Broadband filtering antenna designed by utilizing characteristic mode theory and wireless communication equipment

Abstract

The invention discloses a broadband filtering antenna designed by using a characteristic mode theory and wireless communication equipment, and the antenna employs a two-layer dielectric substrate structure, and takes a metasurface as a basic structure. Through the design that partial units of the metasurface are reduced, the partial units of the metasurface are slotted, multiple gaps are etched in the ground, and a parasitic strip is added beside a microstrip feeder line, broadband single-frequency radiation and multi-radiation zero point controllability are achieved. Wherein the metasurface generates a second resonance point and a third resonance point, and generates a second radiation zero point at the same time; a transverse seam is formed in the ground to generate a first resonance point, and a vertical seam is formed in the ground to generate a third radiation zero point; the tail end of the microstrip feeder line is designed to be an open-circuit branch knot with a specific length to generate a first radiation zero point. The parasitic strip generates a fourth radiation zero point. The antenna has the broadband performance and the multi-radiation zero point controllable characteristic, and is suitable for wireless communication scenes such as the N77 frequency band of 5G communication and the like.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a broadband filter antenna and wireless communication device designed using characteristic mode theory. Background Technology

[0002] With the continuous development of wireless communication technology, radio frequency (RF) front-end equipment is also evolving towards lower power consumption, miniaturization, and integration. Filtered antennas integrate the functions of both antennas and filters, playing a crucial role in improving system efficiency and integration. However, antenna bandwidth that cannot cover the entire communication frequency band leads to frequent antenna switching, reducing system efficiency and hindering the low-power implementation of communication systems. Furthermore, traditional filtered antenna designs suffer from unclear filtering mechanisms and immature design processes, resulting in significant variations in antenna design time and costs. The proposal of broadband filtered antennas designed using characteristic mode theory helps to cover the entire communication frequency band, improve out-of-band suppression levels, and provide a better mechanistic explanation and design process for filtered antennas. Summary of the Invention

[0003] The primary objective of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a broadband filtering antenna designed using characteristic mode theory. This antenna has a simple and reliable structure. While fully covering the target frequency band, it uses characteristic mode theory to analyze and realize the potential radiation nulls of the antenna structure and introduces multiple controllable radiation nulls, effectively improving the filtering performance and the interpretability of the filtering mechanism, thus meeting the requirements of modern communication for low power consumption, miniaturization, and integration of equipment.

[0004] A second objective of the present invention is to provide a wireless communication device.

[0005] The first objective of this invention is achieved through the following technical solution: a broadband filtering antenna designed using characteristic mode theory, the antenna comprising a first dielectric substrate, a second dielectric substrate, a ground plane, a first horizontal slot and its associated orthogonal first vertical slot, a second vertical slot and its associated orthogonal second horizontal slot, a microstrip feed line, parasitic stripes, a first metasurface element, a second metasurface element, a first rectangular slot, and a second rectangular slot; the lower surface of the first dielectric substrate is provided with a microstrip feed line and two parasitic stripes symmetrically distributed around the vertical central axis of the microstrip feed line; the ground plane is disposed on the upper surface of the first dielectric substrate; the first horizontal slot and its associated orthogonal first vertical slot and the second vertical slot and their associated orthogonal second horizontal slot are disposed on the ground plane; the second vertical slot and its associated orthogonal second horizontal slot... There are two second transverse seams as a whole, distributed on both ends of the first transverse seam. The second dielectric substrate is set above the ground. The first metasurface unit and the second metasurface unit are set on the second dielectric substrate. There are multiple first metasurface units, which are evenly distributed in an H-shape. The second metasurface unit is a smaller metasurface unit than the first metasurface unit. It is distributed on both sides of the first metasurface unit located in the center, that is, it fills part of the two empty areas in the H-shape. The first metasurface unit located in the center has a first rectangular groove on each of its other two edges. The two first metasurface units closest to the first metasurface unit located in the center each have a second rectangular groove on the edge of the side closest to the first metasurface unit located in the center.

