A VHF and UHF band antenna

Abstract

The present invention provides a VHF and UHF band antenna, which comprises: a top loading plate, a conductive floor and a radiator, and the radiator is disposed between the top loading plate and the conductive floor. The radiator includes at least one connecting portion and at least one bending portion, and the at least one connecting portion is connected to the at least one bending portion; the top end and the bottom end of the at least one bending portion are respectively connected to the top loading plate and the conductive floor; at least two slots are formed on both sides of the radiator. The VHF and UHF band antenna realizes the miniaturization and broadband of the antenna, and at the same time has a high gain and a good radiation pattern, and can be used in an airborne VHF / UHF communication system.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and particularly to a VHF and UHF band antenna.

Background Art

[0002] As an omnidirectional antenna, the monopole antenna has excellent radiation performance and is widely used in many communication devices. Various monopole antennas are equipped on ground stations, vehicle-mounted radios, individual soldier backpacks, ships, and airplanes. In the VHF / UHF frequency band, the size of the omnidirectional monopole antenna is generally relatively large, which is not conducive to the concealed installation of the antenna. For the airborne knife-shaped antenna, it is also restricted by its aerodynamic shape. Therefore, it is necessary to miniaturize the monopole antenna broadband. The existing monopole antennas are difficult to simultaneously meet the requirements of broadband, miniaturization, and high gain.

Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a VHF and UHF band antenna, which can achieve miniaturization and broadband of the antenna, and at the same time has relatively high gain and good radiation pattern, and can be used in airborne VHF / UHF communication systems.

[0004] To solve the above technical problem, an embodiment of the present invention provides a VHF and UHF band antenna, which includes:

[0005] A top loading plate;

[0006] A conductive floor; and

[0007] A radiator disposed between the top loading plate and the conductive floor;

[0008] The radiator includes at least one connecting portion and at least one bending portion, and the at least one connecting portion is connected to the at least one bending portion; the top end and the bottom end of the at least one bending portion are respectively connected to the top loading plate and the conductive floor; at least two slits are formed on both sides of the radiator.

[0009] Preferably, the at least one bending portion is a right-angle bending portion.

[0010] Preferably, the at least one bending portion includes a first bending portion, a second bending portion, and a third bending portion; the at least one connecting portion includes a first connecting portion, a second connecting portion, a third connecting portion, and a fourth connecting portion;

[0011] The first bending portion is connected between the first connecting portion and the second connecting portion, the second bending portion is connected between the second connecting portion and the third connecting portion, and the third bending portion is connected between the third connecting portion and the fourth connecting portion.

[0012] Preferably, the top and bottom ends of the second bent portion are respectively connected to the top loading plate and the conductive floor, and the top and bottom ends of the second connecting portion are respectively connected to the top loading plate and the conductive floor; the top and bottom ends of the third connecting portion are respectively connected to the top loading plate and the conductive floor; the bottom ends of the first bent portion, the third bent portion, the first connecting portion and the fourth connecting portion are all connected to the conductive floor.

[0013] Preferably, the second connecting portion includes a first connecting plate connected to the first bent portion and a second connecting plate connected to the second bent portion, and the length of the second connecting plate is greater than that of the first connecting plate; the bottom end of the first connecting plate is connected to the conductive floor, and the top and bottom ends of the second connecting plate are respectively connected to the top loading plate and the conductive floor;

[0014] The third connecting portion includes a third connecting plate connected to the second bent portion and a fourth connecting plate connected to the third bent portion, and the length of the third connecting plate is greater than that of the fourth connecting plate; the top and bottom ends of the third connecting plate are respectively connected to the top loading plate and the conductive floor, and the bottom end of the fourth connecting plate is connected to the conductive floor.

[0015] Preferably, the at least two slits include a first slit and a second slit; the first slit is formed in the first connecting portion, the first bent portion and the second connecting portion and sequentially penetrates through the first connecting portion, the first bent portion and the second connecting portion; the second slit is formed in the fourth connecting portion.

