Multi-frequency common-caliber antenna based on decoupling mechanism

Abstract

The invention discloses a multi-frequency common-aperture antenna based on a decoupling mechanism. The antenna comprises at least one low-frequency antenna unit used for radiating or receiving a first frequency band signal; the at least one high-frequency antenna unit is arranged on the aperture surface shared by the low-frequency antenna unit and is used for radiating or receiving a second frequency band signal; wherein the high-frequency antenna units present a current absorption or current guiding effect in a first frequency band and are used for regulating and controlling near-field distribution among the low-frequency antenna units, and coupling suppression with directivity or a shielding effect is formed in the first frequency band. The high-frequency antenna unit has dual functions of decoupling and radiation, constructs a mutual-benefit common-caliber multi-frequency antenna system, and has important technical breakthrough significance and engineering application value in multi-frequency-band antenna design.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas in wireless communication and radar systems, and in particular relates to a multi-frequency co-aperture antenna based on a decoupling mechanism. Background Art

[0002] With the growing demand for multi-band, highly integrated antenna systems in fields such as wireless communications, radar detection, and satellite communications, common-aperture antenna technology has gradually become a research hotspot. This technology integrates antenna units operating in multiple frequency bands on the same physical aperture, achieving system miniaturization, lightweighting, and resource reuse. It is particularly suitable for space-constrained applications (such as satellites, seekers, and vehicle-mounted equipment). However, due to the high degree of spatial overlap of antenna units in different frequency bands, significant electromagnetic coupling issues often occur. In particular, near-field coupling between low-frequency antenna units can cause pattern distortion, reduced isolation, and unstable system performance.

[0003] While existing co-aperture multi-band antennas achieve multi-band integration, they often suffer from strong coupling between frequency bands, particularly between low-frequency elements. Because antenna elements of different frequency bands are coplanarly arranged on the same aperture, near-field electromagnetic interference between them is difficult to avoid. Low-frequency antennas are particularly susceptible to current induction and field disturbances from surrounding elements during operation, leading to performance degradation such as pattern distortion, gain reduction, and insufficient isolation.

[0004] Traditional decoupling methods, such as adding isolation covers, absorbing materials, or introducing additional metal structures, can alleviate the coupling problem to a certain extent, but they have the following disadvantages:

[0005] (1) Increased structural complexity: Additional structures usually increase the volume of the antenna, affecting the co-aperture integration effect;

[0006] (2) Reduced efficiency: Absorbing materials or isolation covers may introduce additional losses, reducing radiation efficiency;

[0007] (3) Poor frequency adaptability: Some filtering or impedance matching decoupling solutions have performance degradation in non-designed frequency bands and are difficult to operate in a wideband mode.

[0008] (4) Waste of resources: The high-frequency antenna is only used as a radiation unit and fails to play its multiple functional values ​​at the system level.

[0009] In summary, it is difficult for existing technologies to balance the compactness of the common aperture structure, the independence of the multi-frequency antennas, and the efficiency of the overall system. Summary of the Invention

[0010] In order to overcome the shortcomings and deficiencies of the prior art, an object of the present invention is to provide a multi-frequency co-aperture antenna based on a decoupling mechanism.

[0011] The present invention is implemented as follows: a multi-frequency co-aperture antenna based on a decoupling mechanism, the antenna comprising:

[0012] at least one low-frequency antenna unit, configured to radiate or receive signals in a first frequency band;

[0013] At least one high-frequency antenna unit, arranged on an aperture plane shared with the low-frequency antenna unit, for radiating or receiving signals in the second frequency band;

[0014] The high-frequency antenna unit exhibits a current absorption or current guiding effect in the first frequency band, and is used to regulate the near-field distribution between the low-frequency antenna units to obtain coupling suppression with directivity or shielding effect in the first frequency band.

[0015] Preferably, the high-frequency antenna unit is adjusted through structural parameters to achieve current absorption or current guiding effect in the first frequency band.

