A coupled high-order filter circuit and antenna

Abstract

The application discloses a coupling high-order filter circuit, which comprises a first circuit and a second circuit working in different frequency bands, wherein the first circuit can cause interference to the second circuit; and a filter structure, which comprises a coupling filter circuit and a high-order filter circuit, wherein the coupling filter circuit is coupled with the first circuit, the electric length of the filter structure is greater than that of the first circuit, and the current coupled from the second circuit to the first circuit is filtered through the coupling filter circuit.

Description

Technical Field

[0001] This invention relates to the field of filtering technology, and in particular to a coupled high-order filtering circuit and antenna. Background Technology

[0002] When base station antennas are designed for multiple frequencies, common low-frequency bands include 617–894 MHz and 698–960 MHz, while common high-frequency bands include 1.4–1.7 GHz and 2.3–3.8 GHz. Mutual coupling occurs between radiating elements operating in the low-frequency and high-frequency bands, leading to harmonic overlap when operating simultaneously. The resulting radiation strikes the low-frequency radiating element, inducing current in the radiating arm. This surface current causes energy loss in the low-frequency radiating arm, while the high-frequency radiated signal experiences energy coupling, deteriorating isolation. Furthermore, the low-frequency signal is blocked, causing distortion in the radiation pattern and a shift in the main radiation direction. To address these issues, filtering techniques are needed. In existing high-order filtering units, microstrip line open-circuit stubs or probe conductive grounding are typically used to filter wavelengths outside the operating frequency band. However, existing high-order filtering units have two main problems: 1. They affect the original antenna circuit equipped with the high-order filtering unit, reducing its impedance bandwidth and / or radiation gain; 2. The higher the frequency band of incoming radio waves filtered by the high-order filtering unit, the greater the impact of the high-order filtering unit on the original antenna circuit. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a coupled high-order filter circuit that can filter incoming currents operating in other frequency bands without interfering with the operation of the original circuit, and can also broaden the filter bandwidth.

[0004] According to a first aspect of the present invention, a coupled high-order filter circuit includes: a first circuit and a second circuit operating in different frequency bands, wherein the first circuit interferes with the second circuit; and a filter structure, wherein the filter structure includes a coupled filter circuit and a high-order filter circuit, wherein the coupled filter circuit is coupled to the first circuit, and the electrical length of the filter structure is greater than the electrical length of the first circuit, and the current coupled from the second circuit to the first circuit is filtered out by the coupled filter circuit.

[0005] According to some embodiments of the present invention, a first dielectric substrate is included, and the filter structure and the first circuit are disposed on the first dielectric substrate to facilitate coupling between the filter structure and the first circuit.

[0006] According to some embodiments of the present invention, a second dielectric substrate and a third dielectric substrate are included. The filtering structure is disposed on the second dielectric substrate, and the first circuit is disposed on the third dielectric substrate. The second dielectric substrate and the third dielectric substrate are detachably connected. The capacitance value between the filtering structure and the first circuit is controlled by the thickness of the second dielectric substrate, thereby adjusting its filtering effect. The detachable connection facilitates installation.

[0007] According to some embodiments of the present invention, the filtering structure is distributed inside the first circuit; while keeping the original circuit structure unchanged, a filtering structure with widened bandwidth, coupled with the original circuit and having filtering function is distributed in a limited space.

[0008] According to some embodiments of the present invention, the first circuit adopts a dual-polarized half-wave oscillator and its two polarized radiating arms are orthogonal in the ±45° direction. The filter structure is located inside the radiating arms and is symmetrically distributed about the central axis of the radiating arms in the ±45° direction. By adjusting the electrical length of the filter structure, the second circuit can be ensured to work normally within its own operating frequency band while filtering the coupling current of the second circuit to the first circuit.

