A high-isolation dual-radiation-mode dual-frequency filtering antenna

Abstract

The application discloses a high-isolation dual-radiation-mode dual-frequency filtering antenna, and relates to the technical field of antennas of wireless communication terminals; the high-isolation dual-radiation-mode dual-frequency filtering antenna comprises a first dielectric substrate to a fourth dielectric substrate which are sequentially arranged from bottom to top; a pair of differential feeding lines arranged on the lower surface of the first dielectric substrate; an intermediate metal surface arranged between the first dielectric substrate and the second dielectric substrate; a pair of feeding extension branches arranged between the second dielectric substrate and the third dielectric substrate; a circular patch arranged between the third dielectric substrate and the fourth dielectric substrate; an upper metal surface and a ring-shaped patch arranged on the upper surface of the fourth dielectric substrate; a feeding probe vertically penetrating the center of each dielectric substrate; and a plurality of groups of metalized short-circuit through holes; the application utilizes the resonant characteristics of the structure itself and electromagnetic mixed coupling effects to obtain dual-frequency dual-band filtering responses; and adopts a feeding mode combining differential feeding and probe feeding and orthogonal mode excitation to realize high isolation between the dual-frequency bands.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology for wireless communication terminals, and specifically relates to a dual-radiation mode dual-frequency filtering antenna with high isolation. Background Technology

[0002] With the rapid development of technologies such as 5G / 6G communication, vehicle-to-everything (V2X) communication, drone swarms, satellite communication, and smart cities, wireless communication systems are facing increasingly complex and diverse service demands. Emerging application scenarios such as high-definition video transmission, low-latency industrial automation, vehicle-to-vehicle collaborative sensing, and drone relay networking place unprecedentedly high demands on the coverage, signal stability, anti-interference performance, and multi-service concurrent processing capabilities of wireless terminal equipment. Against this backdrop, high-isolation antennas with dual-band omnidirectional / directional radiation capabilities have become a research hotspot. Omnidirectional antennas, with their 360-degree uniform coverage, can effectively solve the signal fluctuation problem caused by azimuth changes during user movement; directional antennas, through high-gain beam focusing, can achieve long-distance, high-speed point-to-point data transmission, offering significant advantages in interference avoidance and energy concentration. However, traditional antenna designs typically can only implement one radiation mode. When facing the requirement of simultaneous operation of dual frequency bands, two independent reconfigurable antenna systems are often needed, leading to increased terminal size, higher costs, and intensified inter-port coupling. Meanwhile, Filtennas, by integrating the filtering circuitry with the radiating element, can not only suppress out-of-band interference and reduce system noise, but also significantly reduce the insertion loss, size redundancy, and port coupling problems associated with traditional discrete filters. However, most existing Filtenna research focuses on unidirectional (directional) radiation modes, making it difficult to directly apply to omnidirectional radiation scenarios. Furthermore, designing Filtennas that simultaneously support dual-band, dual-radiation modes (directional / omnidirectional) while maintaining high isolation remains a significant challenge.

[0003] In recent years, research on dual-band dual-mode filtered antennas has made some progress, but investigations have revealed the following shortcomings in existing technologies: Some dual-band filtered antennas can only achieve dual-band operation at a single port, lacking port isolation and independent control capabilities. These designs typically use a single feed point to excite two resonant modes or achieve dual-band response through a multi-mode resonator. Although the structure is compact, the two frequency bands share the same input port, making it impossible to simultaneously and independently transmit and receive signals from different frequency bands. A few reported dual-port dual-band antennas, while achieving two independent ports, are designed with both frequency bands in directional radiation mode, lacking differentiated configurations for radiation modes. However, in many practical scenarios, systems prefer one frequency band for omnidirectional radiation for wide-area coverage and the other for high-speed point-to-point data transmission with directional high gain. Most antennas suffer from low structural reuse; these designs often simply piece together two independent antenna elements from different frequency bands on the same dielectric substrate. This "1+1" integration scheme results in a large overall antenna size and high structural redundancy.

