Low profile broadband high isolation dual-frequency co-axial antenna

Abstract

The utility model discloses a kind of low profile wideband high-isolation dual-frequency common aperture antennas, it is related to common aperture antenna technical field, radiation layer includes Ku band radiation patch, dielectric substrate five, PMI foam, four ka band radiation patch two, dielectric substrate four, four Ka band radiation patch one and dielectric substrate three, dielectric substrate five and PMI foam are all provided with four rectangular array through slot, Ka band radiation patch one is provided with cross slot;Feed layer includes coupling gap, dielectric substrate two, feed line, dielectric substrate one and multiple ground columns.Antenna profile height is reduced to, and can be conformal with carrier;Realize Ku band operating bandwidth is above 30%, Ka band is above 20%;Realize dual-band two-dimensional scanning range is in ≥±50 °, realize two-dimensional wide-angle coverage;Realize different frequency port isolation ≥40dB.

Description

Technical Field

[0001] This utility model relates to the field of common aperture antenna technology, and in particular to a low-profile broadband high-isolation dual-frequency common aperture antenna. Background Technology

[0002] The concept of common-aperture antennas was first proposed in 1982. Since then, with the continuous development of antenna technology, numerous scholars both domestically and internationally have participated in the research of common-aperture antennas, proposing a variety of novel structures and designs. At the same time, the application scenarios of common-aperture antennas have become more diversified, leading to research on common-aperture phased array antennas.

[0003] Common-aperture phased array antennas can be structurally classified into two types: brick-type and tile-type. Brick-type structures utilize depth dimensions to provide the functionality of multi-layer arrays found in tile-type structures. They can be manufactured using monolithic integrated circuit technology, making them suitable for low-cost manufacturing. Their transmitter and receiver (T / R) components adopt a vertical layout and horizontal assembly, often perpendicular to the radiating aperture. Brick-type structures typically use printed circuit dipole arrays. Tile-type phased array antennas, on the other hand, often employ planar radiators such as microstrip patches and microstrip dipoles. Their T / R components adopt a horizontal layout, vertical assembly, and vertical interconnection.

[0004] With the continuous development of chip technology, phased array antennas are gradually moving towards integration and miniaturization, and tile-type phased array antennas are increasingly becoming a focus of academic and engineering research. Compared to phased array antennas with a brick-like structure, tile-type co-aperture phased array antennas, because they do not rely on the depth dimension of the structure to provide corresponding performance, typically have advantages such as small size, light weight, low profile, high integration, easy conformal design, and flexible use. However, they also face problems such as large mutual interference between array elements and high integration difficulty.

[0005] In 2019, SYLiu et al. designed a tile-type Ku / Ka dual-band common-aperture phased array antenna. This antenna consists of planar dipoles operating in the Ku band and square patch elements operating in the Ka band. Due to mutual coupling and surface wave modes during beam scanning, a scanning dead zone effect was generated, affecting the maximum scanning angle of the array. To address this, the authors introduced a metal shielding aperture and a DGS structure to cut off surface wave transmission and suppress structural interference. The DGS structure has the advantages of simplicity and compactness, and it can generate resonance without relying on the establishment of a periodic structure, exhibiting good bandgap characteristics. Ultimately, the dual-band array achieved relative bandwidths of 10.7% and 9.1% in the Ku and Ka bands, respectively, with a two-dimensional scanning range covering ±45°.

[0006] In 2024, SLLu et al. proposed a low-profile Ku-band dual-polarized / Ka-band single-polarized co-aperture phased array antenna. This antenna uses dual-polarized slots and square ring patches as radiators for the Ku and Ka bands, respectively, arranged alternately. The Ka-band radiator is located above the Ku-band radiator, and the metal surface surrounding the Ku-band dual-polarized slot serves as the ground for the Ka-band antenna. By adding metal shielding holes around the Ka-band and rationally designing the feed port position for the Ka-band, mutual interference during dual-band beam scanning was reduced; achieving ±45° beam scanning in the Ku-band dual-polarization and ±30° beam scanning in the Ka-band.

