Triple-band wideband indoor antenna with trap structure

Abstract

The application relates to the technical field of wireless communication, and discloses a three-frequency wideband room-dividing antenna with a trap structure, which comprises a first radiating unit, a first substrate, first radiating structures and first feeding structures which are arranged on two sides of the first substrate, a second radiating unit, a second substrate, second radiating structures, second feeding structures and a trap structure, wherein the second radiating structures and the second feeding structures are arranged on two sides of the second substrate, the second radiating structures comprise four second radiating arms which are arranged in an angular symmetry, the second feeding structures comprise two second feeding branches which are arranged in a cross, the middle parts of the second feeding branches are arranged opposite to two adjacent second radiating arms, and the two ends of the second feeding branches are arranged opposite to the other two second radiating arms, the middle part of each second feeding branch is provided with a feeding point, and the trap structure is a metal line arranged on the second substrate and surrounding the outer periphery of the second radiating structures. The application has the advantages of small volume, support for 2G / 3G / 4G / 5G frequency bands, and the function of a trap frequency band of 2.9-3.1 GHz.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to a tri-band broadband indoor antenna with a notch filter structure. Background Technology

[0002] Indoor distributed antennas are a type of antenna used in mobile communication systems, primarily for indoor signal coverage. They are used in places requiring indoor distributed systems for coverage, such as subway stations, hotels, guesthouses, and office buildings. Dual-polarized wall-mounted antennas are widely used in WLAN and LTE wireless communication systems as indoor distributed antennas. Currently, wall-mounted antennas operate in frequency bands of 800-960MHz, 1.71-2.69GHz, and 3.3-3.7GHz, with a typical design where one antenna corresponds to one operating frequency band. However, with the development of wall-mounted antennas and indoor distributed systems demanding miniaturization and integration, the application of broadband vibrators has also become widespread. According to the International Telecommunication Union (ITU), the 2.9-3.1GHz band is used for radio navigation and positioning. This frequency band lies between the 3G / 4G (1.71-2.69GHz) and 5G (3.4-3.6GHz) bands. For antennas supporting 2G / 3G / 4G / 5G coexistence, it is necessary to develop dual-polarized antennas with a notch filter frequency of 2.9-3.1GHz. The two main challenges of this type of antenna are widening the antenna bandwidth to 1.7-3.7GHz while maintaining good suppression performance in the 2.9-3.2GHz band. Currently, the main full-band coverage indoor distributed antenna solutions on the market use three antenna elements to cover the 690-960MHz, 1.71-2.69GHz, and 3.3-3.7GHz bands respectively. This solution results in a larger overall antenna size and coupling problems between the antenna elements, leading to reduced antenna radiation. Summary of the Invention

[0003] This invention is made to solve the above-mentioned technical problems. Its purpose is to provide a tri-band broadband indoor antenna with a notch filter structure, which is small in size, supports 2G / 3G / 4G / 5G frequency bands, and also has the function of notch filter band 2.9-3.1GHz.

[0004] To achieve the above objectives, the present invention provides a tri-band broadband indoor antenna with a notch filter structure, comprising: a first radiating element, including a first substrate and a first radiating structure and a first feeding structure disposed on both sides thereof; and a second radiating element, including a second substrate, a second radiating structure, a second feeding structure, and a notch filter structure, wherein the second radiating structure and the second feeding structure are disposed on both sides of the second substrate, the second radiating structure includes four symmetrically arranged second radiating arms, the second feeding structure includes two intersecting second feeding branches, the middle part of the second feeding branch is arranged facing two adjacent second radiating arms, and the two ends are respectively arranged facing two other second radiating arms, each second feeding branch has a feeding point in the middle, and the notch filter structure is a metal line disposed on the second substrate and surrounding the outer periphery of the second radiating structure.

[0005] Preferably, the second radiating arm has a groove in the middle.

