A wide beam filtered end-fire antenna

Abstract

The invention discloses a wide-beam filtering end-fire antenna, in which double-sided stepped three-wire parallel resonators are placed on the upper and lower sides of the cut angle of a trapezoidal top-open resonant cavity, and the beam broadening effect, radiation impedance adjustment effect and resonance effect of the double-sided stepped three-wire parallel resonator on vertical polarization radiation are utilized, and the resonance, coupling and beam broadening effects of the trapezoidal top-open resonant cavity and the resonance of two substrate integrated waveguide resonant cavities are combined to realize wide-beam end-to-end radiation with a fourth-order filtering response, and can take into account vertical polarization work, functional fusion degree, beam broadening degree, frequency selectivity, size and cross-polarization level.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a wide beam filtering end-fire antenna. Background Art

[0002] The maximum radiation direction of the end-fire antenna is in the direction of the antenna axis. It has the advantages of high gain, simple structure, low profile and easy integration with RF circuits. The wide-beam end-fire antenna has a wide beam width in the antenna ground plane, which is beneficial for wide coverage scenarios or improving the scanning range of the end-fire antenna phased array in the ground plane. On the basis of wide-beam end-fire, the filtering function is further integrated to realize a wide-beam filtered end-fire antenna, which enables a single end-fire antenna to simultaneously realize wide-beam radiation and filtering functions, effectively reducing the cost and complexity of the wireless system, providing better signal selectivity, suppressing out-of-band interference and stray signals, and thus improving communication quality. Therefore, the wide-beam filtered end-fire antenna has many advantages and has high engineering and application value for improving the performance of wireless communication systems.

[0003] Most of the current wide-beam end-fire antennas are horizontally polarized and do not have filtering functions. The main design methods are: adding refractive metamaterials on both sides of the dipole to refract electromagnetic waves; adding a non-resonant director along the bending direction to the bent dipole; introducing a vertical arm into the bent dipole; and a four-blade conical vibrator. The above methods achieve horizontally polarized beam broadening, but fail to integrate filtering functions and achieve vertical polarization. There are one or more problems such as low beam broadening, no increase in the number of resonance orders, high cross-polarization level, and large size. For wide-beam end-fire antennas that integrate filtering functions, there is only one way to achieve horizontal polarization, that is, the method of cascading multiple-order resonant cavities with bent dipoles, so the vertical polarization method cannot be achieved, and there are problems such as too many non-radiative resonators, low functional integration, insufficient frequency selectivity, and high cross-polarization level. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a wide-beam filtered end-fire antenna is proposed, which can realize vertical polarization operation while taking into account the functional integration, beam widening, frequency selectivity, size and cross-polarization level.

[0005] Technical solution: A wide beam filter end-fire antenna, comprising from left to right a substrate integrated waveguide resonant cavity 1, a substrate integrated waveguide resonant cavity 2, a trapezoidal top open resonant cavity, and two double-sided stepped three-wire parallel resonators; the antenna is symmetrical about the center plane, and the two double-sided stepped three-wire parallel resonators are respectively located outside the two cut corners of the trapezoidal top open resonant cavity;

[0006] The coaxial probe is connected to the substrate integrated waveguide resonant cavity 1, and the transmission signal is fed to the substrate integrated waveguide resonant cavity 1 through the coaxial probe, and is coupled step by step to the substrate integrated waveguide resonant cavity 2, the trapezoidal top open resonant cavity, and the two double-sided stepped three-wire parallel resonators.

[0007] Furthermore, the trapezoidal top open resonant cavity includes two layers of cut-corner rectangular metal grounds arranged relatively on the upper and lower surfaces of the dielectric substrate; the cut-corner rectangular metal ground is composed of a trapezoidal part at the top and a rectangular part at the bottom, and the edge of the rectangular part is provided with a metallized through hole connecting the upper and lower layers; the length of the cut-corner rectangular metal ground is between 0.16λ0 and 0.20λ0, the width is between 0.25λ0 and 0.29λ0, the cut-corner length is between 0.04λ0 and 0.08λ0, the angle between the cut-corner direction and the horizontal line is between 47° and 53°, and λ0 is the air wavelength corresponding to the center frequency.

