High-performance communication antenna housing with ultra-wide passband and passband bilateral high-speed roll-off

Abstract

The invention discloses a high-performance communication antenna housing with an ultra-wide passband and passband bilateral high-speed roll-off. The antenna housing is a frequency selective surface composed of a plurality of periodic unit structures which are tightly arranged in a planar array mode. Each periodic unit structure is divided into a dielectric layer and a metal layer, the top-layer metal patch is attached to the upper surface of the top-layer dielectric, the upper-layer metal patch is attached to the upper surface of the middle-layer dielectric, and the lower-layer metal patch is attached to the lower surface of the middle-layer dielectric by rotating 90 degrees relative to the upper-layer metal patch; the upper-layer metal patch and the lower-layer metal patch are electrically connected through a via hole, and the bottom-layer metal patch is attached to the lower surface of the bottom-layer medium; and the electromagnetic waves in the free space are selectively filtered by the antenna housing and then required working frequency band electromagnetic waves are output. The ultra-wide band-pass filter has the advantages of ultra-wide band-pass, high-speed roll-off of two sides of the band-pass, small and stable insertion loss in the band-pass, excellent angle and polarization stability, and huge application value in the fields of modern communication, radar, military national defense and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and particularly to a high-performance communication radome with an ultra-wide passband and bilateral high-speed roll-off in the passband, which can be applied to high-frequency 5G communication and radar. Background Art

[0002] With the rapid development of 5G technology, the demand for spectrum resources in communication systems has increased significantly, and at the same time, higher requirements for high bandwidth, high speed, and low latency of signal transmission have been put forward. In this context, the performance of traditional radomes can no longer meet the requirements of 5G communication. 5G communication systems often need to cover multiple frequency bands to support different scenarios (such as wide-area coverage in the low-frequency band, high-speed transmission of dense users in the high-frequency band, etc.), which poses new challenges to the passband range, bandwidth, and out-of-band interference suppression performance of radomes.

[0003] The performance of existing communication radomes is difficult to meet the requirements of 5G communication, and there are mainly the following problems: the passband range is limited, unable to cover multiple frequency bands, difficult to balance wide-area coverage in the low-frequency band and high-speed transmission in the high-frequency band, and difficult to support the transmission of large-bandwidth signals required by 5G systems; the out-of-band suppression performance is poor, vulnerable to interference between frequency bands, reducing communication quality, and unable to effectively avoid interference signals; the manufacturing cost is relatively high, and it is difficult to achieve large-scale applications in scenarios with high economic requirements.

[0004] Through a large number of literature research, industry analysis, and technical research, designing an integrated filtering radome using a periodic metamaterial structure is a feasible solution. A radome is a housing used to protect an antenna or the entire microwave system from the environment and is widely used in wireless systems. The frequency selective surface (FSS) is often used to design radomes. The FSS radome has frequency selectivity characteristics, can maintain a high transmittance within a specified frequency band range, and rapidly roll off outside the passband to effectively suppress the transmission of out-of-band signals. This characteristic enables it to ensure signal stability in multi-band communication, reduce interference between frequency bands, and thus improve the overall performance of the communication system. This is particularly important for antenna systems that need to support 5G multi-band and high-speed transmission. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a high-performance communication radome with an ultra-wide passband and bilateral high-speed roll-off in the passband. Through the ingenious coupling design between three layers and four metals, it has stable and efficient selective transmission for electromagnetic waves incident from all directions in space.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A high-performance communication radome with an ultra-wide passband and a bilateral high-speed roll-off in the passband is a frequency selective surface mainly composed of multiple identical periodic unit structures closely arranged in a planar array form.

[0008] Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes an upper dielectric D1, a middle dielectric D2, and a lower dielectric D3 arranged in sequence from top to bottom. The metal layer includes a top metal patch P1, an upper metal patch P 21 , a lower metal patch P 22 , and a bottom metal patch P3 arranged in sequence from top to bottom.

