A broadband circularly polarized substrate integrated dielectric resonator filter antenna

Abstract

The present invention discloses a broadband circularly polarized substrate integrated dielectric resonator filter antenna. A multi-mode circularly polarized substrate integrated dielectric resonator is constructed by applying structures such as an annular back cavity structure, an equivalent metal wall, and a rectangular short patch to a 3×3 rectangular dielectric sheet. The three structures suppress the cross-polarization electric field and optimize the main polarization electric field, thereby effectively improving gain fluctuation and widening the axial ratio bandwidth. Combined with the filtering effect of an E-type microstrip feeding structure, a broadband circularly polarized substrate integrated dielectric resonator filter antenna with stable gain is realized. Furthermore, the substrate can be integrated, and both cross-section and size can be taken into consideration.

Description

Technical Field

[0001] The present invention relates to a microwave communication device, in particular to a substrate integrated dielectric resonator filtering antenna. Background Art

[0002] Circularly polarized antennas have advantages in resisting multipath interference and avoiding polarization mismatch, and are widely used in satellite communications, intelligent transportation, radio frequency identification and other fields. As the speed and capacity of wireless systems increase, the bandwidth of circularly polarized antennas also needs to be improved to achieve broadband circularly polarized antennas. At the same time, broadband dielectric resonator circularly polarized antennas implemented with dielectrics have the characteristics of small size, low loss and high radiation efficiency. However, traditional circularly polarized dielectric resonator antennas are often complex in design, large in size, high in processing cost and difficult to integrate, resulting in their generally low operating frequency band. Therefore, substrate-integrated dielectric resonator antennas are needed to improve their integrability. Furthermore, integrating the filtering function into the substrate-integrated dielectric resonator antenna to achieve a broadband circularly polarized substrate-integrated dielectric resonator filter antenna can reduce the number of components and effectively reduce loss and cost. Therefore, broadband circularly polarized substrate-integrated dielectric resonator filter antenna has great research significance and engineering value.

[0003] Currently, there are three main design approaches for circularly polarized dielectric resonator filter antennas. The first uses oblique annular slots to excite rectangular dielectric resonators to achieve circularly polarized radiation, and implements filtering through a series microstrip filter. However, this approach suffers from narrow operating bandwidth, large size, non-substrate integration, and a high profile. The second approach uses cross-shaped slots to excite the orthogonal dielectric modes of cylindrical or rectangular column dielectric resonators to achieve circularly polarized radiation. Alternatively, grooves in elliptical dielectric resonators are used to perturb their orthogonal dielectric modes to achieve circularly polarized radiation, or metal strips are used to perturb the dielectric resonator to achieve circularly polarized radiation. Radiation nulls are generated through comb branches, magnetic flux ring loading, or parallel resonators to achieve filtering. However, this approach still suffers from narrow operating bandwidth and non-substrate integration. The third approach uses an F-type microstrip feedline to excite a Y-shaped slot, which in turn couples and excites a stepped rectangular column dielectric resonator. The Y-shaped slot mode and the orthogonal dielectric modes of the dielectric resonator are used to broaden the bandwidth of the circularly polarized radiation, and the F-type microstrip feedline is used to provide filtering. However, this approach suffers from poor in-band gain stability, non-substrate integration, and a high profile. Therefore, it is necessary to propose a substrate-integrated circularly polarized dielectric resonator filter antenna with broadband working and stable gain, while taking into account both profile and size. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned existing technologies, a broadband circularly polarized substrate integrated dielectric resonator filter antenna is proposed, which can simultaneously achieve wide operating bandwidth, stable in-band gain and substrate integration, and can take into account both cross-section and size.

