A dual-band planar sleeve monopole antenna based on substrate integrated coaxial line

Abstract

The application discloses a double-frequency planar sleeve monopole antenna based on a substrate integrated coaxial line, which comprises a feeding structure based on a substrate integrated coaxial line, a sleeve antenna composed of double planar parasitic dipoles and a monopole, and a grounded coplanar waveguide. The structure of the application has two groups of parasitic dipoles on the upper side and the lower side of a longer metal inner conductor, forms a sleeve antenna structure, and forms double frequencies due to the different lengths of the parasitic dipoles and the different distances from the ground, and meanwhile, the substrate integrated coaxial line structure is adopted at the front end to feed, so that the integration of the antenna and the feeding network is realized. The application adopts the substrate integrated coaxial line technology, realizes the double-frequency planar sleeve monopole antenna, and the double-frequency planar sleeve monopole antenna based on the substrate integrated coaxial line has the characteristics of miniaturization, high integration and double-frequency band.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and specifically to a dual-frequency planar sleeve monopole antenna based on a substrate-integrated coaxial line. Background Technology

[0002] In recent years, with the rapid development of wireless communication technology, in the practical application of high-speed wireless communication under complex electromagnetic environments and mobile conditions, mobile communication devices not only need to transmit multimedia information with high quality, but also need to meet specific requirements such as broadband, anti-interference, miniaturization, and multi-band support. As the device that radiates and receives signals in mobile communication devices, the requirements for antennas in wireless communication systems are also becoming increasingly stringent.

[0003] Traditional monopole antennas are widely used in wireless communication systems due to their simple structure, omnidirectional radiation, and ease of impedance matching. Sleeve antennas are an improvement on monopole antennas. As a typical form of broadband dipole antenna, the initial research on sleeve antennas can be traced back to World War II. However, in the following fifty years, theoretical research on sleeve antennas has not been given much attention. The reason for this is that the monopole or dipole radiators used in sleeve antennas have insurmountable difficulties in antenna miniaturization. In addition, the structure of sleeve antennas itself also faces challenges such as parasitic dipoles affecting array phase, narrowing of operating bandwidth, and increase in antenna size when combined with planar processing technology.

[0004] Furthermore, achieving dual-band operation for antennas is a pressing need in today's wireless communication technology. Typical quarter-wavelength monopoles are usually designed to operate in one band; however, many modern applications, such as wireless LANs or cellular networks, require antennas to operate in dual or multi-band environments. Extensive research has been conducted on dual-band monopoles in the past. Examples include designs using two folded monopoles sharing the same microstrip feed or employing double-stepped patch monopoles to achieve dual-band operation. Studies have found that while these designs achieve good impedance matching in both bands, their radiation patterns differ significantly due to their different electrical dimensions at different frequencies. For dual-band communication systems, similar coverage in both bands is crucial to prevent significant performance degradation when switching between bands. Moreover, the antennas reported in these studies require large ground planes, which is incompatible with the miniaturization and integration trends in modern communications. Summary of the Invention

[0005] Purpose of the invention: This invention provides a miniaturized, highly integrated, dual-band dual-frequency planar sleeve monopole antenna based on a substrate-integrated coaxial line.

[0006] Technical solution: The present invention is a dual-frequency planar sleeve monopole antenna based on substrate integrated coaxial line, including an antenna structure and a metallized through-hole that runs through the entire antenna structure from top to bottom; the antenna structure is provided with a top metal layer, an upper dielectric layer, a metal inner conductor, an intermediate adhesive layer, a lower dielectric layer, and a bottom metal layer from top to bottom;

[0007] The top metal layer and the bottom metal layer are exactly the same size and their projections overlap. The top metal layer is provided with a top metal conductor and a top parasitic oscillator in sequence along the length extension direction. The bottom metal layer is provided with a bottom metal conductor and a bottom parasitic oscillator in sequence along the length extension direction.

[0008] The inner metal conductor includes a straight wire and a metal compensating piece located in the middle of the wire.

[0009] The metallized vias include two rows of oscillator vias and two rows of conductor vias; the oscillator vias pass through the top parasitic oscillator, the upper dielectric layer, the metal compensating sheet, the middle adhesive layer, the lower dielectric layer, and the bottom parasitic oscillator in sequence from top to bottom; the conductor vias pass through the top metal conductor, the upper dielectric layer, the middle adhesive layer, the lower dielectric layer, and the bottom metal conductor in sequence from top to bottom.