[0004] In summary, to meet the urgent needs of modern wireless communication systems for miniaturization, high integration, high isolation, and dual-mode hybrid coverage, this invention proposes a high-isolation dual-radiation mode dual-frequency filtered antenna to address the aforementioned shortcomings. This antenna achieves independent operation of two frequency bands by sharing the same radiating aperture: the low-frequency band uses a directional radiation mode, suitable for high-speed point-to-point transmission; the high-frequency band uses an omnidirectional radiation mode, suitable for wide-area coverage and signaling interaction. The two frequency bands are independently excited by different feed ports, and each band introduces a filtering null point through the antenna's own resonant structure, eliminating the need for external filters. Compared to existing technologies, this invention achieves high-reusability integrated design and unifies dual-band, dual-radiation mode, high isolation, and in-band radiation and out-of-band suppression in terms of performance. Summary of the Invention

[0005] The purpose of this invention is to propose a high-isolation dual-radiation mode dual-frequency filtering antenna. Specifically, it utilizes a closed circular substrate integrated cavity and patch for integrated antenna and filter design, sharing the same radiating aperture to achieve independent operation of two frequency bands. Specifically, a probe is used to feed and excite the circular substrate integrated cavity, the (main radiating) circular patch, and the ring (parasitic) patch to achieve omnidirectional resonant modes, generating high-frequency radiation and introducing radiation nulls in the upper and lower sidebands. Differential feeding is used to excite the circular patch and the ring patch to achieve directional resonant modes, generating low-frequency radiation and introducing radiation nulls in the upper and lower sidebands. High isolation is achieved by employing differential feeding and optimizing the probe excitation position. The antenna structure proposed in this invention is simple, using only three core components (circular substrate integrated cavity, circular patch, and ring patch) to complete the dual-frequency dual-mode high isolation design, reducing processing difficulty and manufacturing costs. It can be widely used in 5G / 6G communication, vehicle-to-everything (V2X) systems, UAV relay, and cognitive radio systems. Furthermore, the patch participates in the resonance and radiation of two frequency bands simultaneously, and a single structural element is reused by multiple frequency bands, achieving a high structural reuse rate for the antenna.

[0006] To achieve the above objectives, the technical solution of the present invention is: a high-isolation dual-radiation mode dual-frequency filter antenna, comprising:

[0007] The first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate are stacked sequentially from bottom to top;

[0008] A pair of differential feed lines disposed on the lower surface of the first dielectric substrate;

[0009] An intermediate metal surface disposed between the first dielectric substrate and the second dielectric substrate;

[0010] A pair of power-feeding extension branches are disposed between the second dielectric substrate and the third dielectric substrate;

[0011] A circular patch disposed between the third dielectric substrate and the fourth dielectric substrate;

[0012] The upper metal surface and the annular patch are disposed on the upper surface of the fourth dielectric substrate;

[0013] A feed probe is vertically penetrating the center of each dielectric substrate; wherein, the center of the middle metal surface is provided with a first circular groove to avoid contact with the feed probe, the center of the circular patch is provided with a second circular groove to avoid contact with the feed probe, and the center of the upper metal surface is provided with a feed hole for the feed probe to pass through, and the upper metal surface is electrically connected to the feed probe.

[0014] A number of first metallized short-circuit vias that vertically penetrate the fourth dielectric substrate to connect the upper metal surface and the circular patch;

[0015] A plurality of second metallized short-circuit vias are perpendicularly penetrating the first dielectric substrate and the second dielectric substrate to connect the differential feed line and the feed extension stub.

[0016] A number of third metallized short-circuit vias that vertically penetrate the third and fourth dielectric substrates to connect the power supply extension stubs and the annular patch.

[0017] A plurality of fourth metallized short-circuit vias and a plurality of fifth metallized short-circuit vias are formed that vertically penetrate the second dielectric substrate, the third dielectric substrate and the fourth dielectric substrate to connect the annular patch and the intermediate metal surface.

[0018] Preferably, a rectangular coordinate system of xyz is established with the central axis of the feed probe as the z-axis, then:

[0019] The pair of differential feed lines are arranged symmetrically about the x-axis;

[0020] The pair of feed extension stubs are arranged symmetrically about the x-axis;

[0021] Several second metallized short-circuit vias are symmetrically arranged about the x-axis;

[0022] Several of the aforementioned third metallized short-circuit vias are symmetrically arranged about the x-axis;

[0023] Several of the aforementioned fourth metallized short-circuit vias are symmetrically arranged about the x-axis;

[0024] Several of the fifth metallized short-circuit vias are symmetrically arranged about the y-axis.

[0025] Preferably, a plurality of the first metallized short-circuit vias are arranged at equal intervals along the circumferential direction; the center of the circular substrate integrated cavity formed by the upper metal surface, the circular patch, and the plurality of the first metallized short-circuit vias is located on the same straight line as the center of the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, the upper metal surface, the circular patch, the annular patch, and the middle metal surface.