[0008] Furthermore, the double-sided stepped three-wire parallel resonator includes two layers of long metal strips and short metal strips arranged relatively on the upper and lower surfaces of the dielectric substrate, the length of the short metal strips is between 0.19λ0 and 0.23λ0, and the length of the long metal strips is between 0.21λ0 and 0.25λ0; on each side of the dielectric substrate, two long metal strips are symmetrically located on both sides of one short metal strip; three metal strips are arranged in parallel, flush with one end close to the cut-corner rectangular metal ground, and parallel to the incision of the cut-corner rectangular metal ground.

[0009] Beneficial effects: Existing wide beam end-fire antennas or wide beam filtering end-fire antennas cannot support vertical polarization work, and have one or more of many problems such as low functional integration, low beam broadening, poor frequency selectivity, large size and high cross-polarization level. The present invention places double-sided stepped three-wire parallel resonators on the upper and lower sides of the cut angle of the trapezoidal top opening resonant cavity, and utilizes the beam broadening effect, radiation impedance adjustment effect and resonance effect of the double-sided stepped three-wire parallel resonator on vertical polarization radiation, combined with the resonance, coupling and beam broadening effects of the trapezoidal top opening resonant cavity and the resonance of two substrate integrated waveguide resonant cavities, to achieve wide beam end radiation with fourth-order filtering response, and can take into account vertical polarization work, functional integration, beam broadening, frequency selectivity, size and cross-polarization level.

[0010] Specifically, the double-sided stepped three-wire parallel resonator is composed of a double-layer metal long and short strips and a dielectric substrate. The length of the metal short strip is between 0.19λ0 and 0.23λ0, and the length of the metal long strip is between 0.21λ0 and 0.25λ0. The long and short step distribution can correspond to the vertical polarization guiding effect of a wider frequency band, realize beam broadening within the entire frequency band, and can couple and introduce the vertical polarization signal in the trapezoidal top opening resonant cavity, thereby improving the overall radiation impedance matching and providing a reflection zero point within the working frequency band.

[0011] The trapezoidal top open resonant cavity is composed of two layers of cut-corner rectangular metal ground, three rows of metalized through holes and a dielectric substrate. The cut-corner length is between 0.04λ0 and 0.08λ0, and the angle between the cut-corner direction and the horizontal line is between 47° and 53°. It works at TE 101 The half-mode mode of the double-sided stepped three-wire parallel resonator is beneficial to improving the strength of the vertical electric field at both ends, ensuring that there is enough vertical polarization signal coupled to the double-sided stepped three-wire parallel resonator. At the same time, it is beneficial to reduce the resonant frequency of the trapezoidal top opening resonant cavity, realize its miniaturization, facilitate beam broadening, and provide a reflection zero point within the working frequency band.

[0012] The substrate integrated waveguide resonant cavity 1 and the substrate integrated waveguide resonant cavity 2 are composed of two layers of rectangular metal ground, a dielectric substrate and metallized through holes around them, and both work in TE 101 mode, each providing a reflection zero point within the working frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional structure diagram of the wide beam filtering end-fire antenna of the present invention;

[0014] Figure 2 It is a schematic diagram of the top view of the structure of the wide beam filtering end-fire antenna of the present invention;

[0015] Figure 3 It is a schematic diagram of the upward structure of the wide beam filtering end-fire antenna of the present invention;

[0016] Figure 4 For the embodiment of the present invention S Parameter simulation response;

[0017] Figure 5 The present invention is added with a double-sided ladder three-wire parallel resonator before and after H Surface simulation beam width comparison;

[0018] Figure 6 is a gain simulation curve of an embodiment of the present invention;

[0019] Figure 7The embodiment of the present invention at 17.53 GHz, 18 GHz, 18.5 GHz, 18.93 GHz H Surface simulation pattern. DETAILED DESCRIPTION

[0020] The present invention will be further explained below in conjunction with the accompanying drawings.