[0006] Preferably, the center reference point of the first metasurface unit located at the center coincides with the center reference point of the second dielectric substrate.

[0007] Preferably, the center reference point of the first horizontal seam coincides with the center reference point of the ground. There are two first vertical seams, which are symmetrically distributed about the vertical center axis of the first horizontal seam. There are also two second vertical seams, which are symmetrically distributed about the vertical center axis of the ground. Each second vertical seam is matched with two second horizontal seams, which are symmetrically distributed about the horizontal center axis of the second vertical seam.

[0008] Preferably, the antenna has four radiation nulls from low frequency to high frequency, namely the first radiation null, the second radiation null, the third radiation null, and the fourth radiation null, in order of frequency from low to high. The antenna has three resonant points within the frequency band, namely the first resonant point, the second resonant point, and the third resonant point, in order of frequency from low to high.

[0009] Preferably, the microstrip feed line generates a first radiation null point, and the left and right movement of the first radiation null point can be controlled by controlling the length of the microstrip feed line. The parasitic strip generates a fourth radiation null point, and the length of the parasitic strip is half the wavelength corresponding to the frequency of the fourth radiation null point. The left and right movement of the fourth radiation null point can be controlled by controlling the length of the parasitic strip.

[0010] Preferably, the end of the microstrip feed line is designed as an open-circuit stub with half a wavelength corresponding to the first radiation zero frequency.

[0011] Preferably, the metasurface formed by the first metasurface unit and the first rectangular groove can generate a second resonant point. The left and right movement of the second resonant point can be controlled by controlling the width of the first rectangular groove. The metasurface formed by the first metasurface unit and the second rectangular groove can simultaneously generate a third resonant point and a second radiation zero point. The left and right movement of the third resonant point and the second radiation zero point can be controlled by controlling the width of the second rectangular groove.

[0012] Preferably, the first horizontal slit and the first vertical slit can generate a first resonant point, and the left and right movement of the first resonant point can be controlled by controlling the length of the first horizontal slit. The second vertical slit and the second horizontal slit can generate a third radiation zero point, and the left and right movement of the third radiation zero point can be controlled by controlling the length of the second vertical slit.

[0013] Preferably, the ground plane, microstrip feed line, parasitic strip, first metasurface unit and second metasurface unit are made of copper.

[0014] Preferably, the ground surface covers the entire upper surface of the first dielectric substrate.

[0015] The second objective of this invention is achieved through the following technical solution: a wireless communication device, including the broadband filter antenna designed using the characteristic mode theory described above.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. The antenna of this invention uses a metasurface as its basic structure, generating a second and third resonant point, as well as a second radiation null. By slotting the metasurface, the second and third resonant points and the second radiation null are controlled. A third radiation null is generated by creating a vertical slot in the ground. A first radiation null is generated by designing the microstrip feed line end as an open-circuit stub of a specific length. A fourth radiation null is generated by adding parasitic stripes. Ultimately, this antenna achieves single-frequency filtering characteristics and excellent broadband performance.

[0018] 2. The antenna of this invention employs slotting on metasurface elements, adjusting the size of some metasurface elements, creating vertical slots on the ground plane, opening stubs in the microstrip feed line, and incorporating parasitic stripes, thus realizing a broadband filter antenna designed using characteristic mode theory. The antenna's matching bandwidth is 29.8% (3.2-4.32GHz), satisfying broadband characteristics. The peak gain within the passband is 7.4dBi. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0020] Figure 2 This is a top view of the second dielectric substrate of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0021] Figure 3 This is a top view of the first dielectric substrate of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0022] Figure 4 This is a bottom view of the first dielectric substrate of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0023] Figure 5 This is a cross-sectional view of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0024] Figure 6 The image shows the S-parameters of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0025] Figure 7 This is a gain curve of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention.

[0026] Figure 8 The XOZ plane radiation pattern of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 3.28 GHz.

[0027] Figure 9 The XOZ plane radiation pattern of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 3.76 GHz.

[0028] Figure 10 The XOZ plane radiation pattern of the broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 4.24 GHz.

