A broadband high-gain microstrip filtering array antenna

Abstract

The present application belongs to the field of antenna design, and relates to a filter array antenna, and specifically provides a wideband high-gain microstrip filter array antenna, which provides a beneficial reference method for the optimal design and performance improvement of the wideband high-gain filter array antenna, so that the wideband high-gain microstrip filter array antenna can be more widely applied to more scenes. The filter characteristics and the radiation characteristics of the rectangular patch unit structure are optimized by loading a short-circuit metal probe, opening a U-shaped slot and a rectangular slot, and loading an L-shaped branch, and the array structure is designed based on the unit structure. The filter and radiation characteristics of the array are further optimized by adopting the microstrip slot coupling feed probe excitation structure with inherent filter characteristics and resonance characteristics, and the 1*2 array topology structure in the form of mirror symmetry, so that the filter and radiation characteristics of the array are further optimized. Finally, the designed microstrip filter array antenna has the advantages of wideband and high gain, and the antenna structure is simple and convenient to process, and can be used to form a larger array to obtain higher gain.

Description

Technical Field

[0001] This invention belongs to the field of antenna design, specifically to a wideband high-gain microstrip filter array antenna. Background Technology

[0002] In recent years, with the increasing demand for mobile communication devices, mobile communication and wireless communication technologies have made rapid progress, and filter antennas, as a new type of device, have received widespread attention. The core advantage of filter antennas is their integrated design. This integrated design of the filter and antenna reduces problems associated with cascaded designs, such as long design cycles, poor system stability, and increased overall losses, making it an increasingly common design approach in current communication systems. Simultaneously, the trend towards miniaturization and integration in communication systems is becoming increasingly apparent, leading to greater demand, and the design approach of filter antennas perfectly aligns with these two requirements.

[0003] Currently, there are many types of single-filter antenna devices. To expand the application scenarios of filter antennas, some single-antenna structures have been optimized into filter array antennas for applications requiring higher gain. Most existing filter array antennas are microstrip type, which has advantages such as low profile, low loss, and simple fabrication; however, the use of microstrip structures inevitably results in narrow-band characteristics, leading to the narrow-band nature of most microstrip filter array antennas. To improve the bandwidth of microstrip filter array antennas, some researchers have proposed extending the array bandwidth by adding resonant points to the filter circuit; however, the insertion loss introduced by the additional filter circuit inevitably reduces the array gain. Therefore, designing a wideband, high-gain microstrip filter array antenna remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a broadband high-gain microstrip filter array antenna, offering a useful reference method for the optimized design and performance improvement of broadband high-gain filter array antennas, enabling them to be applied more widely in more scenarios.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A broadband high-gain microstrip filter array antenna, comprising, from top to bottom: a metal patch layer 1, a first dielectric substrate 2, a metal strip 3, a second dielectric substrate 4, a metal ground layer 5, a third dielectric substrate 6, a microstrip feed line 9, and an excitation metal probe 7 and a short-circuit metal probe 8; characterized in that:

[0007] The metal patch layer 1 is disposed on the upper surface of the first dielectric substrate 2 and has a symmetrical structure along its two center lines. The metal patch layer is composed of two rectangular patches with their long sides facing each other and arranged along the Y direction. Four rectangular slots are opened on the outer long side of the rectangular patches and are arranged along the X direction. Two U-shaped slots are opened on the inner long side of the rectangular patches and two L-shaped branches are loaded simultaneously. The short branches of the L-shaped branches are loaded vertically on the rectangular patches, and the long branches point to the edge of the first dielectric substrate along the Y direction. The U-shaped slots are arranged along the X direction and the opening end is located at the edge of the rectangular patches. Multiple short-circuit metal probes 8 are disposed on the wide edge of the rectangular patches. The short-circuit metal probes are embedded in the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate. Their top ends are connected to the rectangular patches, and their bottom ends are flush with the lower surface of the third dielectric substrate.

[0008] The metal strip 3 is disposed on the lower surface of the first dielectric substrate and the upper surface of the second dielectric substrate, and is located at the center. The metal strip is disposed along the X direction. The metal strip is connected to two rectangular patches respectively through the excitation metal probe 7. The excitation metal probe is embedded in the first dielectric substrate.

