X-band miniaturized wideband magneto-electric dipole filtering antenna

Abstract

The application relates to the technical field of communication antennas, in particular to an X-waveband miniaturized wideband magnetoelectric dipole filter antenna. The antenna comprises a magnetoelectric dipole radiation structure composed of an electric dipole patch and two rows of metal short-circuit through holes. The patch is arranged on the upper surface of an upper layer dielectric substrate, the short-circuit through holes are connected to the patch at the upper end and penetrate through the two layer dielectric substrates to be connected to a metal ground plate at the lower end. A square closed loop metal ring is arranged on the upper surface of the upper layer dielectric substrate, and is connected to the outer periphery of the patch and is in contact with the patch. A Π-shaped feeding structure is located between the two rows of short-circuit through holes, and comprises a horizontal metal patch and two metal through holes with different lengths. The horizontal patch is coplanar and adjacent to the patch. The first metal through hole is connected to the horizontal patch at the upper end and penetrates through the two layer substrates to be connected to a feeding probe at the lower end. The second metal through hole is connected to the horizontal patch at the upper end, penetrates through the upper layer substrate at the lower end, and the lower end is suspended. The antenna has the performances of wide impedance bandwidth, high out-of-band suppression and wide beam coverage, and has a compact structure and high integration degree.

Description

Technical Field

[0001] This application relates to the field of communication antenna technology, specifically to an X-band miniaturized broadband magnetoelectric dipole filter antenna. Background Technology

[0002] With the continuous development of modern wireless communication, microwave sensing, and radar detection technologies, the X-band (8-12 GHz), with its moderate transmission loss, high resolution, and excellent rain attenuation resistance, has become the core operating frequency band for airborne radar, satellite communication, high-precision guidance, and radio frequency detection systems. Currently, radio frequency front-ends are showing a trend towards integration and multi-functionality. Broadband antennas, as the core passive components of the radio frequency front-end, can achieve wideband electromagnetic signal transmission and reception based on a single radiating structure. This simplifies the complexity of terminal antenna array deployment, reduces electromagnetic coupling effects between radio frequency devices, and improves system channel capacity and operational stability, meeting the engineering application requirements of integrated multi-functional radio frequency systems.

[0003] However, the wide impedance bandwidth of X-band broadband antennas makes them susceptible to receiving harmonic components and spurious electromagnetic signals from adjacent out-of-band frequencies. These interference signals can couple to the RF receiving link through the antenna's radiating port. High-power electromagnetic signals from adjacent frequencies can cause adjacent-channel interference to the X-band operating passband signal, raising the system noise floor, reducing the output signal-to-noise ratio, and consequently causing communication data errors, radar target deviation, and signal distortion. This leads to a decrease in the reliability and environmental adaptability of RF detection and communication systems. Therefore, high-performance X-band RF systems place high demands on the out-of-band suppression performance and electromagnetic interference immunity of broadband antennas.

[0004] To suppress out-of-band spurious interference and optimize the purity of RF passband signals, existing RF front-end architectures often employ a separate cascaded design of a broadband bandpass filter and a broadband antenna, utilizing the frequency selectivity of the filter to suppress out-of-band interference signals. In the X-band, this separate cascaded structure introduces additional transmission insertion loss, causing a decrease in antenna radiation efficiency. Simultaneously, independent filtering components increase the overall physical size and structural weight of the RF front-end, hindering the engineering implementation of miniaturized and lightweight integrated RF systems. This results in technical problems such as high system insertion loss, low structural integration, and redundant spatial layout.

[0005] Therefore, how to integrate the filtering function and the radiation structure while ensuring the broadband radiation performance of the antenna, and at the same time meet the comprehensive requirements of miniaturization, low loss and high out-of-band suppression of the X-band RF front end, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In view of this, this application proposes a miniaturized broadband magnetoelectric dipole filter antenna for the X-band.