[0006] Preferably, the notch filter structure consists of four L-shaped metal lines respectively disposed on the outside of the second radiating arm.

[0007] Preferably, the second radiating unit further includes a guiding structure disposed on the second substrate, and a support column is provided between the guiding structure and the second substrate.

[0008] Preferably, the second radiation unit further includes a second reflector, which is disposed on both sides of the second substrate, and a support column is provided between the second reflector and the second substrate.

[0009] Preferably, the second radiating arm has an installation area in the middle that faces the support column.

[0010] Preferably, the end of the second power supply branch has a tortuous structure.

[0011] Preferably, the first radiating unit includes a first substrate, a first radiating structure, and a first feeding structure. The first radiating structure and the first feeding structure are respectively disposed on both sides of the first substrate. The first radiating structure includes four symmetrically arranged first radiating arms at the four corners. The first feeding structure includes two intersecting T-shaped first feeding branches. The two ends of the first feeding branches are respectively disposed opposite to the two opposing first radiating arms.

[0012] Preferably, the first radiating unit further includes a first reflector, which is disposed on both sides of the first substrate, and the two sides of the first reflector are bent toward one side of the first substrate.

[0013] Preferably, a short-circuit post is provided between the first reflector and the first radiating arm.

[0014] Based on the above description and practical application, the tri-band broadband indoor antenna with notch filter structure described in this invention comprises two radiating elements, which can be used to radiate 2G and 3G / 4G / 5G signals respectively. The second radiating element incorporates a notch filter structure to suppress signals in the 2.9-3.2GHz band, thus enabling the transmission and reception of 3G / 4G / 5G signals with a single radiating element. Simultaneously, the second radiating structure and second feeding structure in the second radiating element ensure that the antenna has strong and stable gain in 3G / 4G / 5G bands. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a three-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the structure of the second radiating element in a three-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0017] Figure 3 This is a planar schematic diagram of the first substrate in a tri-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0018] Figure 4 This is a schematic diagram of the structure of the first radiating element in a tri-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0019] Figure 5 This is a planar schematic diagram of the first substrate in a tri-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0020] Figure 6 This is a schematic diagram of the S-parameters of a three-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0021] Figure 7 This is a gain diagram of a three-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0022] Figure 8 This is a schematic diagram of the port isolation of a three-band broadband indoor antenna with a notch filter structure according to one embodiment of the present invention.

[0023] Figure 9 This is a comparison diagram of the standing wave ratio (SWR) of a three-band broadband indoor antenna with and without a notch structure, and with and without a guide structure, according to one embodiment of the present invention.

[0024] Figure 10This is a gain comparison diagram of a tri-band broadband indoor antenna with and without a notch structure, and with and without a guide structure, according to one embodiment of the present invention.

[0025] The attached figures are labeled as follows:

[0026] 1. Base plate; 2. First radiating unit; 21. First substrate; 22. First radiating structure; 221. First radiating arm; 23. First feeding structure; 231. First feeding branch; 24. First reflector; 25. Short-circuit post; 3. Second radiating unit; 31. Second substrate; 32. Second radiating structure; 321. Second radiating arm; 322. Slot; 33. Second feeding structure; 331. Second feeding branch; 34. Notch filter structure; 35. Directing structure; 36. Second reflector; 4. Support post; 5. Feeder line. Detailed Implementation

