A K / Ka band dual-frequency common-aperture antenna unit based on microstrip structure

Abstract

The application provides a K / Ka-band dual-frequency common-aperture antenna unit based on a microstrip structure.The antenna unit is a 7-layer PCB laminated structure, including 6-layer dielectric substrates and 7-layer metal layers, wherein the 7-layer metal layers include, from top to bottom, K-band radiation components located on the 3rd and 4th layers, Ka-band radiation components located on the 1st and 2nd layers, a feed structure and an isolation metal via wall located on the 5th and 6th layers.The metal layers from top to bottom are a Ka-band parasitic circular patch, a Ka-band radiation circular patch, a K-band parasitic annular patch, a K-band radiation annular patch, a K-band feed annular patch, a metal ground plate, a feed network, and an isolation metal via wall and a feed probe existing in the PCB structure.The application simplifies the architecture of a conventional dual-frequency common-aperture antenna, and has the advantages of high isolation, high aperture utilization and compact size, and is an excellent choice for the application of a millimeter wave frequency band dual-frequency system.

Description

Technical Field

[0001] This invention relates to the field of microwave and millimeter-wave antenna technology, and in particular to a K / Ka band dual-band common-aperture antenna element based on a microstrip structure. Specifically, it relates to a compact, highly isolated, and easily integrated K / Ka band dual-band common-aperture antenna element based on a microstrip structure. Background Technology

[0002] With the rapid development of low-Earth orbit satellite communication, 5G / 6G millimeter-wave communication, and modern radar detection technologies, the demand for high communication capacity and high transmission rates is increasing. K-band and Ka-band, with their advantages of wide available bandwidth and strong anti-interference capabilities, have become core frequency bands of great interest in broadband satellite communication and radio frequency microwave systems. To meet the stringent requirements of modern communication equipment, such as airborne, spaceborne, or vehicle-mounted terminals, for lightweight, miniaturized, and highly integrated designs, antenna systems typically need to operate simultaneously in both transmit and receive bands.

[0003] Traditionally, dual-band communication is achieved using two separate antennas, each responsible for a different frequency band. However, this discrete design occupies a significant amount of physical space, resulting in a bulky and heavy antenna system that fails to meet the miniaturization and compactness requirements of modern terminal devices. Therefore, integrating antennas for different frequency bands into a single physical aperture—a technique known as dual-band common-aperture technology—has become a crucial research direction in the antenna field.

[0004] Currently, existing technologies for realizing K / Ka band dual-band common-aperture antennas mainly include waveguide structures and microstrip structures. While common-aperture antennas based on waveguide or horn structures can achieve high radiation efficiency and power capacity, they have high profiles, large size, heavy weight, and are difficult to integrate with planar RF front-end circuits at high density. In contrast, microstrip antennas have significant advantages such as low profile, light weight, and ease of conformal fabrication with RF circuits, and are widely used in phased array antennas. However, existing K / Ka band dual-band common-aperture antenna designs based on microstrip structures still have the following technical defects or shortcomings: severe mutual coupling and isolation problems between frequency bands: The frequency spacing of the K-band and Ka-band is relatively close. When the radiating elements of the two bands are arranged within the same limited physical aperture, strong electromagnetic coupling easily occurs between the high- and low-frequency radiating structures, leading to deterioration of the isolation between the two bands and seriously affecting the system's transmission and reception performance. Complex structure and difficult impedance matching: To suppress interference, existing microstrip common-aperture antennas often require complex multi-layer stacked structures, complex feeding networks (such as interleaved feeding), or additional decoupling structures. This not only increases the difficulty and cost of antenna fabrication and manufacturing, but also introduces additional insertion loss, reducing the overall radiation efficiency of the antenna.

[0005] Therefore, there is an urgent need in this field for a K / Ka band dual-frequency co-aperture microstrip antenna element that has a low profile, simple structure, is easy to fabricate and array, and can achieve both high isolation and good radiation performance, in order to overcome the above-mentioned defects of the existing technology. Summary of the Invention

[0006] This invention addresses the shortcomings of existing K / Ka band co-aperture antennas, such as complex structure, high profile, low isolation between high and low frequency bands, and difficulty in arraying within a limited aperture. It proposes a K / Ka band dual-frequency co-aperture antenna element based on a microstrip structure.

