenna out-of-band suppression, and improve the anti-interference ability; a stepped waveguide coaxial conversion structure is used to convert the electromagnetic field TE in the waveguide 10 The mode is converted into a coaxial TEM mode to feed the circular waveguide horn structure; and the coaxial probe is used to excite the TM in the circular waveguide horn structure. 01 mode, radiating a conical beam in the far field, and the all-metal structure meets the high power capacity requirements; by setting spherical depressions on both sides of the spherical resonant cavity, the polarization degenerate mode in the cavity is excited and the coupling strength that meets the designed bandwidth and out-of-band suppression is provided; the stepped waveguide coaxial conversion structure is used as the mode conversion structure of the fourth-order dual-mode filtering structure and the conical beam circular horn, and a three-level stepped structure is used to realize the conversion of mode and impedance, and realize the integrated design of the waveguide filter and the conical beam radiation structure, which has the characteristics of low loss, high efficiency and high power capacity of the all-metal antenna, and can improve the detection distance of the fuze system; it also significantly improves the out-of-band suppression capability and improves the anti-interference performance of the fuze system.

[0084] In the present invention, a waveguide structure is used to improve the power capacity of the antenna, and the all-metal electromagnetic performance makes the antenna have a very high radiation efficiency; the fourth-order filtering structure based on the single-cavity dual-mode not only controls the impedance bandwidth of the antenna, but also significantly improves the out-of-band suppression capability, so that the antenna gain is significantly attenuated outside the frequency band, and the antenna's anti-interference ability is improved. In addition, the tuning and coupling structure of the present invention is very low in sensitivity to the process, and there is no sudden change in the structure, which can well reduce the problems of deterioration of filtering performance caused by processing errors and high-order modes introduced by sudden structures.

[0085] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A Ka-band conical beam antenna, characterized in that: It comprises a filtering unit (1), a waveguide conversion unit (2) and a circular waveguide horn (3) whose central axes are located on the same straight line and are connected in sequence; The filtering unit (1) is used to filter the input electromagnetic energy to obtain an electromagnetic wave of a preset frequency after filtering; The wave conversion unit (2) is used to convert the TE 10 The mode electromagnetic wave is converted into a coaxial TEM mode electromagnetic wave; The circular waveguide horn (3) is used to respond to the electromagnetic wave of the coaxial TEM mode and stimulate the TM 01 The mode radiates and radiates a conical beam pattern in the far field of the antenna; The filtering unit (1) comprises a waveguide flange (11), an input coupling structure (12), a first spherical resonant cavity (13), an inductive coupling diaphragm (14), a second spherical resonant cavity (15) and an output coupling structure (16); One end of the input coupling structure (12) is connected to the waveguide flange (11), and the other end of the input coupling structure is connected to one end of the first spherical resonant cavity (13); the other end of the first spherical resonant cavity (13) is connected to one end of the inductive coupling diaphragm (14), the other end of the inductive coupling diaphragm (14) is connected to one end of the second spherical resonant cavity (15), the other end of the second spherical resonant cavity (15) is connected to one end of the output coupling structure (16), and the other end of the output coupling structure (16) is connected to the input end of the waveguide conversion unit (2); An input coupling window is provided at one end of the first spherical resonant cavity (13), and the input coupling window is used to be connected to the input coupling structure (12); a first resonant cavity coupling window is provided at the other end of the first spherical resonant cavity, and the first resonant cavity coupling window is used to be connected to one end of the inductive coupling diaphragm (14); The side walls of the first spherical resonant cavity (13) are respectively provided with first spherical recesses (131), the two first spherical recesses (131) are located on both sides of the longitudinal center plane of the first spherical resonant cavity (13), and the normal lines of the two first spherical recesses (131) coincide with each other; wherein the normal line of the first first spherical recess (131) and the upper end of the longitudinal center plane of the first spherical resonant cavity (13) form an angle of 45°, and the normal line of the second first spherical recess (131) and the lower end of the longitudinal center plane of the first spherical resonant cavity (13) form an angle of 45°; A second resonant cavity coupling window is provided at one end of the second spherical resonant cavity (15), and the second resonant cavity coupling window is used to be connected to the other end of the inductive coupling diaphragm (14); an output coupling window is provided at the other end of the second spherical resonant cavity (15), and the output coupling window is used to be connected to the output coupling structure (16); Second spherical recesses (151) are respectively provided on the side walls of both sides of the second spherical resonant cavity (15), and the two second spherical recesses (151) are located on both sides of the longitudinal center plane of the second spherical resonant cavity (15), and the normal lines of the two second spherical recesses (151) coincide with each other; wherein the normal line of the first second spherical recess (151) and the lower end of the longitudinal center plane of the second spherical resonant cavity (15) form an angle of 45°, and the normal line of the second second spherical recess (151) and the upper end of the longitudinal center plane of the second spherical resonant cavity (15) form an angle of 45°.