[0007] Currently, there are various implementation schemes for co-aperture phased array antennas with brick-like and tile-like structures, but simultaneously achieving the dual-band two-dimensional wide-angle scanning performance remains challenging. In particular, for co-aperture phased array antennas operating in the Ku / Ka band, the frequency ratio of the operating bands is close to 2:1, with the high frequency falling within the second harmonic of the low frequency. This means that the two bands are prone to interference. Often, at specific scanning angles, complex factors such as radiator obstruction and the generation of higher-order modes cause deterioration of the port reflection coefficient and the generation of scanning blind spots, making it difficult to simultaneously achieve the dual-band and two-dimensional wide-angle scanning performance.

[0008] The existing technical solutions have the following main technical shortcomings:

[0009] ① Traditional common-aperture brick-type phased array antennas are heavy and bulky, which is not conducive to system integration;

[0010] ② Traditional common-aperture antennas have narrow operating bandwidths. Under current technology, the operating bandwidth of Ku band is less than 20%, and that of Ka band is less than 10%.

[0011] ③ Traditional common-aperture antennas have a small scanning range. Under current technology, the two-dimensional scanning range is about ±45°, which makes it difficult to achieve two-dimensional wide-angle coverage.

[0012] ④ Traditional common-aperture antennas have poor isolation between different frequency ports. Since the frequency ratio of the operating frequency band is close to 2:1, the high frequency falls within the second harmonic of the low frequency, and the two frequency bands are prone to crosstalk, causing abnormal high-frequency antenna beams. Utility Model Content

[0013] To address the shortcomings of existing technologies, this utility model provides a low-profile, broadband, high-isolation dual-frequency common-aperture antenna. To address the issues of large weight and size, a microstrip tile phased array antenna design is adopted to reduce the profile height. To address the narrow operating bandwidth, the antenna's operating bandwidth is expanded by increasing the number of resonant points. To address the small scanning range, two-dimensional wide-angle coverage is achieved. To address the poor isolation of inter-frequency ports, the isolation of inter-frequency ports is improved.

[0014] In order to achieve the purpose of this utility model, the following solution is proposed:

[0015] A low-profile, broadband, high-isolation dual-frequency common-aperture antenna is provided, which adopts a tile-type phased array antenna design and includes a radiating layer and a feed layer located at its bottom.

[0016] The radiating layer, from top to bottom, includes a Ku-band radiating patch, dielectric substrate five, PMI foam, four Ka-band radiating patches two, dielectric substrate four, four Ka-band radiating patches one, and dielectric substrate three. Dielectric substrate five and PMI foam are each provided with four rectangular arrays of through slots. The Ku-band radiating patch is located between the four through slots. The positions of Ka-band radiating patch one and Ka-band radiating patch two correspond to each other. The positions of Ka-band radiating patch two and through slots correspond to each other. Ka-band radiating patch one is provided with a cross-shaped groove that divides itself into four equal parts.

[0017] The feed layer, from top to bottom, includes coupling gaps, dielectric substrate two, feed lines, dielectric substrate one, and multiple grounding posts. The coupling gaps include Ku-band coupling gaps and Ka-band coupling gaps. Dielectric substrate two is also provided with Ku-band clearance holes and Ka-band clearance holes. The feed lines include Ku-band vertically polarized feed lines and Ka-band horizontally polarized feed lines.

[0018] Furthermore, in the radiating layer, the dielectric substrates are all high-frequency board material TSM-DS3, and the dielectric substrates are bonded together by PP, all of which are Rogers 4450F.

[0019] Furthermore, in the feed layer, the dielectric substrate is a high-frequency substrate TSM-DS3.

[0020] Furthermore, the Ku-band radiating patch is strip-shaped.

[0021] This design employs a tile-type phased array antenna, with an antenna size of [missing information]. ,in To accommodate the wavelength corresponding to the center frequency in the low-frequency band, the Ku and Ka elements in this scheme are arranged in a one-to-four configuration, integrated together in a square aperture with a side length of 0.48. Both the Ku and Ka elements are arranged in a full array with equal spacing. This design simplifies the array layout, facilitates low sidelobes, ensures a consistent environment around the Ku antenna for easy simulation analysis, and allows for standardized T / R modules with consistent feed interfaces. Furthermore, the compact structure and the larger number of Ka elements enable higher gain.

