Dual-band wideband omnidirectional antenna based on multi-mode resonance

Abstract

A kind of dual-band broadband omnidirectional antenna based on multimode resonance, comprising radiation structure, feed structure and feed connector;Radiation structure includes upper microstrip layer, radiation structure dielectric plate, metal column and lower microstrip layer arranged in turn;Upper microstrip layer includes two symmetrical radiation branches, and feed connection is arranged between the two radiation branches;Feed structure is vertically inserted on the radiation structure at one end, is connected with the radiation structure by solder pad, and is connected with the feed connector at the other end.The symmetrical radiation branch excites the first and second odd-order dipole mode, ensures the good omnidirectional radiation of low frequency band, and produces the resonance of high frequency band.The direction pattern of the second odd-order dipole mode current on the first long side and the second long side of the U-shaped bending unit is opposite, which can change the pattern of the mode into an omnidirectional pattern.The bending loading branch introduces the first even-order dipole mode, improves the impedance matching of high and low frequency bands, expands the bandwidth of high and low frequency, and at the same time reduces the size of the antenna.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antenna, in particular to a dual-band wideband omnidirectional antenna based on multi-mode resonance. BACKGROUND

[0002] Omnidirectional antennas have been widely used due to their good omnidirectional radiation characteristics. However, the bandwidth of traditional half-wave dipole antennas is narrow, and they can usually only ensure omnidirectional radiation in a single frequency band, which greatly limits their application in communication systems.

[0003] To solve this problem, researchers have proposed some effective methods in the past two decades, such as combining low-frequency antennas and high-frequency antennas. Patent "omnidirectional antenna" (CN 207474675 U) discloses: through the combination of low-frequency ring antenna and high-frequency ring antenna to form a dual-band ring antenna; the antenna can work in low frequency band (0.768-0.96GHz) and high frequency band (1.7-2.7GHz), but the half-wave beam width of the high frequency band is narrow and the directional diagram is unstable. Patent "dual-band antenna" (CN 109659675 B) discloses: by capacitively coupling a patch antenna to a monopole antenna, exciting the TM20 mode of the patch and the quarter-wave monopole mode of the monopole, the antenna works in dual-band, and the radiation pattern almost does not change when the impedance bandwidth exceeds 80%, but the maximum radiation direction of the antenna is not on the plane of 0 degree elevation. Therefore, it is an urgent problem in the field of antenna technology to design a dual-band wideband omnidirectional antenna with wide bandwidth, small size, stable radiation characteristics and dual-band, which has great practical significance and application demand. SUMMARY

[0004] The technical problem to be solved by the present application is to design a dual-band wideband omnidirectional antenna with wide bandwidth, small size and stable radiation characteristics.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] A dual-band wideband omnidirectional antenna based on multi-mode resonance, comprising a radiation structure, a feed structure and a feed connector; the radiation structure comprises an upper microstrip layer, a radiation structure dielectric plate, a metal column and a lower microstrip layer arranged in sequence; the upper microstrip layer comprises two symmetrical radiation branches, and a feed connection part is arranged between the two radiation branches; the radiation structure dielectric plate has a slot for inserting the feed structure; the lower microstrip layer comprises a first solder pad and a second solder pad, and the first solder pad and the second solder pad are connected with the upper microstrip layer through the metal column; the feed structure comprises a feed layer, a feed structure dielectric plate and a ground plate arranged in sequence, one end of the feed structure is vertically inserted into the radiation structure and connected with the radiation structure through a solder pad, and the other end is connected with the feed connector; the feed layer of the feed structure is connected with the inner core of the feed connector, and the ground plate is connected with the outer conductor of the feed connector.

[0007] In one embodiment, the two symmetrical radiation branches excite first and second odd-order dipole modes, i.e. half-wavelength dipole and three half-wavelength dipole modes, wherein the first odd-order dipole mode ensures omnidirectional radiation in a low frequency band, and the second odd-order dipole mode generates resonance of the antenna in a high frequency band.