[0026] Preferably, the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, and the intermediate metal surface have the same length and width dimensions; wherein, the length L and the width W satisfy: 0.68λ c ≤L=W≤0.87λ c , λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0027] Preferably, the radius R7 of the circular patch satisfies 0.15λ. c ≤R7≤0.20λ c The radius R1 of the upper metal surface satisfies 0.13λ. c ≤R1≤0.17λ cAnd R7≠R1, where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0028] Preferably, the inner radius R2 and outer radius R3 of the annular patch respectively satisfy: 0.16λ c ≤R²≤0.23λ c 0.25λ c ≤R3≤0.33λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0029] Preferably, the distance R8 between the center of the plurality of second metallized short-circuit vias and the z-axis satisfies 0.18λ. c ≤R8≤0.22λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0030] Preferably, the distances between the centers of the plurality of third metallized short-circuit vias and the z-axis, and the distances between the centers of the plurality of fourth metallized short-circuit vias and the z-axis, are all R5, and the distance R5 satisfies 0.24λ. c ≤R5≤0.27λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0031] Preferably, the distance R4 between the center of each of the fifth metallized short-circuit vias and the z-axis satisfies 0.22λ. c ≤R4≤0.24λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0032] Preferably, the filtered antenna supports both high-frequency omnidirectional bands and low-frequency directional bands, wherein:

[0033] The high-frequency omnidirectional band is implemented as follows:

[0034] Direct power is supplied via a power supply probe to excite the circular patch to operate in TM mode. 02 model;

[0035] Direct power is supplied via a power probe, energizing the circular substrate integrated cavity, which is enclosed by the upper metal surface, the circular patch, and several first metallized short-circuit vias, to operate in TM mode. 01 The mode generates a resonant point in the passband of the high-frequency omnidirectional band and a gain radiation zero in the lower sideband of the passband of the high-frequency omnidirectional band; wherein, the frequency positions of the resonant point in the passband of the high-frequency omnidirectional band and the gain radiation zero in the lower sideband of the passband are adjusted by changing the cavity size of the circular substrate integrated cavity.

[0036] By coupling and exciting the annular patch with a circular patch, a new resonant point is generated in the passband of the high-frequency omnidirectional band. Through the electromagnetic hybrid coupling effect between the annular and circular patches, a new gain radiation zero is generated in the upper sideband of the passband of the high-frequency omnidirectional band. The frequency positions of the new resonant point and the new gain radiation zero are adjusted by changing the size of the annular patch.

[0037] The low-frequency directional band is implemented as follows:

[0038] A differential feed structure, consisting of differential feed lines and feed extension stubs, excites a circular patch to operate in TM. 11 The pattern forms the main coupling path for energy from the input end to the radiation space;

[0039] The differential feed structure excites the annular patch to operate in TM. 11 The mode forms a cross-coupled path for energy from the input to the radiation space. The main coupling path and the cross-coupled path cancel each other out at the frequency that satisfies the equal amplitude and phase inversion condition, generating a gain radiation zero in the lower sideband of the passband in the low-frequency directional band. The frequency position of the gain radiation zero in the lower sideband of the passband in the low-frequency directional band is adjusted by changing the length of the feed extension stub.

[0040] The TM of the ring patch is achieved through the third and fourth metallized short-circuit vias. 11 The pattern field distribution is perturbed, causing the TM of the ring patch to... 11 The mode frequency is shifted from a position below the low-frequency directional band passband to within the low-frequency directional band passband, generating a resonant point within the low-frequency directional band passband. Through the electromagnetic hybrid coupling effect between the ring patch and the circular patch, a gain radiation null point is generated in the upper sideband of the low-frequency directional band passband. The frequency position of the gain radiation null point in the upper sideband of the low-frequency directional band passband is adjusted by changing the position of the third metallized short-circuit via.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1) Simple structure: The dual-frequency dual-mode high isolation design is completed with only three core components (circular substrate integrated cavity, circular patch, and ring patch), avoiding multi-layer stacking, large number of slots or complex defect structures, reducing processing difficulty and manufacturing cost.

[0043] 2) Differentiated radiation modes: low-frequency directional beam, suitable for long-distance, high-gain point-to-point communication; high-frequency omnidirectional radiation mode, used for wide-area coverage.

[0044] 3) High structural reuse rate: In this invention, the circular substrate integrated cavity, circular patch, and ring patch are coupled to each other and jointly participate in the operation of two frequency bands. Each unit of the circular patch and the ring patch contributes to both frequency bands simultaneously.

[0045] 4) High isolation: The present invention uses both differential feeding and probe feeding methods to generate resonant modes with orthogonal field distribution in the dual frequency bands. High isolation is achieved by utilizing the natural suppression of common-mode interference (from a single probe) by the differential port; at the same time, the feeding positions are optimized and the two are spatially staggered, which further reduces direct coupling.

