A high-performance communication antenna cover with super-wide passband and double-edge high-speed roll-off

Abstract

This invention discloses a high-performance communication radome with an ultra-wide passband and high-speed roll-off on both sides of the passband. The radome is a frequency-selective surface composed of multiple periodic unit structures arranged in a planar array. Each periodic unit structure is divided into a dielectric layer and a metal layer. The top metal patch is attached to the upper surface of the top dielectric layer, the upper metal patch is attached to the upper surface of the middle dielectric layer, and the lower metal patch is rotated 90° relative to the upper metal patch and attached to the lower surface of the middle dielectric layer. The upper and lower metal patches are electrically connected through vias, and the bottom metal patch is attached to the lower surface of the bottom dielectric layer. Electromagnetic waves in free space are selectively filtered by the radome and output as electromagnetic waves in the required operating frequency band. This invention features an ultra-wide passband with high-speed roll-off on both sides of the passband, low and stable insertion loss within the passband, and excellent angular and polarization stability, making it of great value in modern communications, radar, and military defense fields.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a high-performance communication radome with an ultra-wide passband and high-speed roll-off on both sides of the passband, which can be applied to high-frequency 5G communication and radar. Background Technology

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

[0003] The performance of existing communication antenna radomes is insufficient to meet the needs of 5G communication, mainly due to the following problems: limited passband range, unable to cover multiple frequency bands, difficulty in balancing wide-area coverage of low-frequency bands and high-speed transmission of high-frequency bands, and difficulty in supporting the large bandwidth signal transmission required by 5G systems; poor out-of-band suppression performance, susceptible to interference between frequency bands, reducing communication quality, and unable to effectively avoid interference signals; and high manufacturing cost, making it difficult to achieve large-scale application in scenarios with high economic requirements.

[0004] Through extensive literature review, industry analysis, and technical research, an integrated filter radome designed with a periodic metamaterial structure has been identified as a feasible solution. A radome is an outer shell used to protect antennas or the entire microwave system from environmental influences. It is widely used in wireless systems, and frequency selective surfaces (FSS) are commonly employed in radome design. FSS radomes possess frequency selectivity, maintaining high transmittance within a specified frequency band while rapidly rolling off outside the passband to effectively suppress out-of-band signal transmission. This characteristic ensures signal stability in multi-band communication, reduces inter-band interference, and thus improves the overall performance of the communication system. This is particularly important for antenna systems that need to support 5G multi-band, high-speed transmission. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a high-performance communication radome with an ultra-wide passband and high-speed roll-off on both sides of the passband. Through the ingenious coupling design between the three-layer structure and the four metal layers, it has stable and efficient selective transmission of electromagnetic waves incident from all directions in space.

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

[0007] The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband is a frequency selective surface mainly composed of multiple identical periodic unit structures arranged in a planar array.

[0008] Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes, from top to bottom, an upper dielectric D1, an intermediate dielectric D2, and a lower dielectric D3. The metal layer includes, from top to bottom, a top metal patch P1, an upper metal patch P2, and a lower metal patch P3. 21 Lower metal patch P 22 and the underlying metal patch P3;

[0009] The top metal patch P1 is attached to the upper surface of the top dielectric D1. 21 The top metal patch P1, top dielectric D1, middle dielectric D2, bottom dielectric D3, and bottom metal patch P3 are all square, attached to the upper surface of the intermediate layer dielectric D2. 22 With the upper metal patch P 21 The structure and dimensions are the same, with the lower metal patch P. 22 Compared to the upper metal patch P 21 Rotate 90° and attach it to the lower surface of the intermediate layer medium D2, the upper metal patch P 21 and the lower metal patch P 22 Electrical connections are made through their own vias, and the bottom metal patch P3 is attached to the lower surface of the bottom dielectric D3; electromagnetic waves in free space are selectively filtered by the radome and then output as electromagnetic waves in the required operating 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 mainly composed of multiple repeating units arranged closely in 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 to form a square metal patch T2. 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.