[0007] This invention is achieved through the following technical solution: This invention proposes a K / Ka band dual-band common-aperture antenna unit based on a microstrip structure. The antenna unit is a 7-layer PCB stacked structure, including 6 dielectric substrate layers and 7 metal layers. Specifically, the structure of each layer from top to bottom is as follows: The upper surface of the first dielectric substrate forms the first metal layer, i.e., a Ka-band parasitic circular patch, and the lower surface forms the second metal layer, i.e., a Ka-band radiating circular patch; the upper surface of the second dielectric substrate is the second metal layer, and the lower surface forms the third metal layer, i.e., a K-band parasitic annular patch; the upper surface of the third dielectric substrate is the third metal layer, and the lower surface forms the fourth metal layer, i.e., a K-band radiating annular patch; the upper surface of the fourth dielectric substrate is the fourth metal layer, and the lower surface forms the fifth metal layer, i.e., a K-band feeding annular patch; the upper surface of the fifth dielectric substrate is the fifth metal layer, and the lower surface forms the sixth metal layer, i.e., a metal ground plane; the sixth… The upper surface of the dielectric substrate is the 6th metal layer, and the lower surface is formed by the 7th metal layer, which is the power supply network layer.

[0008] Furthermore, the K-band radiating annular patch and the K-band parasitic annular patch constitute a K-band radiating component, and the center-to-center distance between them is equal to the thickness of the third dielectric substrate. h Kp The K-band radiating component consists of a K-band parasitic annular patch on the third metal layer and a K-band radiating annular patch on the fourth metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the third dielectric substrate; wherein, the inner diameter and outer diameter of the radiating annular patch are respectively... R Kri and R Kro The inner and outer diameters of the parasitic annular patch are respectively R Kpi and R Kpo .

[0009] Furthermore, the Ka-band radiating circular patch and the Ka-band parasitic circular patch constitute a Ka-band radiating component, and the center-to-center distance between them is equal to the thickness of the first dielectric substrate. h KapThe Ka-band radiating component consists of a Ka-band parasitic circular patch on a first metal layer and a Ka-band radiating circular patch on a second metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the first dielectric substrate; wherein, the radius of the parasitic circular patch is... R Kap The radius of the radial circular patch is R Kar .

[0010] Furthermore, the K-band radiating component and the Ka-band radiating component share the same radiating aperture, and their spacing in the z-direction is the same as the spacing between the Ka-band radiating circular patch and the K-band parasitic annular patch in the z-direction, which is also the thickness of the second dielectric substrate. h Kar .

[0011] Furthermore, the antenna unit includes a feeding structure, which includes a K-band feeding structure and a Ka-band feeding structure, and further includes a K-band feeding probe, a Ka-band feeding probe, a K-band power divider phase shifter network, a Ka-band power divider phase shifter network, a K-band filter matching structure, and a Ka-band filter matching structure.

[0012] Furthermore, in the K-band feed structure, the K-band feed probe passes through the 5th and 6th dielectric substrates, connecting the K-band feed ring patch located above the 5th dielectric substrate and the K-band power divider / phase shifter network located below the 6th dielectric substrate. The probe radius is... R f Furthermore, it is separated from the metal ground plane between the 5th and 6th dielectric substrates. The separation method involves creating a groove in the metal ground plane at the center of the probe, with a radius of [missing information]. R cut .

[0013] Furthermore, the K-band fed annular patch feeds the K-band radiating annular patch via electromagnetic coupling, with the spacing in the z-direction equal to the thickness of the fourth dielectric substrate layer. h ou The distance between it and the metal floor is h Kr The K-band power divider phase shifter network and the K-band filter matching structure are connected in parallel on the K-band feed probe.