[0008] In one embodiment, each of the radiation branches is composed of a pair of main branches, a pair of loading branches and a pair of U-shaped bending units; the two radiation branches are symmetrical about the Y direction or the X direction; the pair of main branches in each radiation branch are symmetrical about the X direction or the Y direction and are connected on the inner side; the loading branches are in a bending structure and are respectively connected to the outer side of one main branch; the first long side and the second long side of the U-shaped bending unit are in the same symmetrical direction as the main branch, the U-shaped bending unit is respectively connected to one main branch, the second long side of the U-shaped bending unit is located on the outer side of the main branch, and the slot of the U-shaped bending unit faces one loading branch.

[0009] In one embodiment, the second long side of the U-shaped bending unit has opposite current directions of the second odd-order dipole mode, so as to cancel the current in the opposite direction of the main radiation current in the second odd-order dipole mode, and convert the directional diagram of the second odd-order dipole mode into an omnidirectional directional diagram; the loading branch introduces a first even-order dipole mode, i.e. a full-wavelength dipole mode, so as to make the virtual part of the low frequency and the high frequency pass through two zero points respectively, and expand the bandwidth of the high frequency band and the low frequency band.

[0010] In one embodiment, the length of the first long side and the second long side is changed to improve the non-circularity of the antenna; the width of the main branch is changed to adjust the impedance of the antenna, improve the impedance matching, and expand the bandwidth of the high frequency band and the low frequency band.

[0011] In one embodiment, the first solder pad is connected with the feed connection part through the metal column, and the second solder pad is connected with the radiation branch through the metal column.

[0012] In one embodiment, the width of the end of the feeding structure connected with the radiation structure is slightly less than the length of the slot, and the thickness of the feeding structure dielectric plate is slightly less than the width of the slot.

[0013] In one embodiment, the length direction is the symmetrical direction of the main branch, the total length of each main branch and each U-shaped bending unit is L1, and the center frequency free space wavelength of the low frequency band of the antenna is λ1, wherein 0.25λ1≤L1≤0.5λ1; the length of each main branch is L 21 , the total length of each U-shaped bending unit is L 22 , and the width of each main branch is W 21 , wherein L 22 > 12.5mm 21 , 12.5mm < W 21 < 20mm.

[0014] In one embodiment, the distance between the two radiation branches of the upper microstrip layer is W 57 , the width of the feeding connection part is W5, and the width of the slot is W7, wherein W5 < W 57 , W7 < W 57 .

[0015] In one embodiment, the feeding connector is a coaxial connector, the inner conductor of which is connected with the feeding layer, and the outer conductor of which is connected with the ground plate; the feeding layer is rectangular, and the width is W 91 ; the ground plate has the same shape as the feeding structure dielectric plate; the metal column is a metalized via hole, and the radius is R; the feeding structure dielectric plate is composed of a dielectric plate, the thickness of the dielectric plate is h, and the relative dielectric constant is ε r , wherein 0.2mm ≤ W 91 ≤ 8mm, 0.2mm ≤ R ≤ 1.2mm, 0.1mm < h ≤ W7, and 1 ≤ ε r ≤ 4.4.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] The upper and lower symmetrical radiation branches excite the first and second odd-order dipole modes, i.e. half-wavelength dipole mode and three half-wavelength dipole mode. The first odd-order dipole mode ensures good omnidirectional radiation in the low frequency band, and the second odd-order dipole mode produces resonance in the high frequency band of the antenna. For the U-shaped bending unit, the current directions of the second odd-order dipole mode on the first long side and the second long side are opposite, which cancels the current in the second odd-order dipole mode that is opposite to the direction of the main radiation current, and converts the directional diagram of the second odd-order dipole mode into an omnidirectional directional diagram. By changing the lengths of the first long side and the second long side, the non-circularity of the antenna can be improved. In addition, the U-shaped bending unit also reduces the overall size of the antenna, achieving miniaturization. For the loaded loading branch, the current path is increased, and the first even-order dipole mode, i.e. full-wavelength dipole mode, is introduced. The newly added resonance point can make the low frequency and high frequency pass through two zero points respectively, improve the impedance matching of the high and low frequency bands, and expand the bandwidth of the high and low frequency bands. In addition, the loading branch in the form of bending also realizes the miniaturization of the antenna. For the main radiation branch, by changing its width, the impedance of the antenna can be adjusted, the impedance matching can be improved, and the bandwidth of the high and low frequency bands can be expanded. BRIEF DESCRIPTION OF DRAWINGS