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

[0013] 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 vias;

[0014] A metal strip T4 is disposed at the axis of symmetry of the intermediate layer medium D2. The metal strip T4 is perpendicular to two opposite sides of the intermediate layer medium D2. The first metal patch pair T3 is mainly composed of two identical first metal patches, which are symmetrically attached to opposite sides of the intermediate layer medium D2. The edges of the intermediate layer medium D2 where the first metal patches are located are perpendicular to the metal strip T4. The second metal patch pair T5 is mainly composed of two identical second metal patches, which are symmetrically attached to the intermediate layer medium. On both sides of material D2, the edge of the intermediate layer medium D2 where the second metal patch is located is parallel to the metal strip T4; both ends of the metal strip T4 are provided with vias, and neither of the two vias is connected to the first metal patch T4; each second metal patch is provided with a via, and the via on the second metal patch is located at the axis of symmetry of the intermediate layer medium D2 perpendicular to the metal strip T4, and the distance from the via 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;

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

[0016] The first metal patch is rectangular, and one of the long sides of each first metal patch is aligned with the side containing itself in the intermediate layer medium 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 of itself in the intermediate layer medium D2 and there is a gap.

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

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

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

[0021] The beneficial effects of this invention are:

[0022] The radome design of this invention uses multimode coupling technology to achieve miniaturization of the frequency selective surface structure. The final unit size is about 0.24λ, and more units can be placed in the same area, so that the manufactured board is closer to an infinite periodic structure. However, this miniaturization is still suitable for processing and production using traditional PCB processes.

[0023] The multimode coupling between the top, middle, and bottom metal layers of this invention provides an ultra-wide passband with extremely low insertion loss for the radome. For electromagnetic waves incident perpendicularly to the radome, after passing through each layer of the radome structure, the passband insertion loss is less than 3dB in the 2.48GHz–6.81GHz frequency band and less than 1dB in the 2.74GHz–6.65GHz frequency band. When the incident angle reaches 60°, the average insertion loss of TE and TM polarization in the 2.74GHz–6.65GHz frequency band is less than 0.5dB.

[0024] The intermediate layer of this invention provides a wide-bandwidth stopband with high-speed roll-off on both sides of the radome through a modified Jerusalem cross metal structure. When spatial electromagnetic waves are incident perpendicularly on the radome, the stopband suppression is greater than 15dB in the 1.68GHz–2.04GHz and 7.25GHz–7.93GHz frequency bands, and the roll-off velocities on both sides of the passband reach 25.6dB / GHz and 31.48dB / GHz, respectively.

[0025] The unique structural design of this invention gives it an ultra-wide passband and ultra-high selectivity. Furthermore, its transmission response remains stable within an incident angle range of ±60°, and its transmission null point is remarkably stable with virtually no shift, ensuring the normal operation of the radome system. In addition, the invention employs a completely symmetrical design, resulting in stable electromagnetic dual-polarization performance and supporting both TE and TM polarization modes.

[0026] This invention has extremely high application value in antenna device miniaturization, 5G and other modern communications, radar and military communications.

[0027] In summary, this invention is suitable for mobile communication radome designs featuring a wide passband, high roll-off on both sides of the passband, and high angular and polarization stability. It exhibits low and stable insertion loss within the ultra-wide passband, high suppression stopbands on both sides of the passband, excellent angular and polarization stability, and is easy to implement. It has significant application value in modern communications, radar, and military defense fields. This radome not only meets the ultra-wideband requirements of 5G communication, ensuring rapid attenuation of out-of-band signals, but also enhances anti-interference capabilities in complex 5G communication environments, providing crucial support for high-performance, low-latency 5G communication and meeting the multi-band operating requirements of modern communication systems. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural diagram of the radome according to an embodiment of the present invention;

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

[0030] Figure 3 These are metal structure views of each layer of the unit structure of the present invention;

[0031] Figure 4 This is a view showing the top and bottom metal structures and their equivalent LC elements in the unit structure of this invention;

[0032] Figure 5 This is a view showing the intermediate layer metal structure and its equivalent LC element in the unit structure of this invention;

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

[0034] Figure 7 These are curves showing the influence of the length of the metal strips in the upper and lower metal patches on the transmission performance of the radome in this invention.