[0007] Specifically, this application is implemented through the following technical solution: A miniaturized broadband magnetoelectric dipole filter antenna for the X-band includes: A magnetoelectric dipole radiation structure includes an electric dipole patch and two rows of metal short-circuit vias; the electric dipole patch is disposed on the upper surface of an upper dielectric substrate; the metal short-circuit vias are respectively connected to the electric dipole patch at their upper ends and penetrate through the upper and lower dielectric substrates at their lower ends to connect to a metal ground plane; A square closed-loop metal ring is disposed on the upper surface of the upper dielectric substrate and externally connected to the outer periphery of the electric dipole patch, and the square closed-loop metal ring is connected to the electric dipole patch. A Π-shaped power supply structure is disposed between the two rows of metal short-circuit vias, including a horizontal metal patch and two metal vias of different lengths; the horizontal metal patch and the electric dipole patch are coplanarly adjacent, and the upper ends of the two metal vias are connected to the horizontal metal patch; wherein, the first metal via penetrates downward through the upper dielectric substrate and the lower dielectric substrate and connects to the power supply probe, and the metal ground plate has a circular opening corresponding to the power supply probe; the second metal via penetrates downward only through the upper dielectric substrate and its lower end is suspended.

[0008] The embodiments of this application have at least the following technical effects: First, the magnetoelectric dipole radiation structure relies on a composite configuration of electric and magnetic dipoles, possessing basic radiation performance with wide bandwidth, symmetrical radiation pattern, low back lobe radiation level, and excellent cross-polarization characteristics. At the same time, by utilizing its own quarter-wavelength open-circuit reflection characteristics, it forms a low-frequency radiation null point in the lower stopband, achieving basic passband frequency selection and out-of-band interference suppression.

[0009] Second, the square closed-loop metal ring is connected to the outer periphery of the electric dipole patch, effectively extending the current transmission path on the surface of the radiating element. This reduces the physical size of the electric dipole patch without sacrificing radiation performance, thus achieving antenna miniaturization. At the same time, the high-frequency out-of-band excitation generates an anti-phase current that is opposite to the current on the surface of the electric dipole patch. The two cancel each other out in far-field radiation, thereby forming a stable radiation null point in the upper stopband and significantly improving the out-of-band suppression level of the upper stopband.

[0010] Third, the Π-shaped feeding structure introduces a new resonant mode at high frequencies in the operating passband through an equivalent open-circuit stub formed by two metal through holes of different lengths and a horizontal metal patch, effectively widening the antenna impedance bandwidth. At the same time, its band-stop resonant mode generates a radiation null point in the upper stopband, further optimizing the frequency selectivity and out-of-band suppression capability of the antenna in the high-frequency band.

[0011] Fourth, through the multi-structure collaborative design of the magnetoelectric dipole radiation structure, the square closed-loop metal ring and the Π-shaped feed structure, a multi-frequency controllable radiation null can be constructed without the need for additional filter devices. This enables the antenna to simultaneously possess comprehensive performance of wide impedance bandwidth, high out-of-band suppression and compact structure, effectively reducing the overall insertion loss of the RF system and reducing structural size and layout redundancy. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Some specific embodiments of this application will be described in detail below with reference to the drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings indicate the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is an exploded schematic diagram of the overall structure of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 2 This is a front view of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 3 This is a side view of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 4 This is a top view of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 5 This is a top view of the upper dielectric substrate shown in an exemplary embodiment of this application; Figure 6 This is a top view of the lower dielectric substrate shown in an exemplary embodiment of this application; Figure 7 This is a top view of a metal floor shown in an exemplary embodiment of this application; Figure 8 The reflection coefficient shown in an exemplary embodiment of this application | S 11 |Simulation graph of the curve; Figure 9 This is a simulation diagram of the antenna gain curve shown in an exemplary embodiment of this application; Figure 10 is an antenna radiation pattern illustrating an exemplary embodiment of this application.

[0013] Among them, 1. Metal patch layer; 1-1. Electric dipole patch; 1-2. Horizontal metal patch; 2. Upper dielectric substrate; 2-1. Metal short-circuit via; 2-2. First metal via; 2-3. Second metal via; 3. Lower dielectric substrate; 4. Metal ground plane; 4-1. Power supply probe; 5. Square closed-loop metal ring. Detailed Implementation

[0014] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0015] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0016] As mentioned earlier, the existing split-cascade architecture suffers from high insertion loss, structural redundancy, and low integration, making it difficult to meet the comprehensive requirements of X-band RF front-ends for miniaturization, low loss, and high out-of-band rejection.

[0017] Based on this, this application proposes a miniaturized broadband magnetoelectric dipole filter antenna for the X-band. By integrating the radiating structure and the filtering structure, the antenna size is reduced while achieving synergistic optimization of wide impedance bandwidth and high out-of-band suppression.