[0009] The top metal patch P1 is attached to the upper surface of the top dielectric D1, and the upper metal patch P 21 is attached to the upper surface of the middle dielectric D2. The top metal patch P1, the top dielectric D1, the middle dielectric D2, the lower dielectric D3, and the bottom metal patch P3 are all square. The lower metal patch P 22 has the same structure and size as the upper metal patch P 21 . The lower metal patch P 22 is attached to the lower surface of the middle dielectric D2 by rotating 90° relative to the upper metal patch P 21 . The upper metal patch P 21 and the lower metal patch P 22 are electrically connected through their own vias. The bottom metal patch P3 is attached to the lower surface of the bottom dielectric D3. The electromagnetic wave in free space is selectively filtered by the radome and then outputs the electromagnetic wave of the required working frequency band.

[0010] The top metal patch P1 and the bottom metal patch P3 have the same structure and size, and the top dielectric D1 and the bottom dielectric D3 have the same structure and size.

[0011] The top metal patch P1 and the bottom metal patch P3 are both mainly composed of multiple repeating units closely arranged in a planar array form. Each repeating unit includes a cross-shaped metal patch T1 and square corner patches located at the four corners around the cross-shaped metal patch T1. The square corner patches between every four adjacent repeating units are connected into one body to form a square metal patch T2. There are gaps between the cross-shaped metal patch T1 and the square corner patches, and between the cross-shaped metal patches T1 in adjacent repeating units.

[0012] The top metal patch P1 and the bottom metal patch P3 are respectively attached to the centers of the top dielectric D1 and the bottom dielectric D3.

[0013] The upper metal patch P 21 and the lower metal patch P 22 are both mainly composed of a first metal patch pair T3, a second metal patch pair T5, a metal strip T4, and vias.

[0014] A metal strip T4 is provided at the axis of symmetry of the intermediate layer dielectric D2. The metal strip T4 is perpendicular to two opposite sides of the intermediate layer dielectric D2. The first metal patch pair T3 is mainly composed of two identical first metal patches, and the two first metal patches are symmetrically attached to two opposite sides of the intermediate layer dielectric D2 respectively. The side of the intermediate layer dielectric D2 where the first metal patch is located is perpendicular to the metal strip T4. The second metal patch pair T5 is mainly composed of two identical second metal patches, and the two second metal patches are symmetrically attached to two opposite sides of the intermediate layer dielectric D2 respectively. The side of the intermediate layer dielectric D2 where the second metal patch is located is parallel to the metal strip T4. Through holes are provided at both ends of the metal strip T4, and the two through holes are not connected to the first metal patch pair T4. A through hole is provided on each second metal patch, and the through hole on the second metal patch is provided at the axis of symmetry of the intermediate layer dielectric D2 perpendicular to the metal strip T4, and the distance from the through hole on the second metal patch to the center of the intermediate layer dielectric D2 is equal to the distance from the through holes at both ends of the metal strip T4 to the center of the intermediate layer dielectric D2.

[0015] Upper layer metal patch P 21 The two through holes provided on the second metal patch pair T5 in the middle are respectively coaxially and correspondingly connected to the lower layer metal patch P 22 in the middle, and the through holes at both ends of the metal strip T4; the lower layer metal patch P 22 The through holes provided on the second metal patch pair T5 in the middle are respectively coaxially and correspondingly connected to the upper layer metal patch P 21 in the middle, and the through holes at both ends of the metal strip T4.

[0016] The first metal patch is rectangular, and one long side of each first metal patch is flush with the side where it is located in the intermediate layer dielectric D2.

[0017] The two ends of the second metal patch are stepped, and the long side of each second metal patch is parallel to the side where it is located in the intermediate layer dielectric D2 and there is a gap.

[0018] The top layer dielectric D1, the intermediate layer dielectric D2, and the bottom layer dielectric D3 are all made of a board with a dielectric constant of 3 and a dielectric loss tangent value of 0.001.

[0019] The frequency of the electromagnetic wave incident on the radome is 1.5 GHz - 8 GHz. When the angle of the electromagnetic wave incident on the radome changes within the range of ±60°, the zero point position does not change.

[0020] A high-performance communication radome with ultra-wide bandwidth and bilateral high-speed roll-off in the passband is applied to modern communication, radar, and military communication of 5G.