[0014] Furthermore, in the Ka-band feed structure, the Ka-band feed probe passes through layers 2 to 6 of the dielectric substrate, connecting the Ka-band radiating circular patch located above layer 2 of the dielectric substrate and the Ka-band power divider / phase shifter network located below layer 6 of the dielectric substrate. The probe radius is... R fIt is isolated from the metal ground plane between the 5th and 6th dielectric substrates; the Ka-band power divider phase shifter network and the Ka-band filter matching structure are connected in parallel on the Ka-band feed probe.

[0015] Furthermore, the antenna element also includes an isolation metal via wall, which consists of 12 metal vias centered on the antenna center. R Kri With radius , they are evenly distributed on the circumference at a central angle of 30 degrees, with the radius of each metal via being . R f It connects the metal floor, the K-band radiating circular patch, and the K-band parasitic ring patch.

[0016] Furthermore, when the antenna is in operation, the K-band received signal is coupled to the K-band feed structure through the K-band radiating component, and output after filtering, matching and power divider phase shifting network; the Ka-band transmitted signal is radiated outward through the Ka-band power divider phase shifting network and filtering matching structure, and then through the feed probe to excite the Ka-band radiating component to radiate outward.

[0017] The beneficial effects of this invention are: (1) This invention integrates a K-band receiving microstrip antenna and a Ka-band transmitting antenna and system within the same antenna element-level aperture. In terms of the radiating structure, both bands employ radiating and parasitic patch coupling, thereby expanding the bandwidth of the dual-band antenna. Regarding the feeding structure, slots are made in the radiating structure of the K-band microstrip antenna to introduce the feeding structure of the Ka-band antenna. Simultaneously, the introduction of an insulating metal wall reduces electromagnetic coupling between the two bands and optimizes the radiating structure of the K-band. The final designed K / Ka dual-band common-aperture antenna... S 11 The transmit and receive antennas with a bandwidth of -10 dB cover 17.7 GHz ~ 21.2 GHz and 27.5 GHz ~ 31 GHz, respectively, with relative bandwidths of 18% and 12%, meeting the broadband requirements.

[0018] (2) This invention achieves dual-band orthogonal circular polarization performance of a common-aperture antenna element by designing a power divider phase-shifting network cascaded with an antenna, featuring right-hand circular polarization for Ka-band transmission and left-hand circular polarization for K-band reception. In the feed network layer of the dielectric substrate, a Wilkinson power divider is introduced to achieve equal-amplitude power division, and a quarter-wavelength microstrip line is introduced at one of the output terminals to achieve a 90-degree phase shift. These two components combine to form a power divider phase shifter. The K-band and Ka-band power divider phase shifters together constitute the power divider phase-shifting network of the common-aperture element. Ultimately, the K / Ka dual-band common-aperture antenna achieves excellent performance with a left-hand circular polarization axial ratio of less than 5 dB within the 17.7 GHz ~ 21.2 GHz range and a right-hand circular polarization axial ratio of less than 5 dB within the 27.5 GHz ~ 31 GHz range.

[0019] (3) This invention achieves high isolation between the two frequency bands by connecting a filter stub in parallel at the antenna feed. The filter stub is a folded microstrip line of a specified length, the length of which is determined by the required filtering bandwidth. The filter stub connected in parallel at the K-band antenna feed reduces the signal input to the Ka-band and optimizes the impedance matching effect of the K-band to a certain extent; the filter stub in the Ka-band also reduces the signal input to the K-band and optimizes the impedance matching effect of the Ka-band to a certain extent. Finally, the K / Ka dual-band common-aperture antenna achieves good performance with an isolation greater than 20dB in both the 17.7 GHz ~ 21.2 GHz and 27.5 GHz ~ 31 GHz frequency bands. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a three-dimensional structural diagram of a K / Ka band dual-frequency co-aperture microstrip antenna in an example.

[0022] Figure 2 This is a three-dimensional structural side view of a K / Ka band dual-frequency co-aperture microstrip antenna in an example.

[0023] Figure 3 This is a bottom view of a K / Ka band dual-frequency co-aperture microstrip antenna as an example, which mainly shows the structure of the antenna's feed network layer.