[0009] According to some embodiments of the present invention, the second circuit includes a first unit and a second unit operating in different frequency bands, the first unit and the second unit being distributed on different sides of the first circuit; the first circuit employs a dual-polarized half-wave oscillator with its two polarized radiating arms orthogonally arranged in ±45° directions, the filtering structure being located inside the radiating arms and asymmetrically distributed about the central axis of the radiating arms in the ±45° direction; the filtering bandwidth corresponding to the filtering structure closer to the first unit is located in the frequency band of the first unit, and the filtering bandwidth corresponding to the filtering structure closer to the second unit is located in the frequency band of the second unit; it can filter out radio waves emitted by the first unit and the second unit while ensuring that the second circuit operates normally within its own operating frequency band; that is, when the filtering structure is asymmetrically distributed on the first circuit, it can simultaneously filter out the coupling current of the second circuit coupled to the first circuit in two different operating frequency bands.

[0010] According to some embodiments of the present invention, the second circuit adopts a dual-polarized half-wave oscillator with its two polarized radiating arms orthogonally arranged in ±45° directions; the first circuit adopts a dual-polarized half-wave die-cast oscillator with its two polarized radiating arms orthogonally arranged in ±45° directions, and the radiating arms of the first circuit have a double-layer coupling structure. The filtering structure extends into the double-layer coupling structure to couple with the radiating arms of the first circuit, thereby filtering the coupling current from the second circuit to the first circuit and ensuring the working state of the second circuit.

[0011] According to some embodiments of the present invention, a connection structure is included, wherein a through hole is provided on the radiating arm of the first circuit, and the connection structure is connected to the filter structure through the through hole. The gap distance between the filter structure and the radiating arm of the first circuit is adjusted by adjusting the length of the connection structure, thereby adjusting the coupling amount between the coupling filter circuit and the radiating arm.

[0012] According to some embodiments of the present invention, the filter structure 30 is a metal conductor bar.

[0013] The coupled high-order filter circuit according to embodiments of the present invention has at least the following beneficial effects: when the minimum straight-line distance between the first circuit and the second circuit is less than one operating wavelength of the second circuit, the current of the second circuit is coupled to the first circuit, causing the first circuit to generate an induced current and feeding back an electric field to the second circuit, thereby interfering with the original operating state of the second circuit; after the coupled filter circuit in the filter structure is coupled to the first circuit, and because the high-order filter circuit extends the electrical length, the electrical length of the filter structure is much greater than the electrical length of the first circuit, when the current reaches the first circuit and generates an induced current, the induced current will be coupled to the coupled filter circuit and filtered out by it, so it will not interfere with the second circuit, and the high-order filter unit in the filter structure makes the filter bandwidth 2 to 3 times that of the conventional filter circuit bandwidth.

[0014] An antenna according to a second aspect of the present invention includes a coupled high-order filter circuit as described in any of the preceding claims.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings;

[0017] Figure 1 This is a circuit diagram of a filter circuit;

[0018] Figure 2 This is a topology diagram of the coupling between the radiating unit 10 and the filter circuit in Embodiment 1;

[0019] Figure 3 yes Figure 2 A three-dimensional structural diagram;

[0020] Figure 4 This is an array topology diagram of radiating element 10 and radiating element 20 in Embodiment 1;

[0021] Figure 5 This is an array topology diagram of radiating element 10 and radiating element 20 in Embodiment 1;

[0022] Figure 6 This is another array topology diagram of radiation unit 10 and radiation unit 20 in Embodiment 1;

[0023] Figure 7 This is an array topology diagram of radiating unit 10 and radiating unit 20 in Embodiment 2;

[0024] Figure 8 This is an array topology diagram of radiating unit 10 and radiating unit 20 in embodiment 3;

[0025] Figure 9 yes Figure 8 Cross-sectional structural diagram. Detailed Implementation

[0026] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limiting this invention.

[0028] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0029] Reference Figures 1 to 9This invention discloses a coupled high-order filter circuit, comprising a filter structure 30, a first circuit and a second circuit operating in different frequency bands. When the minimum straight-line distance between the first circuit and the second circuit is less than one operating wavelength of the second circuit, the first circuit will interfere with the second circuit. The filter structure 30 includes a coupled filter circuit and a high-order filter circuit. The coupled filter circuit is coupled to the first circuit, and the electrical length of the filter structure 30 is much greater than the electrical length of the first circuit. The coupled filter circuit filters out the current coupled from the second circuit to the first circuit. This filter structure 30 can be applied to active and passive circuits such as different types of antenna elements, feed networks, and isolation strips to filter external interference.