[0021] The beneficial effects of the present invention are:

[0022] The radome design of the present invention adopts the multi-mode coupling technology to realize the miniaturization design of the frequency selective surface structure. The final unit size is about 0.24λ, and more units can be placed within the same area, making the fabricated board closer to the infinite periodic structure. However, this degree of miniaturization is still suitable for processing and production by traditional PCB technology.

[0023] The multi-mode coupling between the top layer metal, the middle layer and the bottom layer metal of the present invention provides an ultra-wide passband with extremely low insertion loss for the radome. For the electromagnetic wave vertically incident on the radome, after passing through the respective layer structures of the radome in sequence, the passband insertion loss is less than 3 dB in the frequency range of 2.48 GHz - 6.81 GHz, and less than 1 dB in the frequency band range of 2.74 GHz - 6.65 GHz; when the incident angle reaches 60°, the average insertion loss of TE and TM polarizations is less than 0.5 dB in the frequency band of 2.74 GHz - 6.65 GHz.

[0024] The middle layer of the present invention provides a stopband with high-speed roll-off on both sides of the broadband through the alienated Jerusalem cross metal structure. When the space electromagnetic wave is vertically incident on the radome, the stopband suppression is greater than 15 dB in the frequency bands of 1.68 GHz - 2.04 GHz and 7.25 GHz - 7.93 GHz, and the roll-off speeds on both sides of the passband reach 25.6 dB / GHz and 31.48 dB / GHz respectively.

[0025] The unique structural design of the present invention enables the present invention to have an ultra-wide passband and ultra-high selectivity, and within the incident angle range of ±60°, its transmission response remains stable, the transmission zeros are quite stable and basically do not shift, ensuring the normal operation of the radome system. In addition, the present invention adopts a completely symmetric design, making its electromagnetic dual-polarization performance stable and supporting both TE and TM polarization modes at the same time.

[0026] The present invention has extremely high application value in the miniaturization of antenna devices, modern communications such as 5G, radar and military communications.

[0027] Generally speaking, the present invention is applicable to the design of mobile communication radomes with a wide passband width, high-speed roll-off on both sides of the passband, high angle and polarization stability, small and stable insertion loss within the ultra-wide passband, a stopband with high suppression on both sides of the passband, excellent angle and polarization stability, and easy engineering implementation. It has great application value in the fields of modern communications, radar and national defense. This radome can not only meet the requirements of 5G communication for an ultra-wide frequency band, ensuring the rapid attenuation of out-of-band signals. This design can improve the anti-interference ability in a complex 5G communication environment, provide key support for high-performance and low-latency 5G communication, and is applicable to the multi-band working requirements of modern communication systems. Description of the Drawings

[0028] Figure 1 is the three-dimensional structure diagram of the radome in the embodiment of the present invention;

[0029] Figure 2 is the three-dimensional structure diagram of the periodic unit structure of the present invention;

[0030] Figure 3 is the view of the metal structures of each layer of the unit structure of the present invention;

[0031] Figure 4 is the corresponding view of the top and bottom layer metal structures and their equivalent LC elements in the unit structure of the present invention;

[0032] Figure 5 is the corresponding view of the middle layer metal structure and its equivalent LC element in the unit structure of the present invention;

[0033] Figure 6 is the corresponding view of the equivalent circuit elements of the unit structure of the present invention;

[0034] Figure 7 is the curve of the influence of the length of the metal strips in the upper and lower layer metal patches on the transmission performance of the radome in the present invention;

[0035] Figure 8 is the curve of the influence of the long side length of the second metal patch in the upper and lower layer metal patches on the transmission performance of the radome in the present invention;

[0036] Figure 9 is the transmission performance curve of the radome of the present invention for vertically incident TE and TM polarization modes;

[0037] Figure 10 is the curve of the influence of the incident angle of electromagnetic waves in the TE polarization mode on the performance of the radome of the present invention;

[0038] Figure 11 is the curve of the influence of the incident angle of electromagnetic waves in the TM polarization mode on the performance of the radome in the present invention. Detailed implementation manners

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] The high-performance communication radome in specific implementation is as Figure 1 shown, and is mainly a frequency selective surface composed of multiple identical periodic unit structures closely arranged in a planar array;