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

[0036] Figure 9 The radome of this invention has transmission performance curves for vertical incidence TE and TM polarization modes;

[0037] Figure 10 This is the curve showing the effect of the electromagnetic wave incident angle on the performance of the radome of this invention in TE polarization mode;

[0038] Figure 11 This is the curve showing the effect of the incident angle of the TM polarized mode electromagnetic wave on the performance of the radome in this invention. Detailed Implementation

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

[0040] Specific implementations of high-performance communication antenna radomes, such as Figure 1 As shown, the frequency selective surface is mainly composed of multiple identical periodic unit structures arranged closely in a planar array.

[0041] Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes, from top to bottom, an upper dielectric D1, an intermediate dielectric D2, and a lower dielectric D3. The metal layer includes, from top to bottom, a top metal patch P1, an upper metal patch P2, and a lower metal patch P3. 21 Lower metal patch P22 and the underlying metal patch P3;

[0042] The top metal patch P1 is attached to the upper surface of the top dielectric D1. 21 The top metal patch P1, top dielectric D1, middle dielectric D2, bottom dielectric D3, and bottom metal patch P3 are all square, attached to the upper surface of the intermediate layer dielectric D2. 22 With the upper metal patch P 21 The structure and size are the same, with the lower metal patch P 22 Compared to the upper metal patch P 21 Rotate 90° and attach it to the lower surface of the intermediate layer medium D2, the upper metal patch P 21 and the lower metal patch P 22 Electrical connections are made via their own vias. The bottom metal patch P3 is attached to the lower surface of the bottom dielectric D3, and the final arrangement of the metal layers is as follows: Figure 2 As shown, electromagnetic waves in free space are selectively filtered by the radome to remove clutter and output electromagnetic waves in the required operating frequency band.

[0043] When electromagnetic waves in free space are incident on an radome, they exhibit selective characteristics for specific incident frequencies. This allows signals within the antenna's operating frequency band to pass through normally, while effectively suppressing frequencies on either side of the operating band, exhibiting high-speed roll-off characteristics. This frequency selectivity stems from the periodic structural resonance of the radome and its spatial bandpass filtering characteristics. Through a combination of capacitive and inductive bandgap and mesh metal structures, the radome resonates at specific frequencies. By optimizing the geometry, dimensions, and material properties of the metal structure, the passband range, center frequency, and roll-off rate can be precisely adjusted to form a bandpass filter structure that selectively transmits signals in the desired frequency band.

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

[0045] Both the top metal patch P1 and the bottom metal patch P3 are mainly composed of multiple repeating units arranged closely in 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 to form a square metal patch T2. There are uniform gaps between the cross-shaped metal patch T1 and the square corner pieces, and at all points of the cross-shaped metal patch T1 in adjacent repeating units.

[0046] Top metal patch P1 and bottom metal patch P3 are respectively attached to the center of top medium D1 and bottom medium D3.

[0047] The repeating unit has a central axis symmetry structure. The top metal patch P1 and the bottom metal patch P3 are both square, and the four sides of the top metal patch P1 and the bottom metal patch P3 are the boundary 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] Upper metal patch P 21 and the lower metal patch P 21 All are centrally symmetrical structures, with an upper metal patch P. 21 and the lower metal patch P 22 Each is mainly composed of a first metal patch pair T3, a second metal patch pair T5, a metal strip T4, and four vias;

[0049] A metal strip T4 is disposed at the axis of symmetry on the surface of the intermediate layer dielectric D2. The metal strip T4 is perpendicular to two opposite sides of the intermediate layer dielectric D2. A first metal patch pair T3 mainly consists of two identical first metal patches, symmetrically attached to opposite sides of the intermediate layer dielectric D2. The edges of the intermediate layer dielectric D2 containing the first metal patches are perpendicular to the metal strip T4. A second metal patch pair T5 mainly consists of two identical second metal patches, symmetrically attached to the remaining opposite sides of the intermediate layer dielectric D2. On both sides, the edges of the intermediate layer medium D2 where the second metal patch is located are parallel to the metal strip T4; both ends of the metal strip T4 are provided with vias, the two vias are connected through the metal strip T4 and the two vias are not connected to the first metal patch T3; each second metal patch is provided with a via, the vias on the second metal patch are located at the axis of symmetry 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;

[0050] Upper metal patch P 21 The second metal patch in the middle has two vias on T5 and the lower metal patch P respectively. 22 The vias at both ends of the middle metal strip T4 are coaxially electrically connected, thereby enabling it to connect with the lower metal patch P. 22 Electrical connection of the middle metal strip T4; lower metal patch P 22 The second metal patch is connected to the via on T5 and the upper metal patch P. 21 The vias at both ends of the middle metal strip T4 are coaxially electrically connected, thereby enabling connection with the upper metal patch P. 21 The electrical connection of the metal strip T4 in the middle, the final three-layer PCB structure is as follows: Figure 2 As shown.