[0018] The antenna comprises a magnetoelectric dipole radiating structure, a square closed-loop metal ring, and a Π-shaped feed structure. The magnetoelectric dipole radiating structure consists of an electric dipole patch and two rows of metal short-circuit vias, providing basic radiation and generating low-frequency radiation nulls. The square closed-loop metal ring is externally connected to the outer periphery of the electric dipole patch, extending the surface current path to achieve antenna miniaturization and simultaneously exciting a reverse-phase current in the upper stopband to form a radiation null. The Π-shaped feed structure is positioned between the two rows of metal short-circuit vias, coupling and feeding the magnetoelectric dipole radiating structure to extend the impedance bandwidth and construct additional radiation nulls in the upper stopband. The magnetoelectric dipole radiating structure, the square closed-loop metal ring, and the Π-shaped feed structure work together to form a multi-frequency controllable radiation null.

[0019] The embodiments described in this specification will now be described in detail.

[0020] Figure 1 This is an exploded view of the overall structure of an X-band miniaturized broadband magnetoelectric dipole filter antenna, as illustrated in an exemplary embodiment of this application. Figure 1 As shown, this application proposes a miniaturized broadband magnetoelectric dipole filter antenna for the X-band, comprising: The magnetoelectric dipole radiation structure includes an electric dipole patch 1-1 and two rows of metal short-circuit vias 2-1; the electric dipole patch 1-1 is disposed on the upper surface of the upper dielectric substrate 2; the metal short-circuit vias 2-1 are connected to the electric dipole patch 1-1 at their upper ends and pass through the upper dielectric substrate 2 and the lower dielectric substrate 3 at their lower ends and then connected to the metal ground plane 4. A square closed-loop metal ring 5 is disposed on the upper surface of the upper dielectric substrate 2 and externally connected to the outer periphery of the electric dipole patch 1-1. The square closed-loop metal ring 5 is connected to the electric dipole patch 1-1. A Π-shaped power supply structure is disposed between two rows of metal short-circuit vias 2-1, including a horizontal metal patch 1-2 and two metal vias of different lengths (first metal via 2-2 and second metal via 2-3); the horizontal metal patch 1-2 and the electric dipole patch 1-1 are coplanar and adjacent, and the upper ends of the two metal vias are connected to the horizontal metal patch 1-2; wherein, the first metal via 2-2 penetrates downward through the upper dielectric substrate 2 and the lower dielectric substrate 3 and connects to the power supply probe 4-1, and the metal ground plate 4 is provided with a circular opening corresponding to the power supply probe 4-1; the second metal via 2-3 penetrates downward only through the upper dielectric substrate 2 and its lower end is suspended.

[0021] The antenna proposed in this embodiment can achieve integrated antenna radiation characteristics and frequency selective filtering performance, avoiding the inherent technical defects of traditional split cascade architecture. While ensuring antenna radiation performance, it also has signal filtering function, which can effectively reduce the overall insertion loss of the radio frequency system and reduce the structural size. It is an effective technical solution to meet the design requirements of miniaturization, low loss and high anti-interference of microwave radio frequency systems, and can meet the use requirements of demanding application scenarios such as X-band high-precision detection and lightweight airborne radio frequency.

[0022] By integrating the radiation structure and the filtering structure, the antenna radiation performance is guaranteed while also providing signal filtering function. This effectively reduces the overall insertion loss of the RF system, reduces the structural size, and meets the design requirements of miniaturization, low loss, and high anti-interference of microwave RF systems.

[0023] The antenna body adopts a magnetoelectric dipole radiation structure with a composite configuration of electric and magnetic dipoles. This radiation structure possesses inherent electromagnetic radiation characteristics such as wide operating bandwidth, symmetrical radiation pattern, low back lobe radiation level, and excellent cross-polarization characteristics. Furthermore, it can form a low-frequency radiation null based on its own structure, achieving basic passband frequency selection and out-of-band interference suppression performance. On this basis, a square closed-loop metal ring 5 is externally connected to the electric dipole patch 1-1. This structure effectively extends the current transmission path on the surface of the radiating element, reducing the antenna's physical size without sacrificing electromagnetic performance, thus achieving miniaturization. Simultaneously, the square closed-loop metal ring 5 can generate an anti-phase current through high-frequency out-of-band excitation, achieving far-field radiation destructive, thereby forming a stable radiation null in the upper stopband and significantly improving the out-of-band suppression level in the upper stopband.