[0024] Figure 4 This is a graph showing the S-parameters of a K / Ka band dual-frequency co-aperture microstrip antenna in an example.

[0025] Figure 5 This is a graph showing the gain and axial ratio of a K / Ka band dual-frequency co-aperture microstrip antenna in an example.

[0026] The markings in the diagram are as follows: 1: Ka-band parasitic circular patch; 2: Ka-band radiating circular patch; 3: K-band parasitic ring patch; 4: K-band radiating ring patch; 5: K-band feed patch; 6: Metal ground plane; 7: Ka-band feed probe; 8: K-band feed probe; 9: Isolating metal via wall structure; 10: K-band feed network; 11: Ka-band feed network. Detailed Implementation

[0027] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention proposes a K / Ka band dual-band common-aperture antenna element based on a microstrip structure. The antenna element is a 7-layer PCB stack-up structure, including 6 dielectric substrate layers and 7 metal layers. The 7 metal layers include, from top to bottom, K-band radiating components located on layers 3 and 4, Ka-band radiating components located on layers 1 and 2, a feed structure located on layers 5 and 6, and an isolation metal via wall. The metal layers, from top to bottom, are a Ka-band parasitic circular patch, a Ka-band radiating circular patch, a K-band parasitic ring patch, a K-band radiating ring patch, a K-band feed ring patch, a metal ground plane, a feed network, and an isolation metal via wall and feed probe present in the PCB structure.

[0029] Specifically, in combination Figures 1-5This invention proposes a K / Ka band dual-band common-aperture antenna element based on a microstrip structure. The antenna element is a 7-layer PCB stack-up structure, including 6 dielectric substrate layers and 7 metal layers. The specific structure of each layer from top to bottom is as follows: The upper surface of the 1st dielectric substrate forms the 1st metal layer, i.e., a Ka-band parasitic circular patch, and the lower surface forms the 2nd metal layer, i.e., a Ka-band radiating circular patch; the upper surface of the 2nd dielectric substrate forms the 2nd metal layer, and the lower surface forms the 3rd metal layer, i.e., a K-band parasitic annular patch; the upper surface of the 3rd dielectric substrate forms the 3rd metal layer, and the lower surface forms the 4th metal layer, i.e., a K-band radiating annular patch; the upper surface of the 4th dielectric substrate forms the 4th metal layer, and the lower surface forms the 5th metal layer, i.e., a K-band feed annular patch; the upper surface of the 5th dielectric substrate forms the 5th metal layer, and the lower surface forms the 6th metal layer, i.e., a metal ground plane; the upper surface of the 6th dielectric substrate forms the 6th metal layer, and the lower surface forms the 7th metal layer, i.e., a feed network layer.

[0030] Furthermore, the K-band radiating annular patch and the K-band parasitic annular patch constitute a K-band radiating component, and the center-to-center distance between them is equal to the thickness of the third dielectric substrate. h Kp The K-band radiating component consists of a K-band parasitic annular patch on the third metal layer and a K-band radiating annular patch on the fourth metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the third dielectric substrate; wherein, the inner diameter and outer diameter of the radiating annular patch are respectively... R Kri and R Kro The inner and outer diameters of the parasitic annular patch are respectively R Kpi and R Kpo Furthermore, h Kp = 0.4 mm, R Kri = 1 mm, R Kro = 2.2 mm, R Kpi = 1 mm, R Kpo = 2.35mm.

[0031] Furthermore, the Ka-band radiating circular patch and the Ka-band parasitic circular patch constitute a Ka-band radiating component, and the center-to-center distance between them is equal to the thickness of the first dielectric substrate. h KapThe Ka-band radiating component consists of a Ka-band parasitic circular patch on a first metal layer and a Ka-band radiating circular patch on a second metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the first dielectric substrate; wherein, the radius of the parasitic circular patch is... R Kap The radius of the radial circular patch is R Kar Furthermore, h Kap = 0.2 mm, R Kap = 1.25 mm, R Kar = 1.1 mm.