[0046] 5) No complex filter structure: The introduction of the filter characteristics of this invention does not depend on the loading of parasitic filter structures, but utilizes the resonance characteristics of the structure itself. Therefore, the structural complexity and design complexity are much lower than those of existing designs. Attached Figure Description

[0047] Figure 1 This is an exploded three-dimensional structural diagram of the present invention;

[0048] Figure 2 This is a top view of the dielectric substrate 4 of the present invention, including the upper metal surface of the cavity and the annular patch;

[0049] Figure 3 This is a top view of the dielectric substrate 3 of the present invention, including a circular patch and a power supply extension branch;

[0050] Figure 4 This is a top view of the dielectric substrate 1 of the present invention, including the grooved metal surface and the differentially fed microstrip line;

[0051] Figure 5 This is a simulation diagram of the S-parameter curve of the present invention;

[0052] Figure 6 This is a simulation diagram of the gain curve of the present invention;

[0053] Figure 7 This is the simulated radiation pattern of the present invention at a low frequency of 2.9 GHz.

[0054] Figure 8 This is the simulated radiation pattern of the present invention at a high frequency of 6.5 GHz.

[0055] In the picture:

[0056] 1-First dielectric substrate; 2-Second dielectric substrate; 3-Third dielectric substrate; 4-Fourth dielectric substrate; 5-Intermediate metal surface; 6-Differential feed line; 7-Feed extension branch; 8-Circular patch; 9-Upper metal surface; 10-Annular patch; 11-First metallized short-circuit via; 12-First circular groove; 13-Second circular groove; 14-Feed probe; 15-Second metallized short-circuit via; 16-Third metallized short-circuit via; 17-Fourth metallized short-circuit via; 18-Fifth metallized short-circuit via; 19-Feed hole. Detailed Implementation

[0057] The following is in conjunction with the appendix Figure 1-8 The technical solution of the present invention will be described in detail below.

[0058] This invention proposes a high-isolation dual-radiation mode dual-frequency filtered antenna, comprising:

[0059] The first dielectric substrate 1, the second dielectric substrate 2, the third dielectric substrate 3, and the fourth dielectric substrate 4 are stacked sequentially from bottom to top;

[0060] A pair of differential feed lines 6 for exciting directional frequency bands are disposed on the lower surface of the first dielectric substrate 1;

[0061] An intermediate metal surface 5 is disposed between the upper surface of the first dielectric substrate 1 and the lower surface of the second dielectric substrate 2;

[0062] A pair of power-feeding extension branches 7 are disposed between the upper surface of the second dielectric substrate 2 and the lower surface of the third dielectric substrate 3;

[0063] A circular patch 8 is disposed between the upper surface of the third dielectric substrate 3 and the lower surface of the fourth dielectric substrate 4;

[0064] The upper metal surface 9 and the annular patch 10 are disposed on the upper surface of the fourth dielectric substrate 4;

[0065] A power supply probe 14 is vertically inserted through the center of each dielectric substrate; wherein, the center of the middle metal surface 5 is provided with a first circular groove 12 to avoid contact with the power supply probe 14, and the center of the circular patch 8 is provided with a second circular groove 13 to avoid contact with the power supply probe 14. The radii of the first circular groove 12 and the second circular groove 13 are slightly larger than the radius of the power supply probe 14 to prevent short circuit; the center of the upper metal surface 9 is provided with a power supply hole 19, the size of which is slightly larger than the size of the power supply probe, for the power supply probe 14 to pass through, and the two need to make contact by soldering;

[0066] A plurality of first metallized short-circuit vias 11 are perpendicularly penetrating the fourth dielectric substrate 4 to connect the upper metal surface 9 and the circular patch 8; wherein the plurality of first metallized short-circuit vias are arranged at equal intervals along the circumferential direction.

[0067] A plurality of second metallized short-circuit vias 15 are perpendicularly penetrating the first dielectric substrate 1 and the second dielectric substrate 2 to connect the differential feed line 6 and the feed extension stub 7; wherein, the second metallized short-circuit vias 15 and the feed extension stub 7 constitute an L-shaped microstrip line.

[0068] A plurality of third metallized short-circuit vias 16 perpendicularly penetrating the third dielectric substrate 3 and the fourth dielectric substrate 4 to connect the power supply extension stub 7 and the annular patch 10.