[0009] The metal floor layer 5 is disposed on the lower surface of the second dielectric substrate and the upper surface of the third dielectric substrate. An I-shaped slit is formed at the center of the metal floor layer. The I-shaped slit is arranged along the Y direction and its center coincides with the center of the metal strip along the Z direction.

[0010] The microstrip feed line 9 is disposed on the lower surface of the third dielectric substrate and is disposed along the X direction. The microstrip feed line 9, the metal ground layer 5, the metal strip 3 and the excitation metal probe 7 together constitute the excitation structure of the microstrip gap-coupled power-to-probe.

[0011] Furthermore, the rectangular gap is located at the non-excitation edge (outer long side) of the metal patch layer 1 and is opened along the X direction; specifically, the rectangular gap should be located at the weak current position of the main mold, and the length of the rectangular gap should be adjusted according to the actual matching effect, and should not exceed half the width of the rectangular patch.

[0012] Furthermore, the loading point of the L-shaped stub is located at the excitation edge (inner long side) of the metal patch layer and close to the wide edge of the metal patch layer; specifically, the L-shaped stub should be at the current zero point position of the higher-order mode 1.

[0013] Furthermore, the U-shaped gap is located at the excitation edge (inner long side) of the metal patch layer 1 and close to the position of the excitation metal probe 7; specifically, the sum of the vertical distance (distance in the Y direction) between the U-shaped gap and the excitation probe and the length of the U-shaped gap should be 0.15λ0~0.25λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0014] The working principle of this invention is as follows:

[0015] Traditional standard rectangular patch structures exhibit lateral radiation characteristics in their main mode, while modes similar to the main mode are non-lateral radiation modes. Therefore, it is difficult to achieve broadband lateral radiation characteristics through multi-mode excitation. This invention introduces a short-circuited metal probe along the narrow side of the traditional standard rectangular patch, causing the patch to generate another higher-order mode 1 with lateral radiation characteristics. Broadband characteristics are then achieved by exciting two patch modes (the main mode and higher-order mode 1). The resonant frequency of higher-order mode 1 is lower than that of the main mode, and higher-order mode 1 is a mode with its own low-frequency sideband excitation null, thus the antenna exhibits good low-frequency selectivity. To improve high-frequency sideband selectivity, this invention adds U-shaped gaps on both sides of the feed position, causing the main mode to also generate a sideband excitation null at high frequencies. This excitation null optimizes the high-frequency selectivity of the antenna. It should be noted that the presence of a sideband excitation null in the mode itself means that at a certain frequency, the field at the excitation position is very weak, preventing the mode from being successfully excited by the designed excitation structure, thus resulting in an excitation null. This excitation null corresponds to a radiation null on the gain curve. Building upon this, to further extend the unit bandwidth, this invention extends the current path of higher-order mode 1 by loading rectangular gaps and L-shaped stubs, thereby lowering its resonant frequency while keeping the resonant frequency of the main mode unchanged, thus expanding the bandwidth. Note: The loaded rectangular gaps should be located at the weak current position of the main mode, and the L-shaped stubs should also avoid affecting the main mode.

[0016] The above process enables the rectangular patch unit to exhibit excellent filtering and broadband radiation characteristics. By rationally arranging this unit to form an array topology and applying a suitable feeding excitation structure, a filter array antenna with broadband high-gain characteristics can be realized. This invention fully utilizes the array aperture by placing two designed rectangular patch structures in a mirror-symmetrical manner, thereby achieving high-gain characteristics within a limited size. In addition, this invention replaces the original dual-probe excitation structure with a microstrip slot-coupled feed-to-probe excitation structure to feed the designed 1×2 array. This excitation structure changes the original dual-port feed to a single-port feed, making it more suitable for large array designs. More importantly, the designed microstrip slot-coupled feed-to-probe excitation structure has inherent filtering and resonant characteristics, further improving the array's bandwidth and filtering characteristics.

[0017] In summary, the beneficial effects of this invention are as follows:

[0018] This invention provides a broadband high-gain microstrip filter array antenna. The filtering and radiation characteristics of the rectangular patch element structure are optimized by loading short-circuited metal probes, creating U-shaped and rectangular slots, and loading L-shaped stubs. An array structure is then designed based on this element structure. By employing a microstrip slot-coupled feed-probe-grounded excitation structure with inherent filtering and resonant characteristics, and a mirror-symmetric 1×2 array topology, the filtering and radiation characteristics of the array are further optimized. The final designed microstrip filter array antenna possesses the advantages of broadband high gain. Furthermore, the antenna structure is simple and easy to fabricate, and it can be used to form larger arrays to achieve even higher gains. Attached Figure Description

[0019] Figure 1 This is a side view of the broadband high-gain microstrip filter array antenna of the present invention.

