A waveguide cavity filter antenna loaded with a cfsir electromagnetic structure
By designing a waveguide cavity filter antenna with a CFSIR electromagnetic structure, the antenna and filter are integrated into one unit, solving the problem of large size and poor performance of traditional RF front-end devices, and realizing the miniaturization and multifunctionality of the RF front-end.
Patent Information
- Application Number
- CN202211370787.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-03
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2042-11-03
AI Technical Summary
Traditional RF front-end antennas and filters are usually designed separately, resulting in large device size and poor performance, and increased additional losses.
The waveguide cavity filter antenna with CFSIR electromagnetic structure is designed as a fusion antenna and filter. By setting a defect structure and CFSIR filter structure on the upper surface metal substrate and setting a ring-shaped folded multi-segment impedance network on the lower surface metal substrate, a SIW resonant cavity is formed to achieve coplanar waveguide feeding.
It achieves miniaturization and multifunctionality of the RF front end, reduces the resonant frequency of the resonant cavity, increases the product of the equivalent permeability and dielectric constant of the SIW resonant cavity, and improves radiation and filtering characteristics.
Smart Images
Figure CN115548674B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of filtered antenna technology, and more specifically, to a waveguide cavity filtered antenna with a CFSIR electromagnetic structure. Background Technology
[0002] With the rapid development of communication technology, communication systems are placing increasingly higher demands on the miniaturization, integration, and multifunctionality of radio frequency (RF) front-end devices. Traditional RF front-end antennas and filters are typically designed separately and connected via matching networks. This not only increases the size of the RF front-end but also introduces additional losses, reducing system performance. Consequently, existing filtered antennas are bulky and have poor performance.
[0003] In view of this, this specification proposes a waveguide cavity filter antenna with a CFSIR (complementary folded stepped-impedance resonator) electromagnetic structure, which integrates the antenna and filter into a single communication device. This enables a single passive device to simultaneously possess filtering and electromagnetic radiation characteristics, while eliminating the connection matching network between the antenna and the filter, greatly reducing the size of the RF front end and realizing the miniaturization of passive microwave devices. Summary of the Invention
[0004] The present invention aims to provide a waveguide cavity filter antenna with a CFSIR electromagnetic structure, comprising an upper surface metal substrate, a lower surface metal substrate, a microstrip line, and a dielectric substrate. The upper surface metal substrate includes a defect structure and a CFSIR filter structure; the lower surface metal substrate includes a ring-shaped folded multi-segment impedance network; the microstrip line is a trapezoidal microstrip line fed in the form of a coplanar waveguide; the dielectric substrate contains a SIW structure; the upper surface metal substrate includes a connection port, through which the upper surface metal substrate is connected to the microstrip line; by providing metal through-holes at the edge of the upper surface metal substrate, the upper surface metal substrate and the lower surface metal substrate are connected to the dielectric substrate to form an SIW resonant cavity.
[0005] Furthermore, a ring-shaped folded multi-segment impedance network is provided on the lower surface metal substrate and within the SIW structure; the ring-shaped folded multi-segment impedance network includes 10x10 ring-shaped folded multi-segment impedance units.
[0006] Furthermore, the annular folded multi-segment impedance unit includes a polygonal frame structure and a connection structure connecting adjacent annular folded multi-segment impedance units; the basic structure of the polygonal frame structure is a square frame, the sides of the square frame form a 45-degree angle with the sides of the dielectric substrate, and rectangular sub-frames extend vertically outward from the center of the four sides of the square frame; the connection structure is provided at the four corners of the square frame, and the connection structure is a connecting line forming a 90-degree or 0-degree angle with the dielectric substrate.
[0007] Furthermore, the defect structure includes a first defect structure, a second defect structure, and a third defect structure, which are disposed within the area formed by the metal through-hole. The first defect structure is rectangular and is disposed along the third edge of the upper surface metal substrate. The third edge is parallel to the first edge where the connection port is located, and the long side of the first defect structure is parallel to the third edge. The second and third defect structures are rectangular and are symmetrically disposed along the first edge with the connection port as the center. The long sides of the second and third defect structures are parallel to the first edge, and the distance between the opposite sides of the second and third defect structures is greater than the length of the connection port.