[0016] Preferably, the structural parameter adjustment includes: adjusting the size of the high-frequency patch so that it has an equivalent electrical length in the first frequency band to excite the parasitic current mode, introducing a slot structure at the edge of the patch to guide the current distribution path, and adding a resonant arm or a metal additional structure around the patch to enhance its ability to absorb or guide low-frequency near-field electromagnetic energy.

[0017] Preferably, the difference between the radiation performance of the high-frequency antenna unit in the second frequency band and in the independent working state is within the acceptable range set by the engineering and does not affect the performance of the high-frequency antenna unit as the main radiation structure.

[0018] Preferably, the low-frequency antenna unit includes a plurality of linearly arranged low-frequency units, and the low-frequency unit is a patch antenna; the high-frequency antenna unit is a slot antenna or a slot array antenna; wherein the high-frequency antenna unit surrounds the low-frequency antenna unit in a mirror-symmetrical or interlaced arrangement.

[0019] Preferably, the antenna includes a metal layer 1, a dielectric layer 2, a metal layer 2, a dielectric layer 2, a metal layer 3 and a substrate arranged from top to bottom; wherein the high-frequency antenna unit is arranged in the metal layer 1, and the low-frequency antenna unit is arranged in the metal layer 2, and the high-frequency antenna unit and the low-frequency antenna unit are connected to the metal layer 3 through a probe.

[0020] Preferably, the high-frequency antenna unit is divided into a high-frequency decoupling network and a high-frequency unit; wherein, the high-frequency decoupling network is used to form a decoupling network to suppress the coupling of the low-frequency antenna unit; the high-frequency unit is randomly distributed by optimizing the directional pattern of the high-frequency array.

[0021] The present invention overcomes the shortcomings of the prior art and provides a multi-frequency co-aperture antenna based on a decoupling mechanism. By designing the high-frequency antenna unit as a functional decoupling network, its resonant characteristics are manipulated to optimize the near-field electromagnetic distribution of the low-frequency antenna unit, thereby significantly reducing the coupling interference between the low-frequency units. This achieves a "mutually beneficial" performance improvement of high frequency to low frequency, balancing co-aperture integration, efficient radiation, and low interference characteristics, making it suitable for antenna systems with multi-frequency coexistence. The antenna of the present invention can be widely used in multi-band co-aperture antenna systems, highly integrated phased array antennas, satellite communication terminals, millimeter-wave radars, and next-generation wireless communication equipment.

[0022] Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

[0023] (1) Significantly reduce coupling interference between low-frequency units: The high-frequency antenna unit of the present invention is not only used for high-frequency radiation, but also acts as an endogenous decoupling network in the low-frequency band, effectively regulating the low-frequency near-field distribution, improving isolation, improving directional pattern distortion, and enhancing low-frequency communication or detection performance.

[0024] (2) Improve structural integration and reduce system volume: The present invention can achieve decoupling function without adding additional isolation structure, absorbing materials or complex feeding network, maintain the compactness and lightweight of the common aperture antenna structure, and is suitable for small space integration applications.

[0025] (3) Enhanced system resource utilization efficiency: The high-frequency unit of the present invention not only performs its own high-frequency function but also plays a low-frequency auxiliary role, thereby achieving "mutual benefit" of antenna functions and improving the overall system performance and cost-effectiveness.

[0026] (4) Good frequency compatibility and scalability: The decoupling mechanism proposed in the present invention does not rely on a specific filtering structure or fixed frequency point, is applicable to a variety of frequency band combinations and scalable array configurations, and adapts to the multi-frequency collaborative application requirements in complex electromagnetic environments.

[0027] (5) Easy to implement and debug in engineering: The present invention is designed and optimized based on the antenna structure itself, and has designability and simulatability, which facilitates engineering parameter adjustment and actual manufacturing without significantly increasing the process difficulty.