[0021] like Figures 1 to 3 As shown, a wide beam filtering end-fire antenna is composed of a top metal structure 1, a dielectric substrate 2, a bottom metal structure 3, a metallized through hole 4, and a coaxial probe 5.

[0022] The top metal structure 1 and the bottom metal structure 3 are respectively located on the upper surface and the lower surface of the dielectric substrate 2 . The metallized through hole 4 vertically penetrates the dielectric substrate 2 to connect the top metal structure 1 and the bottom metal structure 3 .

[0023] The top metal structure 1 is composed of a top rectangular metal ground 101 with a top circular groove 106, a top rectangular metal ground 2 102, a top cut corner rectangular metal ground 103, four top metal short strips 104 and two top metal long strips 105, and is symmetrical about the horizontal line. The top rectangular metal ground 101, the top rectangular metal ground 2 102 and the top cut corner rectangular metal ground 103 are arranged from left to right, and the width (x-axis direction) of the top cut corner rectangular metal ground 103 is smaller than the width of the top rectangular metal ground 2 102. Among them, the length (y-axis direction) of the top cut corner rectangular metal ground 103 is between 0.16λ0~0.20λ0, the width (x-axis direction) is between 0.25λ0~0.29λ0, the cut corner length is between 0.04λ0~0.08λ0, the angle between the cut corner direction and the horizontal line is between 47°~53°, and λ0 is the air wavelength corresponding to the center frequency. The top metal short strips 104 are symmetrically located on both sides of the top metal long strips 105, and the two are flush with one end close to the top corner cut rectangular metal ground 103, and are parallel to the upper and lower cuts of the top corner cut rectangular metal ground 103, wherein the length of the top metal short strips 104 is between 0.19λ0 and 0.23λ0, and the length of the top metal long strips 105 is between 0.21λ0 and 0.25λ0.

[0024] The bottom metal structure 3 is composed of a bottom rectangular metal ground 1 301 with a bottom circular groove 307, a bottom rectangular metal ground 2 302, a bottom corner rectangular metal ground 303, four bottom metal short strips 304, two bottom metal long strips 305 and a bottom rectangular metal ground 3 306. Among them, the bottom rectangular metal ground 1 301, the bottom rectangular metal ground 2 302, the bottom corner rectangular metal ground 303, the bottom metal short strips 304 and the bottom metal long strips 305 are aligned with the top rectangular metal ground 1 101, the top rectangular metal ground 2 102, the top corner rectangular metal ground 103, the top metal short strips 104 and the top metal long strips 105 respectively, and the sizes are the same.

[0025] The probe core 501 of the coaxial probe 5 vertically passes through the bottom circular groove 307 and is flush with the top circular groove 106. In this embodiment, the coaxial probe 5 adopts an SMA (SubMiniature version A) interface. In order to ensure that the SMA head is well grounded, the bottom rectangular metal ground 306 is located on the left side of the bottom rectangular metal ground 1 301 and contacts the SMA head.

[0026] The metallized through hole 4 is composed of a vertical metallized through hole 1 401, a vertical metallized through hole 2 402 with a non-porous area in the middle, a vertical metallized through hole 3 403 with a non-porous area in the middle, two long horizontal metallized through holes 404, and two short horizontal metallized through holes 405. Among them, the length of the non-porous area of ​​the vertical metallized through hole 2 402 is between 0.11λ0 and 0.15λ0, and the length of the non-porous area of ​​the vertical metallized through hole 3 403 is between 0.12λ0 and 0.16λ0. The two long horizontal metallized through holes 404 are located at the upper and lower edges respectively, the vertical metallized through hole 1 401 is located at the left edge, the vertical metallized through hole 3 403 is located at the right edge, and the vertical metallized through hole 2 402 is located between the vertical metallized through hole 1 401 and the vertical metallized through hole 3 403. The two short horizontal metallized through holes 405 are located at the upper and lower edges of the cut-corner rectangular metal ground.