[0024] In addition, a Π-shaped feeding structure is used to couple the magnetoelectric dipole radiating element. This feeding structure can introduce a new resonant point at the high frequency of the operating passband, effectively widening the antenna impedance bandwidth. At the same time, it can build an additional radiation null at the target frequency point in the upper stopband, further optimizing the frequency selectivity and out-of-band suppression capability of the antenna in the high-frequency band.

[0025] This application utilizes a multi-structure collaborative design of a magnetoelectric dipole radiation structure, a square closed-loop metal ring, and a Π-shaped feed structure to construct a multi-frequency controllable radiation null without the need for additional filtering devices. This enables the antenna to simultaneously possess comprehensive performance characteristics such as wide impedance bandwidth, high out-of-band suppression, and wide beam coverage. The overall structure is compact, highly integrated, and simple in configuration, effectively solving the technical problems of weak out-of-band anti-interference capability, high insertion loss of the split filter architecture, and overall structural redundancy in traditional X-band broadband antennas.

[0026] Next, combine Figure 2-7 The content of this application provides a detailed description of the antenna structure.

[0027] Figure 2 This is a front view of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 3 This is a side view of an X-band miniaturized broadband magnetoelectric dipole filter antenna illustrated in an exemplary embodiment of this application. Figure 2-3 As shown, in some embodiments, each row of metal short-circuit vias 2-1 includes a plurality of metal vias arranged at equal intervals, and the two rows of metal short-circuit vias 2-1 are symmetrically distributed about two vertical axes of symmetry.

[0028] For example, each row of metal short-circuit vias 2-1 is provided with three metal vias at equal intervals, and the two rows of metal short-circuit vias 2-1 are symmetrically distributed about the X-axis and Y-axis, respectively.

[0029] The overall thickness of the antenna is H1+H2. The length of the metal short-circuit via 2-1 is configured to be equal to the overall thickness of the antenna, H1+H2, so that the upper end of the metal short-circuit via 2-1 is reliably connected to the electric dipole patch 1-1 and the lower end is reliably connected to the metal ground plane 4. Here, H1 is the sum of the thickness of the metal patch layer 1 and the upper dielectric substrate 2, and H2 is the sum of the thickness of the lower dielectric substrate 3 and the metal ground plane 4.

[0030] In this embodiment, two rows of metal short-circuit vias 2-1 and electric dipole patches 1-1 together constitute a magnetoelectric dipole radiation unit: the metal short-circuit vias 2-1 are equivalent to magnetic dipoles, and the electric dipole patches 1-1 are equivalent to electric dipoles, forming a complementary radiation structure. Specifically, the equally spaced metal short-circuit vias 2-1 form a balanced magnetic current loop between the electric dipole patches 1-1 and the metal ground plane 4, and the biaxial symmetrical distribution of the two rows of metal short-circuit vias 2-1 about the X and Y axes ensures the spatial symmetry of the magnetic current distribution, thereby giving the antenna inherent electromagnetic radiation characteristics such as wide impedance bandwidth, symmetrical radiation pattern, low back lobe radiation level, and excellent cross-polarization characteristics.

[0031] Furthermore, since the lower end of the metal short-circuit via 2-1 is connected to the metal ground plate 4 and the upper end is connected to the electric dipole patch 1-1, its overall length H1+H2 corresponds to the effective height of the magnetic dipole. This allows the magnetoelectric dipole radiation structure to form a quarter-wavelength open-circuit reflection characteristic based on its own structure, generating a radiation null point at low frequencies, and achieving basic passband frequency selection and out-of-band interference suppression performance.

[0032] In some embodiments, the antenna forms three radiation nulls through multi-structure collaboration, including: a lower stopband radiation null formed by the quarter-wavelength open-circuit reflection characteristic of the magnetoelectric dipole radiation structure, a first upper stopband radiation null formed by the band-stop resonance effect of the Π-shaped feed structure, and a second upper stopband radiation null formed by the far-field cancellation effect of the anti-phase current of the square closed-loop metal ring 5.

[0033] In this embodiment, the magnetoelectric dipole radiation structure relies on the quarter-wavelength open-circuit structure formed by the electric dipole patch 1-1 and two rows of metal short-circuit vias 2-1 to form total reflection at a specific low-frequency point, so that the input energy cannot be effectively radiated, thereby generating a lower stopband radiation zero point in the lower stopband and realizing basic passband low-end frequency selection.