[0032] Furthermore, the K-band radiating component and the Ka-band radiating component share the same radiating aperture, and their spacing in the z-direction is the same as the spacing between the Ka-band radiating circular patch and the K-band parasitic annular patch in the z-direction, which is also the thickness of the second dielectric substrate. h Kar Furthermore, h Kar = 0.4 mm.

[0033] Furthermore, the antenna unit includes a feeding structure, which includes a K-band feeding structure and a Ka-band feeding structure, and further includes a K-band feeding probe, a Ka-band feeding probe, a K-band power divider phase shifter network, a Ka-band power divider phase shifter network, a K-band filter matching structure, and a Ka-band filter matching structure.

[0034] Furthermore, in the K-band feed structure, the K-band feed probe passes through the 5th and 6th dielectric substrates, connecting the K-band feed ring patch located above the 5th dielectric substrate and the K-band power divider / phase shifter network located below the 6th dielectric substrate. The probe radius is... R f Furthermore, it is separated from the metal ground plane between the 5th and 6th dielectric substrates. The separation method involves creating a groove in the metal ground plane at the center of the probe, with a radius of [missing information]. R cut Furthermore, the subsequent work, which involves creating circular grooves in the floor to ensure that the power supply probe does not contact the floor, follows the same method.

[0035] Furthermore, the K-band fed annular patch feeds the K-band radiating annular patch via electromagnetic coupling, with the spacing in the z-direction equal to the thickness of the fourth dielectric substrate layer. h ou The distance between it and the metal floor is h KrThe K-band power divider phase-shifting network and the K-band filter matching structure are connected in parallel on the K-band feed probe. Further, R f = 0.1 mm, R cut = 0.2 mm, h ou = 0.128 mm, h Kr = 0.6 mm.

[0036] Furthermore, in the Ka-band feed structure, the Ka-band feed probe passes through layers 2 to 6 of the dielectric substrate, connecting the Ka-band radiating circular patch located above layer 2 of the dielectric substrate and the Ka-band power divider / phase shifter network located below layer 6 of the dielectric substrate. The probe radius is... R f It is isolated from the metal ground plane between the 5th and 6th dielectric substrates; the Ka-band power divider phase shifter network and the Ka-band filter matching structure are connected in parallel on the Ka-band feed probe.

[0037] Furthermore, the antenna element also includes an isolation metal via wall, which consists of 12 metal vias centered on the antenna center. R Kri With radius , they are evenly distributed on the circumference at a central angle of 30 degrees, with the radius of each metal via being . R f It connects the metal floor, the K-band radiating circular patch, and the K-band parasitic ring patch.

[0038] Furthermore, when the antenna is in operation, the K-band received signal is coupled to the K-band feed structure through the K-band radiating component, and output after filtering, matching and power divider phase shifting network; the Ka-band transmitted signal is radiated outward through the Ka-band power divider phase shifting network and filtering matching structure, and then through the feed probe to excite the Ka-band radiating component to radiate outward.

[0039] Example The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 , Figure 2 and Figure 3 As shown, the K / Ka band dual-band common-aperture antenna element based on a microstrip structure of the present invention is a 7-layer PCB stack-up structure, including 6 dielectric substrate layers and 7 metal layers. All dielectric substrates use Rogers RO4350B high-frequency board material with a dielectric constant εr = 3.48 and a loss tangent tanδ = 0.0037; the metal layers use 1 oz thick copper foil. The structure and parameters of each layer from top to bottom are as follows: [Table showing thickness of the first dielectric substrate layer]. hKap =0.2 mm, with a first metal layer (Ka-band parasitic circular patch) formed on its upper surface and a second metal layer (Ka-band radiating circular patch) formed on its lower surface; the thickness of the second dielectric substrate is... h Kar =0.4mm, its upper surface is the second metal layer, and the lower surface forms the third metal layer, namely the K-band parasitic annular patch; the thickness of the third dielectric substrate is... h Kp =0.4 mm, its upper surface is the third metal layer, and the lower surface forms the fourth metal layer, namely the K-band radiation annular patch; the thickness of the fourth dielectric substrate is... h ou =0.128 mm, its upper surface is the fourth metal layer, and the lower surface forms the fifth metal layer, i.e., the K-band feed patch; the thickness of the fifth dielectric substrate is... h Kr =0.6 mm, its upper surface is the 5th metal layer, and the lower surface forms the 6th metal layer, i.e., the metal ground plane; the thickness of the 6th layer dielectric substrate is... h f =0.254 mm, its upper surface is the 6th metal layer, and the lower surface forms the 7th metal layer, namely the power supply network layer.