[0029] Figure 11 The YOZ plane radiation pattern of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 3.28 GHz.

[0030] Figure 12The YOZ plane radiation pattern of a broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 3.76 GHz.

[0031] Figure 13 The YOZ plane radiation pattern of the broadband filter antenna designed using characteristic mode theory according to an embodiment of the present invention is shown at 4.24 GHz. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0033] Example 1

[0034] Currently, traditional filter antennas suffer from the problem that their bandwidth cannot fully cover the required frequency band, leading to frequent antenna switching and reduced system efficiency. Furthermore, traditional filter antenna design methods suffer from unclear explanations of filtering mechanisms and immature design processes, hindering improvements in design efficiency. This embodiment discloses a broadband filter antenna designed using characteristic mode theory, achieving broadband matching and flexible control of the radiated null point through structural innovation. See also... Figures 1 to 5 As shown, it includes a first dielectric substrate 7, a second dielectric substrate 5, a ground plane 6, a first horizontal slot 11 and its associated orthogonal first vertical slot 12, a second vertical slot 9 and its associated orthogonal second horizontal slot 10, a microstrip feed line 8, parasitic strips 13, a first metasurface unit 1, a second metasurface unit 2, a first rectangular groove 3, and a second rectangular groove 4; the lower surface of the first dielectric substrate 7 is provided with a microstrip feed line 8 and two parasitic strips 13 symmetrically distributed around the vertical central axis of the microstrip feed line 8; the ground plane 6 is provided on the upper surface of the first dielectric substrate 7; the first horizontal slot 11 and its associated orthogonal first vertical slot 12 and the second vertical slot 9 and its associated orthogonal second horizontal slot 10 are provided on the ground plane 6; the second vertical slot 9 and its associated orthogonal second horizontal slot 10 serve as a... There are two units in total, distributed on both ends of the first transverse slit 11. The second dielectric substrate 5 is disposed above the ground 6. The first metasurface unit 1 and the second metasurface unit 2 are disposed on the second dielectric substrate 5. There are multiple first metasurface units 1, which are evenly distributed in an H-shape. The second metasurface unit 2 is a smaller metasurface unit than the first metasurface unit 1. It is distributed on both sides of the first metasurface unit 1 located in the center, that is, it fills part of the two empty areas in the H-shape. A first rectangular groove 3 is provided on each of the other two edges of the first metasurface unit 1 located in the center. The two first metasurface units 1 closest to the first metasurface unit 1 located in the center each have a second rectangular groove 4 on the edge of the side closest to the first metasurface unit 1 located in the center.

[0035] Preferably, the center reference point of the first metasurface unit 1 located at the center coincides with the center reference point of the second dielectric substrate 5.

[0036] Preferably, the center reference point of the first horizontal seam 11 coincides with the center reference point of the ground 6. There are two first vertical seams 12, which are symmetrically distributed about the vertical center axis of the first horizontal seam 11. There are two second vertical seams 9, which are symmetrically distributed about the vertical center axis of the ground 6. Each second vertical seam 9 is matched with two second horizontal seams 10, which are symmetrically distributed about the horizontal center axis of the second vertical seam 9.

[0037] This embodiment uses a metasurface structure composed of a first metasurface unit 1 and a second metasurface unit 2 as the basic structure, generating a second resonant point and a third resonant point, as well as a second radiation null. By opening a first rectangular slot 3 and a second rectangular slot 4 on the metasurface, the second resonant point, the third resonant point, and the second radiation null are controlled. A second vertical slot 9 is opened on the ground to generate a third radiation null. A first radiation null is generated by designing the end of the microstrip feed line 8 as an open-circuit stub corresponding to half the wavelength of the first radiation null frequency. A fourth radiation null is generated by adding a parasitic strip 13 with a length corresponding to half the wavelength of the fourth radiation null frequency. Ultimately, this antenna achieves single-frequency filtering characteristics and good broadband characteristics.

[0038] Preferably, the first dielectric substrate 7 and the second dielectric substrate 5 use Rogers RO4003C dielectric with a dielectric constant of 3.55 and a loss tangent of 0.0029.