[0010] Furthermore, the antenna structure includes a substrate integrated coaxial line and a monopole sleeve antenna along its length extension direction. The portion containing the top metal conductor and the bottom metal conductor is the substrate integrated coaxial line; the portion containing the top parasitic vibrator and the bottom parasitic vibrator is the monopole sleeve antenna.

[0011] Furthermore, both the oscillator through holes and the conductor through holes are provided in two rows and are symmetrically distributed; one row of oscillator through holes and the other row of oscillator through holes are symmetrically arranged with the conductor as the central axis; one row of conductor through holes and the other row of conductor through holes are also symmetrically arranged with the conductor as the central axis.

[0012] Furthermore, the top-layer parasitic oscillator is provided with two rows of metal strips arranged symmetrically with the conductor as the central axis; the bottom-layer parasitic oscillator is also provided with two rows of metal strips arranged symmetrically with the conductor as the central axis.

[0013] Furthermore, the top-layer parasitic oscillator is provided in two sets, namely the first parasitic oscillator and the second parasitic oscillator; the bottom-layer parasitic oscillator is provided in two sets, namely the third parasitic oscillator and the fourth parasitic oscillator; the oscillator through-hole passes through the first parasitic oscillator and the third parasitic oscillator; the second parasitic oscillator and the fourth parasitic oscillator are solid metal strips.

[0014] Furthermore, the top metal conductor and the bottom metal conductor are square metal sheets.

[0015] Furthermore, the projections of the upper dielectric layer, the intermediate adhesive layer, and the lower dielectric layer overlap; the width of the square metal sheet is the same as the width of the upper dielectric layer.

[0016] Furthermore, a test interface is provided at the end of the substrate-integrated coaxial line away from the monopole sleeve antenna. The test interface includes a grounded coplanar waveguide, a metallized blind aperture, and a metal disk.

[0017] Furthermore, the grounding coplanar waveguide is located at the end of the top metal conductor away from the top parasitic oscillator, the metal disk is located at the end of the conductor away from the sleeve antenna, the metallized blind hole passes through the top metal conductor and the upper dielectric layer from top to bottom, and the grounding coplanar waveguide is connected to the metal disk through the metallized blind hole.

[0018] Furthermore, the dual-frequency planar sleeve monopole antenna is fabricated using PCB processing technology. Metal is plated on the upper surface of the upper dielectric layer to form the top metal conductor and the top parasitic vibrator. Metal is plated on the lower surface of the upper dielectric layer to form the inner metal conductor. Metal is plated on the lower surface of the lower dielectric layer to form the bottom metal conductor and the bottom parasitic vibrator. The upper dielectric layer, the intermediate adhesive layer, and the lower dielectric layer are sequentially bonded and laminated. Holes are drilled at the corresponding positions of the metallized through holes and metallized blind holes, and metal is plated between the holes to achieve electrical connection.

[0019] Beneficial Effects: This invention has the following significant effects: 1. Miniaturization: The antenna structure of this invention is based on a substrate-integrated coaxial line design, reducing the cross-section. It also uses a metal inner conductor to connect the substrate-integrated coaxial line and the monopole sleeve antenna. 2. Integration: The integrated design of the substrate-integrated coaxial line's feed structure and the double-sleeve structure simultaneously integrates the dual-frequency sleeve antenna with the feed structure. Furthermore, the antenna structure of this invention does not require a large ground plane for use, facilitating the integration of the antenna with microwave and millimeter-wave circuits. 3. Dual-band operation: By setting two sets of parasitic elements in the top and bottom layers, and setting the operating frequency points according to the different lengths and distances from the ground plane of the parasitic elements, the first and third parasitic elements are short-circuited, allowing the antenna to operate in the high-frequency band. The first, third, second, and fourth parasitic elements work together to allow the antenna to operate in the low-frequency band, achieving dual-band operation with similar coverage in both bands, and avoiding significant performance degradation when switching bands. Attached Figure Description

[0020] Figure 1 This is an exploded view of the antenna structure of the present invention;

[0021] Figure 2 This is a diagram of the top metal layer structure.