[0041] The radiation components of this invention include a Ka-band radiation component and a K-band radiation component, both sharing the same physical aperture, with a spacing in the z-direction equal to the thickness of the second dielectric substrate. h Kar =0.4 mm. The Ka-band radiating component consists of a Ka-band parasitic circular patch on the first metal layer and a Ka-band radiating circular patch on the second metal layer arranged coaxially. The operating bandwidth is extended through electromagnetic coupling via the first dielectric substrate. The radius of the radiating circular patch, optimized by simulation, is... R Kar =1.1 mm, radius of parasitic circular patch R Kap =1.25 mm. The K-band radiating component consists of a K-band parasitic annular patch on the third metal layer and a K-band radiating annular patch on the fourth metal layer arranged coaxially. The operating bandwidth is extended through electromagnetic coupling via the third dielectric substrate. The inner diameter of the radiating annular patch is... R Kri =1 mm, outer diameter R Kro =2.2 mm, inner diameter of parasitic annular patch R Kpi =1 mm, outer diameter R Kpo =2.35 mm; the K-band radiating ring patch has a ring structure with a central through hole for passing through the Ka-band feed probe, realizing the common aperture integration of the dual-band feed structure.

[0042] The isolation metal via wall consists of 12 metallized vias, all with a radius of [missing information]. R f =0.1 mm. These 12 vias are centered on the antenna center. R Kri =1 mm as the radius, evenly arranged along the circumference at a central angle of 30°, vertically penetrating through the 2nd to 5th dielectric substrates, while electrically connecting the 3rd metal layer (K-band parasitic annular patch), the 4th metal layer (K-band radiating annular patch), and the 6th metal layer (metal ground plane), to block the surface wave propagation between the K-band and Ka-band radiating structures and reduce electromagnetic coupling between frequency bands.

[0043] The power supply structure is divided into K-band and Ka-band power supply structures, integrating a power divider phase-shifting network and a filter matching structure. The K-band power supply structure includes two K-band power supply probes, a K-band power supply patch, a K-band power divider phase-shifting network, and a K-band filter matching structure. The radii of the two K-band power supply probes are both... R f =0.1 mm, vertically penetrating the 5th and 6th dielectric substrates, with its upper end electrically connected to the K-band feed patch of the 5th metal layer, and its lower end electrically connected to the output terminal of the K-band power divider / phase shifter network of the 7th metal layer; the metal ground plane has a radius of 0.1 mm at the position where the feed probe passes through. R cut A circular isolation groove of 0.2 mm ensures no electrical contact between the feed probe and the metal ground plane; the K-band feed patch and the K-band radiating ring patch are electromagnetically coupled through the fourth dielectric substrate to feed the K-band radiating components; the K-band power divider phase-shifting network adopts a Wilkinson power divider and a quarter-wavelength phase-shifting line cascaded structure. The Wilkinson power divider splits the input signal into two equal paths, one of which passes through a waveguide wavelength corresponding to the K-band center frequency of 19.45 GHz. λ gK A 90° phase shift is achieved using a 4 / 4 microstrip line. The two signals are fed into two orthogonally placed K-band feed probes to excite the K-band radiating component to generate a left-hand circularly polarized wave. The K-band filter matching structure is a folded microstrip line connected in parallel to the input of the K-band power divider phase shifter network. Its length is equal to the waveguide wavelength corresponding to the Ka-band center frequency of 29.25 GHz. λ gKa / 4 exhibits high impedance characteristics in the Ka band, which is used to suppress Ka band signals from entering the K band feed structure, while optimizing the impedance matching of the K band.