[0039] Preferably, the ground plane 6, microstrip feed line 8, parasitic strip 13, first metasurface unit 1 and second metasurface unit 2 are made of copper.

[0040] Preferably, the ground surface 6 covers the entire upper surface of the first dielectric substrate 7.

[0041] See Figure 6 As shown, the simulation curves of the S-parameters of the broadband filter antenna designed using characteristic mode theory in this embodiment are displayed. From the figure, it can be seen that the antenna's |S... 11 The -10dB bandwidth is 29.8% (3.2-4.32GHz), and it is used in the N77 band (3.3-4.2GHz) for 5G communication.

[0042] See Figure 7 The figure shows the simulated gain curve of the broadband filter antenna designed using characteristic mode theory in this embodiment. As can be seen from the figure, the peak gain in the passband reaches 7.4 dBi. Four radiation nulls are introduced at 2.8, 4.76, 4.92, and 5.08 GHz on the gain curve.

[0043] See Figure 8 , Figure 9 and Figure 10 As shown, the XOZ radiation patterns of the broadband filter antenna designed using characteristic mode theory in this embodiment are displayed at 3.28, 3.76, and 4.24 GHz. It can be seen from the figure that the antenna has good side-firing radiation characteristics at this frequency and the cross-polarization ratio is greater than 36 dB.

[0044] See Figure 11 , Figure 12 and Figure 13 As shown, the radiation field patterns of the broadband filter antenna designed using the characteristic mode theory in this embodiment at 3.28, 3.76, and 4.24 GHz are displayed. It can be seen from the figure that the antenna has good side-firing radiation characteristics at these frequencies, and the cross-polarization ratio is greater than 36 dB.

[0045] In summary, this invention constructs a metasurface using first and second metasurface units, generating a second and third resonant point, and simultaneously generating a second radiation null. By creating first and second rectangular slots on the metasurface, the second, third, and second radiation null points are controlled. A vertical slot on the ground generates a third radiation null. The microstrip feed line is designed with an open-circuit stub at half the wavelength corresponding to the first radiation null frequency, generating a first radiation null. A parasitic strip with a length corresponding to half the wavelength of the fourth radiation null frequency is added, generating a fourth radiation null. Ultimately, broadband single-frequency filtering characteristics are achieved, with |S 11 The bandwidth of -10dB reaches 29.8% (3.2-4.32GHz), the peak gain in the passband is 7.4dBi, and four controllable radiated nulls are introduced at 2.8, 4.76, 4.92 and 5.08GHz. The cross-polarization ratio is greater than 36dB, which meets the communication requirements of the N77 band for 5G communication.

[0046] Example 2

[0047] This embodiment discloses a wireless communication device, including the broadband filter antenna designed using characteristic mode theory as described in Embodiment 1.

[0048] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A broadband filter antenna designed using characteristic mode theory, characterized in that, The antenna includes a first dielectric substrate (7), a second dielectric substrate (5), a ground plane (6), a first horizontal slot (11) and its associated orthogonal first vertical slot (12), a second vertical slot (9) and its associated orthogonal second horizontal slot (10), a microstrip feed line (8), parasitic strips (13), a first metasurface element (1), a second metasurface element (2), a first rectangular slot (3), and a second rectangular slot (4); the lower surface of the first dielectric substrate (7) is provided with a microstrip feed line (8) and two parasitic strips (13) symmetrically distributed around the vertical central axis of the microstrip feed line (8); the ground plane (6) is provided on the upper surface of the first dielectric substrate (7); the first horizontal slot (11) and its associated orthogonal first vertical slot (12) and second vertical slot (9) and their associated orthogonal second horizontal slot (10) are provided on the ground plane (6); the second vertical slot (9) and its associated orthogonal first vertical slot (12) and second vertical slot (9) are provided on the ground plane (6); the second vertical slot (9) and its associated orthogonal first vertical slot (10) are provided on the ground plane (6); the second vertical slot (9) and its associated orthogonal first vertical slot (12) and second ... There are two transverse seams (10) as a whole, and they are distributed on both ends of the first transverse seam (11). The second dielectric substrate (5) is set above the ground (6). The first metasurface unit (1) and the second metasurface unit (2) are set on the second dielectric substrate (5). There are multiple first metasurface units (1) and they are evenly distributed in an H shape. The second metasurface unit (2) is a smaller metasurface unit than the first metasurface unit (1). It is distributed on both sides of the first metasurface unit (1) located in the center, that is, it fills the two empty areas in the H shape. The first metasurface unit (1) located in the center has a first rectangular groove (3) on each of its other two sides. The two first metasurface units (1) closest to the first metasurface unit (1) located in the center each have a second rectangular groove (4) on their side edge closest to the first metasurface unit (1) located in the center.