[0051] Lower metal patch P 22 Compared to the upper metal patch P 21 Rotate 90° and attach it to the lower surface of the intermediate layer medium D2, the upper metal patch P 21 The vias at both ends of the middle metal strip T4 and the lower metal patch P 22 The second metal patch is aligned with the via on T5, and the upper metal patch P... 21 The second metal patch on T5 has a via on the lower metal patch P. 22 The vias at both ends of the middle metal strip T4 are aligned, and the upper metal patch P... 21 Metal strip T4 and underlying metal patch P 22 The metal strips T4 in the middle are perpendicular to each other;

[0052] The first metal patch is rectangular, and one of the long sides of each first metal patch is aligned with the side of itself in the intermediate layer medium D2, serving as the edge of the periodic unit structure.

[0053] The two ends of the second metal patch are stepped, and the long side of each second metal patch is parallel to the side of itself in the intermediate layer medium D2 and there is a gap.

[0054] The length direction of each first metal patch and second metal patch is the same as the direction of its own edge in the intermediate layer medium D2.

[0055] The length of the metal strip T4 should be set as long as possible while meeting the above requirements.

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

[0057] The frequency of the electromagnetic waves incident on the radome is 1.5GHz-8GHz. When the angle of the electromagnetic waves incident on the radome varies within ±60°, the passband performance remains stable and the null position remains basically unchanged.

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

[0059] Antenna radomes are used in modern 5G communications, radar, and military communications.

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

[0061] The radome in this invention employs multimode coupling technology for frequency-selective surface structure design. A single-mode resonant unit typically consists of a pair of parallel capacitors and inductors, generating a transmission pole in the transmission response. Replicating an identical resonant unit at a suitable location through displacement produces a multi-screen effect, increasing the number of poles and achieving passband widening and reduced in-band insertion loss. By retaining the capacitors of the two resonant units and adding a dielectric layer between them, merging the inductors of the two resonant units into this layer, a frequency-selective structure composed of layered LC resonant units is obtained, resulting in a wider transmission bandwidth. Adding parallel LC resonant units in the intermediate layer further increases the number of poles, achieving an ultra-wide passband frequency-selective structure. Adding series LC resonant units in the intermediate layer introduces resonant zeros on both sides of the ultra-wide passband, enabling high-speed roll-off on both sides of the passband.

[0062] The radome in this invention miniaturizes the top and bottom capacitor sheets to improve the angular stability of the frequency-selective surface. Simultaneously, through a modified Jerusalem cross structure and the strong coupling effect of the metal on both sides of the thin dielectric in the middle layer, nulls are introduced on both sides of the ultra-wide passband. The strong coupling capacitors that generate these nulls are less affected by the direction of the incident electromagnetic wave; therefore, the nulls of the proposed structure exhibit excellent angular stability.

[0063] The top and bottom metal patches are arranged alternately with cross-shaped metal patches T1 and square metal patches T2, which are equivalent to capacitors. Together with the middle layer metal strip T4 (equivalent to an inductor), they form a layered LC resonant unit, which can generate two transmission poles. The middle layer metal patch P... 21 A pair of metal patches T3 and metal strip T4 form a resonant unit, providing the third pole. The equivalent LC correspondence of each layer structure is shown in the figure below. Figure 4 , 5 As shown.

[0064] Meanwhile, the upper metal patch P 21 The first metal patch T3, the second metal patch T5, and the metal strip T4 can be cleverly arranged to provide two sets of series LC circuits, which can provide transmission zeros on both sides of the passband, namely 1.9 GHz and 7.5 GHz, greatly improving the selectivity of the model. The capacitance that generates 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. Therefore, the zero of the proposed structure has excellent angular stability. Finally, the corresponding diagrams of the structure and equivalent LC circuit of this invention and the equivalent circuit model are shown below. Figure 4 , 5 As shown in Figure 6.