[0027] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0028] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. It should be noted that in this disclosure, the terms "comprising," "configured with," and "set in" are used to indicate an open-ended inclusion, meaning that additional elements / components / etc. may exist besides those listed; the terms "first," "second," etc., are used only as labels and are not intended to limit the number or order of objects; the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0029] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] This embodiment discloses a three-band broadband indoor antenna with a notch filter structure. Figure 1 The three-dimensional structure of the tri-band broadband indoor antenna with notch filter is shown; Figure 2 The structure of the second radiating element in the tri-band broadband indoor antenna with notch structure is shown, and the second radiating structure provided on the lower surface of the second substrate is shown in the form of dashed lines. Figure 3 The planar structure of the second substrate in this tri-band broadband indoor antenna with notch filter structure is shown, specifically... Figure 2 The figure shows the structure of the upper surface of the second substrate, and also shows the second power feeding structure of the lower surface of the second substrate in the form of dashed lines. Figure 4 The structure of the first radiating element in the tri-band broadband indoor antenna with notch structure is shown, and the first radiating structure provided on the lower surface of the first substrate is shown in the form of dashed lines. Figure 5 The planar structure of the first substrate in this tri-band broadband indoor antenna with a notch filter structure is shown, specifically... Figure 4 The figure shows the structure of the lower surface of the first substrate, and also shows the first power supply structure on the upper surface of the first substrate in the form of dashed lines.

[0031] Please refer to Figures 1 to 5 The tri-band broadband indoor antenna with a notch filter structure includes a first radiating element 2 and a second radiating element 3, both fixed on the same base plate 1. The first radiating element 2 is a low-frequency radiating element used to radiate signals in the 2G (800-960MHz) frequency band; the second radiating element 3 is a high-frequency radiating element used to radiate signals in the 3G / 4G (1.71-2.69GHz) and 5G (3.4-3.6GHz) frequency bands.

[0032] In this embodiment, the first radiating unit 2 includes a first substrate 21, a first radiating structure 22, and a first feeding structure 23. The first radiating structure 22 and the first feeding structure 23 are respectively disposed on both sides of the first substrate 21, and in this embodiment, they are both metal lines printed on the first substrate 21. The first radiating structure 22 includes four symmetrically arranged first radiating arms 221, such as... Figure 5As shown, the four first radiating arms 221 form a 2×2 array, which can constitute a cross dipole structure and has a good signal radiation effect. The outer periphery of the first radiating arm 221 is generally rectangular, and the middle is hollowed out to make the first radiating arm 221 generally ring-shaped. By controlling the size of the empty area between the first radiating arms 221, the impedance of the first radiating unit 2 can also be adjusted.

[0033] The first feeding structure 23 includes two intersecting T-shaped first feeding branches 231, with each end of the first feeding branch 231 positioned opposite to two opposing first radiating arms 221. For example... Figure 5 As shown, the upper head of the first feed branch 231 faces the two adjacent first radiating arms 221, and correspondingly, the lower tail of the first feed branch 231 faces the other two adjacent first radiating arms 221. Since the first feed branch 231 and the first radiating structure 22 are respectively located on both sides of the first substrate 21, in this embodiment, the head and tail of the first feed branch 231 are coupled to the first radiating arms 221 to achieve signal radiation. Specifically, the tail of the first feed branch 231 is provided with a feed point and is connected to the antenna feed line 5. In use, the signal source via the combiner enters the first feed branch 231 through the feed line 5. The two first feed branches 231 can handle signals with different polarizations, and finally transmit the signal to the first radiating arms 221 for radiation through coupling.

[0034] It should be noted that, since the two first feed branches 231 are responsible for signals of different polarizations, in order to prevent the two first feed branches 231 from connecting at their intersection, the middle part of one of the first feed branches 231 is moved to the lower surface of the first substrate 21, and the first feed branches 231 on the upper and lower surfaces are connected together through metal vias. Figure 4 and Figure 5 It can be understood that the two ends of each first feed branch 231 are respectively set opposite to two first radiating arms 221, and finally the signal is transmitted in the form of coupling.

[0035] In addition, in this embodiment, the first radiating unit 2 further includes a first reflector 24 disposed on the base plate 1. The first reflector 24 is a metal plate, which, along with the first feeding structure 23, is disposed on both sides of the first substrate 21. It is used to reflect signals radiated to one side to the first feeding structure 23, ultimately causing the signal to radiate away from the wall, ensuring that the user can receive a wireless signal with better strength. Furthermore, bending both sides of the first reflector 24 towards the first substrate 21 can further improve the signal reflection effect, which is beneficial for reducing the half-power beamwidth and increasing the gain.