2. The broadband filter antenna designed using characteristic mode theory according to claim 1, characterized in that, The center reference point of the first metasurface unit (1) located at the center coincides with the center reference point of the second dielectric substrate (5).

3. The broadband filter antenna designed using characteristic mode theory according to claim 1, characterized in that, The center reference point of the first horizontal seam (11) coincides with the center reference point of the ground (6). There are two first vertical seams (12), which are symmetrically distributed about the vertical center axis of the first horizontal seam (11). There are two second vertical seams (9), which are symmetrically distributed about the vertical center axis of the ground (6). Each second vertical seam (9) is matched with two second horizontal seams (10), which are symmetrically distributed about the horizontal center axis of the second vertical seam (9).

4. The broadband filter antenna designed using characteristic mode theory according to claim 1, characterized in that, The antenna has four radiation nulls from low frequency to high frequency, namely the first radiation null, the second radiation null, the third radiation null, and the fourth radiation null, in order of frequency from low to high. The antenna has three resonant points within the frequency band, namely the first resonant point, the second resonant point, and the third resonant point, in order of frequency from low to high.

5. The broadband filter antenna designed using characteristic mode theory according to claim 4, characterized in that, The microstrip feed line (8) generates a first radiation null point. The left and right movement of the first radiation null point can be controlled by controlling the length of the microstrip feed line (8). The parasitic strip (13) generates a fourth radiation null point. The length of the parasitic strip (13) is half the wavelength corresponding to the frequency of the fourth radiation null point. The left and right movement of the fourth radiation null point can be controlled by controlling the length of the parasitic strip (13).

6. The broadband filter antenna designed using characteristic mode theory according to claim 5, characterized in that, The end of the microstrip feed (8) is designed as an open-circuit stub with half a wavelength corresponding to the first radiation zero frequency.

7. The broadband filter antenna designed using characteristic mode theory according to claim 4, characterized in that, The metasurface formed by the first metasurface unit (1) and the first rectangular groove (3) can generate a second resonant point. By controlling the width of the first rectangular groove (3), the left and right movement of the second resonant point can be controlled. The metasurface formed by the first metasurface unit (1) and the second rectangular groove (4) can simultaneously generate a third resonant point and a second radiation zero point. By controlling the width of the second rectangular groove (4), the left and right movement of the third resonant point and the second radiation zero point can be controlled.

8. The broadband filter antenna designed using characteristic mode theory according to claim 4, characterized in that, The first horizontal slit (11) and the first vertical slit (12) can generate a first resonant point. By controlling the length of the first horizontal slit (11), the left and right movement of the first resonant point can be controlled. The second vertical slit (9) and the second horizontal slit (10) can generate a third radiation zero point. By controlling the length of the second vertical slit (9), the left and right movement of the third radiation zero point can be controlled.

9. The broadband filter antenna designed using characteristic mode theory according to claim 1, characterized in that, The ground plane (6), microstrip feed line (8), parasitic strip (13), first metasurface unit (1) and second metasurface unit (2) are made of copper; the ground plane (6) covers the entire upper surface of the first dielectric substrate (7).

10. A wireless communication device, characterized in that, Including the broadband filter antenna designed using characteristic mode theory as described in any one of claims 1-9.

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