[0065] The radome in this invention adopts a quasi-symmetrical design concept, specifically reflected in the rotational symmetry between the top and bottom metal patches and the rotational symmetry between the two metal patches on both sides of the middle layer. The structure realizes the dual-polarization stability design of electromagnetic waves in TE and TM modes.

[0066] This invention is applicable to the design of mobile communication radomes with wide passband, high-speed roll-off on both sides of the passband, and high angular and polarization stability. It features low and stable insertion loss within the ultra-wide passband, high-suppression stopbands on both sides of the passband, and excellent angular and polarization stability. It has significant application value in modern communications, radar, and military defense fields.

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

[0068] like Figure 2 As shown, the radome of the present invention adopts frequency selective surface technology composed of a periodic unit structure array. Each periodic unit structure consists of three dielectric layers and four metal layers. When electromagnetic waves in free space are incident on the radome, they will produce selective characteristics for electromagnetic waves of a specific incident frequency, so that the signal in the antenna operating frequency band can pass through normally, while having a good suppression effect on the frequency bands on both sides of the antenna operating frequency band, exhibiting high-speed roll-off characteristics.

[0069] The dielectric substrate used in this invention is Rogers RO3003, with a periodic cell size of 16mm. This substrate is characterized by its very low dielectric loss, thus having a smaller impact on passband insertion loss. However, this substrate is relatively expensive. In practical applications, substrates with similar dielectric constants can be selected for design and manufacturing to reduce production costs.

[0070] When the dimensions of the cross-shaped patch T1 and the square patch T2 in the top and bottom metal patches P1 and P3 increase, the passband shifts towards lower frequencies. This is mainly because T1 and T2 control the size of the capacitance C1 in the equivalent circuit. When their dimensions increase, the capacitance C1 increases, thus shifting the resonant frequency to lower frequencies. Similarly, when the width of the second metal patch increases, the passband will shift towards higher frequencies, while the stopband shifts less. This is mainly because when the width of the second metal patch increases, its equivalent inductance decreases accordingly, resulting in a larger transmission pole. Since this inductance also affects the transmission zero, the stopband will also shift towards higher frequencies.

[0071] Upper metal patch P 21 and the lower metal patch P 22 The modified Jerusalem cross structure formed by T4, T5, and T6 is an innovative design feature of this invention. In a traditional Jerusalem cross, the inductance is directly proportional to the length l1 of the metal strip T4 and inversely proportional to its width w1, while the capacitance is directly proportional to the length l2 and width w2 of the second metal patch. Following the traditional Jerusalem cross design, increasing the capacitance inevitably reduces the inductance, preventing the structure from resonating at low frequencies in the passband. Therefore, an innovation was made to the traditional Jerusalem cross structure by printing the second metal patch and the metal strip T4 on both sides of the PCB board and electrically connecting them through via T6. This simultaneously increases the equivalent capacitance and inductance, forming a stopband at low frequencies. Furthermore, to improve the angular stability of the stopband structure, a first metal patch is introduced directly above the metal strip T4, introducing a highly angularly stable coupling capacitor C3, which is less susceptible to the influence of the electromagnetic wave incident angle. Table 1 details the impact of the dimensions of structures T4 and T5 on the stopband performance. Figure 9 The effects of structures T4 and T5 on the transmission performance of the radome in this invention are described in detail.

[0072] Table 1. Influence of structural dimensions T4 and T5 on transmission performance

[0073]

[0074]

[0075] The transmission characteristic curve of this embodiment when electromagnetic waves are incident perpendicularly is as follows: Figure 10 As shown, the passband insertion loss is less than 3dB in the 2.48GHz–6.81GHz frequency band and less than 1dB in the 2.74GHz–6.65GHz frequency band; the stopband rejection is greater than 15dB in the 1.68GHz–2.04GHz and 7.25GHz–7.93GHz frequency bands, and the roll-off velocities on both sides of the passband reach 25.6dB / GHz and 31.48dB / GHz, respectively. Furthermore, it can be observed that the transmission performance in both TE and TM polarization modes is completely consistent, effectively meeting the design requirements of 5G communication radomes.