[0030] The high-order filter circuit includes multiple band-stop high-order filter units of different sizes. The band-stop high-order filter units are designed using open-circuit stubs, interdigitated high-order filter units, and quarter-wavelength coupling stubs, which increases the electrical length and widens the filter bandwidth.

[0031] The principle of this invention is as follows: Since the minimum straight-line distance between the first circuit and the second circuit is less than one operating wavelength of the second circuit, the current of the second circuit is coupled to the first circuit, causing the first circuit to generate an induced current and feeding back an electric field to the second circuit, thereby interfering with the original operating state of the second circuit. After the coupling filter circuit in the filter structure 30 is coupled to the first circuit, and because the higher-order filter circuit extends the electrical length, the electrical length of the filter structure 30 is much greater than the electrical length of the first circuit. When the current reaches the first circuit and generates an induced current, the induced current will be coupled to the coupling filter circuit and filtered out by it, so it will not interfere with the second circuit. Furthermore, the higher-order filter unit in the filter structure 30 makes the filter bandwidth 2 to 3 times that of the conventional filter circuit.

[0032] like Figure 1 As shown, in order to increase the electrical length of the filter structure 30, the circuit between the two ends of the filter structure 30 is bent to form multiple bends, so that the electrical length of the filter structure 30 is much greater than the electrical length of the first circuit.

[0033] In some embodiments, such as Figure 2 As shown, a first dielectric substrate 40, a filter structure 30, and a first circuit are disposed on the first dielectric substrate 40 to facilitate coupling between the filter structure 30 and the first circuit.

[0034] In some embodiments, such as Figure 2 As shown, the filter structure 30 is distributed inside the first circuit; keeping the original circuit structure unchanged, the filter structure 30, which has widened the bandwidth, is coupled with the original circuit, and has filtering function, is distributed in a limited space.

[0035] In some embodiments, such as Figure 8 and Figure 9 As shown, the system includes a second dielectric substrate and a third dielectric substrate. A filter structure 30 is disposed on the second dielectric substrate, and a first circuit is disposed on the third dielectric substrate. The second and third dielectric substrates are detachably connected. A second dielectric substrate, composed of the same or different materials, can be fixed near the third dielectric substrate using rivets, plastic parts, hot melt guns, clips, etc., to achieve a fixed coupling relationship between the filter structure 30 and the existing circuit. The circuit of the filter structure 30 mounted on the second dielectric substrate can be formed by bending metal strips or by covering the filter circuit onto a PCB board. Furthermore, the capacitance value between the filter structure 30 and the first circuit is controlled by the thickness of the second dielectric substrate, thereby adjusting its filtering effect and facilitating the installation of the filter structure 30.

[0036] This invention can be applied to antennas to filter out wavelengths in other frequency bands without affecting the voltage standing wave ratio and radiation pattern of the radiating element, thus ensuring the stability and consistency of the radiating element. Below are six topology diagrams of antenna radiating elements and three specific embodiments applying the filtering structure 30 to the radiating element, including embodiment 1. Figures 2 to 6 The topology diagram in Example 2 includes Figure 7 The topology diagram, included in Example 3 Figure 8 and Figure 9 The topology diagram.

[0037] Example 1: As Figure 2 and Figure 3 As shown, the filter structure 30 is mounted on the existing circuit of the antenna radiating component to form a new circuit structure. The radiating unit 10 mainly includes a balun matching circuit and a radiating component. The balun matching circuit includes balun 111 and balun 112. The radiating component includes radiating arm 121 and radiating arm 122. The radiating arms 121 and 122 are orthogonally placed at +45° and -45° for transmitting and receiving signals. The radiating arms are spaced apart by the filter structure 30. The filter structure 30 is composed of a number of striplines connected in series and is coupled to the radiating unit 10.