2. A Ka-band conical beam antenna according to claim 1, characterized in that: The inductive coupling diaphragm (14) is a cross-elliptical coupling diaphragm; the cross-elliptical coupling diaphragm is placed at the center connecting line of the first spherical resonant cavity (13) and the second spherical resonant cavity (15); The cross-elliptical coupling diaphragm comprises a transverse elliptical coupling diaphragm and a longitudinal elliptical coupling diaphragm arranged in a cross shape; wherein the major axis of the transverse elliptical coupling diaphragm is arranged perpendicular to the longitudinal center plane of the first spherical resonant cavity (13), and the major axis of the longitudinal elliptical coupling diaphragm is arranged parallel to the longitudinal center plane of the first spherical resonant cavity (13).

3. The Ka-band conical beam antenna according to claim 1, characterized in that: The waveguide conversion unit (2) comprises a conversion cavity (21), an impedance conversion structure (22) and a coaxial structure (23); The conversion cavity (21) is arranged between the output end of the filter unit (1) and the feeding end of the circular waveguide horn (3); a rectangular cavity (211) is provided at the center of one end of the conversion cavity (21), and a coaxial mounting hole (212) is provided at the other end of the conversion cavity (21); the impedance transformation structure (22) is arranged in the rectangular cavity (211), and the bottom of the impedance transformation structure (22) is connected to the bottom plate of the rectangular cavity (211); the coaxial structure (23) is coaxially arranged in the coaxial mounting hole (212), one end of the coaxial structure (23) is connected to the impedance transformation structure (22), and the other end of the coaxial structure (23) is connected to the feeding end of the circular waveguide horn (3).

4. A Ka-band conical beam antenna according to claim 3, characterized in that: The impedance transformation structure (22) comprises a first step structure (221), a second step structure (222) and a third step structure (223) which are sequentially arranged along the long axis center line direction of the rectangular cavity (211); The bottom surfaces of the first stepped structure (221), the second stepped structure (222) and the third stepped structure (223) are all connected to the bottom plate of the rectangular cavity (211), and the top surfaces of the first stepped structure (221), the second stepped structure (222) and the third stepped structure (223) extend toward the top plate of the rectangular cavity (211); The first stepped structure (221), the second stepped structure (222) and the third stepped structure (223) are all rectangular parallelepiped structures, and their heights increase successively; a rectangular groove is provided on the top surface of the third stepped structure, and the rectangular groove is arranged close to one side of the coaxial mounting hole (212).

5. The Ka-band conical beam antenna according to claim 3, characterized in that: The coaxial structure (23) comprises a coaxially arranged cylindrical inner conductor (231) and a cylindrical outer conductor (232); the cylindrical outer conductor (232) is coaxially inserted into the coaxial mounting hole (212); and the cylindrical inner conductor (231) is coaxially arranged in the cylindrical outer conductor (232); wherein air is filled between the cylindrical inner conductor (231) and the cylindrical outer conductor (232).

6. The Ka-band conical beam antenna according to claim 1, characterized in that: The circular waveguide horn (3) comprises a circular waveguide structure (31), an open circular horn (32) and a probe structure (33); the circular waveguide structure (31) and the open circular horn (32) are concentrically connected; wherein one end of the circular waveguide structure (31) is connected to the waveguide conversion unit (2), and the other end of the circular waveguide structure (31) is connected to the open circular horn (32); The probe structure (33) is coaxially inserted in the center of the circular waveguide structure (31), one end of the probe structure (33) is connected to the output end of the waveguide conversion unit (2), and the other end of the probe structure (33) extends toward one end of the open circular horn (32).

7. The Ka-band conical beam antenna according to claim 1, characterized in that: The manufacturing process of the Ka-band conical beam antenna is as follows: According to the design requirements of the Ka-band conical beam antenna, the antenna substrate is obtained by using a photo-curing additive manufacturing process; The antenna substrate is subjected to surface metallization treatment by using a chemical copper plating method to obtain the Ka-band conical beam antenna.

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