[0008] Furthermore, the side lengths of the first defect structure are 30mm and 9mm, respectively, and the side lengths of the second and third defect structures are 10mm and 1mm, respectively.
[0009] Furthermore, the upper surface metal substrate is a square metal substrate with a side length of 32mm.
[0010] Furthermore, the dielectric substrate is a Taconic TLX-6 series substrate with a thickness of 1.575 mm, a dielectric constant of 2.65, and a loss tangent of 0.0022.
[0011] Furthermore, the CFSIR electromagnetic structure is symmetrically arranged along the vertical line of the connection port.
[0012] Furthermore, the lower surface metal substrate and the dielectric plate are rectangular, the length of the long side of the dielectric plate and the lower surface metal substrate is the sum of the side length of the upper surface metal substrate and the length of the microstrip line, and the short side of the dielectric plate and the lower surface metal substrate is the side length of the upper surface metal substrate; the upper surface metal substrate and the microstrip line are stacked on the dielectric plate, and metal through holes are provided at the edges except for the connection port; the upper surface metal substrate and the lower surface metal substrate are connected through the metal through holes penetrating the dielectric plate, and the SIW structure is the area formed by the metal through holes on the dielectric plate.
[0013] Furthermore, the connection port is symmetrically arranged along the perpendicular line of the edge of the upper surface metal substrate, and the connection port includes a connection portion for connecting the microstrip line and a notch, with the notch arranged on both sides of the connection portion.
[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:
[0015] Some embodiments in this specification, by integrating antennas and filters, design filter antennas with good radiation and filtering characteristics, achieving advantages such as miniaturization, multifunctionality, and high efficiency of the RF front end.
[0016] Some embodiments in this specification, by setting a ring-shaped folded multi-segment impedance network inside the antenna, cause the electromagnetic wave at the feed port to generate a slow wave effect, effectively improving the product of the equivalent permeability and dielectric constant of the SIW resonant cavity, thereby reducing the resonant frequency of the resonant cavity and further realizing the miniaturization of the resonant cavity size. Attached Figure Description
[0017] Figure 1 An exemplary structural diagram of a waveguide cavity filter antenna with a CFSIR electromagnetic structure provided for some embodiments of the present invention;
[0018] Figure 2 This is an exemplary structural diagram of the upper surface metal substrate provided in some embodiments of the present invention;
[0019] Figure 3 This is an exemplary structural diagram of the lower surface metal substrate provided in some embodiments of the present invention;
[0020] Figure 4 A comparison diagram of return loss between a waveguide cavity filter antenna with a CFSIR electromagnetic structure and an antenna without a slow wave structure, provided for some embodiments of the present invention;
[0021] Figure 5 Maximum gain diagram of a slow-wave substrate integrated waveguide filter antenna with a loaded CFSIR electromagnetic structure provided in some embodiments of the present invention;
[0022] Icons: 1-Upper surface metal substrate, 2-Dielectric board, 3-First defect structure, 4-CFSIR filter structure, 5-Second defect structure, 6-Third defect structure, 7-Metal via, 8-Microstrip line, 9-Ring folded multi-segment impedance network, 10-Ring folded multi-segment impedance unit, 11-Lower surface metal substrate. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0024] Figure 1 This is an exemplary structural diagram of a waveguide cavity filter antenna with a CFSIR electromagnetic structure, provided for some embodiments of the present invention. For example... Figure 1 As shown, the waveguide cavity filter antenna with CFSIR electromagnetic structure includes an upper surface metal substrate 1, a microstrip line 8, a dielectric substrate 2, and a lower surface metal substrate 11.