[0034] The Π-shaped feed structure generates a first radiation null in the upper stopband due to its own band-stop resonant mode. The Π-shaped feed structure includes a horizontal metal patch 1-2 and two metal vias of different lengths. The first metal via 2-2 penetrates both dielectric substrates (upper dielectric substrate 2 and lower dielectric substrate 3) and connects to the feed probe 4-1. The second metal via 2-3 penetrates only the upper dielectric substrate 2 and is suspended at its lower end, making the horizontal metal patch 1-2 and the two metal vias an equivalent open-circuit stub. At the target frequency in the upper stopband, this Π-shaped structure exhibits band-stop resonant characteristics, generating a current null in its coupling region. This prevents the signal from being effectively coupled to the magnetoelectric dipole radiator, thus forming a first radiation null in the upper stopband near the high end of the passband. Simultaneously, this Π-shaped feed structure introduces a new resonant mode at high frequencies in the operating passband, effectively widening the antenna's impedance bandwidth.

[0035] For the second radiation null point in the upper stopband, the square closed-loop metal ring 5 is connected to the outer periphery of the electric dipole patch 1-1. On the one hand, it extends the effective transmission path of the surface current of the radiating structure, thereby reducing the physical size of the electric dipole patch 1-1 and realizing antenna miniaturization. On the other hand, outside the high-frequency band, the square closed-loop metal ring 5 excites an anti-phase current that is opposite to the surface current of the electric dipole patch 1-1. The two cancel each other out in far-field radiation, producing a radiation cancellation effect, thus forming a stable second radiation null point in the upper stopband, which significantly enhances the out-of-band suppression level of the antenna's upper stopband.

[0036] By coordinating the multi-structure control of three radiation null points, the antenna can achieve integrated design with wide impedance bandwidth, high out-of-band suppression and compact structure without the need for additional filtering devices.

[0037] In some embodiments, the thickness of the upper dielectric substrate 2 is 4.7 mm, the thickness of the lower dielectric substrate 3 is 0.3 mm, and both dielectric substrates are made of Rogers RT5880 material.

[0038] In this embodiment, the Rogers RT5880 has a dielectric constant of 2.2 and a tangent loss of 0.0009. Using a microwave dielectric substrate with a low dielectric constant and low loss tangent helps reduce the confinement effect of electromagnetic energy within the dielectric, decreases the quality factor, and thus effectively extends the antenna impedance bandwidth. Simultaneously, the extremely low dielectric loss suppresses the radiation efficiency attenuation caused by ohmic loss, ensuring gain stability during X-band broadband operation.

[0039] Furthermore, the upper dielectric substrate 2, with a relatively large thickness of 4.7 mm, provides ample vertical height space for the magnetoelectric dipole radiation structure, allowing the metal short-circuit via 2-1 to have sufficient electrical length to form effective magnetic dipole radiation. Simultaneously, this thickness differs from the 0.3 mm thickness of the lower dielectric substrate 3, resulting in different penetration depths for the first metal via 2-2 and the second metal via 2-3 in the Π-shaped feed structure. This constructs the equivalent open-circuit stub required for band-stop resonance, ensuring that the Π-shaped feed structure can introduce new resonant modes at high frequencies in the operating passband to expand the bandwidth, while simultaneously constructing a radiation null in the upper stopband. The lower dielectric substrate 3, with a smaller thickness of 0.3 mm, can compress the overall antenna profile height while ensuring structural support strength, reducing the influence of parasitic parameters in the feed path, and creating a compact transition structure between the metal ground plane 4 and the feed probe 4-1. Using the same material for both dielectric substrates can avoid electromagnetic reflection and impedance discontinuity caused by interlayer dielectric constant mismatch, simplify the lamination process of multilayer substrates, and improve the consistency of antenna electrical performance and structural reliability.

[0040] The coordinated configuration of the dielectric substrate parameters in this application enables the antenna to achieve a wide impedance bandwidth of 8.00GHz-12.06GHz while maintaining a compact planar size, thus meeting the comprehensive requirements of X-band RF front-end for broadband, miniaturization and low loss.