[0076] like Figure 11The diagram illustrates the impact of varying electromagnetic wave incident angles on the radome's transmission performance. Within an incident angle range of ±60°, an increase in incident angle inevitably leads to increased passband insertion loss in TE mode and a decrease in stopband bandwidth in TM mode due to the change in wave impedance. However, it's evident that regardless of TE or TM mode, the passband performance remains consistently good, with the average insertion loss within the band consistently less than 0.5dB, achieving transparency to the antenna's operating signal. In TE mode, the stopband width widens with increasing incident angle, but the passband width remains stable. In TM mode, the stopband width decreases with increasing incident angle, but even at 60° incident angle, the low-frequency and high-frequency stopband widths still reach 500MHz and 200MHz, respectively, while the transmission passband width remains stable. The position of the transmission null remains stable in both TE and TM modes.

[0077] Therefore, this invention achieves low-loss transmission of working signals in 5G communication, high suppression of signals on both sides of the working signal, and a high-performance antenna shield design with relatively stable angle and dual polarization performance.

Claims

1. A high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband, characterized in that: The radome is a frequency selective surface mainly composed of multiple identical periodic unit structures arranged closely in a planar array. Each periodic unit structure is divided into a dielectric layer and a metal layer. The dielectric layer includes, from top to bottom, an upper dielectric D1, an intermediate dielectric D2, and a lower dielectric D3. The metal layer includes, from top to bottom, a top metal patch P1, an upper metal patch P2, and a lower metal patch P3. 21 Lower metal patch P 22 and the underlying 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, top dielectric D1, middle dielectric D2, bottom dielectric D3, and bottom metal patch P3 are all square, attached to the upper surface of the intermediate layer dielectric D2. 22 With the upper metal patch P 21 The structure and dimensions are the same, with the lower metal patch P. 22 Compared to the upper metal patch P 21 Rotate 90° and attach it to the lower surface of the intermediate layer medium D2, the upper metal patch P 21 and the lower metal patch P 22 Electrical connections are made through their own vias, and the bottom metal patch P3 is attached to the lower surface of the bottom dielectric D3; electromagnetic waves in free space are selectively filtered by the radome and then output as electromagnetic waves in the required operating frequency band.

2. The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband as described in claim 1, 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. The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband as described in claim 2, characterized in that: The top metal patch P1 and the bottom metal patch P3 are mainly composed of multiple repeating units arranged closely in 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 to form a square metal patch T2. 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 medium D1 and the bottom medium D3.

4. The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband as described in 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 vias; A metal strip T4 is disposed at the axis of symmetry of the intermediate layer medium D2. The metal strip T4 is perpendicular to two opposite sides of the intermediate layer medium D2. The first metal patch pair T3 is mainly composed of two identical first metal patches, which are symmetrically attached to opposite sides of the intermediate layer medium D2. The edges of the intermediate layer medium D2 where the first metal patches are located are perpendicular to the metal strip T4. The second metal patch pair T5 is mainly composed of two identical second metal patches, which are symmetrically attached to the intermediate layer medium. On both sides of material D2, the edge of the intermediate layer medium D2 where the second metal patch is located is parallel to the metal strip T4; both ends of the metal strip T4 are provided with vias, and neither of the two vias is connected to the first metal patch T3; each second metal patch is provided with a via, and the via on the second metal patch is located at the axis of symmetry of the intermediate layer medium D2 perpendicular to the metal strip T4, and the distance from the via 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 second metal patch in the middle has two vias on T5 and the lower metal patch P respectively. 22 The vias at both ends of the middle metal strip T4 are coaxially connected; the lower metal patch P 22 The second metal patch in the middle is connected to the vias on T5 and the upper metal patch P respectively. 21 The through holes at both ends of the T4 metal strip are coaxially connected.

5. The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband as described in claim 4, characterized in that: The first metal patch is rectangular, and one of the long sides of each first metal patch is aligned with the side containing itself in the intermediate layer medium D2.

6. The high-performance communication radome with ultra-wide passband and high-speed roll-off on both sides of the passband as described in claim 4, characterized in that: The two ends of the second metal patch are stepped, and the long side of each second metal patch is parallel to the side of itself in the intermediate layer medium D2 and there is a gap.

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

001.

8. The high-performance communication radome 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 waves incident on the radome is 1.5GHz-8GHz, and the zero point position does not change when the angle of the electromagnetic waves incident on the radome changes within the range of ±60°.

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

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