[0005] Technical solution: A broadband circularly polarized substrate integrated dielectric resonator filtering antenna, comprising: a first metal layer, an upper dielectric substrate, a second metal layer, an intermediate dielectric substrate, a metal ground layer, a bottom dielectric substrate, and a bottom metal layer arranged in sequence from top to bottom; the first metal layer comprises a square ring-shaped metal sheet, and the inner side edges of the square ring-shaped metal sheet respectively have inwardly protruding rectangular metal structures, and the four protruding parts are rotationally symmetrically distributed; a rectangular short patch and a rectangular long patch are distributed inside the square ring-shaped metal sheet; the upper dielectric substrate comprises a 3×3 rectangular dielectric sheet and a peripheral dielectric structure, and the peripheral dielectric structure is aligned with the square ring-shaped metal sheet up and down; there are dielectric-free areas between the 3×3 rectangular dielectric sheets and the peripheral dielectric structure, and the 3×3 rectangular dielectric sheets and the peripheral dielectric structure are connected to form an integral dielectric structure through a plurality of internal dielectric connecting strips and a plurality of external dielectric connecting strips; the second metal layer comprises The first metal layer has a rectangular long patch 1 and a rectangular long patch 2 of the same size, which are aligned vertically with the rectangular long patch 1; a stepped groove is etched on the metal layer, and the stepped groove is composed of upper and lower horizontal arms and vertical grooves connecting the upper and lower horizontal arms; the stepped groove is opposite to five dielectric plates in the 3×3 rectangular dielectric plate; the bottom metal layer is an E-shaped metal structure; metallized blind holes 1 are periodically arranged around the inner edge of the square ring-shaped metal plate and connected to the metal layer to form a ring-shaped back cavity structure; metallized blind holes 2 connect the rectangular long patch 1 and the rectangular long patch 2 to form an equivalent metal wall; the first metal layer, the upper dielectric substrate, the second metal layer, the middle dielectric substrate, the metal layer, the metallized blind hole 1 and the metallized blind hole 2 constitute a ring-shaped back cavity substrate integrated dielectric resonator, which serves as the radiator of the antenna; the bottom metal layer, the bottom dielectric substrate and the metal layer constitute an E-shaped microstrip feeding structure.

[0006] Furthermore, in the upper dielectric substrate, the dielectric sheet located in the upper left corner of the 3×3 rectangular dielectric sheets is distributed below the rectangular short patch of the first metal layer, and the right edges of the two overlap with each other; the dielectric sheet located in the center of the 3×3 rectangular dielectric sheets is distributed below the rectangular long patch of the first metal layer, and the left edges of the two overlap with each other.

[0007] Furthermore, the E-shaped metal structure includes a metal strip, two T-shaped strips and a rectangular metal strip; wherein, the metal strip is arranged horizontally, and one end is located in the middle of one side of the antenna, and the rectangular metal strip is connected to the other end of the metal strip located in the center of the antenna; the two T-shaped strips are symmetrically arranged on both sides of the middle of the metal strip.

[0008] Furthermore, the transverse inner side length of the square ring-shaped metal sheet is between 0.66λ0 and 0.68λ0, and the longitudinal inner side length is between 0.62λ0 and 0.64λ0; the inwardly protruding rectangular metal structure has a width in the longitudinal direction of 0.052λ0 and 0.053λ0, and a length in the transverse direction of 0.382λ0 and 0.42λ0.

[0009] Furthermore, the width of the short rectangular patch in the transverse direction is between 0.068λ0 and 0.072λ0, and the length in the longitudinal direction is between 0.087λ0 and 0.089λ0; the width of the long rectangular patch in the transverse direction is between 0.056λ0 and 0.058λ0, and the length in the longitudinal direction is between 0.14λ0 and 0.16λ0.

[0010] Furthermore, the lengths of the upper and lower transverse arms of the stepped groove are between 0.22λ0 and 0.24λ0, and the length of the longitudinal vertical groove is between 0.32λ0 and 0.34λ0.

[0011] Beneficial effects: Existing circularly polarized dielectric resonator filter antennas have not achieved substrate integration, and there are problems such as too narrow working bandwidth or wide working bandwidth but poor in-band gain stability, as well as problems of high profile or large size. The present invention applies structures such as an annular back cavity structure, an equivalent metal wall, and a rectangular short patch to a 3×3 rectangular dielectric sheet to form a multi-mode annular back cavity substrate integrated dielectric resonator. The three structures suppress the cross-polarization electric field and optimize the main polarization electric field, effectively improving gain fluctuation and widening the axial ratio bandwidth. Combined with the filtering effect of the E-type microstrip feeding structure, a broadband circularly polarized substrate integrated dielectric resonator filter antenna with stable gain is realized. The substrate can be integrated, and both profile and size can be taken into consideration.