[0022] Figure 3 This is a side view of the antenna structure of the present invention;

[0023] Figure 4 A schematic diagram of the reflection coefficient for parameter simulation;

[0024] Figure 5 Simulation diagram of E-plane main polarization and cross polarization at 433MHz;

[0025] Figure 6 Simulation diagram of H-plane main polarization and cross polarization at 433MHz;

[0026] Figure 7 Simulation diagram of E-plane main polarization and cross polarization at 868MHz;

[0027] Figure 8 Simulation diagram of H-plane main polarization and cross polarization at 868MHz.

[0028] In the figure, 1 is the top metal conductor, 2 is the upper dielectric layer, 3 is the inner metal conductor, 4 is the middle adhesive layer, 5 is the lower dielectric layer, 6 is the bottom metal conductor, 7 is the conductor via, 8 is the metallized blind via, 9 is the grounded coplanar waveguide, 10 is the vibrator via, 11 is the second parasitic vibrator, 12 is the fourth parasitic vibrator, 13 is the first parasitic vibrator, 14 is the third parasitic vibrator, 15 is the metal compensating plate, 16 is the wire, and 17 is the metal disk. Detailed Implementation

[0029] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0030] Please see Figures 1 to 3 As shown, this invention discloses a dual-frequency planar sleeve monopole antenna based on a substrate-integrated coaxial line, including an antenna structure and a metallized through-hole that runs through the entire antenna structure from top to bottom. The antenna structure consists of, from top to bottom, a top metal layer, an upper dielectric layer 2, a metal inner conductor 3, an intermediate adhesive layer 4, a lower dielectric layer 5, and a bottom metal layer.

[0031] The top metal layer and the bottom metal layer are identical in size and their projections overlap. The top metal layer has a top metal conductor 1 and a top parasitic oscillator arranged sequentially along its length; the bottom metal layer has a bottom metal conductor 6 and a bottom parasitic oscillator arranged sequentially along its length.

[0032] The inner metal conductor 3 includes a straight wire 16 and a metal compensating piece 15 located in the middle of the wire 16.

[0033] The metallized vias include two rows of oscillator vias 10 and two rows of conductor vias 7. The oscillator vias 10, from top to bottom, sequentially penetrate the top parasitic oscillator, the upper dielectric layer 2, the metal compensation plate 15, the intermediate adhesive layer 4, the lower dielectric layer 5, and the bottom parasitic oscillator. The conductor vias 7, from top to bottom, sequentially penetrate the top metal conductor 1, the upper dielectric layer 2, the intermediate adhesive layer 4, the lower dielectric layer 5, and the bottom metal conductor 6. In this embodiment, both the oscillator vias 10 and the conductor vias 7 are provided in two rows and are symmetrically distributed. One row of oscillator vias 10 and the other row of oscillator vias 10 are symmetrically arranged with the conductor 16 as the central axis; one row of conductor vias 10 and the other row of conductor vias 7 are also symmetrically arranged with the conductor 16 as the central axis.

[0034] In this embodiment, the projections of the upper dielectric layer 2, the intermediate adhesive layer 4, and the lower dielectric layer 5 overlap. The intermediate adhesive layer 4 tightly connects the upper dielectric layer 2 and the lower dielectric layer 5. The top metal layer covers the upper surface of the upper dielectric layer 2, and the bottom metal layer covers the lower surface of the lower dielectric layer 5. A metal inner conductor 3 is located at the center line of the length extension direction of the portion of the lower surface of the upper dielectric layer 2 that overlaps with the intermediate adhesive layer 4. In this embodiment, the top metal conductor 1 and the bottom metal conductor 6 are square metal sheets. The width of the square metal sheet is the same as the width of the upper dielectric layer 2. The width of the conductor 16 is uniform and its length is less than the length of the upper dielectric layer 2. Both the upper dielectric layer 2 and the lower dielectric layer 5 are TU883 printed circuit boards with a thickness of 0.762 mm, and the intermediate adhesive layer 4 is a TU883 printed circuit board with a thickness of 0.18 mm.