[0020] Figure 2 This is a schematic diagram of the metal patch layer in the broadband high-gain microstrip filter array antenna of the present invention.

[0021] Figure 3 This is a schematic diagram of the metal strip structure in the broadband high-gain microstrip filter array antenna of the present invention.

[0022] Figure 4 This is a schematic diagram of the metal ground plane in the broadband high-gain microstrip filter array antenna of the present invention.

[0023] Figure 5 This is a schematic diagram of a standard rectangular patch cell structure.

[0024] Figure 6 The reflection coefficient and gain diagram are for a standard rectangular patch cell structure.

[0025] Figure 7 This is a diagram showing the main mode current distribution of a standard rectangular patch cell structure.

[0026] Figure 8 This is a schematic diagram of the standard rectangular patch deformation structure 1.

[0027] Figure 9 The reflection coefficient and gain diagram are for the standard rectangular patch deformation structure 1.

[0028] Figure 10 The diagram shows the current distribution of the standard rectangular patch deformed structure 1, where (a) represents the higher-order mode 1 (low-frequency resonance) and (b) represents the main mode (high-frequency resonance).

[0029] Figure 11 This is a schematic diagram of the standard rectangular patch deformation structure 2.

[0030] Figure 12The reflection coefficient and gain diagram are for the standard rectangular patch deformation structure 2.

[0031] Figure 13 The diagram shows the current distribution of the standard rectangular patch deformed structure 2, where (a) represents the higher-order mode 1 (low-frequency resonance) and (b) represents the main mode (high-frequency resonance).

[0032] Figure 14 This is a schematic diagram of the unit structure of the broadband high-gain microstrip filter array antenna of the present invention.

[0033] Figure 15 The diagram shows the reflection coefficient and gain of the unit structure of the broadband high-gain microstrip filter array antenna of the present invention.

[0034] Figure 16 The diagram shows the current distribution of the unit structure of the broadband high-gain microstrip filter array antenna of the present invention, where (a) is the higher-order mode 1 (low-frequency resonance) and (b) is the main mode (high-frequency resonance).

[0035] Figure 17 This is a schematic diagram of the 1×2 array structure for dual-probe excitation of the present invention.

[0036] Figure 18 The diagram shows the reflection coefficient and gain of the 1×2 array antenna excited by the dual probes of this invention.

[0037] Figure 19 This is a schematic diagram of the excitation structure of the microstrip slot coupled feed probe of the antenna of the present invention;

[0038] Figure 20 The diagram shows the current distribution of the microstrip feed structure of the broadband high-gain microstrip filter array antenna of the present invention at 5 GHz and 9.7 GHz, where (a) is 5 GHz and (b) is 9.7 GHz.

[0039] Figure 21 The diagram shows the reflection coefficient and gain of the broadband high-gain microstrip filter array antenna of this invention.

[0040] Figure 22 This is a radiation efficiency diagram of the broadband high-gain microstrip filter array antenna of the present invention.

[0041] Figure 23 The radiation patterns of the broadband high-gain microstrip filter array antenna of the present invention are shown when it operates at 5.8 GHz, 6.5 GHz and 7.3 GHz, where (a) is 5.8 GHz, (b) is 6.5 GHz and (c) is 7.3 GHz. Detailed Implementation

[0042] To make the objectives, technical solutions, and technical effects of this invention more complete and clear, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] This embodiment provides a broadband high-gain microstrip filter array antenna, the structure of which is as follows: Figure 1 As shown, from top to bottom, it includes: a metal patch layer 1, a first dielectric substrate 2, a metal strip 3, a second dielectric substrate 4, a metal ground plane layer 5, a third dielectric substrate 6, and a microstrip feed line 9; the first dielectric substrate has an embedded excitation metal probe 7 and a short-circuit metal probe 8, and both the second and third dielectric substrates have embedded short-circuit metal probes 8; the metal patch layer 1 is printed on the upper surface of the first dielectric substrate 2, the metal strip 3 is printed on the lower surface of the first dielectric substrate 2, the metal ground plane layer 5 is printed on the upper surface of the third dielectric substrate 6, and the microstrip feed line 9 is printed on the lower surface of the third dielectric substrate 6; the excitation metal probe 7 passes through the first dielectric substrate 2, with its top end connected to the metal patch layer 1 and its bottom end connected to the metal strip 3; the short-circuit metal probe 8 passes through the first dielectric substrate 2, the second dielectric substrate 4, the metal ground plane layer 5, and the third dielectric substrate 6, with its top end connected to the metal patch layer 1 and its bottom end flush with the lower surface of the third dielectric substrate.