[0036] Furthermore, in this embodiment, a support post 4 is provided between the first substrate 21 and the first reflector 24 to fix and support the first substrate 21. Simultaneously, the feed line 5 is located inside the support post 4, thereby connecting to the first feed structure 23, avoiding surface routing and simplifying the internal structure of the antenna. A short-circuit post 25 is also provided between the first reflector 24 and the first radiating arm 221. The short-circuit post 25 is made of metal, with its upper end directly connected to the first radiating arm 221 and its lower end connected to the first reflector 24. This allows some of the antenna current to be diverted to ground, improving the antenna's bandwidth.

[0037] In this embodiment, the first radiating element 2 can meet the operating bandwidth of 806-960MHz, and can achieve stable gain and low cross-polarization within this operating frequency band. In other embodiments, the specific composition of the first radiating structure 22 and the first feeding structure 23 can also be changed, and low-frequency radiating elements commonly used in the prior art can be adopted, which can also meet the operating bandwidth of 806-960MHz.

[0038] Please combine Figure 2 and Figure 3 In this embodiment, the second radiating unit 3 includes a second substrate 31, a second radiating structure 32, a second feeding structure 33, and a notch filter structure 34. The second radiating structure 32 and the second feeding structure 33 are respectively disposed on both sides of the second substrate 31. In this embodiment, both are metal lines printed on the second substrate 31. The second radiating structure 32 is disposed on... Figure 2 The lower surface of the second substrate 31. The second radiating structure 32 includes four symmetrically arranged second radiating arms 321, the portions of which near the center of the second substrate 31 are connected together, such as... Figure 3 As shown, the four second radiating arms 321 are essentially a single integrated structure. That is, the second radiating structure 32 extends in four directions to form four radiating arms, which have excellent omnidirectional radiation performance. A slot 322 is also formed in the middle of each second radiating arm 321. By controlling the length and width of the slot 322, the impedance of the second radiating unit 3 can be adjusted, giving the second radiating unit 3 a better signal radiation effect. Furthermore, with the slot 322, the second radiating structure 32 can form eight arms distributed in a scattering pattern, further improving the omnidirectional performance of the second radiating unit 3 when radiating signals.

[0039] The second feeding structure 33 includes two intersecting second feeding branches 331. Each second feeding branch 331 is a strip-shaped metal structure, with its middle portion facing two adjacent second radiating arms 321, and its two ends facing two other second radiating arms 321 respectively. (Combined with...) Figure 3As can be clearly seen, the second feed branches 331 are respectively positioned above the four second radiating arms 321 from one end to the other. By setting two second feed branches 331, both sides of each second radiating arm 321 can be covered. With the grooves 322 provided, all eight arms can be coupled to the second feed branches 331. A feed point is provided in the middle of the two feed branches, and the second substrate 31 and the second radiating structure 32 are provided with through holes opposite to the feed point for the feed line to pass through. The feed line of the second radiating unit 3 is not shown in the attached drawings of this embodiment. After being led out from the combiner, the routing direction of the feed line can be set according to the actual structure, and it is finally connected to the two feed points. The two second feed branches 331 can handle signals of different polarizations, and finally transmit the signals to the second radiating arms 321 for radiation through coupling. In addition, in this embodiment, the end of the second power supply branch 331 is also set as a tortuous structure, which can improve the coupling effect between the second power supply branch 331 and the second radiating arm 321.