[0018] The specific structure of the application will be described in detail below with reference to the drawings

[0019] Figure 1 It is a three-dimensional structure schematic diagram of a dual-band wideband omnidirectional antenna based on multi-mode resonance.

[0020] Figure 2 It is a bottom view of the radiation structure of a dual-band wideband omnidirectional antenna based on multi-mode resonance.

[0021] Figure 3 It is a top view of the radiation structure of a dual-band wideband omnidirectional antenna based on multi-mode resonance.

[0022] Figure 4 It is a partial structure detail enlarged schematic diagram of the top view of the microstrip of a dual-band wideband omnidirectional antenna based on multi-mode resonance.

[0023] Figure 5 It is a structure schematic diagram of the feeding structure of a dual-band wideband omnidirectional antenna based on multi-mode resonance.

[0024] Figure 6 It is a directional diagram of a dual-band wideband omnidirectional antenna based on multi-mode resonance at 1.2 GHz, wherein (a) is the simulation result of the E plane at 1.2 GHz, and (b) is the simulation result of the H plane at 1.2 GHz.

[0025] Figure 7The figure is a directional diagram of a dual-band wideband omnidirectional antenna based on multi-mode resonance of the application at 3.5 GHz, wherein (a) is the simulation result of the E plane at 3.5 GHz; and (b) is the simulation result of the H plane at 3.5 GHz.

[0026] Figure 8 The figure is a port reflection coefficient curve of a dual-band wideband omnidirectional antenna based on multi-mode resonance of the application.

[0027] Figure 9 The figure is an impedance curve of a dual-band wideband omnidirectional antenna based on multi-mode resonance of the application.

[0028] Figure 10 The figure is a port gain and efficiency change graph of a dual-band wideband omnidirectional antenna based on multi-mode resonance of the application.

[0029] wherein, Figures 1 to 5 In the figure, 11 is a radiation structure, 12 is a feeding structure, 13 is a feeding joint, 2 is a radiation branch, 21 is a main branch, 22 is a U-shaped bending unit, 221 is a first long side, 223 is a second long side, 3 is a loading branch, 4 is a metal column, 5 is a feeding connection part, 61 is a radiation structure dielectric plate, 62 is a feeding structure dielectric plate, 7 is a slot, 81 is a first solder pad, 82 is a second solder pad, 91 is a feeding layer, and 92 is a ground plate. DETAILED DESCRIPTION

[0030] The application will be further described in detail with reference to the technical content, structural features, achieved purposes and effects of the application and in conjunction with the accompanying drawings.

[0031] Embodiment 1

[0032] Please refer to Figures 1 to 5 A dual-band wideband omnidirectional antenna based on multi-mode resonance comprises a radiation structure 11, a feeding structure 12 and a feeding joint 13. The radiation structure 11 comprises, in sequence, an upper microstrip layer, a radiation structure dielectric plate 61, a metal column 4 and a lower microstrip layer. The upper microstrip layer is arranged on the upper surface of the radiation structure dielectric plate 61 and comprises a feeding connection part 5 and two symmetrically arranged radiation branches 2.

[0033] For the convenience of description, the thickness direction of the radiation structure dielectric plate 61 is defined as the Z direction, and the directions perpendicular to the Z direction are defined as the X direction and the Y direction.