[0022] This solution employs a slot coupling design for the Ku-band antenna. By combining slot coupling with PMI foam, the antenna bandwidth is effectively extended. The Ku-band signal is delivered from the SMP through a vertically polarized feed line and then coupled to the Ku-band radiating patch via slot coupling. The Ku-band radiating patch uses a strip structure to reduce obstruction of the Ka-band radiating patch. The Ka-band antenna uses a stacked patch design with slot coupling. The Ka-band signal is delivered from the SMP through a horizontally polarized feed line and then coupled to Ka-band radiating patch one via slot coupling. A new resonant point is generated through Ka-band radiating patch two, effectively extending the antenna's operating bandwidth. At the same time, the parasitic patch can improve the antenna gain.

[0023] In this scheme, the Ku and Ka antennas are independently positioned, achieving spatial diversity. Furthermore, the polarization of the two antennas is orthogonal, with the Ku antenna being vertically polarized and the Ka antenna being horizontally polarized. Due to polarization mismatch at high frequencies, the second harmonic signal from the Ku antenna is unlikely to enter the channel of the Ka antenna. In addition, the feed line of the Ka antenna has metallized vias, so a relatively high channel isolation can be achieved between the Ku and Ka antennas in the high-frequency band.

[0024] In this design, metal clearance holes are opened above the SMP pin positions of both the Ka and Ku antennas. The purpose is to allow the inner core of the SMP to pass through the stripline, which facilitates subsequent processing and assembly, and also makes it easier to integrate with the back-end TR.

[0025] The beneficial effects of this utility model are as follows:

[0026] 1. To correspond to the wavelength of the center frequency in the low-frequency band, the antenna profile height provided by this invention is reduced to [missing information]. Furthermore, it can conform to the carrier;

[0027] 2. Achieve a Ku-band operating bandwidth of over 30% and a Ka-band bandwidth of over 20%;

[0028] 3. Achieve dual-band two-dimensional scanning range of ≥±50°, realizing two-dimensional wide-angle coverage;

[0029] 4. Achieve inter-frequency port isolation ≥ 40dB. Attached Figure Description

[0030] Figure 1 An exploded view of the antenna is shown;

[0031] Figure 2 A side view of the antenna is shown;

[0032] Figure 3 The array element distribution diagram is shown;

[0033] Figure 4 The bandwidth diagram of the Ku antenna at S11 is shown;

[0034] Figure 5 The bandwidth diagram of the Ka antenna at S11 is shown;

[0035] Figure 6 The diagram shows the isolation of the different frequency ports when Ka-band is excited;

[0036] Figure 7 The diagram shows the isolation of different frequency ports during Ku-band excitation;

[0037] Figure 8 The Ku-band beam scanning characteristics are shown.

[0038] Figure 9 The Ka-band beam scanning characteristics are shown. Detailed Implementation

[0039] like Figure 1 , Figure 2 As shown, this embodiment provides a low-profile broadband high-isolation dual-frequency common-aperture antenna, which adopts a tile-type phased array antenna design and consists of two parts: a radiating layer and a feeding layer.

[0040] like Figure 1 As shown, the radiating layer, from top to bottom, includes a Ku-band radiating patch, dielectric substrate five, PMI foam, four Ka-band radiating patches two, dielectric substrate four, four Ka-band radiating patches one, and dielectric substrate three. Dielectric substrate five and PMI foam each have four rectangular arrays of through slots. The Ku-band radiating patches are strip-shaped and located between the four through slots. Ka-band radiating patches one and two correspond in position, and Ka-band radiating patches two correspond in position to the through slots. Ka-band radiating patches one have a cross-shaped groove dividing itself into four equal parts. All dielectric substrates are high-frequency TSM-DS3 substrates, bonded together with Rogers 4450F PP.

[0041] like Figure 2 As shown, the feed layer, from top to bottom, includes coupling slots, a second dielectric substrate, feed lines, a first dielectric substrate, and multiple grounding posts. The coupling slots include Ku-band and Ka-band coupling slots. The second dielectric substrate also has Ku-band and Ka-band clearance vias. The feed lines include Ku-band vertically polarized feed lines and Ka-band horizontally polarized feed lines. In the feed layer, the dielectric substrates are all high-frequency TSM-DS3 substrates.