[0044] In this embodiment, the first dielectric substrate 2, the second dielectric substrate 4, and the third dielectric substrate 6 are all made of RogersRT / duroid 5880 material. The length of each of the three dielectric substrates is L = 50 mm and the width is W = 45 mm. The thickness of the first dielectric substrate 2 is t1 = 2 mm, and the thicknesses of the second dielectric substrate 4 and the third dielectric substrate 6 are both t2 = 0.5 mm. The total thickness of the three dielectric substrates does not exceed 5 mm, which meets the low profile requirement. It should be noted that the thickness parameters can be adaptively adjusted according to specific practical requirements.

[0045] like Figure 2 As shown, the metal patch layer 1 is composed of two rectangular patches with identical structural dimensions. The long side of the rectangular patches is set along the Y direction, and the metal patch layer 1 is symmetrical about the centerline (X-axis and Y-axis) of the first dielectric substrate. The distance between the two rectangular patches is d = 4 mm, the length of the rectangular patch is l1 = 48.5 mm, and the width is w1 = 12.5 mm. Four rectangular slots are loaded on the long side of the outer side of the rectangular patches, and the length of each rectangular slot is l. f =3mm, width is w f =2mm, the rectangular gap closest to the x-axis is d from the x-axis. f1 =7.5mm, the rectangular slit furthest from the x-axis is w. f +d f1 +d f2 =13.5mm; The long side of the inner side of the rectangular patch is loaded with two U-shaped gaps, and the distance of the U-shaped gaps from the x-axis is d. u =2mm, the outer dimension length of the U-shaped gap is l u =6mm, width is wu =2.5mm; Two L-shaped branches are loaded on the long side of the inner side of the rectangular patch, and the distance of the L-shaped branches from the x-axis is d. l =17mm, the length of the L-shaped branch is l l1 +l l2 =1mm + 6mm = 7mm, width is w l =0.5mm.

[0046] like Figure 3 As shown, the metal strip 3 is printed at the center of the lower surface of the first dielectric substrate 2, and the long side of the metal strip 3 is arranged along the X direction; the length of the metal strip 3 is l. t =15mm, width is w t =2mm.

[0047] like Figure 4 As shown, a metal ground plane 5 is printed on the upper surface of the third dielectric substrate 6, and an I-shaped slot is provided on it. The I-shaped slot is located at the center of the metal ground plane 5 and is arranged along the Y direction. The center of the slot coincides with the center of the metal strip 3. A microstrip feed line 9 is printed on the lower surface of the third dielectric substrate 6. The microstrip feed line 9, the metal ground plane 5, the metal strip 3 and the excitation metal probe 7 together constitute the excitation structure of the microstrip slot coupled feed probe of the antenna of the present invention.

[0048] To further illustrate the working principle of the aforementioned broadband high-gain microstrip filter array antenna, this invention also provides the evolution process of the unit structure and the array feeding structure, which are described below in conjunction with... Figures 5 to 23 Detailed explanation:

[0049] like Figure 5 As shown, a standard rectangular patch structure was selected as the initial unit structure. A coaxial probe was used to excite the patch structure, with the excitation position at the center of its long side, offset from the center of its narrow side. This excitation method can excite a mode field polarized in the x-direction. Figure 6 As shown in the reflection coefficient curve, the standard rectangular patch structure exhibits no filtering characteristics. Only the main mold in the standard rectangular patch structure shows lateral radiation characteristics; the current distribution of the main mold is as follows. Figure 7 As shown. To extend the bandwidth, a new lateral radiation mode needs to be introduced. This invention designs a modified structure 1 of the standard rectangular patch by introducing a short-circuit metal probe along the narrow side of the traditional rectangular patch structure, as shown. Figure 8 As shown. Because the short-circuited metal probe alters the boundary conditions of the rectangular patch structure, the structure exhibits two lateral modes: higher-order mode 1 and the dominant mode; from such... Figure 9As shown in the gain and reflection curves, the deformed structure 1 exhibits a radiation null at low frequencies, displaying filtering characteristics. This is because the higher-order mode 1 of the low-frequency resonance has an excitation null at 6.5 GHz, meaning that higher-order mode 1 cannot be excited at 6.5 GHz, and no other mode produces good radiation at 6.5 GHz. Therefore, the deformed structure 1 exhibits radiation null characteristics at 6.5 GHz and filtering characteristics in the frequency band below 6.5 GHz. The current distribution of higher-order mode 1 and the dominant mode is as follows: Figure 10 As shown. To further optimize the high-frequency filtering characteristics of the structure, as... Figure 11 The deformed structure 2 shown was designed by creating two U-shaped gaps next to the excitation location, enabling the main mode to generate an excitation null at a high frequency of 8.2 GHz, while preventing other modes from radiating near 8.2 GHz. Therefore, deformed structure 2 achieves good high-frequency filtering characteristics, as shown in its gain and reflection curves. Figure 12 As shown, the current distribution of higher-order mode 1 and the dominant mode is as follows: Figure 13 As shown.

[0050] Up to this point, modified structure 2 has achieved good high- and low-frequency filtering performance, but its bandwidth is currently only 7%. To further expand the bandwidth of the unit structure and prepare for the design of a broadband array structure, modified structure 2 has been further optimized as follows: Figure 14 The structure shown is the unit structure ultimately used in the array antenna of this invention, and its gain and reflection curves are as follows. Figure 15 As shown, the current distribution of higher-order mode 1 and the dominant mode is as follows: Figure 16 As shown. By adding rectangular slots and L-shaped stubs to extend the current path of higher-order mode 1, the resonant frequency of higher-order mode 1 is reduced, while the resonant frequency of the dominant mode remains unchanged, thereby achieving bandwidth expansion. Specifically, by adding four rectangular slots to the non-excitation edge (the long side of the rectangular patch away from the excitation probe is called the non-excitation edge), the current path of higher-order mode 1 is extended, thereby reducing the resonant frequency of higher-order mode 1. Figure 13 The area enclosed in the black box is the location where the rectangular gap is applied. At this location, the main mode current is weak, therefore the resonant frequency of the main mode is not affected. Since the applied gap affects the cell matching performance, its ability to extend the current path of higher-order mode 1 is limited. Therefore, this invention also applies two L-shaped branches on the excitation edge (the long side of the rectangular patch near the excitation probe is called the excitation edge) to further extend the current path of higher-order mode 1. Figure 16The current distributions of the higher-order mode 1 and the principal mode shown clearly demonstrate that both the rectangular gap and the L-shaped stub prolong the current path of the higher-order mode 1, while having almost no impact on the current path of the principal mode. As the resonant frequency of the higher-order mode 1 is lowered, the resonant frequency of the principal mode remains unchanged, and the operating bandwidth of the cell is extended from 7% to 14%. It should be noted that the added rectangular gap and L-shaped stub have almost no effect on the filtering characteristics of the cell; therefore, as... Figure 14 The unit structure shown has broadband filtering characteristics.

[0051] Based on the above unit structure, a 1×2 array structure was designed. Research showed that by placing the two units in mirror-symmetric arrangement, optimal aperture utilization can be achieved. Simultaneously, applying differential excitation signals to these two units can excite lateral radiation modes (higher-order mode 1 and the dominant mode), such as... Figure 17 As shown; Figure 18 The figure shows the reflection coefficient and gain curves of the array under dual-probe differential excitation. It can be seen that, similar to the element characteristics, the array exhibits excellent low-frequency filtering, but its high-frequency filtering performance needs improvement. This is because the dual-probe excitation method offers no benefit to improving the filtering characteristics; it only serves an excitation function. To optimize the array's filtering characteristics, this invention designs an excitation structure for a microstrip slot-coupled feed-to-probe configuration, as shown below. Figure 19 As shown; this excitation structure changes the original dual-port excitation to single-port excitation. Compared to the dual-probe excitation structure, the microstrip slot-coupled feed-to-probe excitation structure is more suitable for designing large array feed structures because it has fewer ports. Secondly, the microstrip slot-coupled feed-to-probe excitation structure has inherent filtering and resonant characteristics, which not only expands the passband bandwidth but also optimizes the out-of-band filtering effect of the array. Specifically, a microstrip feed mode is introduced, which, together with the original higher-order mode 1 and the main mode, constitutes the array's passband mode. Due to the resonance of three modes, the array's bandwidth is further expanded. In addition, the microstrip slot-coupled feed structure itself has two transmission zeros, namely, at 5GHz and 9.7GHz, energy cannot be transferred from the microstrip feed line to the array structure because the magnetic field of the microstrip feed line is weakest at the I-shaped gap position on the ground, and cannot couple upwards. Figure 20 As shown.