[0069] A plurality of fourth metallized short-circuit vias 17 and a plurality of fifth metallized short-circuit vias 18 are perpendicularly penetrating the second dielectric substrate 2, the third dielectric substrate 3 and the fourth dielectric substrate 4 to connect the annular patch 10 and the intermediate metal surface 5; wherein, the plurality of fourth metallized short-circuit vias 17 and the plurality of fifth metallized short-circuit vias 18 are respectively arranged symmetrically about two radial orthogonal axes of the feed probe 14.

[0070] The second metallized short-circuit via 15, the third metallized short-circuit via 16, the fourth metallized short-circuit via 17, and the fifth metallized short-circuit via 18 have the same via radius.

[0071] In this embodiment, a rectangular coordinate system is established with the central axis of the feed probe 14 as the z-axis, then:

[0072] The pair of differential feed lines 6 are symmetrical about the x-axis;

[0073] The pair of feed extension stubs 7 are symmetrical about the x-axis;

[0074] Several of the second metallized short-circuit vias 15 are symmetrical about the x-axis;

[0075] Several of the third metallized short-circuit vias 16 are symmetrical about the x-axis;

[0076] Several of the fourth metallized short-circuit vias 17 are symmetrical about the x-axis;

[0077] Several of the fifth metallized short-circuit vias 18 are symmetrical about the y-axis.

[0078] In this embodiment, the center of the circular substrate integrated cavity formed by the upper metal surface 9, the circular patch 8, and a plurality of first metallized short-circuit vias 11 is located on the same straight line as the center of the first dielectric substrate 1, the second dielectric substrate 2, the third dielectric substrate 3, the fourth dielectric substrate 4, the upper metal surface 9, the circular patch 8, the annular patch 10, and the middle metal surface 5.

[0079] In this embodiment, the first dielectric substrate 1, the second dielectric substrate 2, the third dielectric substrate 3, the fourth dielectric substrate 4, and the intermediate metal surface 5 have the same length and width dimensions; wherein, the length L and the width W satisfy: 0.68λ c≤L=W≤0.87λ c , λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0080] In this embodiment, the radius R7 of the circular patch 8 satisfies 0.15λ. c ≤R7≤0.20λ c The radius R1 of the upper metal surface 9 satisfies 0.13λ. c ≤R1≤0.17λ c And R7≠R1, where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0081] In this embodiment, the inner radius R2 and outer radius R3 of the annular patch 10 respectively satisfy: 0.16λ c ≤R²≤0.23λ c 0.25λ c ≤R3≤0.33λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0082] In this embodiment, the distance R8 between the center of a plurality of the second metallized short-circuit vias 15 and the z-axis satisfies 0.18λ. c ≤R8≤0.22λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0083] In this embodiment, the distances between the centers of the plurality of third metallized short-circuit vias 16 and the z-axis, and the distances between the centers of the plurality of fourth metallized short-circuit vias 17 and the z-axis are all R5, and the distance R5 satisfies 0.24λ. c ≤R5≤0.27λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0084] In this embodiment, the distance R4 between the center of each of the fifth metallized short-circuit vias 18 and the z-axis satisfies 0.22λ. c ≤R4≤0.24λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

[0085] In this embodiment, the filtered antenna supports both high-frequency omnidirectional bands and low-frequency directional bands, wherein:

[0086] The high-frequency omnidirectional band is implemented as follows:

[0087] Direct power is supplied via power supply probe 14, energizing the circular patch 8 to operate in TM mode. 02 model;

[0088] The combined boundary formed by the first metallized short-circuit via 11 is directly fed through the feed probe 14, stimulating the circular substrate integrated cavity to operate in TM mode. 01 The mode generates a resonant point in the passband of the high-frequency omnidirectional band and a gain radiation zero in the lower sideband of the passband of the high-frequency omnidirectional band; this gain radiation zero can be explained by the cavity resonance as equivalent to a band-stop resonant cavity; the frequency positions of the resonant point in the passband of the high-frequency omnidirectional band and the gain radiation zero in the lower sideband of the passband are adjusted by changing the cavity size of the circular substrate integrated cavity.

[0089] By coupling the circular patch 8 to excite the annular patch 10, a new resonant point is generated in the passband of the high-frequency omnidirectional band. Through the electromagnetic hybrid coupling effect between the annular patch 10 and the circular patch 8, a new gain radiation zero point is generated in the upper sideband of the passband of the high-frequency omnidirectional band. The position of the gain radiation zero point can be controlled by changing the electrical coupling strength or magnetic coupling strength between the two patches. That is, the frequency position of the new resonant point and the new gain radiation zero point can be adjusted by changing the size of the annular patch 10.