[0040] The notch structure 34 is a metal line disposed on the second substrate 31 and surrounding the outer periphery of the second radiating structure 32, such as... Figure 2 and Figure 3 As shown, in this embodiment, the notch structure 34 consists of four L-shaped metal lines respectively disposed outside the second radiating arm 321. These lines form a parasitic structure on the outer periphery of the second radiating structure 32, constituting a notch resonator. The notch resonator is loaded with an LC resonant circuit, and the notch frequency band is adjusted by changing the values ​​of L and C. The distance between the notch resonator and the second radiating structure 32 can be equivalent to a capacitance C, and the arm length of the notch resonator can be equivalent to an inductance L. By adjusting the length of the notch resonator and its distance from the second radiating structure 32, the notch frequency band can be adjusted, enabling notch filtering in the 2.9-3.1 GHz frequency band within the second radiating unit 3. By introducing this notch structure 34 into the non-mobile communication frequency band (2.9-3.1 GHz), band-stop characteristics are generated within the target frequency band to suppress energy reception, thus achieving a good balance between the contradiction of wide bandwidth and high gain. In the non-notch band (1.71-2.69 GHz and 3.4-3.6 GHz), the induced current of the notch structure 34 is very weak. However, in the notch band (2.9-3.1 GHz), the current in the notch structure 34 is strongly coupled by the second radiating structure 32. This strong induced current generates secondary radiation, which in turn changes the current distribution on the surface of the second radiating structure 32, causing impedance mismatch in the second radiating element 3 at that frequency, ultimately achieving the notch effect. In other embodiments, the shape of the notch structure 34 can also be changed, for example, by making it arc-shaped. As long as it is ensured to be a metal line located on the outer periphery of the second radiating structure 32, the notch effect can be achieved for the required frequency band by changing its length, width, and spacing from the second radiating structure 32.

[0041] In addition, in this embodiment, the second radiating unit 3 further includes a guiding structure 35 disposed on the second substrate 31. The guiding structure 35 is a metal sheet with four support pillars 4 between it and the second substrate 31. That is, the guiding structure 35 is fixedly mounted on the second substrate 31 by the four support pillars 4. To accommodate the four support pillars 4, a mounting area facing the support pillars 4 is also provided in the middle of the second radiating arm 321, i.e., a hollowed-out area is provided in the middle of the second radiating arm 321 for mounting the support pillars 4. The loading of the guiding structure 35 is essentially a reactance loading, which can improve the initial reactance value of the second radiating structure 32. The guiding structure 35 is coupled by the second radiating structure 32, generating an induced current and forming a radiation field, which compensates for the beam dip of the antenna at high frequencies. Generally speaking, wide bandwidth and stable high gain are a pair of contradictory parameters. Wide bandwidth means that the gain will not be very stable within the passband. Specifically, as the radiation pattern increases with frequency, beam splitting and dip phenomena will occur, resulting in reduced gain and instability of beamwidth. In this embodiment, by setting the guiding structure 35, the far-field superposition of the radiated waves generated by it and the second radiating structure 32 is utilized to narrow the beamwidth in the non-notch band, achieving a balance between stable high gain and wide bandwidth. Simultaneously, because the high-frequency gain is relatively stable, it can bring a better gain suppression effect, i.e., the difference between the maximum passband gain and the minimum stopband gain. Ultimately, the guiding structure 35 improves the beam dip problem of the ultra-wideband radiating structure at high frequencies, enabling the antenna to obtain stable high gain at high frequencies, achieving the goals of enhanced impedance bandwidth and improved far-field radiation performance.

[0042] Furthermore, in this embodiment, the second radiating unit 3 also includes a second reflector 36, which is a metal plate. It and the guiding structure 35 are disposed on opposite sides of the second substrate 31, respectively, to reflect signals radiated to one side to the second feeding structure 33, ultimately causing the signal to radiate away from the wall, ensuring that the user can receive a stronger wireless signal. A support column 4 is provided between the second reflector 36 and the second substrate 31 to achieve a fixed connection between the second substrate 31 and the second reflector 36.