[0012] Specifically, the 3×3 rectangular dielectric sheet is located in the center of the antenna. It is connected to the upper dielectric substrate through four external dielectric strips to form an integral dielectric structure, which is easy to integrate and works as a whole with the middle dielectric substrate and the metal ground with stepped grooves. Y-slot die and mode, providing the basis for broadband circular polarization work.

[0013] The metallized blind holes are periodically arranged around the inner edge of the top square ring metal sheet and connected to the metal layer to form a ring-shaped back cavity structure to suppress the y-direction slot mode and The right-handed circularly polarized electric field distribution generated during mode combination effectively solves the gain notch problem and broadens the axial ratio frequency range in the low-frequency region.

[0014] Metalized blind via 2 is used to connect rectangular long patch 1 and rectangular long patch 2 to form an equivalent metal wall. This can suppress the right-handed circularly polarized electric field in the central patch area of ​​the 3×3 rectangular dielectric patch and optimize the left-handed circularly polarized electric field of the dielectric patch to its left, so that the antenna gain remains smooth and stable and the axial ratio in the high-frequency region is greatly improved.

[0015] The short rectangular patch can optimize the left-hand circularly polarized electric field in the patch area at the upper left corner of the 3×3 rectangular dielectric sheet, adjust the high-frequency axial ratio to a certain extent, and optimize the axial ratio bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the cross-sectional structure of the antenna;

[0017] Figure 2 is a schematic structural diagram of the first metal layer;

[0018] Figure 3 Schematic diagram of the structure of the upper dielectric substrate;

[0019] Figure 4 is a schematic structural diagram of the second metal layer;

[0020] Figure 5 It is a schematic diagram of the structure of the metal formation;

[0021] Figure 6 Schematic diagram of the structure of the bottom metal layer;

[0022] Figure 7 For antenna |S 11 | and gain simulation results;

[0023] Figure 8 is the simulation result of the antenna’s axial ratio;

[0024] Figure 9 is the simulation efficiency curve of the antenna;

[0025] Figure 10 is the simulated radiation pattern of the antenna at 9.4 GHz;

[0026] Figure 11 is the simulated radiation pattern of the antenna at 10.4 GHz;

[0027] Figure 12 This is the simulated radiation pattern of the antenna at 11.4 GHz. DETAILED DESCRIPTION

[0028] The present invention will be further explained below with reference to the accompanying drawings.

[0029] like Figure 1As shown, a broadband circularly polarized substrate integrated dielectric resonator filter antenna includes, from top to bottom, a first metal layer 1, an upper dielectric substrate 2, a second metal layer 3, an intermediate dielectric substrate 4, a metal ground layer 5, a bottom dielectric substrate 6, and a bottom metal layer 7. The antenna also includes a plurality of metallized blind vias 1 8 and a plurality of metallized blind vias 2 9, wherein the dielectric constant of the upper dielectric substrate 2 is greater than the dielectric constants of the intermediate dielectric substrate 4 and the bottom dielectric substrate 6.

[0030] like Figure 2 As shown, the first metal layer 1 includes a square ring-shaped metal sheet 101, a short rectangular patch 102, and a long rectangular patch 103. The inner side of the square ring-shaped metal sheet 101 has inwardly protruding rectangular metal structures, and the four protrusions are distributed in a rotationally symmetrical manner. The short rectangular patch 102 and the long rectangular patch 103 are distributed within the square ring-shaped metal sheet 101. The length of the inner side of the square ring-shaped metal sheet 101 along the horizontal (x-axis) is between 0.66λ0 and 0.68λ0, and the length of the inner side along the vertical (y-axis) is between 0.62λ0 and 0.64λ0, where λ0 is the free-space wavelength corresponding to the center frequency. The inwardly protruding rectangular metal structure has a width along the y-axis of between 0.052λ0 and 0.053λ0, and a length along the x-axis of between 0.382λ0 and 0.42λ0. The width of the short rectangular patch 102 in the x-axis direction is between 0.068λ0 and 0.072λ0, and the length in the y-axis direction is between 0.087λ0 and 0.089λ0. The width of the long rectangular patch 103 in the x-axis direction is between 0.056λ0 and 0.058λ0, and the length in the y-axis direction is between 0.14λ0 and 0.16λ0.