[0090] The low-frequency directional band is implemented as follows:

[0091] The differential feed structure, consisting of differential feed line 6 and feed extension stub 7, excites the circular patch 8 to operate in TM mode. 11 The pattern forms the main coupling path for energy from the input end to the radiation space (feed-circular patch 8-free space);

[0092] The differential feed structure excites the annular patch 10 to operate in TM mode. 11 The mode forms a cross-coupled path for energy from the input end to the radiation space (feed-ring patch 10-free space). The main coupling path and the cross-coupled path satisfy the condition of equal amplitude and phase inversion at a certain frequency, thus canceling each other out and generating a gain radiation zero in the lower sideband of the passband in the low-frequency directional band. The frequency position of the gain radiation zero in the lower sideband of the passband in the low-frequency directional band is adjusted by changing the length of the feed extension stub 7.

[0093] The TM of the annular patch 10 is obtained by excitation through a differential feed structure. 11 The initial frequency of the mode is too low; the TM of the annular patch 10 is controlled by the third metallized short-circuit via 16 and the fourth metallized short-circuit via 17. 11 The pattern field distribution is perturbed, causing the TM of the annular patch 10 to... 11The mode frequency is shifted up to the passband of the low-frequency directional band, generating a resonant point within the passband. Through the electromagnetic hybrid coupling effect between the ring patch 10 and the circular patch 8, a zero-gain radiation point is generated in the upper sideband of the low-frequency directional band passband. Similarly, the position of the third metallized short-circuit via 16 can be changed to affect the TM of the ring patch 10. 11 The mode and the upper sideband gain radiation zero point are adjusted.

[0094] In this embodiment, the thickness h1 of the first dielectric substrate 1 and the thickness h4 of the fourth dielectric substrate 4 are both 1 mm, the thickness h2 of the second dielectric substrate 2 is 1.1 mm, and the thickness h3 of the third dielectric substrate 3 is 1.4 mm, and all of them use a Rogers 5880 dielectric substrate.

[0095] The upper metal surface 9 has a radius of 15.1 mm, and the feed hole 19 at the center of the upper metal surface 9 has a radius of 0.64 mm; the annular patch 10 has an inner radius of 20.4 mm and an outer radius of 31 mm.

[0096] The center of the second metallized short-circuit via 15 is 19 mm from the z-axis; the center of the third metallized short-circuit via 16 is 25 mm from the z-axis; the center of the fourth metallized short-circuit via 17 is 25 mm from the z-axis, and the central angle α of the fourth metallized short-circuit via 17 deviating from the positive y-axis direction is 20°; the fifth metallized short-circuit via 18, which is closest to the z-axis, is 23.6 mm from the z-axis, and the spacing s between adjacent holes in the fifth metallized short-circuit via 18 is 1.8 mm; the diameter D1 of the vias of the second metallized short-circuit via 15, the third metallized short-circuit via 16, the fourth metallized short-circuit via 17, and the fifth metallized short-circuit via 18 is 1 mm.

[0097] The inner radius R6 of the circular substrate integrated cavity is 14.1 mm, the outer radius R1 is 15.1 mm, the diameter D2 of the first metallized through hole 11 is 1 mm, and the difference β6° between the central angles of two adjacent first metallized through holes 11.

[0098] The length L and width W of the middle metal surface 5 are both 80mm, the diameter d2 of the first circular groove 12 is 1.8mm, the radius of the circular patch 8 is 18.6mm, and the diameter d1 of the second circular groove 13 is 1mm.

[0099] The distance S1 between the feeder extension stub 7 and the z-axis is 14.5mm, the width w1 is 3.04mm, and the length l1 is 18.5mm; the width w2 of the differential feeder line 6 is 3.04mm, and the length l2 is 22mm.

[0100] The parameters are shown in Table 1:

[0101] Table 1 Specific structural geometric parameters of each component in this embodiment

[0102]

[0103] In this invention, the circular patch 8, under the excitation of the feed probe 14, operates in a TM mode with omnidirectional radiation characteristics. 02 In this mode, via the TM of the circular patch 8 02 A closed circular substrate integrated cavity is placed in the region of minimum electric field in the mode. This introduces a new resonant point and a zero-gain radiation point without affecting the resonant mode of the circular patch 8. This circular substrate integrated cavity 19 operates in a TM mode with the same omnidirectional radiation characteristics under direct excitation from the feed probe 14. 01 In this mode, an annular patch 10 is added to the outer ring of the circular patch 8. The annular patch 10 is excited by coupling the circular patch 8, thus achieving operation in TM mode. 02 In this mode, the annular patch 10 generates a new resonant point within the band, further widening the bandwidth. Simultaneously, due to the electromagnetic hybrid coupling effect between the annular patch 10 and the circular patch 8, a new gain radiation zero is generated in the upper sideband. Through these two gain radiation zeros in the upper and lower sidebands, the proposed result exhibits bandpass filtering characteristics at high frequencies.