[0041] Figure 4 This is a top view of an X-band miniaturized broadband magnetoelectric dipole filter antenna shown in an exemplary embodiment of this application; Figure 5 This is a top view of the upper dielectric substrate shown in an exemplary embodiment of this application; Figure 6 This is a top view of the lower dielectric substrate shown in an exemplary embodiment of this application; Figure 7 This is a top view of a metal floor shown in an exemplary embodiment of this application. Figure 4-7 As shown, in some embodiments, the main body of the electric dipole patch 1-1 has a length of L1=3.2mm and a width of w1=5.6mm. The distance between the main bodies of the two electric dipole patches 1-1 is S=3.2mm. The ends of the electric dipole patches 1-1 that are close to each other are symmetrically provided with protrusions, the length of the protrusions is g1=0.5mm and the width is g2=1mm. The two electric dipole patches 1-1 are symmetrically arranged on the upper surface of the upper dielectric substrate 2 about two perpendicular X-axis and Y-axis. The length of the horizontal metal patch 1-2 is Ta = 2.6mm, and the width is Tb = 0.7mm.

[0042] In this embodiment, the diameter of the metal short-circuit via 2-1 is Lr1=0.5mm; the radii of the first metal via 2-2 and the second metal via 2-3 are also Lr1=0.5mm; and the diameter Lr2 of the power supply probe 4-1 is greater than Lr1.

[0043] The outer contour of the square closed-loop metal ring 5 has a length of L3 and a width of w3. The width of the arm along the X-axis is w4, and the width of the arm along the Y-axis is w2.

[0044] The synergistic effect of various dimensional parameters: The aspect ratio (L1×w1) of the electric dipole patch 1-1 and the dimensions (Ta×Tb) of the horizontal metal patch 1-2, after being configured with coupling gaps, can achieve good impedance matching and broadband radiation within the working passband; The symmetrical arrangement of the metal short-circuit vias 2-1 at equal intervals and the selection of a diameter of Lr1=0.5mm ensures the uniformity of magnetic dipole radiation and avoids excessive occupation of substrate space by excessively large vias; The length difference between the first metal via 2-2 and the second metal via 2-3 (determined by the thickness difference between the upper dielectric substrate 2 and the lower dielectric substrate 3) causes the Π-shaped feeding structure to form an equivalent open-circuit stub. The dimensions (Ta×Tb) of the horizontal metal patch 1-2 and the via length synergistically determine the frequency position of the band-stop resonant mode, thereby generating the first radiation zero point in the upper stopband and expanding the impedance bandwidth. The magnetoelectric dipole radiation structure itself relies on the quarter-wavelength open-circuit structure formed by the electric dipole patch 1-1 and the metal short-circuit via 2-1 to form a lower stopband radiation zero at low frequencies.

[0045] In some embodiments, the square closed-loop metal ring 5 is connected to the electric dipole patch 1-1, and each side of the square closed-loop metal ring 5 is connected to the corresponding outer edge of the electric dipole patch 1-1.

[0046] In this embodiment, the square closed-loop metal ring 5 is located around the electric dipole patch 1-1, and is coplanar and adjacent to the electric dipole patch 1-1. The square closed-loop metal ring 5 is directly connected to the electric dipole patch 1-1 to form an integrated radiating structure, allowing the current on the surface of the electric dipole patch 1-1 to smoothly transition to the square closed-loop metal ring 5, effectively extending the transmission path of the current on the surface of the radiating element. Therefore, while maintaining the resonant frequency, the physical size of the electric dipole patch 1-1 can be reduced, thereby achieving miniaturization of the overall antenna structure.

[0047] The square closed-loop metal ring of this application simultaneously serves two functions: miniaturization loading and upper stopband filtering. On the one hand, it acts as a current path extension structure to compress the antenna size; on the other hand, it acts as a parasitic resonant structure to introduce anti-phase current to achieve out-of-band radiation suppression, without the need for additional independent filtering devices.

[0048] In some embodiments, the planar dimensions of the antenna are 0.38λ0 × 0.38λ0, where λ0 is the free space wavelength corresponding to the center frequency within the antenna band.

[0049] For example, the outer contour length L3 of the square closed-loop metal ring 5 is 9.6 mm, and the width w3 is 9.6 mm; This physical dimension corresponds to an electrical dimension of approximately 0.38λ0 × 0.38λ0 at the center frequency of the X-band. This electrical dimension significantly reduces the physical space occupied by the antenna, enabling miniaturization of the structure. The overall planar dimensions of the antenna are still constrained to within 9.6mm × 9.6mm, meeting the engineering requirements of the X-band RF front-end for a compact layout.