[0035] In the top and bottom metal layers, the top parasitic oscillator is not connected to the top metal conductor 1. The bottom parasitic oscillator is not connected to the bottom metal conductor 6. The top parasitic oscillator has two rows of metal strips arranged symmetrically about the conductor 16 as the central axis; the bottom parasitic oscillator also has two rows of metal strips arranged symmetrically about the conductor 16 as the central axis. The top parasitic oscillator has two sets without direct connection, namely a first parasitic oscillator 13 and a second parasitic oscillator 11 extending in the same direction, wherein the first parasitic oscillator 13 is located between the second parasitic oscillator 11 and the top metal conductor 1. The bottom parasitic oscillator has two sets without direct connection, namely a third parasitic oscillator 14 and a fourth parasitic oscillator 12 extending in the same direction. The first parasitic oscillator 13 and the third parasitic oscillator 14 have projected overlap; the second parasitic oscillator 11 and the fourth parasitic oscillator 12 have projected overlap. The oscillator through-hole 10 passes through the first parasitic oscillator 13 and the third parasitic oscillator 14; and the second parasitic oscillator 11 and the fourth parasitic oscillator 12 are solid metal strips. Specifically, the oscillator through-hole 10 is projected onto the portion of the metal strips of the first parasitic oscillator 13 and the third parasitic oscillator 14 near the conductor through-hole 7, that is, the oscillator through-hole 10 starts from the end of the two metal strips near the conductor through-hole 7 and ends in the middle of the two metal strips.

[0036] In this configuration, the portions of the first parasitic oscillator 13 and the third parasitic oscillator 14 with through-holes 10 short-circuit the antenna structure's circuitry. The portions without through-holes 10 have a distance from the rear edge of the ground plane equal to one-quarter of the free-space wavelength in the high-frequency band, thus controlling the antenna's operation in the high-frequency band. The second parasitic oscillator 11 and the fourth parasitic oscillator 12 are not directly connected to the first parasitic oscillator 13 and the third parasitic oscillator 14. The second parasitic oscillator 11 and the fourth parasitic oscillator 12 keep the circuitry of this portion of the antenna structure open-circuited. The second parasitic oscillator 11 extends along its length from the end of the first parasitic oscillator 13 furthest from the top metal conductor 1, and the fourth parasitic oscillator 12 extends along its length from the end of the third parasitic oscillator 13 furthest from the bottom metal conductor 6. The distance from the ends of the second parasitic oscillator 11 and the fourth parasitic oscillator 12 to the rear edge of the ground plane is one-quarter of the free-space wavelength in the low-frequency band. The combined action of these four parasitic oscillators controls the antenna's operation in the low-frequency band.

[0037] The antenna structure of this invention comprises, along its length, a substrate-integrated coaxial line and a monopole sleeve antenna. The portion containing the top metal conductor 1 and the bottom metal conductor 6 constitutes the substrate-integrated coaxial line; the portion containing the top parasitic vibrator and the bottom parasitic vibrator constitutes the monopole sleeve antenna.

[0038] Substrate Integrated Coaxial Line (SICL) is a transmission line technology developed based on Substrate Integrated Waveguide (SIW). It retains the closed-loop characteristics of SIW while introducing an inner conductor within the dielectric. The fundamental mode of SICL is a quasi-TEM mode, meaning its characteristic impedance is independent of frequency, and electromagnetic energy is transmitted along the inner conductor rather than diffused throughout the entire structure. Using SICL for feeding facilitates integration with other circuits and reduces energy propagation losses. In this embodiment, a conductor via 7 penetrates the substrate integrated coaxial line from top to bottom, connecting the top metal conductor 1 and the bottom metal conductor 6 to form a closed structure with good shielding. The impedance of the substrate integrated coaxial line is determined by the thickness of the dielectric substrate and the width of the inner metal conductor 3. The port impedance of this invention is 50 ohms, facilitating integration with other integrated circuit structures. A vibrator via 10 penetrates the monopole sleeve antenna from top to bottom, connecting the first parasitic vibrator 13 and the third parasitic vibrator 14 to the widened metal compensation plate 15 to achieve the required short-circuit state for radiation. In this invention, the metal inner conductor 3 in the SICL serves as the feeding structure on the substrate integrated coaxial line. In the length extension direction of the metal inner conductor 3 in the feeding structure, a monopole radiator is formed. With the addition of two sleeve structures that are coplanar with the top and bottom metal layers of the SICL, the planar integration of the feeding and the sleeve antenna is realized, effectively reducing the size of the antenna and realizing the integration and miniaturization of the sleeve antenna.