[0034] In this embodiment, the two radiation branches 2 are symmetric about the X direction, and the feeding connection part 5 is located between the two radiation branches 2. Corresponding to the position of the feeding connection part 5, a slot 7 for inserting the feeding structure 12 is arranged on the radiation structure dielectric plate 61, that is, the slot 7 is also located between the two symmetric radiation branches 2. For example, the feeding connection part 5 is a rectangular connecting sheet.

[0035] The lower microstrip layer comprises a first pad 81 and a second pad 82, which are connected to the upper microstrip layer through a respective metal post 4.

[0036] The feed structure 12 comprises a feed layer 91, a feed structure dielectric board 62 and a ground layer 92 arranged in sequence, one end of the feed structure 12 is vertically inserted into the radiation structure 11 and connected to the radiation structure 11 through a pad, and the other end is connected to the feed connector 13. Specifically, the feed layer 91 of the feed structure 12 is connected to the inner core of the feed connector 13, and the ground layer 92 is connected to the outer conductor of the feed connector 13.

[0037] The present application adopts symmetrical radiation branches 2, which excite the first and second odd-order dipole modes, i.e. half-wavelength dipole and three half-wavelength dipole modes. The first odd-order dipole mode ensures good omnidirectional radiation in the low frequency band, and the second odd-order dipole mode produces resonance of the antenna in the high frequency band.

[0038] Embodiment 2

[0039] On the basis of the above structure, the two radiation branches 2 are symmetrical about the Y direction.

[0040] Embodiment 3

[0041] On the basis of the structure of the above embodiment 1 or embodiment 2, each radiation branch 2 is composed of a pair of main branches 21, a pair of loading branches 3 and a pair of U-shaped bending units 22.

[0042] Among them, when the two radiation branches 2 are symmetrical about the Y direction, the pair of main branches 21 in each radiation branch 2 is symmetrical about the X direction; when the two radiation branches 2 are symmetrical about the X direction, the pair of main branches 21 in each radiation branch 2 is symmetrical about the Y direction.

[0043] The pair of main branches 21 in each radiation branch 2 are connected on the inner side, i.e. the side close to the symmetry axis. In one structure of the present application, referring to Figure 3 and Figure 4 , the single main branch 21 is L-shaped, and the pair of main branches 21 are connected at the bottom to form a U shape.

[0044] The loading branch 3 is a bending structure. In one structure of the present application, referring to Figure 3 and Figure 4 , it is bent three times, and each loading branch 3 is connected to the outer side of a main branch 21, i.e. the side away from the symmetry axis. Obviously, in one radiation branch 2, the pair of loading branches 3 are also symmetrical, and have the same symmetry axis as the pair of main branches 21.

[0045] The U-shaped bending unit 22 has a first long side 221 and a second long side 223, and the directions of the first long side 221 and the second long side 223 are the same as the symmetry direction of the main branch 21. When a pair of main branches 21 forms a U shape, it is obvious that the long sides of the U-shaped bending unit 22 are in the same direction as the side of the main branch 21. For example, the first long side 221 is an extension of the side of the main branch 21, but their widths can be different. Each U-shaped bending unit 22 is connected to a main branch 21, and the second long side 223 of the U-shaped bending unit 22 is located on the outside of the main branch 21, at which time the notch of the U-shaped bending unit 22 faces a loading branch 3, that is, faces the symmetry axis of the two radiating branches 2.

[0046] According to the structure, for the U-shaped bending unit 22, the second odd-order dipole mode current directions on the first long side 221 and the second long side 223 are opposite, which cancels the current in the second odd-order dipole mode current that is opposite to the direction of the main radiation current, and changes the direction pattern of the second odd-order dipole mode to an omnidirectional direction pattern. Thus, by changing the length of the first long side and the first long side, the non-circularity of the antenna can be improved. In addition, the U-shaped bending unit 22 also reduces the overall size of the antenna, achieving miniaturization.