[0038] The first circuit consists of a radiating element 10 operating in the 698–960 MHz range, and the second circuit consists of a radiating element 20 operating in the 1.7–2.7 GHz range. The radiating element 20 is placed near and below the radiating element 10, with the straight-line distance between its center point and the center point of the radiating element 10 being less than half the wavelength of the center frequency of the operating band of the radiating element 20. When the array operates in the 1.7–2.7 GHz range, a portion of the electric field vector emitted by the radiating element 20 strikes the radiating element 10, inducing a current and causing scattering, which in turn affects the array's radiation pattern and parameters to varying degrees. The electrical length of the radiating arm of the radiating element 10 is one-quarter wavelength. The filter structure 30 is coplanar with the radiating arm on the upper surface layer of the first dielectric substrate 40. The filter structure 30 is located inside the radiating arm and is symmetrically distributed about the central axis of the radiating arm in the ±45° direction. The filter structure 30 is used to filter the electromagnetic waves generated by the radiating element 20 in the array. Its symmetrical topology about the radiating element 10 can ensure the stability of the radiation pattern of the antenna radiating element. The operating frequency band of the original circuit radiating element 20 itself is not affected by the filter structure 30.

[0039] Figure 4 and Figure 5 The array consists of n radiating elements 10 ranging from 698 to 960 MHz and 4n radiating elements 20 ranging from 1.4 to 2.7 GHz. Each radiating element 10 has two ports, which control the positive and negative polarization of the radiating element 10. The radiating elements 10 and 20 are assembled on the same reflector. For a compact arrangement, the radiating elements 20 are evenly placed diagonally below the radiating elements 10, spaced a certain distance from them both radially and axially. Figure 4 and Figure 5 As can be seen, radiating element 10 and radiating element 20 intersect in a certain area from a top-down perspective, which causes radiated interference during their operation. Simulation and experimental results demonstrate that by adjusting the electrical length of the filter structure 30 on radiating element 10, the radiation pattern in the 1.4–2.7 GHz operating frequency band can be adjusted while ensuring the array operates normally in the 698–960 MHz range.

[0040] The filter structure 30 consists of a number of striplines connected in series and coupled to the radiating arm. The striplines have different sizes and shapes, which can be rectangular or arcs with varying curvatures. This filter structure 30 can be used as part of a circuit or as a standalone patch component, directly applied over the radiating unit 10 that needs to be filtered.

[0041] In some embodiments, the filter structure 30 is attached to the first dielectric substrate 40 housing the radiating unit 10 via copper plating. Since the current does not significantly flow to the filter structure 30 when the radiating unit 10 operates in the 617–894 MHz frequency band, the radiating unit 10 radiates normally in the 617–894 MHz frequency band, and the installed filter structure 30 does not interfere with this band. Furthermore, since the electrical length of the filter structure 30 is determined based on the radiating unit 20 operating at high frequencies, the filter structure 30 operates in the 1.4–1.7 GHz frequency band. To ensure it meets the quarter-wavelength requirement of this band and eliminates electromagnetic interference in this band without affecting the operation of the radiating arm, further measures are taken.

[0042] like Figure 6 As shown, the array consists of 2n radiating elements 10 operating in the 617–894 MHz range and 12n radiating elements 20 operating in the 2.3–3.8 GHz range. The radiating elements 10 employ a dual-polarized half-wave array, with their two polarized radiating arms orthogonally arranged in ±45° directions. The corresponding electrical length of each radiating arm is a quarter wavelength. The filtering structure 30 is coplanar with the radiating arms on the upper surface layer of the dielectric substrate. The filtering structure 30 is located inside the radiating arms and is symmetrically distributed about the central axis of the radiating arms in the ±45° direction. This filtering structure 30 is used to prevent electromagnetic interference generated by the radiating elements 20 in the array. Its symmetrical topology about the radiating elements 10 ensures the stability of the antenna radiating pattern. By adjusting the filtering structure 30 so that its corresponding filtering bandwidth is between 2.3 GHz and 3.8 GHz, and then connecting it to the radiating arms using coupling technology, the electromagnetic waves emitted by the radiating elements 20 can be filtered out while ensuring that the radiating elements 10 operate normally within their own frequency band. Simulation and experimental results demonstrate that the filtering effect is not affected by the array topology or the number of elements. .