[0031] like Figure 3 As shown, the upper dielectric substrate 2 comprises a 3×3 rectangular dielectric sheet 201, a peripheral dielectric structure 202, five internal dielectric connectors 203, and four external dielectric connectors 204. The peripheral dielectric structure 202 has the same planar shape and dimensions as the square ring-shaped metal sheet 101 of the first metal layer 1, and is aligned vertically. There are dielectric-free regions, i.e., air, between the 3×3 rectangular dielectric sheets 201 and between them and the peripheral dielectric structure 202. The internal dielectric connectors 203 and the four external dielectric connectors 204 connect the 3×3 rectangular dielectric sheet 201 and the peripheral dielectric structure 202 into a single, integrated dielectric structure, facilitating integration and ensuring proper antenna operation. The dielectric sheet in the upper left corner of the 3×3 rectangular dielectric sheet 201 is positioned below the short rectangular patch 102 of the first metal layer 1, with their right edges overlapping. The dielectric sheet in the center of the 3×3 rectangular dielectric sheet 201 is positioned below the long rectangular patch 103 of the first metal layer 1, with their left edges overlapping.

[0032] like Figure 4As shown, the second metal layer 3 includes a second rectangular long patch 301 , which is the same size as the first rectangular long patch 103 of the first metal layer 1 , and the two are aligned vertically.

[0033] like Figure 5 As shown, a stepped groove 501 is etched on the metal layer 5. The lengths of its upper and lower horizontal arms are between 0.22λ0 and 0.24λ0, and the length of the longitudinal groove is between 0.32λ0 and 0.34λ0. The stepped groove 501 directly faces the five dielectric sheets in the 3×3 rectangular dielectric sheet 201.

[0034] like Figure 6 As shown, the bottom metal layer 7 is an E-shaped metal structure, comprising a metal strip 701, two T-shaped strips 702, and a rectangular metal strip 703. The metal strip 701 is arranged horizontally, with one end located in the middle of one side of the antenna. The rectangular metal strip 703 connects the other end of the metal strip 701 located in the center of the antenna. The two T-shaped strips 702 are symmetrically arranged on both sides of the middle of the metal strip 701.

[0035] like Figures 1 to 5 As shown, metallized blind vias 1 (8) are periodically arranged around the inner edge of square ring-shaped metal sheet 101, connecting to metal layer 5 to form a ring-shaped back cavity structure. Metallized blind vias 2 (9) are used to connect rectangular long patch 103 to rectangular long patch 2 (301), forming an equivalent metal wall.

[0036] The first metal layer 1, upper dielectric substrate 2, second metal layer 3, middle dielectric substrate 4, metal ground layer 5, metalized blind via 1 8, and metalized blind via 2 9 form a circular cavity-backed substrate integrated dielectric resonator, serving as the antenna's radiator. The bottom metal layer 7, bottom dielectric substrate 6, and metal ground layer 5 form an E-type microstrip feed structure.

[0037] For the proposed antenna, the signal is coupled to the stepped groove 501 of the metal layer 5 through the E-type microstrip feeding structure of the bottom layer, and further coupled to excite the annular back-cavity substrate integrated dielectric resonator, forming a broadband circularly polarized radiation with stable gain and filtering effect under the action of the overall structure.