[0041] Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes an upper dielectric D1, a middle dielectric D2, and a lower dielectric D3 arranged in sequence from top to bottom. The metal layer includes a top metal patch P1, an upper metal patch P 21 , a lower metal patch P22 and the bottom metal patch P3;

[0042] The top metal patch P1 is attached to the upper surface of the top dielectric D1, and the upper metal patch P 21 is attached to the upper surface of the middle dielectric D2. The top metal patch P1, the top dielectric D1, the middle dielectric D2, the lower dielectric D3, and the bottom metal patch P3 are all square. The lower metal patch P 22 and the upper metal patch P 21 have the same structure and size. The lower metal patch P 22 is attached to the lower surface of the middle dielectric D2 by rotating 90° relative to the upper metal patch P 21 . The upper metal patch P 21 and the lower metal patch P 22 are electrically connected through their own vias. The bottom metal patch P3 is attached to the lower surface of the bottom dielectric D3. Finally, the arrangement of each layer of metal is as Figure 2 shown; The electromagnetic wave in free space is selectively filtered by the radome, removing its clutter and outputting the electromagnetic wave of the required working frequency band.

[0043] When an electromagnetic wave in free space is incident on the radome, it will have a selective characteristic for electromagnetic waves of a specific incident frequency, enabling the signal in the antenna working frequency band to pass through normally, while having a good suppression effect on the frequency bands on both sides of the antenna working frequency band, showing a high-speed roll-off characteristic. This frequency selectivity stems from the resonant effect of the periodic structure of the radome and its spatial band-pass filtering characteristic. Through the combination of capacitive and inductive band grids and grid metal structures, the radome resonates at a specific frequency. By optimizing the geometric shape, size, and material properties of the metal structure, the passband range, center frequency, and roll-off rate can be precisely adjusted to form a band-pass filter structure to selectively transmit the signals of the required frequency band.

[0044] The top metal patch P1 and the bottom metal patch P3 have the same structure and size. The top dielectric D1 and the bottom dielectric D3 have the same structure and size. The upper metal patch P 21 and the lower metal patch P 22 have the same structure and size.

[0045] Both the top metal patch P1 and the bottom metal patch P3 are mainly composed of multiple repeating units closely arranged in a planar array form. Each repeating unit includes a cross-shaped metal patch T1 and square corner patches located at the four corners around the cross-shaped metal patch T1. The square corner patches between every four adjacent repeating units are connected into one body to form a square metal patch T2. There are uniform gaps between the cross-shaped metal patch T1 and the square corner patches, and between the cross-shaped metal patches T1 in adjacent repeating units.

[0046] The top metal patch P1 and the bottom metal patch P3 are respectively attached to the centers of the top dielectric D1 and the bottom dielectric D3.

[0047] The repeating unit is a centrosymmetric structure. Both the top metal patch P1 and the bottom metal patch P3 are square, and the four sides of the top metal patch P1 and the bottom metal patch P3 are the boundaries of the repeating unit, or the horizontal axis of symmetry of the repeating unit, or the vertical axis of symmetry of the repeating unit.

[0048] The upper metal patch P 21 and the lower metal patch P 21 are both centrosymmetric structures. The upper metal patch P 21 and the lower metal patch P 22 are both mainly composed of the first metal patch pair T3, the second metal patch pair T5, the metal strip T4, and four vias;

[0049] A metal strip T4 is provided at the axis of symmetry on the surface of the intermediate dielectric D2. The metal strip T4 is perpendicular to two opposite sides of the intermediate dielectric D2. The first metal patch pair T3 is mainly composed of two identical first metal patches, and the two first metal patches are symmetrically attached to two opposite sides of the intermediate dielectric D2 respectively. The side of the intermediate dielectric D2 where the first metal patch is located is perpendicular to the metal strip T4. The second metal patch pair T5 is mainly composed of two identical second metal patches, and the two second metal patches are symmetrically attached to the remaining two opposite sides of the intermediate dielectric D2 respectively. The side of the intermediate dielectric D2 where the second metal patch is located is parallel to the metal strip T4; Vias are provided at both ends of the metal strip T4. The two vias are connected by the metal strip T4 and the two vias are not connected to the first metal patch pair T3; A via is provided on each second metal patch. The via on the second metal patch is provided at the axis of symmetry of the intermediate dielectric D2 perpendicular to the metal strip T4, and the distance from the via on the second metal patch to the center of the intermediate dielectric D2 is equal to the distance from the vias at both ends of the metal strip T4 to the center of the intermediate dielectric D2;