[0016] Preferably, the VHF and UHF band antenna further includes:

[0017] At least two coupling pieces are arranged on both sides of the radiator; the bottom ends of the at least two coupling pieces are all connected to the conductive floor.

[0018] Preferably, the shape of the top loading plate is circular or oval.

[0019] Preferably, the first bent portion includes a first conductive sheet (20a) and second and third conductive sheets (22a, 24a) arranged in parallel, and the first conductive sheet (20a) is perpendicularly connected between the second and third conductive sheets (22a, 24a); the second conductive sheet (22a) is perpendicularly connected to the first connecting portion, and the third conductive sheet (24a) is perpendicularly connected to the second connecting portion; the length of the third conductive sheet (24a) is equal to that of the second conductive sheet (22a), and the width of the third conductive sheet (24a) is greater than that of the second conductive sheet (22a);

[0020] The second bending portion includes a fourth conductive sheet, and a fifth conductive sheet and a sixth conductive sheet which are arranged in parallel. The fourth conductive sheet is perpendicularly connected between the fifth conductive sheet and the sixth conductive sheet; the fifth conductive sheet is perpendicularly connected to the second connecting portion, and the sixth conductive sheet is perpendicularly connected to the third connecting portion; the length and width of the sixth conductive sheet are respectively equal to the length and width of the fifth conductive sheet.

[0021] The third bending portion includes a seventh conductive sheet (20b), and an eighth conductive sheet (22b) and a ninth conductive sheet (24b) which are arranged in parallel. The seventh conductive sheet (20b) is perpendicularly connected between the eighth conductive sheet (22b) and the ninth conductive sheet (24b); the eighth conductive sheet (22b) is perpendicularly connected to the third connecting portion, and the ninth conductive sheet (24b) is perpendicularly connected to the fourth connecting portion; the length of the ninth conductive sheet (24b) is equal to the length of the eighth conductive sheet (22b), and the width of the eighth conductive sheet (22b) is greater than the width of the ninth conductive sheet (24b).

[0022] Preferably, the VHF and UHF band antenna further includes:

[0023] A broadband matching network connected between the 50Ω coaxial port and the antenna feed end of the at least one bending portion;

[0024] The broadband matching network includes an inductor L1, a capacitor C1, an inductor L2, a capacitor C2, a capacitor C3, an inductor L3, an inductor L4, a capacitor C4, an inductor L5, a capacitor C5 and an inductor L6; the inductor L1 and the capacitor C1 are connected in parallel between the 50Ω coaxial port and one end of the capacitor C3; the inductor L2 and the capacitor C2 are connected in parallel between one end of the capacitor C3 and the ground; the inductor L4, the inductor L5 and the capacitor C5 are connected in series in sequence between the other end of the capacitor C3 and the antenna feed end; one end of the inductor L3 is connected between the capacitor C3 and the inductor L4, and the other end of the inductor L3 is grounded; one end of the capacitor C4 is connected between the inductor L4 and the inductor L5, and the other end of the capacitor C4 is grounded; one end of the inductor L6 is connected between the capacitor C5 and the antenna feed end; the other end of the inductor L6 is grounded.

[0025] Compared with the prior art, the above technical solution has the following advantages: A monopole antenna based on the lumped element loading matching technology is proposed, a metal disk structure is loaded on its top, the radiator is bent, rectangular slots are opened at different positions of the radiator, and a sleeve antenna structure such as a metal coupling sheet is introduced, realizing the miniaturization and broadband of the antenna, and at the same time having a higher gain and a good radiation pattern, and can be used in an airborne VHF / UHF communication system.

Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0027] Figure 1 It is a perspective view of a VHF and UHF band antenna according to an embodiment of the present invention.

[0028] Figure 2 For Figure 1 It is a perspective view of the radiator of the VHF and UHF band antenna shown.

[0029] Figure 3 It is a circuit structure diagram of a broadband matching network according to an embodiment of the present invention.