[0027] The top rectangular metal ground 101, the bottom rectangular metal ground 301, the vertical metallized through hole 1 401, the vertical metallized through hole 2 402, the two long horizontal metallized through holes 404 and the dielectric substrate 2 form a substrate integrated waveguide resonant cavity 1. The top rectangular metal ground 2 102, the bottom rectangular metal ground 2 302, the vertical metallized through hole 2 402, the vertical metallized through hole 3 403, the two long horizontal metallized through holes 404 and the dielectric substrate 2 form a substrate integrated waveguide resonant cavity 2. The top rectangular metal ground 103, the bottom rectangular metal ground 303, the vertical metallized through hole 3 403, the two short horizontal metallized through holes 405 and the dielectric substrate 2 form a trapezoidal top opening resonant cavity. The top metal short strip 104, the top metal long strip 105, the bottom metal short strip 304, the bottom metal long strip 305 and the dielectric substrate 2 form two double-sided ladder three-wire parallel resonators.

[0028] In the present invention, the transmission signal is fed from the bottom coaxial probe to the substrate integrated waveguide resonant cavity 1, and is further coupled to the substrate integrated waveguide resonant cavity 2, the trapezoidal top opening resonant cavity, and the double-sided stepped three-wire parallel resonator. Under the action of the overall structure, wide-beam filtering end-to-end radiation is achieved.

[0029] In this process, the internal electric field of the double-sided ladder three-wire parallel resonator is perpendicular to the strips, and the long and short strips are distributed in half wavelengths along their lengths, and the horizontal electric fields between the long and short strips cancel each other out, thus forming a vertically polarized resonator, providing a resonance point for the filter response; at the same time, the long and short step distribution can correspond to the vertical polarization guidance effect within a wider frequency band, and the length of each strip of the double-sided ladder three-wire parallel resonator can adjust the frequency coverage of the vertical polarization guidance. In addition, the double-sided ladder three-wire parallel resonator can couple the vertical polarization signal in the trapezoidal top open resonant cavity, which is conducive to improving the overall radiation impedance matching.

[0030] The trapezoidal top open resonant cavity has a working frequency band of TE 101 The half-mode mode, whose internal electric field points perpendicular to the substrate, realizes vertical polarization operation. The cut angles at both ends are conducive to improving the strength of the vertical electric field, ensuring that there are enough vertical polarization signals coupled to the double-sided ladder three-wire parallel resonator. The coupling degree between the two is controlled by the distance between the two and the length in the cut angle direction; at the same time, the cut angle is conducive to reducing the resonant frequency of the trapezoidal top open resonant cavity and realizing its miniaturization, which is also conducive to beam broadening. When the trapezoidal top open resonant cavity resonates, it also provides a reflection zero point within the working frequency band.

[0031] Both the substrate integrated waveguide cavity 1 and the substrate integrated waveguide resonant cavity 2 operate at TE 101mode, each providing a reflection zero point within the working frequency band. Therefore, four reflection zero points can be formed as a whole, forming a fourth-order filter response and a fast roll-off of the out-of-band gain, while the beam broadening mainly depends on the double-sided stepped three-wire parallel resonator and the trapezoidal top open resonant cavity.