[0025] Dielectric substrate 2 is a composite dielectric substrate, with the composite dielectric substrate as the main body. Both the upper and lower surfaces of the dielectric substrate are covered with metal substrates. The metal layer on the upper surface (upper surface metal substrate) and the metal ground on the lower surface (lower surface metal substrate) are connected through metallized vias to form the sidewalls of the SIW resonant cavity. One side of the SIW resonant cavity is fed in the form of a coplanar waveguide by connecting microstrip lines 8. A slot is made in the metal substrate 1 on the upper surface of the antenna to introduce the first resonant point of the antenna, thereby exciting the TE102 mode of the resonant cavity antenna, which exhibits good radiation characteristics.
[0026] The CFSIR filter structure 4 is loaded onto the metal substrate on the upper surface of the slow-wave substrate integrated waveguide filter antenna with the CFSIR electromagnetic structure, introducing a second resonant point and forming filtering characteristics.
[0027] The annular folded multi-segment impedance network 9, located on the lower surface metal ground, is composed of N two-dimensionally uniformly distributed annular folded multi-segment impedance units 10. The size of the impedance network is slightly smaller than the size of the SIW resonant cavity. The size of the dielectric substrate 2 is consistent with the length and width of the lower surface metal substrate. For more information about the dielectric substrate 2, see [link to relevant documentation]. Figure 2 And its related descriptions.
[0028] The upper surface metal substrate 1 includes a defect structure and a CFSIR filter structure 4; the microstrip line 8 is a trapezoidal microstrip line fed in the form of a coplanar waveguide; the lower surface metal substrate 11 includes a SIW structure; the upper surface metal substrate 1 includes a connection port, and the upper surface metal substrate 1 is connected to the microstrip line 8 through the connection port; the upper surface metal substrate 1 and the microstrip line 8 are connected to the lower surface metal substrate 11 by setting a metal through hole 7 through the dielectric substrate 2 at the edge of the upper surface metal substrate 1.
[0029] The upper surface metal substrate 1 can be a square metal substrate with a side length of 32mm. Three defect structures are etched on the square metal substrate, such as... Figure 2As shown. This defect structure can couple in the input energy to form electromagnetic waves, exciting the TE102 mode and exhibiting good radiation characteristics. Then, a CFSIR filter structure 4 is loaded onto the metal substrate with the three defect structures etched on it, as shown. Figure 2 As shown, this CFSIR filter structure possesses advantages such as excellent frequency selectivity, high Q value, and high space utilization, facilitating antenna and filter integration design as well as miniaturized filter antenna design. The port utilizes a trapezoidal coplanar waveguide feed, which is beneficial for antenna impedance matching and the excitation of higher-order modes.
[0030] A dielectric substrate 2 with a fixed dielectric constant is loaded below the metal substrate on the upper surface of the antenna. The length of the dielectric substrate 2 is equal to the sum of the side length of the square metal substrate and the length of the microstrip line, and the width of the dielectric substrate 2 is equal to the side length of the square metal substrate. The dielectric substrate forms a SIW cavity within the square metal substrate through a metal via 7 (the metal via penetrates the dielectric substrate, connecting the upper metal substrate and the lower metal ground plane). Feed ports are provided on the walls of the SIW cavity at the microstrip line feed entrances. The dielectric substrate uses the Taconic TLX-6 series, with a thickness of 1.575 mm, a dielectric constant of 2.65, and a loss tangent of 0.0022.
[0031] In some embodiments, the connection port is symmetrically arranged along the perpendicular line of the edge of the upper surface metal substrate 1, and the connection port includes a connection portion for connecting the microstrip line 8 and a notch, with the notch arranged on both sides of the connection portion.
[0032] Figure 2 This is an exemplary structural diagram of the upper surface metal substrate provided in some embodiments of the present invention.
[0033] like Figure 2 As shown, the defect structure includes a first defect structure 3, a second defect structure 5, and a third defect structure 6.