[0047] For the loaded loading branch 3, it increases the current path and introduces the first even-order dipole mode, that is, the full-wavelength dipole mode, and the newly added resonance point can make the low-frequency and high-frequency virtual parts pass through two zero points respectively, improving the impedance matching of the high and low frequency bands and expanding the bandwidth of the high and low frequency bands. Similarly, the loading branch 3 in the form of bending also achieves the miniaturization of the antenna. For the main branch 21, by changing its width, the impedance of the antenna can be adjusted, the impedance matching can be improved, and the bandwidth of the high and low frequency bands can be expanded.

[0048] Embodiment 4

[0049] On the basis of any of the above structures, the metal column 4 passes through the radiating structure dielectric plate 61, the first solder pad 7 is connected with the feed connection part 5 through the metal column 4, and the second solder pad 8 is connected with the radiating branch 2 through another metal column 4. By connecting through the metal column, the solder pad is in communication with the upper microstrip layer of the dielectric plate, and the soldering point of the feed structure 12 and the radiating structure 11 is transferred from the upper microstrip layer to the lower microstrip layer.

[0050] Embodiment 5

[0051] On the basis of any of the above structures, the length of the end where the feed structure 12 is connected with the radiating structure 11 is slightly smaller than the length of the slot 7, and the thickness of the feed structure dielectric plate 62 is slightly smaller than the width of the slot 7. The size of the slot 7 is slightly larger than the size of the feed structure dielectric plate 62, so as to facilitate the assembly of the physical feed structure 12 and the radiating structure 11.

[0052] Embodiment 6

[0053] For the convenience of description, the present invention defines the symmetric direction of a pair of main branches 21 as the length direction.

[0054] Based on any of the above structures, the total length of each main branch 21 and each U-shaped bending unit 22 is L1, and the center frequency free space wavelength of the low-frequency band of the antenna is λ1, where 0.15λ1 ≤ L1 ≤ 0.5λ1. The length of the main branch 21 is L 21 , and the total length of each U-shaped bending unit 22 is L 22 , L1 = L 21 +L 22 , the width of the main branch 21 is W 21 , where L 22 >L 21 , 12.5mm < W 21 < 20mm. The overall structure of the antenna is a half-wave dipole, and L1 is approximately 1 / 4λ1. Limited by size and impedance matching, W 21 should not be too large or too small.

[0055] Embodiment 7

[0056] Based on any of the above structures, the total length of each loading branch 3 is L 31 , and the distance from the connection point of the loading branch 3 and the main branch 21 to the center is L 32 , L3 = L 31 +L 32 , where 8mm < L3 < 32mm. The loading branch 3 is used to introduce the first even-order dipole mode, which is located between the first odd-order dipole mode and the second odd-order dipole mode. Therefore, L3 should be less than one-quarter wavelength of the resonant frequency of the first odd-order dipole mode and greater than one-quarter wavelength of the resonant frequency of the second odd-order dipole mode.

[0057] Embodiment 8

[0058] Based on any of the above structures, the distance between the two radiation branches 2 of the upper microstrip layer is W 57 , the width of the feeding connection part 5 is W5, and the width of the slot 7 is W7, where W5 < W 57 , W7 < W 57 . The feeding connection part 5 and the slot 7 act together to connect the feeding layer 91 and the floor 92 of the feeding structure 12 to the radiation branches 2 respectively. Therefore, the widths of the feeding connection part 5 and the slot 7 should be less than the distance between the two radiation branches 2 respectively to ensure that the distance between the two radiation branches 2 can accommodate the feeding connection part 5 and the slot 7.

[0059] Embodiment 9

[0060] In any of the above structures, the feed terminal is a coaxial terminal, the inner conductor of which is connected to the feed layer 91, and the outer conductor of which is connected to the ground plane 92; the feed layer 91 is rectangular, and its width is W 91 ; the ground plane 92 has the same shape as the feed structure dielectric plate 62; the metal post 4 is a metallized via hole, and its radius is R; the feed structure dielectric plate 62 is made of a dielectric plate, and the thickness of the dielectric plate is h, and its relative dielectric constant is ε r , where 0.2mm≤W 91 ≤8mm, 0.2mm≤R≤1.2mm, 0.1mm<h≤W / 7, 1≤ε r ≤4.4. The width of the feed layer 91 should ensure that the impedance of the feed structure 91 is 50 ohms. The size of the metal post 4 should not be too small or too large, so as to reduce the processing error. The feed structure dielectric plate 62 needs to be inserted into the slot 7, so the thickness h should be smaller than the width W7 of the slot 7. The dielectric constant of the dielectric plate of the feed structure dielectric plate 62 should not be too large, so as to reduce the loss caused by the dielectric plate.