[0030] Figure 4 For Figure 1 It is a simulation diagram of the voltage standing wave ratio of the VHF and UHF band antenna shown.

[0031] Figure 5(a) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f low at that time.

[0032] Figure 5(b) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f1.

[0033] Figure 5(c) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f2.

[0034] Figure 5(d) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f3.

[0035] Figure 5(e) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f4.

[0036] Figure 5(f) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f5.

[0037] Figure 5(g) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f6.

[0038] Figure 5(h) is the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f high at that time.

Detailed implementation manners

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0040] Figure 1 It is a perspective view of a VHF and UHF band antenna 100 for an embodiment. Figure 2 It is Figure 1 A perspective view of the radiator 10 of the VHF and UHF band antenna 100 shown. As Figure 1 and Figure 2 shown, the VHF and UHF band antenna 100 includes a radiator 10, a top loading plate 80, and a conductive floor 90. In this embodiment, the radiator 10 is a full-metal structure, the top loading plate 80 is also a full-metal structure, and the conductive floor 90 is a metal floor.

[0041] Specifically, in an embodiment of the present invention, the shape of the top loading plate 80 is circular or elliptical.

[0042] The radiator 10 is disposed between the top loading plate 80 and the conductive floor 90.

[0043] The radiator 10 includes at least one connecting portion and at least one bending portion, the at least one connecting portion is connected to the at least one bending portion; the top end and the bottom end of the at least one bending portion are respectively connected to the top loading plate 80 and the conductive floor 90; at least two slits are formed on both sides of the radiator 10.

[0044] In this embodiment, the at least one bending portion is a right-angle bending portion.

[0045] In this embodiment, the at least two slits are all rectangular slits.

[0046] Specifically, in an embodiment of the present invention, each bending portion includes a first conductive sheet, and a second conductive sheet and a third conductive sheet arranged in parallel, and the first conductive sheet is perpendicularly connected between the second conductive sheet and the third conductive sheet.

[0047] The at least one bending portion includes a first bending portion 120, a second bending portion 122, and a third bending portion 124. The at least one connecting portion includes a first connecting portion 130, a second connecting portion 132, a third connecting portion 134, and a fourth connecting portion 136.

[0048] The first bending portion 120 is connected between the first connecting portion 130 and the second connecting portion 132. The second bending portion 122 is connected between the second connecting portion 132 and the third connecting portion 134. The third bending portion 124 is connected between the third connecting portion 134 and the fourth connecting portion 136.

[0049] The top and bottom ends of the second bending portion 122 are respectively connected to the top loading plate 80 and the conductive floor 90. The top and bottom ends of the second connecting portion 132 are respectively connected to the top loading plate 80 and the conductive floor 90. The top and bottom ends of the third connecting portion 134 are respectively connected to the top loading plate 80 and the conductive floor 90. The bottom ends of the first bending portion 120, the third bending portion 124, the first connecting portion 130, and the fourth connecting portion 136 are all connected to the conductive floor 90. Specifically, the top ends of the first bending portion 120, the third bending portion 124, the first connecting portion 130, and the fourth connecting portion 136 are not connected to the top loading plate 80.

[0050] Specifically, in an embodiment of the present invention, the first bending portion 120 includes a first conductive sheet 20a, and second conductive sheet 22a and third conductive sheet 24a arranged in parallel. The first conductive sheet 20a is perpendicularly connected between the second conductive sheet 22a and the third conductive sheet 24a. The second conductive sheet 22a is perpendicularly connected to the first connecting portion 130, and the third conductive sheet 24a is perpendicularly connected to the second connecting portion 132. The length of the third conductive sheet 24a is equal to the length of the second conductive sheet 22a, and the width of the third conductive sheet 24a is greater than the width of the second conductive sheet 22a.

[0051] Specifically, in an embodiment of the present invention, the second bending portion 122 includes a fourth conductive sheet, and fifth conductive sheet and sixth conductive sheet arranged in parallel. The fourth conductive sheet is perpendicularly connected between the fifth conductive sheet and the sixth conductive sheet. The fifth conductive sheet is perpendicularly connected to the second connecting portion 132, and the sixth conductive sheet is perpendicularly connected to the third connecting portion 134. The length and width of the sixth conductive sheet are respectively equal to the length and width of the fifth conductive sheet.