[0034] The first defect structure 3, the second defect structure 5, and the third defect structure 6 are disposed within the area where the metal through-hole is formed. Taking the edge of the upper surface metal substrate where the connection port is located as the first edge, the second, third, and fourth edges are respectively located counterclockwise. The first defect structure is rectangular and is disposed along the third edge of the upper surface metal substrate, with the third edge parallel to the first edge where the connection port is located. The long side of the first defect structure 3 is parallel to the third edge. The second defect structure 5 and the third defect structure 6 are rectangular and symmetrically disposed along the first edge with the connection port as the center. The long sides of the second and third defect structures are parallel to the first edge, and the distance between the opposite sides of the second and third defect structures is greater than the length of the connection port.
[0035] The length and width of the first defect structure 3 are L1 = 30 mm and W1 = 9 mm, respectively. The second defect structure 5 and the third defect structure 6 are two defect structures of the same size, with a length and width of L1 = 10 mm and W1 = 1 mm, respectively.
[0036] In some embodiments, the CFSIR electromagnetic structure is symmetrically arranged along the vertical line of the connection port.
[0037] Figure 3 This is an exemplary structural diagram of a lower surface metal substrate provided for some embodiments of the present invention.
[0038] In some embodiments, the lower surface metal substrate 11 is rectangular, with the length of its long side being the sum of the side length of the upper surface metal substrate 1 and the length of the microstrip line, and the short side of the lower surface metal substrate 11 being the side length of the upper surface metal substrate 1. The upper surface metal substrate 1 and the microstrip line 8 are stacked on the dielectric substrate 2, and metal vias are provided at the edges except for the connection ports. The vias connect the microstrip line 11 to the lower surface metal substrate 11 located on the other side of the dielectric substrate. The SIW structure is the area formed by the metal vias on the dielectric substrate.
[0039] like Figure 3 As shown, a ring-shaped folded multi-segment impedance network 9 is etched within the SIW structure corresponding to the square metal substrate on the lower surface metal substrate 11. The ring-shaped folded multi-segment impedance network 9 is composed of 10×10 ring-shaped folded multi-segment impedance units 10.
[0040] In some embodiments, the annular folded multi-segment impedance unit 10 includes a polygonal frame structure and a connection structure connecting adjacent annular folded multi-segment impedance units; the basic structure of the polygonal frame structure is a square frame, the sides of the square frame are at a 45-degree angle to the sides of the dielectric substrate, and rectangular sub-frames extend vertically outward from the center of the four sides of the square frame; a connection structure is provided at the four corners of the square frame, and the connection structure is a connection line at a 90-degree or 0-degree angle to the dielectric substrate.
[0041] In some embodiments, the width of the metal strips in the mesh structure is 0.141 mm (i.e., the width of the frame). The side length of a single mesh is 3 mm (i.e., the size of the annular folded multi-segment impedance unit is 3 mm x 3 mm).
[0042] In some embodiments of this specification, by setting up a ring-shaped folded multi-segment impedance network, the electromagnetic wave at the feed port generates a slow wave effect, which effectively improves the product of the equivalent permeability and dielectric constant of the SIW resonant cavity, thereby reducing the resonant frequency of the resonant cavity and realizing miniaturization of the resonant cavity size.
[0043] Figure 4The diagram shows a comparison of return loss between a waveguide cavity filter antenna with a CFSIR electromagnetic structure and an antenna without a slow wave structure, provided for some embodiments of the present invention.
[0044] like Figure 4 As shown, the return loss of the loaded slow-wave structure is compared with that of the unloaded slow-wave structure, and the operating frequency is reduced by 960MHz, proving that the loaded slow-wave structure in this specification can achieve miniaturization of the resonant cavity size.
[0045] Figure 5 The maximum gain diagram of the slow-wave substrate integrated waveguide filter antenna with CFSIR electromagnetic structure provided in some embodiments of the present invention.