[0061] Test Example

[0062] In order to further illustrate the beneficial effects of the present application, the port reflection coefficient, the antenna pattern and the gain of the antenna of the above embodiment (L1=60mm, L 21 =28.9mm, W 21 =19.1mm, L3=48.3mm, L 31 =15mm, W 57 =3.6mm, W5=2.5mm, W 91 =1.82mm, R=0.3mm, h=0.8mm, ε r =3.5) are simulated and tested by using simulation software and test methods, and the test results are shown in Figures 6 to 10 .

[0063] Figure 6 The E-plane and H-plane patterns of the simulation of the test example, where (a) is the simulation result of the E-plane at 1.2GHz; (b) is the simulation result of the H-plane at 1.2GHz; Figure 7 The E-plane and H-plane patterns of the simulation of the test example, where (a) is the simulation result of the E-plane at 3.5GHz; (b) is the simulation result of the H-plane at 3.5GHz. From Figure 6 and Figure 7 , it can be seen that the antenna not only obtains an omnidirectional radiation pattern at a low frequency band and a high frequency band respectively, but also obtains a low cross polarization of-16.7dB or below in the H-plane.

[0064] Figure 8 The curve of the port reflection coefficient obtained by simulating the test example antenna and varying the working frequency. From Figure 8It can be seen from the simulation results that the port shows good broadband characteristics. The frequency band in which the port reflection coefficient is lower than -10dB in the simulation results is 1.11-2.11GHz and 3.21-4.35GHz, i.e. the impedance bandwidths are 62.1% and 30.2% respectively; the broadband characteristics of the dual-band broadband omnidirectional antenna are well achieved.

[0065] Figure 9 The curve of the impedance of the test example antenna obtained by simulation with respect to the working frequency is shown in Fig. 6. Figure 9 It can be seen from Fig. 6 that the antenna without the loading branch 3 has only two resonance points, while the antenna with the loading branch 3 has three resonance points, and the imaginary parts at low and high frequencies both pass through two zero points, effectively improving the impedance matching.

[0066] Figure 10 The gain and efficiency of the test example antenna obtained by simulation are shown in Fig. 7. Figure 9 It can be seen from Fig. 7 that the antenna obtains a stable gain of about 2.2dBi and an efficiency of about 0.95 at the low frequency band, and a stable gain of about 2dBi and an efficiency of about 0.85 at the high frequency band.

[0067] Here, the first, second, … only represent the differentiation of the names, and do not represent that they are different in importance and position.