[0052] Specifically, in an embodiment of the present invention, the third bending portion 124 includes a seventh conductive sheet 20b, and eighth conductive sheet 22b and ninth conductive sheet 24b arranged in parallel. The seventh conductive sheet 20b is perpendicularly connected between the eighth conductive sheet 22b and the ninth conductive sheet 24b. The eighth conductive sheet 22b is perpendicularly connected to the third connecting portion 134, and the ninth conductive sheet 24b is perpendicularly connected to the fourth connecting portion 136. The length of the ninth conductive sheet 24b is equal to the length of the eighth conductive sheet 22b, and the width of the eighth conductive sheet 22b is greater than the width of the ninth conductive sheet 24b.

[0053] The at least two slits include a first slit 180 and a second slit 182; the first slit 180 is formed in the first connecting portion 130, the first bending portion 120, and the second connecting portion 132 and sequentially penetrates through the first connecting portion 130, the first bending portion 120, and the second connecting portion 132;

[0054] The second slit 182 is formed in the fourth connecting portion 136.

[0055] Specifically, the second connecting portion 132 includes a first connecting plate connected to the first bending portion 120 and a second connecting plate connected to the second bending portion 122, and the length of the second connecting plate is greater than that of the first connecting plate; the bottom end of the first connecting plate is connected to the conductive floor 90, and the top and bottom ends of the second connecting plate are respectively connected to the top loading plate 80 and the conductive floor 90.

[0056] Specifically, the third connecting portion 134 includes a third connecting plate connected to the second bending portion 122 and a fourth connecting plate connected to the third bending portion 124, and the length of the third connecting plate is greater than that of the fourth connecting plate; the top and bottom ends of the third connecting plate are respectively connected to the top loading plate 80 and the conductive floor 90, and the bottom end of the fourth connecting plate is connected to the conductive floor 90. Specifically, the tops of the first connecting plate and the fourth connecting plate are not connected to the top loading plate 80.

[0057] Further, the VHF and UHF band antenna 100 further includes at least two coupling sheets 50 and 60, and the at least two coupling sheets 50 and 60 are disposed on both sides of the radiator 10; the bottom ends of the at least two coupling sheets 50 and 60 are both connected to the conductive floor 90. The tops of the at least two coupling sheets 50 and 60 are not connected to the top loading plate 80. In this embodiment, the shapes of the at least two coupling sheets 50 and 60 are both rectangular. In this embodiment, the at least two coupling sheets 50 and 60 are both of all-metal structures.

[0058] Figure 3 It is a circuit structure diagram of a broadband matching network according to an embodiment of the present invention. Please refer to Figure 3 Furthermore, the VHF and UHF band antenna 100 further includes a broadband matching network, and the broadband matching network is connected between the 50Ω coaxial port and the antenna feed end 190 of the at least one bending portion. Specifically, the antenna feed end 190 is disposed on the second bending portion 122.

[0059] The broadband matching network includes an inductor L1, a capacitor C1, an inductor L2, a capacitor C2, a capacitor C3, an inductor L3, an inductor L4, a capacitor C4, an inductor L5, a capacitor C5, and an inductor L6; the inductor L1 and the capacitor C1 are connected in parallel between the 50Ω coaxial port and one end of the capacitor C3; the inductor L2 and the capacitor C2 are connected in parallel between one end of the capacitor C3 and the ground; the inductor L4, the inductor L5, and the capacitor C5 are connected in series in turn between the other end of the capacitor C3 and the antenna feed end 190; one end of the inductor L3 is connected between the capacitor C3 and the inductor L4, and the other end of the inductor L3 is grounded; one end of the capacitor C4 is connected between the inductor L4 and the inductor L5, and the other end of the capacitor C4 is grounded; one end of the inductor L6 is connected between the capacitor C5 and the antenna feed end 190; the other end of the inductor L6 is grounded.