[0104] In this invention, the circular patch 8, under the excitation of the differential feed line 6 and the feed extension stub 7, operates in a TM mode with directional radiation characteristics. 11 In this mode, a gain radiation null is generated in the lower sideband of the low-frequency band based on the cross-coupling principle. Simultaneously, the circular patch 8 couples and excites the ring patch 10, resulting in the same operation in TM. 11 The ring patch 10 in the mode. The TM of the ring patch 10 is disturbed through the third metallized short-circuit via 16, the fourth metallized short-circuit via 17, and the fifth metallized short-circuit via 18. 11 The field distribution of the pattern will be the TM of the annular patch 10. 11 The mode frequency is raised into the passband, generating a new resonant point within the band. Simultaneously, based on the electromagnetic mixing principle, a new gain radiation zero is generated in the upper sideband. Through these two gain radiation zeros in the upper and lower sidebands, the proposed result also possesses bandpass filtering characteristics in the low-frequency range.

[0105] Figures 5-8 The simulation results are for this omnidirectional planar filter antenna. Figure 5 It can be seen that the antenna's dual-band -10dB |S 11 The isolation levels are 6.5% for low frequencies (2.83-3.02 GHz) and 30% for high frequencies (5.52-7.44 GHz), achieving greater than 64 dB of isolation across the entire operating frequency band. Figure 6As can be seen, the antenna has a maximum gain of 8.2 dBi in the low-frequency directional band and a maximum gain of 6.3 dBi in the high-frequency omnidirectional band. The gain curve exhibits a bandpass filter response due to the two radiation nulls at the sidebands, and a significant rapid roll-off can be observed outside the operating frequency bands of both bands. Figure 7 This indicates that the antenna has stable and good directional radiation within the low-frequency operating band. Figure 8 This indicates that the antenna has an omnidirectional non-circularity of less than 1.3dB within the operating frequency band and has stable omnidirectional radiation performance.

[0106] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-isolation dual-radiation mode dual-frequency filtered antenna, characterized in that, include: The first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate are stacked sequentially from bottom to top; A pair of differential feed lines disposed on the lower surface of the first dielectric substrate; An intermediate metal surface disposed between the first dielectric substrate and the second dielectric substrate; A pair of power-feeding extension branches are disposed between the second dielectric substrate and the third dielectric substrate; A circular patch disposed between the third dielectric substrate and the fourth dielectric substrate; The upper metal surface and the annular patch are disposed on the upper surface of the fourth dielectric substrate; A feed probe is vertically penetrating the center of each dielectric substrate; wherein, the center of the middle metal surface is provided with a first circular groove to avoid contact with the feed probe, the center of the circular patch is provided with a second circular groove to avoid contact with the feed probe, and the center of the upper metal surface is provided with a feed hole for the feed probe to pass through, and the upper metal surface is electrically connected to the feed probe. A number of first metallized short-circuit vias that vertically penetrate the fourth dielectric substrate to connect the upper metal surface and the circular patch; A plurality of second metallized short-circuit vias are perpendicularly penetrating the first dielectric substrate and the second dielectric substrate to connect the differential feed line and the feed extension stub. A number of third metallized short-circuit vias that vertically penetrate the third and fourth dielectric substrates to connect the power supply extension stubs and the annular patch. A plurality of fourth metallized short-circuit vias and a plurality of fifth metallized short-circuit vias that vertically penetrate the second dielectric substrate, the third dielectric substrate and the fourth dielectric substrate to connect the annular patch and the intermediate metal surface. The filtered antenna supports both high-frequency omnidirectional bands and low-frequency directional bands, wherein: The high-frequency omnidirectional band is implemented as follows: Direct power is supplied via a power supply probe to excite the circular patch to operate in TM mode. 02 model; Direct power is supplied via a power probe, energizing the circular substrate integrated cavity, which is enclosed by the upper metal surface, the circular patch, and several first metallized short-circuit vias, to operate in TM mode. 01 The mode generates a resonant point in the passband of the high-frequency omnidirectional band and a gain radiation zero in the lower sideband of the passband of the high-frequency omnidirectional band; wherein, the frequency positions of the resonant point in the passband of the high-frequency omnidirectional band and the gain radiation zero in the lower sideband of the passband are adjusted by changing the cavity size of the circular substrate integrated cavity. By coupling and exciting the annular patch with a circular patch, a new resonant point is generated in the passband of the high-frequency omnidirectional band. Through the electromagnetic hybrid coupling effect between the annular and circular patches, a new gain radiation zero is generated in the upper sideband of the passband of the high-frequency omnidirectional band. The frequency positions of the new resonant point and the new gain radiation zero are adjusted by changing the size of the annular patch. The low-frequency directional band is implemented as follows: A differential feed structure, consisting of differential feed lines and feed extension stubs, excites a circular patch to operate in TM. 11 The pattern forms the main coupling path for energy from the input end to the radiation space; The differential feed structure excites the annular patch to operate in TM. 11 The mode forms a cross-coupled path for energy from the input to the radiation space. The main coupling path and the cross-coupled path cancel each other out at the frequency that satisfies the equal amplitude and phase inversion condition, generating a gain radiation zero in the lower sideband of the passband in the low-frequency directional band. The frequency position of the gain radiation zero in the lower sideband of the passband in the low-frequency directional band is adjusted by changing the length of the feed extension stub. The TM11 mode field distribution of the annular patch is perturbed by the third and fourth metallized short-circuit vias, causing the TM11 mode frequency of the annular patch to shift from a position below the low-frequency directional band passband to within the low-frequency directional band passband. A resonant point is generated within the low-frequency directional band passband, and a gain radiation null is generated in the upper sideband of the low-frequency directional band passband through the electromagnetic hybrid coupling effect between the annular and circular patches. The frequency position of the gain radiation null in the upper sideband of the low-frequency directional band passband is adjusted by changing the position of the third metallized short-circuit via.