[0039] The dual-frequency planar sleeve monopole antenna of the present invention is fabricated using PCB processing technology. Metal is plated on the upper surface of the upper dielectric layer 2 to form the top metal conductor 1 and the top parasitic vibrator. Metal is plated on the lower surface of the upper dielectric layer 2 to form the inner metal conductor 3. Metal is plated on the lower surface of the lower dielectric layer 5 to form the bottom metal conductor 6 and the bottom parasitic vibrator. The upper dielectric layer 2, the intermediate adhesive layer 4, and the lower dielectric layer 5 are sequentially bonded and laminated. Holes are drilled at corresponding positions of metallized through holes and metallized blind holes 8, and metal is plated between the holes to achieve electrical connection.

[0040] In this embodiment, the metal material is copper. The width of the conductor 16 remains constant at 0.85 mm. The width of the metal compensation piece 15 is 13.5 mm. The first parasitic oscillator 13 and the third parasitic oscillator 14 are both 85.6 mm long and 4.5 mm wide. The second parasitic oscillator 11 and the fourth parasitic oscillator 12 are both 84.4 mm long and 4.5 mm wide. Appropriate through-hole dimensions and spacing can reduce processing difficulty while preventing electromagnetic wave leakage. The diameter of the conductor through-hole 7 is 4 mm, the spacing between adjacent conductor through-holes 7 in each row is 6 mm, and the distance between conductor through-holes 7 on both sides is 15 mm. The diameter of the oscillator through-hole 10 is 2 mm, the spacing between adjacent oscillator through-holes 10 in each row is 3 mm, and the distance between oscillator through-holes 10 on both sides is 9 mm. The diameter of the metallized blind hole 8 is 1.2 mm.

[0041] This invention also includes a test interface for facilitating antenna performance testing. The test interface is located at the end of the substrate-integrated coaxial line away from the monopole sleeve antenna, and includes a grounded coplanar waveguide 9, a metallized blind aperture 8, and a metal disk 17. The grounded coplanar waveguide 9 is located at the end of the top metal conductor 1 away from the top parasitic oscillator, and is a GCPW structure with a gap, which separates the connection between the grounded coplanar waveguide 9 and the top metal conductor 1. The metal disk 17 is located at the end of the conductor 16 away from the sleeve antenna. The metallized blind aperture 8 passes through the top metal conductor 1 and the upper dielectric layer 2 from top to bottom, and the grounded coplanar waveguide 9 is connected to the metal disk 17 through the metallized blind aperture 8, realizing the circuit connection between the grounded coplanar waveguide GCPW structure and the inner metal conductor 3. During design, it is necessary to consider that the characteristic impedance of the GCPW is the same as that of SICL, and adjust the width of the outer gap and the position of the metallized blind aperture 8 to adjust the impedance.

[0042] In this example, to measure antenna performance, an antenna model was created and simulation software was used to perform parametric simulation of a dual-frequency planar sleeve monopole antenna based on a substrate-integrated coaxial line. Since the antenna operates in free space, after the antenna model was created, the antenna boundary was set to ideal boundary conditions, and the antenna input port was set to a waveguide port. The performance of the 0-1200MHz frequency band was then analyzed and calculated.

[0043] Please see Figure 4As shown, the reflection coefficient of the antenna in the corresponding frequency band is obtained through performance simulation. From the reflection coefficient, it can be seen that the antenna operates in two frequency bands. The center frequency of the first frequency band is 433MHz, and the -10dB impedance bandwidth of the antenna at this time is 408-458MHz. The center frequency of the second frequency band is 868MHz, and the -10dB impedance bandwidth of the antenna at this time is 828-958MHz.

[0044] Please see Figures 5 to 8 As shown, the main polarization and cross-polarization gain patterns of the antenna in the E-plane and H-plane at the center frequencies of 433MHz and 868MHz were obtained through performance simulation. The main polarization radiation gain of the antenna in the maximum radiation direction in both the E-plane and H-plane is more than 30dBi greater than the cross-polarization radiation gain, indicating good cross-polarization performance.

[0045] In summary, the dual-frequency planar sleeve monopole antenna based on substrate integrated coaxial line of the present invention has the characteristics of miniaturization, high integration and dual frequency band.