[0043] Traditional coaxial cable direct-feed structures, when applied at high frequencies, have high-frequency current flowing through the outer sheath of the coaxial cable. Where there is current flow, there is radiation, resulting in unbalanced feeding, which negatively impacts the antenna's radiation performance. In this embodiment, the second feed structure 33 is a narrower metal structure printed on the second substrate 31, i.e., an integrated balun structure. This is a balanced feed, achieving better impedance matching. Furthermore, while traditional integrated balun structures are located on the antenna support pillar 4, this embodiment integrates it onto the second substrate 31, offering advantages in integration and miniaturization compared to the feed networks of ordinary broadband antennas. Additionally, the direct integration of the second feed structure 33 onto the second substrate 31 in this embodiment also utilizes the coupling between the second feed structure 33 and the second radiating structure 32 to some extent, thereby reducing the mutual impedance between the mirror element generated by the second radiating arm 321 and the reflecting ground. Ultimately, this results in the real and imaginary parts of the input impedance Zin of the second radiating element 3 exhibiting periodic stable oscillations around 50Ω and 0Ω respectively within the broadband range, thus achieving broadband operation.

[0044] In this embodiment, the guiding structure 35 is electromagnetically coupled to the second radiating structure 32, generating an induced current and forming a radiation field. The total radiation field of the second radiating unit 3 is formed by the superposition of the radiation fields of the second radiating structure 32, the mirror oscillator (generated by the second radiating arm 321 and the reflecting ground), and the guiding structure 35. The phase of the total radiation field can be adjusted by the distance between the guiding structure 35 and the second radiating structure, and the intensity of the total radiation field can be adjusted by the size of the guiding structure 35. Simultaneously, the addition of the guiding structure 35 enables the second radiating unit 3 to achieve good impedance matching at high frequencies, thus obtaining a wider impedance bandwidth.

[0045] It should be noted that the first radiating unit 2 and the second radiating unit 3 mentioned above can be connected by a combiner to achieve good matching characteristics. A filtering structure can also be set on the combiner to further filter out signals in the 2.9-3.1GHz frequency band. The specific structure of the combiner is not innovative in this invention, and combiners with filtering functions already exist in the prior art, so its specific structure will not be described in detail here.

[0046] The tri-band broadband directional wall-mounted antenna with notch structure in this invention, compared with the traditional three-element indoor dual-polarized directional wall-mounted antenna, not only reduces the number of antennas, but also further reduces the construction cost of indoor antennas by using two radiating elements to cover three radiation frequency bands.

[0047] In this embodiment, the first radiating arm 221 is a square with a side length of 61.2 mm. The head of the first feed branch 231 has a length of 20 mm and a width of 3.5 mm, and the tail of the first feed branch 231 has a length of 25 mm and a width of 2.5 mm. The second radiating arm 321 is a square with a side length of 25 mm. The notch filter structure 34 is 4.5 mm away from the second radiating arm 321. The guide structure 35 is 15 mm away from the second substrate 31. The second substrate 31 is 35 mm away from the second reflector 36.