[0032] Compared with the best existing technology, the present invention can realize the vertical polarization wide beam filter end-fire antenna, and can take into account the functional integration, beam width, frequency selectivity, size and cross-polarization level. The substrate used in this embodiment is Rogers RO4003C, and the overall size of the antenna is: 0.73λ0×0.93λ0×0.05λ0. The simulated matching response is as follows Figure 4 As shown, it can be seen that it is a fourth-order filter response with four reflection zeros. The -10-dB impedance matching bandwidth covers 17.4-19.0 GHz, that is, the relative bandwidth is 8.7%. Figure 5 The present embodiment is compared with the case without double-sided ladder three-wire parallel resonator structure. H The simulation results of the beam width show that after adding the double-sided stepped three-wire parallel resonator, the beam width is within the range of 17.4-19.0GHz. H The surface beam width widens from 110°~130° to 124°~194°, and it can be seen that the beam width is significantly widened. Figure 6 This is a simulation gain curve of this embodiment. It can be seen that the in-band gain is between 0.32-1.49dBi, the out-of-band gain rolls off quickly, and the frequency selectivity (the ratio of 3dB bandwidth to 10dB bandwidth) can reach 0.8. Figure 7 (a) to (d) show the simulated H-plane radiation patterns at 17.53 GHz, 18 GHz, 18.5 GHz, and 18.93 GHz. Figure 7 It can be seen that the present invention has a wider beam radiation within the working frequency band, and the cross-polarization level is low, and the main polarization is vertical polarization.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A wide beam filtered end-fire antenna, characterized in that: It includes a top metal structure, a dielectric substrate, a bottom metal structure, a metallized through hole, and a coaxial probe; the top metal structure and the bottom metal structure are respectively located on the upper surface and the lower surface of the dielectric substrate, and the metallized through hole vertically penetrates the dielectric substrate to connect the top metal structure and the bottom metal structure; The top metal structure is symmetrical about the horizontal line, including top rectangular metal ground 1, top rectangular metal ground 2, top corner rectangular metal ground, four top metal short strips and two top metal long strips arranged from left to right; a top metal short strip is symmetrically distributed on both sides of each top metal long strip, and the four top metal short strips and the two top metal long strips together form two double-sided step three-line parallel structures; in the two double-sided step three-line parallel structures, the top metal short strips and the top metal long strips are flush with one end of the top corner rectangular metal ground, and are parallel to the upper and lower cuts of the top corner rectangular metal ground respectively; The bottom metal structure includes a bottom rectangular metal ground 1, a bottom rectangular metal ground 2, a bottom corner rectangular metal ground, four bottom metal short strips, two bottom metal long strips and a bottom rectangular metal ground 3 with bottom circular grooves, which are aligned with the top rectangular metal ground 1, the top rectangular metal ground 2, the top corner rectangular metal ground, the top metal short strips and the top metal long strips respectively; The probe core of the coaxial probe vertically passes through the bottom circular groove and is flush with the top circular groove; among the metallized through holes, two long horizontal rows of metallized through holes are located at the upper and lower edges respectively, the vertical row of metallized through holes is located at the left edge, the vertical row of metallized through holes is located at the right edge, and the vertical row of metallized through holes is located between the vertical row of metallized through holes and the vertical row of metallized through holes; the two short horizontal rows of metallized through holes are located at the upper and lower edges of the corner-cut rectangular metal ground; From left to right, a substrate integrated waveguide resonant cavity 1, a substrate integrated waveguide resonant cavity 2, a trapezoidal top open resonant cavity and two double-sided stepped three-wire parallel resonators are formed; the transmission signal is fed to the substrate integrated waveguide resonant cavity 1 through the coaxial probe, and is coupled to the substrate integrated waveguide resonant cavity 2, the trapezoidal top open resonant cavity and the two double-sided stepped three-wire parallel resonators step by step in sequence.

2. The wide beam filtered end-fire antenna according to claim 1, characterized in that: The length of the top-layer cut-corner rectangular metal ground is between 0.16λ0 and 0.20λ0, the width is between 0.25λ0 and 0.29λ0, the cut-corner length is between 0.04λ0 and 0.08λ0, the angle between the cut-corner direction and the horizontal line is between 47° and 53°, and λ0 is the air wavelength corresponding to the center frequency.

3. The wide beam filtering end-fire antenna according to claim 2, characterized in that: The length of the short metal strip of the top layer is between 0.19λ0 and 0.23λ0, and the length of the long metal strip of the top layer is between 0.21λ0 and 0.25λ0.

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