[0050] The width of the arm of the square closed-loop metal ring 5 along the X-axis is w4=0.45mm, and the width of the arm along the Y-axis is w2=0.5mm.

[0051] The arm width parameter is matched with the aspect ratio of the electric dipole patch 1-1, making the current distribution at the junction of the square closed-loop metal ring 5 and the electric dipole patch 1-1 more balanced. This avoids the increase in parasitic capacitance due to excessive arm width or the increase in conductor loss due to excessive arm width. At the same time, the arm width parameter, together with the outer contour size (L3×w3), determines the equivalent electrical length and resonant characteristics of the square closed-loop metal ring 5. This allows it to excite an antiphase current in the high-frequency band that is opposite to the current direction on the surface of the electric dipole patch 1-1. Through far-field radiation cancellation, a stable radiation zero point is formed, thereby producing a significant out-of-band suppression effect in the upper stopband.

[0052] Finally, the performance of the X-band miniaturized broadband magnetoelectric dipole filter antenna proposed in this application was experimentally verified in the embodiments of this application.

[0053] Figure 8 The reflection coefficient shown in an exemplary embodiment of this application | S 11 |Simulation graph of the curve. (Example) Figure 8 As shown, the -10dB impedance bandwidth of the antenna structure in this application is 8.00GHz—12.06GHz, and the relative bandwidth is 40.5%.

[0054] Figure 9 This is a simulation diagram of the antenna gain curve shown in an exemplary embodiment of this application. Figure 9 As shown, the antenna of this application has a minimum gain of 5.7 dBi and a maximum gain of 7.1 dBi. The suppression level from the highest in-band gain to the upper stopband radiation null is greater than 25 dB, and the suppression level to the lower stopband radiation null is greater than 30 dB.

[0055] Figure 10 is an exemplary embodiment of the antenna radiation pattern of this application; wherein, Figure 10(A) is the radiation pattern at 8.2 GHz, Figure 10(B) is the radiation pattern at 10 GHz, and Figure 10(C) is the radiation pattern at 11.6 GHz. As shown in Figure 10, the antenna of this application, based on a miniaturized broadband filtered magnetoelectric dipole antenna in the X-band, has a good gain pattern at the operating frequency.

[0056] Based on the above embodiments of this application, the X-band miniaturized broadband magnetoelectric dipole filter antenna of this application has at least the following advantages: First, broadband operating characteristics. This application employs a Π-shaped feed structure to introduce a high-frequency resonant mode, and combines this with the shape change of the four inner corners of the electric dipole patch to introduce capacitive coupling effect to optimize impedance matching, effectively widening the antenna's operating bandwidth. The antenna's -10 dB impedance bandwidth is 8.00-12.06 GHz, with a relative bandwidth of 40.5%, which can fully cover the X-band operating frequency band. It exhibits stable in-band gain and radiation characteristics, meeting the operational requirements of broadband RF systems such as X-band radar and satellite communications.

[0057] Second, miniaturization and high integration. This application adopts an integrated structure for radiation filtering, eliminating the redundant design of traditional separate filtering circuits. By loading a square metal ring on the outside of the electric dipole patch, the effective path of surface current is extended, effectively reducing the antenna size without sacrificing electromagnetic performance. The antenna planar dimensions are only 9.6mm × 9.6mm (0.38λ0 × 0.38λ0). This application has a compact structure, simple configuration, and convenient processing and assembly, which can meet the integrated application requirements of lightweight and compact X-band RF front-ends.

[0058] Third, high selective filtering performance. This application achieves high selective filtering response by forming three effective radiation nulls through multi-structure synergistic control, with frequencies of 6.4 GHz, 14 GHz, and 18.8 GHz. The low-frequency radiation null (6.4 GHz) is formed by utilizing the inherent quarter-wavelength open-circuit reflection characteristic of the magnetoelectric dipole; the mid-to-high frequency radiation null (14 GHz) is constructed based on the band-stop resonance effect of the Π-shaped feed structure; and the high-frequency radiation null (18.8 GHz) is formed by leveraging the far-field destructive effect of the high-frequency anti-phase current of the directional metal ring. The synergistic effect of these multiple nulls gives the antenna excellent out-of-band attenuation characteristics, effectively improving out-of-band suppression capability and system electromagnetic compatibility, overcoming the shortcomings of traditional broadband antennas such as poor frequency selectivity and weak anti-interference capability.