[0050] The two vias provided on the second metal patch pair T5 in the upper metal patch P 21 are respectively coaxially and correspondingly electrically connected to the vias at both ends of the metal strip T4 in the lower metal patch P 22 so as to realize the electrical connection with the metal strip T4 in the lower metal patch P 22 ; The via provided on the second metal patch pair T5 in the lower metal patch P 22 is coaxially and correspondingly electrically connected to the vias at both ends of the metal strip T4 in the upper metal patch P 21 so as to realize the electrical connection with the metal strip T4 in the upper metal patch P 21 . The final three-layer PCB board structure is as shown in Figure 2 Figure.

[0051] Lower metal patch P 22 Relative to the upper metal patch P 21 It is attached to the lower surface of the middle layer dielectric D2 by rotating 90°. The upper metal patch P 21 The vias at both ends of the metal strip T4 in the middle are aligned with the lower metal patch P 22 The vias on the second metal patch pair T5 in the middle are directly opposite to the vias on the lower metal patch P 21 The vias on the second metal patch pair T5 in the middle are aligned with the vias at both ends of the metal strip T4 in the lower metal patch P 22 The vias at both ends of the metal strip T4 in the upper metal patch P 21 The metal strip T4 in the upper metal patch P 22 The metal strip T4 in it is perpendicular to the lower metal patch P;

[0052] The first metal patch is rectangular, and one of the long sides of each first metal patch is flush with the side where it is located in the middle layer dielectric D2 as the edge of the periodic unit structure.

[0053] Both ends of the second metal patch are stepped, and the long side of each second metal patch is parallel to the side where it is located in the middle layer dielectric D2 and there is a gap.

[0054] The length directions of each first metal patch and the second metal patch are the same as the direction of the side where they are located in the middle layer dielectric D2.

[0055] When the metal strip T4 meets the above requirements, its length is set as long as possible.

[0056] The top layer dielectric D1, the middle layer dielectric D2 and the bottom layer dielectric D3 all use plates with a dielectric constant of 3 and a dielectric loss tangent value of 0.001.

[0057] When the frequency of the electromagnetic wave incident on the radome is 1.5 GHz - 8 GHz and the angle of the electromagnetic wave incident on the radome changes within the range of ±60°, the passband performance remains stable and the zero point position basically does not change.

[0058] After the electromagnetic wave is vertically incident on each layer structure of the radome, the passband insertion loss is less than 3 dB in the frequency band range of 2.48 GHz–6.81 GHz, and the passband insertion loss is less than 1 dB in the frequency band range of 2.74 GHz–6.65 GHz; the stopband suppression is greater than 15 dB in the frequency bands of 1.68 GHz–2.04 GHz and 7.25 GHz–7.93 GHz, and the roll-off speeds on both sides of the passband reach 25.6 dB / GHz and 31.48 dB / GHz respectively. When the incident angle reaches 60°, the average insertion losses of TE and TM polarizations in the frequency band of 2.74 GHz–6.65 GHz are both less than 0.5 dB.

[0059] The radome is applied to modern communication, radar and military communication in 5G.

[0060] The working principle of the radome of the present invention is as follows:

[0061] In the radome of the present invention, a frequency selective surface structure is designed by using a multi-mode coupling technology. A single-mode resonant unit generally consists of a pair of parallel-connected capacitance and inductance, which can generate a transmission pole in the transmission response. Duplicating an identical resonant unit at an appropriate position by displacement will produce a multi-screen effect, which can increase the number of poles, achieving the effects of widening the passband and reducing the in-band insertion loss. Retaining the capacitance of two groups of resonant units and adding a dielectric layer in the middle of the two groups of resonant units, and combining the inductance of the two groups of resonant units in this layer, a frequency selective structure composed of layered LC resonant units can be obtained, and the transmission bandwidth of this structure is wider. By adding LC parallel resonant units in the middle layer, the number of poles can be further increased to obtain a frequency selective structure with an ultra-wide passband. By adding LC series resonant units in the middle layer, resonant zeros can be introduced on both sides of the ultra-wide passband, causing a high-speed roll-off on both sides of the passband.