[0052] like Figure 21 , 22 The figure shows the gain, reflection coefficient, and radiation efficiency of the array antenna in this embodiment. In this embodiment, the reflection coefficient of the array antenna in the 5.69–7.42 GHz frequency band is less than -10 dB, and the -10 dB impedance bandwidth can reach 26.4%. The antenna in this embodiment has a maximum gain of 12 dBi in its operating frequency band, and an out-of-band rejection ratio greater than 20 dB. The average in-band radiation efficiency is as high as 96%, and the maximum out-of-band radiation efficiency does not exceed 20%. Figure 23The diagram shows the radiation patterns of the array antenna in this embodiment at 5.8 GHz, 6.5 GHz, and 7.3 GHz. It can be seen that the antenna has a stable radiation pattern, indicating that the antenna radiation is stable.

[0053] In summary, compared with existing microstrip filter array antennas, the microstrip filter array antenna of this invention has the advantages of wide bandwidth and high gain.

[0054] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A broadband high-gain microstrip filter array antenna, comprising, from top to bottom: The system comprises a metal patch layer (1), a first dielectric substrate (2), a metal strip (3), a second dielectric substrate (4), a metal ground layer (5), a third dielectric substrate (6), a microstrip feed line (9), and excitation metal probes (7) and short-circuit metal probes (8); characterized in that: The metal patch layer (1) is disposed on the upper surface of the first dielectric substrate (2) and has a symmetrical structure along its two midlines. The metal patch layer is composed of two rectangular patches with their long sides facing each other and arranged along the Y direction. Four rectangular slots are opened on the outer long side of the rectangular patch and are arranged along the X direction. Two U-shaped slots are opened on the inner long side of the rectangular patch and two L-shaped branches are loaded at the same time. The short branches of the L-shaped branches are loaded vertically on the rectangular patch and the long branches point to the edge of the first dielectric substrate along the Y direction. The U-shaped slots are arranged along the X direction and the opening end is located at the edge of the rectangular patch. Multiple short-circuit metal probes (8) are disposed on the wide edge of the rectangular patch. The short-circuit metal probes are embedded in the first dielectric substrate, the second dielectric substrate and the third dielectric substrate. Their top ends are connected to the rectangular patch and their bottom ends are flush with the lower surface of the third dielectric substrate. The metal strip (3) is disposed on the lower surface of the first dielectric substrate and the upper surface of the second dielectric substrate, and is located at the center. The metal strip is disposed along the X direction. The metal strip is connected to two rectangular patches respectively through the excitation metal probe (7). The excitation metal probe is embedded in the first dielectric substrate. The metal floor layer (5) is disposed on the lower surface of the second dielectric substrate and the upper surface of the third dielectric substrate. An I-shaped slit is opened at the center of the metal floor layer. The I-shaped slit is disposed along the Y direction and its center coincides with the center of the metal strip along the Z direction. The microstrip feed line (9) is disposed on the lower surface of the third dielectric substrate and is disposed along the X direction. The microstrip feed line (9), the metal ground layer (5), the metal strip (3) and the excitation metal probe (7) together constitute the excitation structure of the microstrip gap coupled power feed probe.

2. The broadband high-gain microstrip filter array antenna according to claim 1, characterized in that, The rectangular gap is located at a weak current position of the main mold, and its length does not exceed half the width of the rectangular patch.

3. The broadband high-gain microstrip filter array antenna according to claim 1, characterized in that, The loading point of the L-shaped stub is located at the current zero point of the higher-order mode 1.

4. The broadband high-gain microstrip filter array antenna according to claim 1, characterized in that, The sum of the vertical distance between the U-shaped slit and the excitation metal probe and the length of the U-shaped slit is 0.15λ0 to 0.25λ0, where λ0 is the free space wavelength corresponding to the center frequency.

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