[0044] The Ka-band feed structure includes two Ka-band feed probes, a Ka-band power divider / phase shifter network, and a Ka-band filter matching structure. The two Ka-band feed probes vertically penetrate the second to sixth dielectric substrate layers, passing through the central via of the K-band radiating annular patch. Their upper ends are electrically connected to the Ka-band radiating circular patch on the second metal layer, and their lower ends are electrically connected to the output terminal of the Ka-band power divider / phase shifter network on the seventh metal layer. The metal ground plane also has a radius [not specified] at the location where the feed probes pass through. R cut A circular isolation slot of 0.2 mm is used; the Ka-band power divider phase-shifting network structure is the same as the K-band power divider phase-shifting network. The Wilkinson power divider splits the input signal into two paths with equal amplitude, one of which passes through a waveguide with a length equal to the waveguide wavelength corresponding to the Ka-band center frequency of 29.25 GHz. λ gKa A 90° phase shift is achieved using a 4 / 4 microstrip line. The two signals are fed into two orthogonally placed Ka-band feed probes to excite the Ka-band radiating component to generate a right-hand circularly polarized wave. The Ka-band filter matching structure is a folded microstrip line connected in parallel to the input of the Ka-band power divider phase shifter network. Its length is equal to the waveguide wavelength corresponding to the K-band center frequency of 19.45 GHz. λ gK / 4 exhibits high impedance characteristics in the K-band, which is used to suppress K-band signals from interfering with the Ka-band feed structure, while optimizing the impedance matching of the Ka-band.

[0045] When the antenna of this invention is operating, the K-band received signal is coupled to the K-band feed structure through the K-band radiating component, and output after filtering, matching, and power divider / phase shifter network; the Ka-band transmitted signal, after passing through the Ka-band power divider / phase shifter network and filtering and matching structure, is excited by the feed probe to radiate the Ka-band radiating component outward. Figure 4 As shown, in this embodiment, the antenna K-band |S 11 |<-10dB bandwidth covers 17.7 GHz~21.2 GHz, with a relative bandwidth of 18%; Ka band |S 22 |<-10 dB bandwidth covers 27.5 GHz~31 GHz, with a relative bandwidth of 12%; dual-band port isolation |S 21 |<-20 dB. As shown in Figure 5, the left-hand circular polarization axial ratio in the K-band (17.7 GHz to 21.2 GHz) is less than 5 dB, with a peak gain of approximately 7.1 dBi; the right-hand circular polarization axial ratio in the Ka-band (27.5 GHz to 31 GHz) is less than 5 dB, with a peak gain of approximately 5.0 dBi.

[0046] In summary, the K / Ka band dual-band co-aperture microstrip antenna proposed in this invention can achieve left-hand circular polarization reception and right-hand circular polarization transmission in the K and Ka bands respectively, simplifying the architecture of traditional dual-band co-aperture antennas. It also has the advantages of high isolation, high aperture utilization, and compact size, making it an excellent choice for millimeter-wave dual-band system applications.

[0047] The foregoing has provided a detailed description of a K / Ka band dual-frequency common-aperture antenna element based on a microstrip structure proposed in this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A K / Ka band dual-frequency common-aperture antenna element based on a microstrip structure, characterized in that, The antenna unit is a 7-layer PCB stack-up structure, including 6 dielectric substrate layers and 7 metal layers. The specific structure of each layer from top to bottom is as follows: The 1st dielectric substrate has a 1st metal layer (Ka-band parasitic circular patch) formed on its upper surface and a 2nd metal layer (Ka-band radiating circular patch) formed on its lower surface; the 2nd dielectric substrate has a 2nd metal layer on its upper surface and a 3rd metal layer (K-band parasitic annular patch) formed on its lower surface; the 3rd dielectric substrate has a 3rd metal layer on its upper surface and a 4th metal layer (K-band radiating annular patch) formed on its lower surface; the 4th dielectric substrate has a 4th metal layer on its upper surface and a 5th metal layer (K-band feed annular patch) formed on its lower surface; the 5th dielectric substrate has a 5th metal layer on its upper surface and a 6th metal layer (metal ground plane) formed on its lower surface; the 6th dielectric substrate has a 6th metal layer on its upper surface and a 7th metal layer (feed network layer) formed on its lower surface.