[0062] In the radome of the present invention, miniaturization processing is performed on the top and bottom layer capacitor plates to improve the angular stability of the frequency selective surface. At the same time, through the dissimilar Jerusalem cross structure and the strong coupling effect of the metal on both sides of the thin dielectric in the middle layer, zeros are introduced on both sides of the ultra-wide passband simultaneously. The strong coupling capacitance generating this zero is not easily affected by the direction of the incident electromagnetic wave, so the zero of the proposed structure has good angular stability performance.

[0063] The top and bottom layer metal patches are arranged alternately by cross-shaped metal patches T1 and square metal patches T2, which are equivalent to capacitance. They and the metal strip T4 (equivalent to inductance) in the middle layer together constitute a layered LC resonant unit, which can generate two transmission poles. A pair of metal patches T3 in the middle layer metal patch P 21 and the metal strip T4 form a set of resonant units to provide a third pole. The equivalent LC of each layer structure is shown in the corresponding diagrams such as Figure 4 、 5 shown.

[0064] At the same time, the first metal patch T3, the second metal patch T5, and the metal strip T4 in the upper layer metal patch P 21 can also provide two sets of series LC through a clever arrangement, which can provide transmission zeros at both sides of the passband, namely 1.9 GHz and 7.5 GHz, greatly improving the selectivity of the model. The capacitance generating this zero includes the strong coupling capacitance C3 generated between the first metal patch T3 and the metal strip T4, which is not easily affected by the angle of the incident electromagnetic wave, so the zero of the proposed structure has good angular stability performance. Finally, the corresponding diagrams of the structure and equivalent LC of the present invention and the equivalent circuit model are respectively asFigure 4 , 5 as shown in 6.

[0065] The radome in the present invention adopts a quasi-symmetric design concept, which is specifically reflected in that the top and bottom metal patches are rotationally symmetric, and the two layers of metal patches on both sides of the middle layer are rotationally symmetric. The structure realizes the dual-polarization stability design of electromagnetic waves in TE and TM modes.

[0066] The present invention is applicable to the design of mobile communication radomes with a wide passband width, high-speed roll-off on both sides of the passband, and high angle and polarization stability. The insertion loss in the ultra-wide passband is small and stable, and there are stopbands with high suppression on both sides of the passband, and the angle and polarization stability are excellent. It has great application value in the fields of modern communication, radar, and military defense.

[0067] As Figure 1 shown, the radome of the present invention adopts the frequency selective surface technology composed of a periodic unit structure array. The embodiment adopts a 20*20 periodic unit array. The unit period in the present invention is 16mm, and the corresponding size can be selected according to specific design objectives in actual applications.

[0068] As Figure 2 shown, the radome of the present invention adopts the frequency selective surface technology composed of a periodic unit structure array. Each periodic unit structure is composed of three dielectric layers and four metal layers. When electromagnetic waves in free space are incident on the radome, it will have a selective characteristic for electromagnetic waves of a specific incident frequency, enabling the signals in the antenna operating frequency band to pass through normally, while having a good suppression effect on the frequency bands on both sides of the antenna operating frequency band, showing a high-speed roll-off characteristic.

[0069] The Rogers RO3003 board is used for the dielectric board in the present invention, and its periodic unit size is 16mm. The characteristic of this board is that its dielectric loss is very small, so the influence on the insertion loss of the passband is smaller. However, the price of this board is relatively high, and in actual applications, a board with a dielectric constant similar to this material can also be selected for design and processing to reduce the production cost.

[0070] When the sizes of the cross-shaped patch T1 and the square metal patch T2 in the top and bottom metal patches P1 and P3 increase, the passband will shift towards the low-frequency direction. This is mainly because T1 and T2 control the size of the capacitor C1 in the equivalent circuit. When their sizes increase, the capacitor C1 increases, thus causing the resonant frequency to shift towards the low frequency. Similarly, when the width of the second metal patch increases, the passband will shift towards the high-frequency direction, and the shift of the stopband is smaller. This is mainly because when the width of the second metal patch increases, its equivalent inductance will decrease correspondingly, causing the transmission pole to increase. Since this inductance also affects the transmission zero point, the stopband will also shift towards the high frequency accordingly.