[0048] The S-parameter diagram of this size tri-band broadband directional wall-mounted antenna with notch filter structure has been tested and is detailed below. Figure 6 The reflection coefficient is less than -12dB in the 0.69-0.96GHz, 1.7-2.7GHz and 3.3-3.7GHz frequency bands. Figure 7 The gain diagram of the tri-band broadband directional wall-mounted antenna with notch filter structure is shown. The gain is greater than 6.2 dBi in the 0.69-0.96 GHz, 1.7-2.7 GHz and 3.3-3.7 GHz bands. Figure 8 This is a schematic diagram of the port isolation of the tri-band broadband directional wall-mounted antenna with notch filter structure. The isolation of the two polarizations is generally less than -25 dBi in the 0.69-0.96 GHz, 1.7-2.7 GHz and 3.3-3.7 GHz frequency bands. Figure 9 The comparison diagram of the standing wave ratio (SWR) of the tri-band broadband indoor antenna with and without notch structure 34 and guide structure 35 shows that after setting notch structure 34 and guide structure 35, the bandwidth with SWR below 1.5 in the target frequency band (2G / 3G / 4G / 5G band) is wider. Figure 10 The image shows a gain comparison of the tri-band broadband indoor antenna with and without notch structure 34 and guide structure 35. With notch structure 34 and guide structure 35, the gain is less than 0 in the 2.9-3.1 GHz band, and there is a significant gain improvement in the 3.3-3.7 GHz band compared to the antenna without these two structures.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A three-frequency wideband indoor antenna with a trap structure, characterized in that, The antenna comprises: a first radiating unit, which is a low-frequency radiating unit, is used for radiating signals in a frequency band of 800-960 MHz, and comprises a first substrate, a first radiating structure and a first feeding structure which are arranged on two opposite sides of the first substrate; a second radiating unit, which is a high-frequency radiating unit, is fixed on the same base plate as the first radiating unit, is used for radiating signals in frequency bands of 1.71-2.69 GHz and 3.4-3.6 GHz, and comprises a second substrate, a second radiating structure, a second feeding structure and a wave-trap structure, wherein the second radiating structure and the second feeding structure are arranged on two opposite sides of the second substrate, the second radiating structure comprises four second radiating arms which are arranged in an angular symmetry, the second feeding structure comprises two second feeding branches which are arranged in a cross shape, the middle part of each second feeding branch is arranged opposite to two adjacent second radiating arms, and the two ends of each second feeding branch are arranged opposite to two other second radiating arms, the middle part of each second feeding branch is provided with a feeding point, and the wave-trap structure is a metal line arranged on the second substrate and surrounding the outer periphery of the second radiating structure; and wherein the middle part of one of the two second feeding branches is moved to the other side surface of the second substrate at the cross position of the two second feeding branches, and the second feeding branch on the upper surface and the second feeding branch on the lower surface are connected together through a metal via hole to avoid the connection of the two second feeding branches at the cross position.

2. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 1, wherein the middle part of each second radiating arm is provided with a slot.

3. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 1, wherein the wave-trap structure comprises four L-shaped metal lines which are arranged on the outer sides of the second radiating arms.

4. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 1, wherein the second radiating unit further comprises a directing structure arranged on the second substrate, and a support column is arranged between the directing structure and the second substrate.

5. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 4, wherein the second radiating unit further comprises a second reflecting plate which is arranged on the two opposite sides of the second substrate together with the directing structure, and a support column is arranged between the second reflecting plate and the second substrate.

6. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 4, wherein the middle part of each second radiating arm is provided with a mounting area which is arranged opposite to the support column.

7. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 1, wherein the end part of each second feeding branch is in a meandering structure.

8. The three-frequency wideband indoor antenna with a wave-trap structure according to claim 1, wherein The first radiating unit comprises a first substrate, a first radiating structure and a first feeding structure, the first radiating structure and the first feeding structure are arranged on two sides of the first substrate, the first radiating structure comprises four first radiating arms arranged in a four-corner symmetry mode, the first feeding structure comprises two first feeding branches in a T shape arranged in a cross mode, two ends of the first feeding branches are arranged opposite to two first radiating arms facing each other respectively; wherein, a middle part of one of the first feeding branches is moved to the other side surface of the first substrate at the cross of the two first feeding branches, and the first feeding branches on the upper and lower surfaces are connected together through a metal via hole, so as to avoid the connection of the two first feeding branches at the cross.

9. The three-frequency broadband indoor antenna with a wave trap structure according to claim 8, wherein, The first radiating unit further comprises a first reflecting plate, the first reflecting plate is arranged on two sides of the first substrate together with the first feeding structure, and two sides of the first reflecting plate are bent to one side of the first substrate.

10. The three-frequency broadband indoor antenna with a wave trap structure according to claim 9, wherein, A shorting post is arranged between the first reflecting plate and the first radiating arm.

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