2. The high-isolation dual-radiation mode dual-frequency filter antenna according to claim 1, characterized in that, Establish an xyz rectangular coordinate system with the central axis of the feed probe as the z-axis, then: The pair of differential feed lines are arranged symmetrically about the x-axis; The pair of feed extension stubs are arranged symmetrically about the x-axis; Several second metallized short-circuit vias are symmetrically arranged about the x-axis; Several of the aforementioned third metallized short-circuit vias are symmetrically arranged about the x-axis; Several of the aforementioned fourth metallized short-circuit vias are symmetrically arranged about the x-axis; Several of the fifth metallized short-circuit vias are symmetrically arranged about the y-axis.

3. The high-isolation dual-radiation mode dual-frequency filter antenna according to claim 1, characterized in that, A plurality of the first metallized short-circuit vias are arranged at equal intervals along the circumferential direction; the center of the circular substrate integrated cavity formed by the upper metal surface, the circular patch, and the plurality of the first metallized short-circuit vias is located on the same straight line as the center of the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, the upper metal surface, the circular patch, the annular patch, and the middle metal surface.

4. The high-isolation dual-radiation mode dual-frequency filter antenna according to claim 1, characterized in that, The first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, and the intermediate metal surface have the same length and width dimensions; wherein, the length L and the width W satisfy: 0.68λ c ≤L=W≤0.87λ c , λ c The center frequency of the medium is the wavelength in the low-frequency band.

5. The high-isolation dual-radiation mode dual-frequency filter antenna according to claim 1, characterized in that, The radius R7 of the circular patch satisfies 0.15λ. c ≤R7≤0.20λ c The radius R1 of the upper metal surface satisfies 0.13λ. c ≤R1≤0.17λ c And R7≠R1, where λ c The center frequency of the medium is the wavelength in the low-frequency band.

6. The high-isolation dual-radiation mode dual-frequency filter antenna according to claim 1, characterized in that, The inner radius R2 and outer radius R3 of the annular patch respectively satisfy: 0.16λ c ≤R²≤0.23λ c 0.25λ c ≤R3≤0.33λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

7. A high-isolation dual-radiation mode dual-frequency filter antenna according to claim 2, characterized in that, The distance R8 between the center of several second metallized short-circuit vias and the z-axis satisfies 0.18λ. c ≤R8≤0.22λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

8. A high-isolation dual-radiation mode dual-frequency filter antenna according to claim 2, characterized in that, The distances between the centers of the third metallized short-circuit vias and the z-axis, and the distances between the centers of the fourth metallized short-circuit vias and the z-axis, are all R5, and the distance R5 satisfies 0.24λ. c ≤R5≤0.27λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

9. A high-isolation dual-radiation mode dual-frequency filter antenna according to claim 2, characterized in that, The distance R4 between the center of each of the fifth metallized short-circuit vias and the z-axis satisfies 0.22λ. c ≤R4≤0.24λ c , where λ c The center frequency of the medium is the wavelength in the low-frequency band.

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