[0059] Fourth, the principle of generating a filtering null using a square ring in this application differs from that of existing open-loop filtering null structures. The principle of loading an open-loop next to a magnetoelectric dipole antenna is that the current generated by the open-loop is in the opposite direction to the current in the electric dipole, canceling each other out and creating a radiation null. The principle of the square ring in this application is that the current directions on the electric dipole and the square ring are symmetrically opposite. Furthermore, the square ring and antenna are integrated into a single design, which also has the advantage of miniaturizing the antenna.

[0060] The above provides a detailed description of the implementation of this application. To obtain miniaturized broadband filtered magnetoelectric dipole antennas with different frequency bands or different radiation null points, different parameters can be adjusted according to the specific situation, such as modifying the size of the electric dipole patch or modifying the length of the square ring.

[0061] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A miniaturized broadband magnetoelectric dipole filter antenna for the X-band, characterized in that, include: The magnetoelectric dipole radiation structure includes an electric dipole patch (1-1) and two rows of metal short-circuit vias (2-1); the electric dipole patch (1-1) is disposed on the upper surface of the upper dielectric substrate (2); the metal short-circuit vias (2-1) are respectively connected to the electric dipole patch (1-1) at their upper ends and pass through the upper dielectric substrate (2) and the lower dielectric substrate (3) at their lower ends and are connected to the metal ground plane (4); A square closed-loop metal ring (5) is disposed on the upper surface of the upper dielectric substrate (2) and externally connected to the outer periphery of the electric dipole patch (1-1). The square closed-loop metal ring (5) is connected to the electric dipole patch (1-1). A Π-shaped power supply structure is disposed between the two rows of metal short-circuit vias (2-1), including a horizontal metal patch (1-2) and two metal vias (2-2, 2-3) of different lengths; the horizontal metal patch (1-2) and the electric dipole patch (1-1) are coplanarly adjacent, and the upper ends of the two metal vias (2-2, 2-3) are connected to the horizontal metal patch (1-2); wherein, the first metal via (2-2) penetrates downward through the upper dielectric substrate (2) and the lower dielectric substrate (3) and is connected to the power supply probe (4-1), and the metal ground plate (4) is provided with a circular opening corresponding to the power supply probe (4-1); the second metal via (2-3) penetrates downward only through the upper dielectric substrate (2) and its lower end is suspended.

2. The antenna according to claim 1, characterized in that, Each row of the metal short-circuit vias (2-1) includes multiple metal vias arranged at equal intervals, and the two rows of metal short-circuit vias (2-1) are symmetrically distributed about two vertical axes of symmetry.

3. The antenna according to claim 1, characterized in that, The antenna forms three radiation nulls through multi-structure collaboration, including: a lower stopband radiation null formed by the quarter-wavelength open-circuit reflection characteristic of the magnetoelectric dipole radiation structure, a first upper stopband radiation null formed by the band-stop resonance effect of the Π-shaped feed structure, and a second upper stopband radiation null formed by the far-field cancellation effect of the anti-phase current of the square closed-loop metal ring.

4. The antenna according to claim 1, characterized in that, The upper dielectric substrate (2) has a thickness of 4.7 mm, the lower dielectric substrate (3) has a thickness of 0.3 mm, and both dielectric substrates are made of Rogers RT5880.

5. The antenna according to claim 1, characterized in that, The electric dipole patch (1-1) has a length of 3.2 mm and a width of 5.6 mm.

6. The antenna according to claim 1, characterized in that, The horizontal metal patch (1-2) has a length of 2.6 mm and a width of 0.7 mm.

7. The antenna according to claim 1, characterized in that, The square closed-loop metal ring (5) is connected to the electric dipole patch (1-1), and each side of the square closed-loop metal ring (5) is connected to the corresponding outer edge of the electric dipole patch (1-1).

8. The antenna according to claim 1, characterized in that, The antenna has a planar dimension of 0.38λ0 × 0.38λ0, where λ0 is the free space wavelength corresponding to the center frequency within the antenna band.

9. The antenna according to claim 8, characterized in that, The outer contour length of the square closed-loop metal ring (5) is 9.6 mm and the width is 9.6 mm.

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