[0046] like Figure 5 As shown, within the operating frequency band, the antenna's actual gain is between 5.5 and 6.7 dBi, exhibiting excellent radiation characteristics. Therefore, the slow-wave substrate integrated waveguide filter antenna with a CFSIR electromagnetic structure of this invention possesses excellent radiation and filtering characteristics, and the slow-wave effect generated by this antenna enables miniaturized design. Thus, the slow-wave substrate with a CFSIR electromagnetic structure can achieve multifunctionality and miniaturization of the antenna, making the waveguide cavity filter antenna with a CFSIR electromagnetic structure provided in this specification a promising candidate for miniaturized and multifunctional applications in RF front-ends.
[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A waveguide cavity filter antenna with a CFSIR electromagnetic structure, comprising an upper surface metal substrate, a lower surface metal substrate, a microstrip line, and a dielectric substrate, characterized in that, The upper surface metal substrate includes a defect structure and a CFSIR filter structure; The lower surface metal substrate includes a ring-shaped folded multi-segment impedance network; The microstrip line is a trapezoidal microstrip line fed in the form of a coplanar waveguide; the dielectric substrate has a SIW structure; the upper surface metal substrate includes a connection port, and the upper surface metal substrate is connected to the microstrip line through the connection port; By providing metal through holes at the edge of the upper surface metal substrate, the upper surface metal substrate and the lower surface metal substrate are connected to the dielectric plate to form an SIW resonant cavity.
2. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The lower surface metal substrate is provided with a ring-shaped folded multi-segment impedance network; the ring-shaped folded multi-segment impedance network includes 10x10 ring-shaped folded multi-segment impedance units.
3. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 2, characterized in that, The annular folded multi-segment impedance unit includes a polygonal frame structure and a connection structure connecting adjacent annular folded multi-segment impedance units. The basic structure of the polygonal frame structure is a square frame. The sides of the square frame form a 45-degree angle with the sides of the medium plate. Rectangular sub-frames extend vertically outward from the center of the four sides of the square frame. The connecting structures are provided at the four corners of the square frame, and the connecting structures are connecting lines that form a 90-degree or 0-degree angle with the edge of the medium plate.
4. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The defect structure includes a first defect structure, a second defect structure, and a third defect structure, wherein the first defect structure, the second defect structure, and the third defect structure are disposed within the area enclosed by the plurality of metal through holes; The first defect structure is rectangular and is disposed along the third edge of the upper surface metal substrate. The third edge is parallel to the first edge where the connection port is located, and the long side of the first defect structure is parallel to the third edge. The second and third defect structures are rectangular and are symmetrically disposed along the first edge with the connection port as the center. The long sides of the second and third defect structures are parallel to the first edge, and the distance formed between the opposite sides of the second and third defect structures is greater than the length of the connection port.
5. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 4, characterized in that, The side lengths of the first defect structure are 30mm and 9mm, respectively, and the side lengths of the second and third defect structures are 10mm and 1mm, respectively.
6. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The upper surface metal substrate is a square metal substrate with a side length of 32mm.
7. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The dielectric substrate is a Taconic TLX-6 series, with a thickness of 1.575 mm, a dielectric constant of 2.65, and a loss tangent of 0.0022.
8. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The CFSIR electromagnetic structure is symmetrically arranged along the vertical line of the connection port.
9. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The lower surface metal substrate and the dielectric plate are rectangular. The length of the long side of the dielectric plate and the lower surface metal substrate is the sum of the side length of the upper surface metal substrate and the length of the microstrip line. The short side of the dielectric plate and the lower surface metal substrate is the side length of the upper surface metal substrate. The upper surface metal substrate and the microstrip line are integrally overlapped and placed on the dielectric substrate, and metal through holes are provided at the edges except for the connection port; the upper surface metal substrate and the lower surface metal substrate are connected through the metal through holes penetrating the dielectric substrate, and the SIW structure is the area formed by the metal through holes on the dielectric substrate.
10. The waveguide cavity filter antenna with a loaded CFSIR electromagnetic structure according to claim 1, characterized in that, The connection port is symmetrically arranged along the perpendicular line of the edge of the upper surface metal substrate. The connection port includes a connection portion for connecting the microstrip line and a notch, with the notch located on both sides of the connection portion.