[0038] In this process, the 3×3 rectangular dielectric sheet 201 of the upper dielectric substrate 2, the middle dielectric substrate 4 and the metal layer 5 with the stepped groove 501 work as a whole. Y-slot die and mode, the four modes form a 90-degree phase difference between each other, forming left-hand circularly polarized radiation, but With y-direction slot die and y-direction slot die with When the modes are combined, a strong right-hand circular polarization electric field distribution will be generated in some small areas, resulting in poor axial ratio and gain within the band, making it difficult to achieve broadband operation and gain stability. When the annular back cavity structure is introduced, the y-direction slot mode and The right-handed circularly polarized electric field distribution generated during mode combination effectively improves gain notch and broadens the axial ratio frequency range in the low-frequency region. The addition of the equivalent metal wall effectively suppresses the right-handed circularly polarized electric field in the central patch of the 3×3 rectangular dielectric patch 201 and optimizes the left-handed circularly polarized electric field in the left patch, maintaining a smooth and stable antenna gain and significantly improving the axial ratio in the high-frequency region. The addition of the short rectangular patch 102 optimizes the left-hand circularly polarized electric field in the upper-left corner patch of the 3×3 rectangular dielectric patch 201, adjusting the high-frequency axial ratio and optimizing the axial ratio bandwidth. As a result, the overall antenna achieves a wide matching bandwidth and axial ratio bandwidth, while maintaining stable gain. The E-shaped microstrip feed structure at the bottom creates a dual-band limiting effect, helping the antenna achieve filtering and feeding the dielectric resonator integrated into the annular cavity-backed substrate and the stepped slot 501. This overall structure enables substrate integration, and its radiation mechanism balances profile and size.

[0039] This embodiment uses a combination of RT6010 substrate and RO4003C substrate, and the overall antenna unit size is 0.63λ0×0.67λ0×0.11λ0. 11 The simulated response of | and gain is as follows Figure 7 As shown, the antenna's 10-dB matching frequency range is 8.4 GHz to 12 GHz, meaning the relative bandwidth can reach 35.3%. The maximum gain within the band can reach 7.6 dBic, and the gain remains stable with a fluctuation range of less than 0.46 dB. At the same time, a radiation zero point appears at 6 GHz and 14 GHz, respectively, to achieve filtering. Figure 8 The simulated axial ratio of the antenna in this embodiment has a 3dB axial ratio frequency range of 9.1GHz to 12.2GHz, that is, the relative bandwidth can reach 29.4%, and the overlapping bandwidth with the 10-dB matching bandwidth can reach 27.38%. Figure 9 This is the efficiency response curve of the antenna, and its maximum efficiency can reach 96.7%. Figure 10 When the antenna of this embodiment is working, the simulated radiation patterns at 9.4 GHz, 10.4 GHz, and 11.4 GHz show that this embodiment is a left-hand circularly polarized antenna, and its half-power beamwidth in the phi = 0° plane is 74.5°, 71.7°, and 59.5°, respectively, and its half-power beamwidth in the phi = 90° plane is 68.7°, 66.3°, and 63.0°, respectively.