[0043] When the structure and operating frequency band of the radiating unit 10 are changed or not, electromagnetic interference from different radiating units 20 can be filtered out by adjusting the size of the filter structure 30 while maintaining the normal operation of the radiating unit 10.

[0044] Example 2: As Figure 7As shown, this array is an FDD+TDD array, consisting of 2n radiating elements 10 operating at 698–960 MHz, 8n radiating elements 21 operating at 1.4–2.7 GHz, and 9n radiating elements 22 operating at 2.3–3.8 GHz. Radiating element 10 forms the first circuit, radiating element 21 forms the first element in the second circuit, and radiating element 22 forms the second element in the second circuit. The array region formed by radiating elements 10 and 21 is the FDD array region, and the MIMO array region formed by radiating elements 22 is the TDD array region. The radiating unit 10 adopts a dual-polarized half-wave array, with its two polarized radiating arms orthogonally arranged in a ±45° direction. The corresponding electrical length of the radiating arm is a quarter wavelength. The filtering structure 30 is coplanar with the radiating arm on the upper surface layer of the dielectric substrate. The filtering structure 30 is located on the inner side of the radiating arm and is asymmetrically distributed about the central axis of the radiating arm in a ±45° direction. The filtering structure 30 is used to block electromagnetic interference generated by the radiating units 21 and 22 in the array. By adjusting the filtering structure 30, the filtering bandwidth corresponding to the filtering structure 30 on the two radiating arms on the side closer to the radiating unit 21 is located in the range of 1.4 to 2.7 GHz, and the filtering bandwidth corresponding to the filtering structure 30 on the two radiating arms on the side closer to the radiating unit 22 is located in the range of 2.3 GHz to 3.8 GHz. By connecting to the radiating arms using coupling technology and appropriately adjusting the size of the filtering structure 30, the electromagnetic waves emitted by the radiating units 21 and 22 can be filtered out while ensuring that the radiating unit 10 operates normally within its own operating frequency band. Simulation and experimental results have shown that when the filtering technology is asymmetrically distributed on the radiating element, it can simultaneously filter out two different operating frequency bands of radiating elements. Therefore, the filtering structure 30 invented in this technology can be flexibly changed according to the types and numbers of other radiating elements in the array.

[0045] Example 3: This example filters out low-frequency waves by coupling current in a high-frequency circuit. When Figure 8 When the array shown is operated in the 698–960 MHz range without the filter structure 30, the electromagnetic waves radiated by the radiating element 10 are mainly divided into two parts: one part is emitted towards the beam pointing angle of the array, and the other part hits the array's reflector. When the electromagnetic wave about to hit the reflector passes through the radiating element 20, a small amount of induced current is generated. This current may be absorbed by the circuit on the radiating element 20, or it may be emitted irregularly outwards from the array. In either case, the energy of the electromagnetic waves hitting the reflector from the radiating element 10 is reduced, ultimately reducing the beam gain radiated by the array in that frequency band. To solve the above problems, the filter structure 30 described in this embodiment is introduced into the above array. Figure 8 and Figure 9As shown, the array consists of one radiating element 10 operating in the 698–960 MHz range and four radiating elements 20 operating in the 1.4–2.7 GHz range. The radiating element 10 employs a dual-polarized half-wave oscillator, with its two polarized radiating arms orthogonally arranged in ±45° directions, and the corresponding electrical length of each radiating arm being a quarter wavelength. The radiating element 20 employs a dual-polarized half-wave die-cast oscillator, with its two polarized radiating arms orthogonally arranged in ±45° directions, and the corresponding electrical length of each radiating arm being a quarter wavelength. It is a double-layer coupling structure, comprising radiating arms 211 and 212. The coupling filter circuit in the filter structure 30 is located between radiating arms 211 and 212 to filter the radiating element 10.