[0071] Upper metal patch P 21 and the lower metal patch P 22 The dissimilar Jerusalem cross structure formed by T4, T5 and T6 in is the design innovation of the present invention. In the traditional Jerusalem cross, the magnitude of the inductance is directly proportional to the length l1 of the metal strip T4 and inversely proportional to the width w1 of the metal strip T4, while the magnitude of the capacitance is directly proportional to the length l2 and the width w2 of the second metal patch. If designed according to the traditional Jerusalem cross method, increasing the capacitance will inevitably result in a decrease in the inductance, and the structure cannot resonate at the low frequency of the passband. Therefore, it is necessary to innovate the traditional Jerusalem cross structure. The second metal patch and the metal strip T4 are printed on both sides of the PCB board and electrically connected through the via T6, which can increase the magnitudes of the equivalent capacitance and inductance simultaneously and form a stopband at low frequencies. In addition, in order to improve the angular stability of the stopband structure, a first metal patch is introduced directly above the metal strip T4, that is, a coupling capacitor C3 with strong angular stability is introduced, and this coupling capacitor is not easily affected by the incident angle of electromagnetic waves. Table 1 specifically describes the influence of the dimensions of the structures T4 and T5 on the stopband performance. Figure 9 Specifically describes the influence of the structures T4 and T5 on the transmission performance of the radome in the present invention.

[0072] Table 1 Influence of the dimensions of the structures T4 and T5 on the transmission performance

[0073]

[0074]

[0075] The transmission characteristic curve of this embodiment when the electromagnetic wave is vertically incident is as Figure 10 shown. In the frequency band range of 2.48 GHz - 6.81 GHz, the passband insertion loss is less than 3 dB, and in the frequency band range of 2.74 GHz - 6.65 GHz, the passband insertion loss is less than 1 dB; in the frequency bands of 1.68 GHz - 2.04 GHz and 7.25 GHz - 7.93 GHz, the stopband suppression is greater than 15 dB, and the roll-off speeds on both sides of the passband reach 25.6 dB / GHz and 31.48 dB / GHz respectively. At the same time, it can be found that the transmission effects in the two polarization modes of TE and TM are completely consistent, well meeting the design requirements of the 5G communication radome.

[0076] As Figure 11As shown, the influence of the change in the incident angle of electromagnetic waves on the transmission performance of the radome is described. It can be found that within the incident angle range of ±60°, as the incident angle increases, due to the change in wave impedance caused by the increase in the incident angle, inevitable problems such as an increase in the passband insertion loss in the TE mode and a decrease in the stopband bandwidth in the TM mode occur. However, it can be seen that with the increase in the angle, in both the TE mode and the TM mode, the passband performance always remains good, and the average insertion loss within the band is always less than 0.5 dB, achieving a transparent effect on the antenna operating signal; for the TE mode, as the incident angle increases, the width of the stopband broadens, but the passband width remains stable. For the TM mode, as the incident angle increases, the width of the stopband decreases, but even at an incident angle of 60°, the stopband widths at low frequency and high frequency can still reach 500 MHz and 200 MHz, respectively, and the transmission passband width remains stable. Whether in the TE or TM mode, the position of the transmission zero point always remains stable.

[0077] Therefore, the present invention realizes a high-performance antenna radome design with low-loss transmission of operating signals in 5G communication, high suppression of signals on both sides of the operating signal, and quite stable angle and dual-polarization performance.