[0040] Compared with existing designs, the circularly polarized dielectric resonator filter antenna proposed in the present invention has the advantages of being able to simultaneously achieve broadband operation, gain stability, and substrate integration, while also taking into account cross-section or size.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A broadband circularly polarized substrate integrated dielectric resonator filter antenna, characterized in that: include: The first metal layer (1), the upper dielectric substrate (2), the second metal layer (3), the middle dielectric substrate (4), the metal ground layer (5), the bottom dielectric substrate (6), and the bottom metal layer (7) are sequentially arranged from top to bottom; The first metal layer (1) comprises a square ring-shaped metal sheet (101), wherein the inner side edges of the square ring-shaped metal sheet (101) respectively have inwardly protruding rectangular metal structures, and the four protruding portions are distributed in a rotationally symmetrical manner; a rectangular short patch (102) and a rectangular long patch (103) are distributed inside the square ring-shaped metal sheet (101); The upper dielectric substrate (2) includes a 3×3 rectangular dielectric sheet (201) and a peripheral dielectric structure (202), and the peripheral dielectric structure (202) is aligned with the square ring-shaped metal sheet (101) in an upper and lower direction; there are dielectric-free areas between the 3×3 rectangular dielectric sheets (201) and between the 3×3 rectangular dielectric sheets (201) and the peripheral dielectric structure (202), and the 3×3 rectangular dielectric sheets (201) and the peripheral dielectric structure (202) are connected to form an integral dielectric structure via a plurality of internal dielectric connecting strips (203) and a plurality of external dielectric connecting strips (204); The second metal layer (3) includes a second rectangular long patch (301) having the same size as the first rectangular long patch (103) of the first metal layer (1), and is aligned vertically with the first rectangular long patch (103); A stepped groove (501) is etched on the metal layer (5), and the stepped groove (501) is composed of upper and lower transverse arms and a vertical groove connecting the upper and lower transverse arms; the stepped groove (501) is opposite to five dielectric sheets in the 3×3 rectangular dielectric sheet (201); the bottom metal layer (7) is an E-shaped metal structure; Metallized blind holes 1 (8) are periodically arranged around the inner edge of the square ring-shaped metal sheet (101) and connected to the metal stratum (5) to form an annular back cavity structure; metallized blind holes 2 (9) connect the rectangular long patch 1 (103) and the rectangular long patch 2 (301) to form an equivalent metal wall; The first metal layer (1), the upper dielectric substrate (2), the second metal layer (3), the middle dielectric substrate (4), the metal ground layer (5), the metalized blind hole 1 (8) and the metalized blind hole 2 (9) constitute a ring-shaped back cavity substrate integrated dielectric resonator, which serves as a radiator of the antenna; the bottom metal layer (7), the bottom dielectric substrate (6) and the metal ground layer (5) constitute an E-type microstrip feeding structure.

2. The broadband circularly polarized substrate integrated dielectric resonator filter antenna according to claim 1, characterized in that: In the upper dielectric substrate (2), the dielectric sheet located at the upper left corner of the 3×3 rectangular dielectric sheets (201) is distributed below the rectangular short patch (102) of the first metal layer (1), and the right edges of the two overlap with each other; and the dielectric sheet located in the center of the 3×3 rectangular dielectric sheets (201) is distributed below the rectangular long patch 1 (103) of the first metal layer (1), and the left edges of the two overlap with each other.

3. The broadband circularly polarized substrate integrated dielectric resonator filter antenna according to claim 1, characterized in that: The E-shaped metal structure comprises a metal strip (701), two T-shaped strips (702) and a rectangular metal strip (703); wherein the metal strip (701) is arranged horizontally, and one end is located in the middle of one side of the antenna, and the rectangular metal strip (703) is connected to the other end of the metal strip (701) located in the center of the antenna; and the two T-shaped strips (702) are symmetrically arranged on both sides of the middle of the metal strip (701).

4. The broadband circularly polarized substrate integrated dielectric resonator filter antenna according to any one of claims 1 to 3, characterized in that: The transverse inner side length of the square ring-shaped metal sheet (101) is between 0.66λ0 and 0.68λ0, and the longitudinal inner side length is between 0.62λ0 and 0.64λ0; the inwardly protruding rectangular metal structure has a longitudinal width between 0.052λ0 and 0.053λ0, and a transverse length between 0.382λ0 and 0.42λ0, where λ0 is the free space wavelength corresponding to the center frequency.

5. The broadband circularly polarized substrate integrated dielectric resonator filter antenna according to claim 4, characterized in that: The width of the rectangular short patch (102) in the transverse direction is between 0.068λ0 and 0.072λ0, and the length in the longitudinal direction is between 0.087λ0 and 0.089λ0; the width of the rectangular long patch (103) in the transverse direction is between 0.056λ0 and 0.058λ0, and the length in the longitudinal direction is between 0.14λ0 and 0.16λ0.

6. The broadband circularly polarized substrate integrated dielectric resonator filter antenna according to claim 5, characterized in that: The lengths of the upper and lower transverse arms of the stepped groove (501) are between 0.22λ0 and 0.24λ0, and the length of the longitudinal vertical groove is between 0.32λ0 and 0.34λ0.

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