[0042] That is, a dual-frequency array element consists of one Ku array element and four Ka array elements. The Ku array element is located at the center, and the four Ka array elements are located in the four quadrants with the center of the array as the dividing line. (Refer to...) Figure 3The Ku-element array is strip-shaped, which reduces the horizontal polarization component of the antenna and reduces the obstruction of the Ka-element array. At the same time, it can be combined with frequency selection technology to optimize the Ku-element array so that it can transmit Ka-band signals. The Ka-element array is placed in a mirror image. By reversing the phase of the elements, the polarization purity of the Ka-band antenna is improved. Meanwhile, the meandering technique is used. In order to increase the effective path of the antenna surface current, a cross slot is opened in the Ka-band radiating patch to introduce disturbance. In this way, the resonant frequency of the antenna can be further adjusted by adjusting the size of the antenna and the slot line, so that it is moved to a lower frequency, thereby realizing the miniaturization of the Ka antenna.

[0043] The dual-band antenna element feed layer forms a closed SIW cavity through grounding posts to ensure sufficient isolation between the dual-band elements. In addition, the Ku and Ka array elements are connected by equally spaced metal isolation posts to form a closed SIW resonant cavity. By performing field analysis on the feed layer, shielding posts are placed at locations with strong resonance interference to improve the isolation between different frequencies. At the same time, H-shaped slots are used, which have frequency selectivity effects, thus further improving the channel isolation between different frequencies.

[0044] Ultimately, the dual-band Ku-band antenna achieves a relative bandwidth of 33.2% and an absolute bandwidth of 5 GHz within an S11 < -10 dB range, according to reference... Figure 4 The Ka antenna achieves a relative bandwidth of 22% and an absolute bandwidth of 7.5 GHz within an S11 < -10 dB range, according to reference... Figure 5 When operating in the Ka band, the Ku band port isolation is ≥55dB, reference. Figure 6 When operating in the Ku band, the port isolation in the Ka band should be ≥40dB, according to reference. Figure 7 .

[0045] By arraying dual-band antennas, the beam characteristics of a 4×4 subarray in the Ku band allow for a two-dimensional scanning range covering ±50°, as referenced. Figure 8 The Ka-band 8×8 subarray and beam characteristics, with a two-dimensional scanning range covering ±50°, reference... Figure 9 .

[0046] The above embodiments are only used to illustrate the technical concept and features of this utility model, and are not intended to be unique or to limit this utility model. Those skilled in the art should understand that various changes or equivalent substitutions made to this utility model without departing from its scope are all within the protection scope of this utility model.

Claims

1. A low-profile, broadband, high-isolation dual-frequency common-aperture antenna, characterized in that, It adopts a tile-type phased array antenna design, including a radiating layer and a feed layer located at its bottom; The radiating layer, from top to bottom, includes a Ku-band radiating patch, dielectric substrate five, PMI foam, four Ka-band radiating patches two, dielectric substrate four, four Ka-band radiating patches one, and dielectric substrate three. Dielectric substrate five and PMI foam are each provided with four rectangular arrays of through slots. The Ku-band radiating patch is located between the four through slots. The positions of Ka-band radiating patch one and Ka-band radiating patch two correspond to each other. The positions of Ka-band radiating patch two and through slots correspond to each other. Ka-band radiating patch one is provided with a cross-shaped groove that divides itself into four equal parts. The feed layer, from top to bottom, includes coupling gaps, dielectric substrate two, feed lines, dielectric substrate one, and multiple grounding posts. The coupling gaps include Ku-band coupling gaps and Ka-band coupling gaps. Dielectric substrate two is also provided with Ku-band clearance holes and Ka-band clearance holes. The feed lines include Ku-band vertically polarized feed lines and Ka-band horizontally polarized feed lines.

2. The low-profile broadband high-isolation dual-frequency common-aperture antenna according to claim 1, characterized in that, In the radiating layer, the dielectric substrates are all high-frequency board material TSM-DS3, and the dielectric substrates are bonded together by PP, all of which are Rogers 4450F.

3. The low-profile broadband high-isolation dual-frequency common-aperture antenna according to claim 1, characterized in that, In the feed layer, the dielectric substrate is a high-frequency substrate TSM-DS3.

4. The low-profile broadband high-isolation dual-frequency common-aperture antenna according to claim 1, characterized in that, The Ku-band radiating patch is strip-shaped.

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