Claims

1. A dual-frequency planar sleeve monopole antenna based on a substrate-integrated coaxial line, characterized in that, It includes an antenna structure and a metallized via that runs through the entire antenna structure from top to bottom; the antenna structure consists of a top metal layer, an upper dielectric layer, a metal inner conductor, an intermediate adhesive layer, a lower dielectric layer, and a bottom metal layer from top to bottom; The top metal layer and the bottom metal layer are exactly the same size and their projections overlap. The top metal layer is provided with a top metal conductor and a top parasitic oscillator in sequence along the length extension direction. The bottom metal layer is provided with a bottom metal conductor and a bottom parasitic oscillator in sequence along the length extension direction. The inner metal conductor includes a straight wire and a metal compensating piece located in the middle of the wire. The metallized vias include two rows of oscillator vias and two rows of conductor vias; the oscillator vias pass through the top parasitic oscillator, the upper dielectric layer, the metal compensating plate, the middle adhesive layer, the lower dielectric layer, and the bottom parasitic oscillator in sequence from top to bottom; the conductor vias pass through the top metal conductor, the upper dielectric layer, the middle adhesive layer, the lower dielectric layer, and the bottom metal conductor in sequence from top to bottom. The antenna structure includes a substrate integrated coaxial line and a monopole sleeve antenna along its length. The part containing the top metal conductor and the bottom metal conductor is the substrate integrated coaxial line; the part containing the top parasitic vibrator and the bottom parasitic vibrator is the monopole sleeve antenna.

2. The dual-frequency planar sleeve monopole antenna based on substrate integrated coaxial line according to claim 1, characterized in that, The oscillator through holes and conductor through holes are provided in two rows and are symmetrically distributed; one row of oscillator through holes and the other row of oscillator through holes are arranged symmetrically with the conductor as the central axis; one row of conductor through holes and the other row of conductor through holes are also arranged symmetrically with the conductor as the central axis.

3. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 2, characterized in that, The top-layer parasitic oscillator has two rows of metal strips arranged symmetrically with the conductor as the central axis; the bottom-layer parasitic oscillator also has two rows of metal strips arranged symmetrically with the conductor as the central axis.

4. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 3, characterized in that, The top-layer parasitic oscillator has two sets, namely the first parasitic oscillator and the second parasitic oscillator; the bottom-layer parasitic oscillator has two sets, namely the third parasitic oscillator and the fourth parasitic oscillator; the oscillator through-hole passes through the first parasitic oscillator and the third parasitic oscillator; the second parasitic oscillator and the fourth parasitic oscillator are solid metal strips.

5. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 1, characterized in that, The top and bottom metal conductors are square metal sheets.

6. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 5, characterized in that, The projections of the upper dielectric layer, the intermediate adhesive layer, and the lower dielectric layer overlap; the width of the square metal sheet is the same as the width of the upper dielectric layer.

7. The dual-frequency planar sleeve monopole antenna based on substrate integrated coaxial line according to claim 1, characterized in that, A test interface is provided at one end of the substrate-integrated coaxial line away from the monopole sleeve antenna. The test interface includes a grounded coplanar waveguide, a metallized blind aperture, and a metal disk.

8. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 7, characterized in that, The grounding coplanar waveguide is located at the end of the top metal conductor away from the top parasitic oscillator, and the metal disk is located at the end of the conductor away from the sleeve antenna. The metallized blind hole passes through the top metal conductor and the upper dielectric layer from top to bottom, and the grounding coplanar waveguide is connected to the metal disk through the metallized blind hole.

9. The dual-frequency planar sleeve monopole antenna based on substrate-integrated coaxial line according to claim 8, characterized in that, This dual-frequency planar sleeve monopole antenna is fabricated using PCB processing technology. Metal is plated on the upper surface of the upper dielectric layer to form the top metal conductor and the top parasitic vibrator. Metal is plated on the lower surface of the upper dielectric layer to form the inner metal conductor. Metal is plated on the lower surface of the lower dielectric layer to form the bottom metal conductor and the bottom parasitic vibrator. The upper dielectric layer, the middle adhesive layer, and the lower dielectric layer are sequentially bonded and laminated. Holes are drilled at the corresponding positions of the metallized through holes and metallized blind holes, and metal is plated between the holes to achieve electrical connection.

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