[0028] In summary, the fundamental functional difference between this invention and existing technologies lies in the fact that the high-frequency antenna unit combines both decoupling and radiation functions, creating a mutually beneficial, co-aperture, multi-band antenna system. In contrast, in conventional technologies, the high-frequency and low-frequency units operate independently, failing to achieve both synergistic decoupling and improved system performance. Therefore, this invention represents a significant technological breakthrough and engineering application value in multi-band antenna design. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is a schematic diagram of the planar structure of the antenna of the present invention;

[0030] Figure 2 1 is a schematic diagram of the layer structure of the antenna of the present invention;

[0031] Figure 3 This is the deterioration of the existing common patch antenna S11 as the scanning angle increases;

[0032] Figure 4 This is the deterioration of the antenna of the present invention as the scanning angle increases. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] An embodiment of the present invention discloses a multi-frequency co-aperture antenna based on a decoupling mechanism, the antenna comprising:

[0035] at least one low-frequency antenna unit, configured to radiate or receive signals in a first frequency band;

[0036] At least one high-frequency antenna unit, arranged on an aperture plane shared with the low-frequency antenna unit, for radiating or receiving signals in the second frequency band;

[0037] Among them, the high-frequency antenna unit exhibits a current absorption or current guiding effect in the first frequency band (that is, the high-frequency antenna unit forms an endogenous decoupling network in the first frequency band), which is used to regulate the near-field distribution between the low-frequency antenna units to obtain coupling suppression with directional or shielding effect in the first frequency band.

[0038] In an embodiment of the present invention, to implement a multi-frequency, co-aperture antenna based on a decoupling mechanism, the following optimization strategy is introduced in the design of the high-frequency antenna unit. This allows the antenna to achieve radiation in the high-frequency band while generating a parasitic response in the low-frequency band, thereby constructing an intrinsic decoupling network:

[0039] (1) Initial design of high-frequency antenna unit structure

[0040] The high-frequency antenna unit adopts a patch structure, with a design center frequency far higher than the low-frequency operating band. The layout adopts a symmetrical layout surrounding the low-frequency unit or evenly filling the array gaps of the low-frequency antenna unit array.

[0041] (2) “Control target” of resonance characteristics in the low frequency band

[0042] High-frequency antenna elements do not operate in their primary radiation mode at low frequencies, but should exhibit parasitic resonance in this frequency band, enabling them to stimulate local current distribution in low-frequency electromagnetic fields, thereby affecting the near-field coupling path. This parasitic response should be "directional" or "selective," meaning it should shield or guide lateral (inter-antenna) field coupling.

[0043] In the present invention, the structural parameter optimization of the high-frequency antenna unit includes the adjustment of the patch size, shape and its additional structure to introduce effective parasitic resonance characteristics in the low-frequency working band, thereby realizing the intrinsic decoupling function. Specifically, by adjusting the size of the high-frequency patch to control its equivalent electrical length in the low-frequency band, introducing a slot structure (such as a U-shaped or T-shaped gap) at the edge to guide the redistribution of low-frequency energy, and adding a resonant arm to enhance the control ability of the near field, and at the same time, by optimizing the grounding method and layout position, further regulating its influence on the low-frequency coupling path, achieving the suppression of the near-field coupling between the low-frequency antenna units, and effectively improving the overall performance of the multi-frequency common-aperture antenna system without affecting the normal radiation performance of the high frequency.

[0044] In an embodiment of the present invention, the difference in radiation performance between the high-frequency antenna unit in the second frequency band and in standalone operation is preferably within an acceptable range set by the project and does not affect the performance of the high-frequency antenna unit as the primary radiating structure. In engineering, antennas of different frequency bands are often placed together to reduce the antenna aperture, thereby reducing the antenna's radiation aperture. However, placing antennas of different frequency bands together can affect and degrade each other's performance. Therefore, placing two antennas together without affecting the radiation of one antenna is a significant advantage.