Claims

1. A high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband, characterized by: The radome is a frequency selective surface mainly composed of a plurality of identical periodic unit structures closely arranged in the form of a planar array; Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes an upper dielectric layer D1, a middle dielectric layer D2 and a lower dielectric layer D3 arranged in sequence from top to bottom. The metal layer includes a top metal patch P1, an upper metal patch P 21 , bottom metal patch P 22 and bottom metal patch P3; The top metal patch P1 is attached to the upper surface of the top dielectric D1. 21 The top metal patch P1, the top dielectric D1, the middle dielectric D2, the lower dielectric D3 and the bottom metal patch P3 are all square. 22 With the upper metal patch P 21 The structure and size are the same, the lower metal patch P 22 Relative to the upper metal patch P 21 Rotate 90° and stick it on the lower surface of the middle layer medium D2. The upper metal patch P 21 and the lower metal patch P 22 The bottom metal patch P3 is attached to the lower surface of the bottom medium D3 through its own via holes for electrical connection; the electromagnetic waves in the free space are selectively filtered by the antenna cover and then output as electromagnetic waves in the required working frequency band.

2. According to claim 1, a high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband, characterized in that: The top metal patch P1 and the bottom metal patch P3 have the same structure and size, and the top dielectric D1 and the bottom dielectric D3 have the same structure and size.

3. According to claim 2, a high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband, characterized in that: The top metal patch P1 and the bottom metal patch P3 are mainly composed of a plurality of repeating units arranged closely in the form of a planar array, each repeating unit includes a cross-shaped metal patch T1 and square corner pieces located at the four corners around the cross-shaped metal patch T1, the square corner pieces between every four adjacent repeating units are connected as a whole to form a square metal patch T2, and there are gaps between the cross-shaped metal patch T1 and the square corner pieces, and between the cross-shaped metal patches T1 in adjacent repeating units; The top metal patch P1 and the bottom metal patch P3 are respectively attached to the center of the top dielectric D1 and the bottom dielectric D3.

4. The high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to claim 1, characterized in that: The upper metal patch P 21 and the lower metal patch P 22 They are mainly composed of a first metal patch pair T3, a second metal patch pair T5, a metal strip T4 and a via; A metal strip T4 is provided at the symmetry axis of the intermediate layer medium D2, and the metal strip T4 is perpendicular to the two opposite sides of the intermediate layer medium D2. The first metal patch pair T3 is mainly composed of two identical first metal patches, and the two first metal patches are symmetrically attached to the two opposite sides of the intermediate layer medium D2, and the side of the intermediate layer medium D2 where the first metal patches are located is perpendicular to the metal strip T4. The second metal patch pair T5 is mainly composed of two identical second metal patches, and the two second metal patches are symmetrically attached to the intermediate layer medium D2. The sides of the intermediate layer medium D2 where the second metal patch is located are parallel to the metal strip T4; vias are provided at both ends of the metal strip T4, and the two vias are not connected to the first metal patch pair T3; each second metal patch is provided with a via, and the vias on the second metal patch are provided at the symmetry axis of the intermediate layer medium D2 perpendicular to the metal strip T4, and the distance from the vias on the second metal patch to the center of the intermediate layer medium D2 is equal to the distance from the vias at both ends of the metal strip T4 to the center of the intermediate layer medium D2; Upper metal patch P 21 The two vias set on the second metal patch pair T5 are respectively connected to the lower metal patch P 22 The vias at both ends of the middle metal strip T4 are coaxially connected; the lower metal patch P 22 The vias set on the second metal patch pair T5 are respectively connected to the upper metal patch P 21 The via holes at both ends of the middle metal strip T4 are coaxially connected to each other.

5. The high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to claim 4, characterized in that: The first metal patches are rectangular, and one of the long sides of each first metal patch is flush with the side of the middle layer medium D2 where the first metal patch is located.

6. The high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to claim 4, characterized in that: Both ends of the second metal patch are in a stepped shape, and the long side of each second metal patch is parallel to the side of the middle layer medium D2 where the second metal patch is located, and there is a gap.

7. The high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to claim 1, characterized in that: The top layer medium D1, the middle layer medium D2 and the bottom layer medium D3 are all made of plates with a dielectric constant of 3 and a dielectric loss tangent value of 0.

001.

8. The high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to claim 1, characterized in that: The frequency of the electromagnetic wave incident on the radome is 1.5 GHz-8 GHz, and when the angle of the electromagnetic wave incident on the radome changes within the range of ±60°, the zero point position does not change.

9. Application of a high-performance communication antenna cover with ultra-wide passband and high-speed roll-off on both sides of the passband according to any one of claims 1 to 8, characterized in that: The radome is used in 5G modern communications, radar and military communications.

Images