[0068] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A dual-band wideband omnidirectional antenna based on multi-mode resonance, characterized in that, The antenna comprises a radiation structure, a feed structure and a feed connector; the radiation structure comprises an upper microstrip layer, a radiation structure dielectric plate, a metal column and a lower microstrip layer arranged in sequence; the upper microstrip layer comprises two symmetrical radiation branches, and a feed connection part is arranged between the two radiation branches; the radiation structure dielectric plate has a slot for inserting the feed structure; the lower microstrip layer comprises a first solder pad and a second solder pad, and the first solder pad and the second solder pad are connected with the upper microstrip layer through the metal column; the feed structure comprises a feed layer, a feed structure dielectric plate and a ground plate arranged in sequence, one end of the feed structure is vertically inserted into the radiation structure and connected with the radiation structure through the solder pad, and the other end is connected with the feed connector; the feed layer of the feed structure is connected with the inner core of the feed connector, and the ground plate is connected with the outer conductor of the feed connector; The two symmetrical radiation branches excite first and second odd-order dipole modes, i.e. half-wavelength dipole and three half-wavelength dipole modes, wherein the first odd-order dipole mode ensures omnidirectional radiation in a low frequency band, and the second odd-order dipole mode produces resonance of the antenna in a high frequency band; Each of the radiation branches is composed of a pair of main branches, a pair of loading branches and a pair of U-shaped bending units; the two radiation branches are symmetrical about the Y direction or the X direction; the pair of main branches in each radiation branch are symmetrical about the X direction or the Y direction and are connected at the inner side; the loading branches are in a bending structure and are symmetrically connected to the outer side of one main branch; the first long side and the second long side of the U-shaped bending unit are in the same symmetrical direction as the main branch, the U-shaped bending unit is connected to one main branch, the second long side of the U-shaped bending unit is located at the outer side of the main branch, and the slot of the U-shaped bending unit faces one loading branch; the second long side of the U-shaped bending unit is in the opposite direction of the second odd-order dipole mode current, so as to offset the current in the opposite direction of the main radiation current in the second odd-order dipole mode current and convert the direction pattern of the second odd-order dipole mode into an omnidirectional direction pattern.

2. A dual-band wideband omnidirectional antenna based on multi-mode resonance according to claim 1, characterized in that, The loading branch introduces a first even-order dipole mode, i.e. a full-wavelength dipole mode, so as to pass two zero points respectively for low frequency and high frequency, thereby expanding the bandwidth of the high and low frequency bands.

3. A dual-band wideband omnidirectional antenna based on multi-mode resonance according to claim 1, characterized in that, By changing the lengths of the first long side and the second long side, the non-circularity of the antenna is improved; by changing the width of the main branch, the impedance of the antenna is adjusted, the impedance matching is improved, and the bandwidth of the high and low frequency bands is expanded.

4. A dual-band wideband omnidirectional antenna based on multi-mode resonance as claimed in claim 1, wherein, The first solder pad is connected with the feed connection part through the metal column, and the second solder pad is connected with the radiation branch through the metal column.

5. A dual-band wideband omnidirectional antenna based on multi-mode resonance as claimed in claim 1, wherein, The length of the end of the feed structure connected with the radiation structure is smaller than the length of the slot, and the thickness of the feed structure dielectric plate is smaller than the width of the slot.

6. A dual-band wideband omnidirectional antenna based on multi-mode resonance as claimed in claim 1, wherein, Taking the symmetric direction of the main branch as the length direction, the total length of each main branch and each U-shaped bending unit is L1, and the free space wavelength of the center frequency of the low-frequency band of the antenna is λ1, where 0.25λ1≤L1≤0.5λ1; the length of each main branch is L 21 , the total length of each U-shaped bending unit is L 22 , the width of each main branch is W 21 , where L 22 >L 21 , 12.5mm <W 21 <20mm, the total length of each loading branch is L2, of which 18mm <L2<32mm。 7. A dual-band wideband omnidirectional antenna based on multi-mode resonance according to claim 6, characterized in that, The interval of the two radiation branches of the upper microstrip layer is W 57 , the width of the feed connection part is W5, and the width of the slot is W7, wherein W5 57 , W7 57 .

8. A dual-band wideband omnidirectional antenna based on multi-mode resonance according to claim 7, characterized in that, The feed terminal is a coaxial terminal, the inner conductor of which is connected to the feed layer, and the outer conductor of which is connected to the ground plane; the feed layer is rectangular, with a width W 91 , the ground plane and the feed structure dielectric plate are of the same shape; the metal column is a metalized via, with a radius R; the feed structure dielectric plate is composed of a dielectric plate, the thickness of the dielectric plate being h, and the relative dielectric constant of the dielectric plate being ε r , wherein 0.2mm≤W 91 ≤8mm, 0.2mm≤R≤1.2mm, 0.1mm<h≤W / 7, 1≤ε r ≤4.4.

Images