[0060] In this embodiment, the height of the VHF and UHF band antenna 100 is 0.09 - 0.095 The width W of the VHF and UHF band antenna 100 is 0.108 - 0.115 The width W of the VHF and UHF band antenna 100 is 0.013 - 0.117 Where f low is the lowest frequency of the electromagnetic wave, is the wavelength corresponding to the lowest frequency of the electromagnetic wave, and c is the speed of light in vacuum.

[0061] Figure 4 is Figure 1 The simulation diagram of the voltage standing wave ratio of the VHF and UHF band antenna 100 shown. It can be seen from Figure 4 that the VHF and UHF band antenna 100 operates in the VHF and UHF frequency bands to achieve a triple frequency bandwidth (f high / f low = 3) (VSWR ≤ 3), which can meet the requirements of short-wave and ultra-short-wave communication.

[0062] Figure 5(a) shows the VHF and UHF band antenna 100 of the present invention at f = f lowThe H-plane gain pattern at [time]. Fig. 5(b) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f1. Fig. 5(c) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f2. Fig. 5(d) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f3. Fig. 5(e) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f4. Fig. 5(f) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f5. Fig. 5(g) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f6. Fig. 5(h) shows the H-plane gain pattern of the VHF and UHF band antenna 100 of the present invention at f = f high The H-plane gain pattern at [time]. Wherein, f low is the lowest operating frequency of the antenna 100, and fh ig h is the highest operating frequency of the antenna 100. It can be seen from Figures 5(a) to 5(h) that the VHF and UHF band antenna 100 has good omnidirectionality and high gain in the H-plane.

[0063] As can be seen from the above description, by using the VHF and UHF band antenna 100 according to the present invention, a monopole antenna based on the lumped element loading matching technology is proposed. A metal disk structure is loaded on its top, the radiator is provided with a bent portion, rectangular slots are opened at different positions of the radiator, and a sleeve structure is introduced, realizing the miniaturization and broadband of the antenna. At the same time, it has high gain and good radiation pattern, and can be used in airborne VHF / UHF communication systems.

[0064] The embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A VHF and UHF band antenna, characterized in that, Comprising: A top loading plate, the top loading plate being of an all-metal structure; A conductive floor; And A radiator, disposed between the top loading plate and the conductive floor; The radiator includes at least one connecting portion and at least one bending portion, the at least one connecting portion being connected to the at least one bending portion; the top end and the bottom end of the at least one bending portion are respectively connected to the top loading plate and the conductive floor; at least two slots are formed on both sides of the radiator.

2. The VHF and UHF band antenna according to claim 1, characterized in that: The at least one bending portion is a right-angle bending portion.

3. The VHF and UHF band antenna according to claim 1, characterized in that: The at least one bending portion includes a first bending portion, a second bending portion and a third bending portion; the at least one connecting portion includes a first connecting portion, a second connecting portion, a third connecting portion and a fourth connecting portion; The first bending portion is connected between the first connecting portion and the second connecting portion, the second bending portion is connected between the second connecting portion and the third connecting portion, the third bending portion is connected between the third connecting portion and the fourth connecting portion; the top end and the bottom end of the second bending portion are respectively connected to the top loading plate and the conductive floor.

4. The VHF and UHF band antenna according to claim 3, wherein: The top end and the bottom end of the second connecting portion are respectively connected to the top loading plate and the conductive floor; the top end and the bottom end of the third connecting portion are respectively connected to the top loading plate and the conductive floor; the bottom ends of the first bending portion, the third bending portion, the first connecting portion and the fourth connecting portion are all connected to the conductive floor.