[0046] In some embodiments, the filter structure 30 is an aluminum strip structure, and the radiating arm 21 is provided with through holes. The connecting structure (such as a plastic screw) is snapped into the filter structure 30 through the through holes. The gap distance between the filter structure 30 and the radiating arm 21 is adjusted by adjusting the length of the connecting structure, thereby adjusting the coupling amount between the coupling filter circuit and the radiating arm.

[0047] Because the electrical length of the aluminum strip is much greater than the operating wavelength of the radiating element 20, and the aluminum strip is coupled to the radiating arm of the radiating element 20, no current flows through the filter structure 30 among the four radiating elements 20, thus not affecting the isolation between the radiating elements 20. Simulation and experimental results demonstrate that the radiating element 20 can operate normally in the 1.4–2.7 GHz range, and the gain of the radiating element 10 when operating in the 698–960 MHz range is essentially the same as the gain when the radiating element 10 operates alone. This embodiment successfully utilizes the broadband coupled filter structure 30 to filter out lower-frequency radio waves in the array while ensuring that antennas operating in higher frequency bands remain at a normal horizontal position.

[0048] It will be readily understood by those skilled in the art that the above preferred methods can be freely combined and superimposed without conflict.

[0049] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A coupled high-order filter circuit, characterized in that, include: The first circuit and the second circuit operate in different frequency bands, and the first circuit will cause interference to the second circuit; The filter structure (30) includes a coupling filter circuit and a higher-order filter circuit. The coupling filter circuit is coupled to the first circuit, and the electrical length of the filter structure (30) is greater than the electrical length of the first circuit. The current coupled from the second circuit to the first circuit is filtered out by the coupling filter circuit. The second circuit uses a dual-polarized half-wave oscillator with its two polarized radiating arms orthogonally arranged in ±45° directions; the first circuit uses a dual-polarized half-wave die-cast oscillator with its two polarized radiating arms orthogonally arranged in ±45° directions, and the radiating arms of the first circuit are double-layer coupled structures. The filtering structure (30) extends into the double-layer coupled structure to couple with the radiating arms of the first circuit to filter the second circuit.

2. The coupled high-order filter circuit according to claim 1, characterized in that: It includes a first dielectric substrate (40), and the filter structure (30) and the first circuit are disposed on the first dielectric substrate (40).

3. The coupled high-order filter circuit according to claim 1, characterized in that: It includes a second dielectric substrate and a third dielectric substrate, the filter structure (30) is disposed on the second dielectric substrate, the first circuit is disposed on the third dielectric substrate, and the second dielectric substrate and the third dielectric substrate are detachably connected.

4. The coupled high-order filter circuit according to claim 1, characterized in that: The filter structure (30) is located inside the first circuit.

5. The coupled high-order filter circuit according to claim 1, characterized in that: The first circuit uses a dual-polarized half-wave oscillator and its two polarized radiating arms are orthogonal in the ±45° direction. The filter structure (30) is located inside the radiating arm and is symmetrically distributed about the central axis of the radiating arm in the ±45° direction to filter the second circuit.

6. The coupled high-order filter circuit according to claim 1, characterized in that: The second circuit includes a first unit and a second unit operating in different frequency bands. The first unit and the second unit are distributed on different sides of the first circuit. The first circuit adopts a dual-polarized half-wave oscillator and its two polarized radiating arms are orthogonal in the ±45° direction. The filter structure (30) is located inside the radiating arm and is asymmetrically distributed about the central axis of the radiating arm in the ±45° direction, so as to filter the first unit and the second unit respectively.

7. The coupled high-order filter circuit according to claim 1, characterized in that: The circuit includes a connection structure. The first circuit has a through hole on its radiating arm. The connection structure is connected to the filter structure (30) through the through hole. The gap distance between the filter structure (30) and the radiating arm of the first circuit is adjusted by adjusting the length of the connection structure.

8. The coupled high-order filter circuit according to claim 1, characterized in that: The filter structure (30) is a metal conductor bar.

9. An antenna, characterized in that: Includes the coupled high-order filter circuit as described in any one of claims 1 to 8.

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