2. The antenna element according to claim 1, characterized in that, The K-band radiating annular patch and the K-band parasitic annular patch constitute a K-band radiating component, and the center-to-center distance between them is equal to the thickness of the third dielectric substrate. h Kp The K-band radiating component consists of a K-band parasitic annular patch on the third metal layer and a K-band radiating annular patch on the fourth metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the third dielectric substrate; wherein, the inner diameter and outer diameter of the radiating annular patch are respectively... R Kri and R Kro The inner and outer diameters of the parasitic annular patch are respectively R Kpi and R Kpo .

3. The antenna element according to claim 2, characterized in that, The Ka-band radiating circular patch and the Ka-band parasitic circular patch constitute a Ka-band radiating component, and the center-to-center distance between them is equal to the thickness of the first dielectric substrate. h Kap The Ka-band radiating component consists of a Ka-band parasitic circular patch on a first metal layer and a Ka-band radiating circular patch on a second metal layer arranged coaxially, extending the operating bandwidth through electromagnetic coupling via the first dielectric substrate; wherein, the radius of the parasitic circular patch is... R Kap The radius of the radial circular patch is R Kar .

4. The antenna element according to claim 3, characterized in that, The K-band radiating component and the Ka-band radiating component share the same radiating aperture. Their spacing in the z-direction is the same as the spacing between the Ka-band radiating circular patch and the K-band parasitic annular patch in the z-direction, and also the thickness of the second dielectric substrate. h Kar .

5. The antenna element according to claim 4, characterized in that, The antenna unit includes a feeding structure, which includes a K-band feeding structure and a Ka-band feeding structure, and further includes a K-band feeding probe, a Ka-band feeding probe, a K-band power divider phase shifter network, a Ka-band power divider phase shifter network, a K-band filter matching structure, and a Ka-band filter matching structure.

6. The antenna element according to claim 5, characterized in that, In the K-band feed structure, the K-band feed probe passes through the 5th and 6th dielectric substrates, connecting the K-band feed ring patch located above the 5th dielectric substrate and the K-band power divider / phase shifter network located below the 6th dielectric substrate. The probe radius is... R f Furthermore, it is separated from the metal ground plane between the 5th and 6th dielectric substrates. The separation method involves creating a groove in the metal ground plane at the center of the probe, with a radius of [missing information]. R cut .

7. The antenna element according to claim 6, characterized in that, The K-band fed annular patch feeds the K-band radiating annular patch via electromagnetic coupling, with the spacing in the z-direction equal to the thickness of the fourth dielectric substrate layer. h ou The distance between it and the metal floor is h Kr The K-band power divider phase shifter network and the K-band filter matching structure are connected in parallel on the K-band feed probe.

8. The antenna element according to claim 5, characterized in that, In the Ka-band feed structure, the Ka-band feed probe passes through layers 2 to 6 of the dielectric substrate, connecting the Ka-band radiating circular patch located above layer 2 and the Ka-band power divider / phase shifter network located below layer 6. The probe radius is [missing information]. R f It is isolated from the metal ground plane between the 5th and 6th dielectric substrates; the Ka-band power divider phase shifter network and the Ka-band filter matching structure are connected in parallel on the Ka-band feed probe.

9. The antenna element according to claim 1, characterized in that, The antenna element also includes an isolation metal via wall, which consists of 12 metal vias centered on the antenna center. R Kri With radius , they are evenly distributed on the circumference at a central angle of 30 degrees, with the radius of each metal via being . R f It connects the metal floor, the K-band radiating circular patch, and the K-band parasitic ring patch.

10. The antenna element according to claim 5, characterized in that, When the antenna is working, the K-band received signal is coupled to the K-band feed structure through the K-band radiating component, and output after filtering, matching and power divider phase shifting network; the Ka-band transmitted signal is radiated outward through the Ka-band power divider phase shifting network and filtering matching structure, and then through the feed probe to excite the Ka-band radiating component to radiate outward.

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