5. The VHF and UHF band antenna according to claim 4, characterized in that, The second connecting portion includes a first connecting plate connected to the first bending portion and a second connecting plate connected to the second bending portion, the length of the second connecting plate being greater than the length of the first connecting plate; the bottom end of the first connecting plate is connected to the conductive floor, the top end and the bottom end of the second connecting plate are respectively connected to the top loading plate and the conductive floor; The third connecting portion includes a third connecting plate connected to the second bending portion and a fourth connecting plate connected to the third bending portion, the length of the third connecting plate being greater than the length of the fourth connecting plate; the top end and the bottom end of the third connecting plate are respectively connected to the top loading plate and the conductive floor, the bottom end of the fourth connecting plate is connected to the conductive floor.

6. The VHF and UHF band antenna according to claim 4, characterized in that, The at least two slots include a first slot and a second slot; the first slot is formed in the first connecting portion, the first bending portion and the second connecting portion and sequentially penetrates through the first connecting portion, the first bending portion and the second connecting portion; the second slot is formed in the fourth connecting portion.

7. The VHF and UHF band antenna according to claim 1, characterized in that, Further comprising: At least two coupling sheets, disposed on both sides of the radiator; the bottom ends of the at least two coupling sheets are all connected to the conductive floor.

8. The VHF and UHF band antenna according to claim 1, characterized in that: The shape of the top loading plate is circular or elliptical.

9. The VHF and UHF band antenna according to claim 4, wherein: The first bending portion includes a first conductive sheet (20a) and second conductive sheets (22a) and third conductive sheets (24a) arranged in parallel, the first conductive sheet (20a) being perpendicularly connected between the second conductive sheets (22a) and the third conductive sheets (24a); the second conductive sheets (22a) are perpendicularly connected to the first connecting portion, the third conductive sheets (24a) are perpendicularly connected to the second connecting portion; the length of the third conductive sheets (24a) is equal to the length of the second conductive sheets (22a), and the width of the third conductive sheets (24a) is greater than the width of the second conductive sheets (22a); The second bent portion includes a fourth conductive sheet, and a fifth conductive sheet and a sixth conductive sheet which are arranged in parallel. The fourth conductive sheet is vertically connected between the fifth conductive sheet and the sixth conductive sheet; the fifth conductive sheet is vertically connected to the second connection portion, and the sixth conductive sheet is vertically connected to the third connection portion; the length and width of the sixth conductive sheet are respectively equal to the length and width of the fifth conductive sheet. The third bent portion includes a seventh conductive sheet (20b), and an eighth conductive sheet (22b) and a ninth conductive sheet (24b) which are arranged in parallel. The seventh conductive sheet (20b) is vertically connected between the eighth conductive sheet (22b) and the ninth conductive sheet (24b); the eighth conductive sheet (22b) is vertically connected to the third connection portion, and the ninth conductive sheet (24b) is vertically connected to the fourth connection portion; the length of the ninth conductive sheet (24b) is equal to the length of the eighth conductive sheet (22b), and the width of the eighth conductive sheet (22b) is greater than the width of the ninth conductive sheet (24b).

10. The VHF and UHF band antenna according to claim 1, characterized in that, It further includes: A broadband matching network connected between the 50Ω coaxial port and the antenna feed end of the at least one bent portion; The broadband matching network includes an inductor L1, a capacitor C1, an inductor L2, a capacitor C2, a capacitor C3, an inductor L3, an inductor L4, a capacitor C4, an inductor L5, a capacitor C5 and an inductor L6; the inductor L1 and the capacitor C1 are connected in parallel between the 50Ω coaxial port and one end of the capacitor C3; the inductor L2 and the capacitor C2 are connected in parallel between one end of the capacitor C3 and the ground; the inductor L4, the inductor L5 and the capacitor C5 are connected in series in sequence between the other end of the capacitor C3 and the antenna feed end; one end of the inductor L3 is connected between the capacitor C3 and the inductor L4, and the other end of the inductor L3 is grounded; one end of the capacitor C4 is connected between the inductor L4 and the inductor L5, and the other end of the capacitor C4 is grounded; one end of the inductor L6 is connected between the capacitor C5 and the antenna feed end; the other end of the inductor L6 is grounded.

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