[0045] In the actual application of the present invention, in the multi-frequency co-aperture antenna of the embodiment of the present invention, the low-frequency antenna unit includes a plurality of arrays of low-frequency units, the low-frequency unit is a patch antenna, and the high-frequency antenna unit is a slot antenna or a slot array antenna; wherein the high-frequency antenna unit surrounds the low-frequency antenna unit in a mirror-symmetrical or interlaced arrangement. In terms of the planar structure, Figure 1As shown, the multi-frequency co-aperture antenna primarily consists of four low-frequency elements in a 1×4 array operating at 7.5 GHz, and multiple high-frequency antenna elements operating at 35 GHz. The low-frequency elements are rectangular patch antennas mounted on a printed circuit board (PCB) and spaced evenly along the y-direction, with a center-to-center spacing of approximately half the wavelength of the frequency band (approximately 20 mm). The low-frequency antenna elements are excited via back- or edge-feeding from a ground plane, making them suitable for narrowband communications or radar systems. The high-frequency antenna elements are also I-shaped patch antennas, but are significantly smaller (with a center frequency of 35 GHz and a half-wavelength of approximately 4.3 mm). They are embedded in or overlap the gaps between the low-frequency elements in the array, and can be arranged symmetrically or quasi-randomly to ensure spatial averaging of electromagnetic environment disturbances. Furthermore, the high-frequency antenna elements operate in a second frequency band without affecting the primary radiation direction of the low-frequency antenna elements. Specifically, the high-frequency antenna unit is divided into two parts. One part is 4 high-frequency antenna units forming a decoupling network, thereby reducing the coupling between low-frequency units, thereby achieving standing wave improvement of the low-frequency units; the other part is the high-frequency unit, which is randomly distributed, and the specific distribution position is determined by the optimization of the directional pattern of the high-frequency array.

[0046] In terms of level structure, Figure 2 As shown, the antenna comprises, from top to bottom, a metal layer 1, a dielectric layer 2, a metal layer 2, a dielectric layer 2, a metal layer 3, and a substrate. Metal layer 1 houses the high-frequency antenna unit, while metal layer 2 houses the low-frequency antenna unit. These high-frequency and low-frequency antenna units are connected to metal layer 3 via probes (metal vias) for power feeding. In practical applications, the substrate is made of high-frequency copper-clad laminate (such as Rogers RO4350B). Furthermore, dielectric layer 2 is significantly thicker than dielectric layer 1. In engineering, because the low-frequency antenna is located beneath dielectric layer 1, dielectric layer 1 cannot be too thick, otherwise it will affect radiation performance. Dielectric layer 2, located beneath both the high-frequency and low-frequency antennas, has a greater height to increase antenna bandwidth. The high-frequency and low-frequency antenna units are fabricated using different layers of masking layers.

[0047] Because the high-frequency and low-frequency antenna units are fabricated on separate metal layers, they achieve directional shielding. Furthermore, the high-frequency and low-frequency antenna units are integrated on the same substrate, forming a co-aperture radiation surface. This prevents interference between the high- and low-frequency antenna units, creating a functional, intrinsic decoupling network in the first frequency band. While maintaining excellent radiation performance in the second frequency band, the high-frequency antenna exhibits a gain variation of less than 0.5dB, ensuring a consistent pattern.

[0048] In this multi-band, co-aperture antenna, four high-frequency patches between the low-frequency antenna elements form a decoupling network. Specifically, in the first frequency band (i.e., outside its operating frequency), the high-frequency patch antenna generates current guidance or parasitic resonant modes through structural parameter design (such as size adjustment and gaps between the high-frequency elements in the decoupling network). These structures exhibit near-field absorption or current-guiding properties at the 7.5 GHz frequency band, effectively perturbing the coupling path between the low-frequency antennas and reducing their mutual coupling. The equivalent electrical length of the high-frequency patches is slightly less than half a wavelength at 7.5 GHz to stimulate current standing waves caused by impedance mismatch. The "I"-shaped slots on the edges guide the current in a directional manner, forming a phase compensation field or neutralizing interference fields. Furthermore, adjustments to the high-frequency antenna elements are derived through simulation optimization (e.g., HFSS, CST), with the goal of achieving an S21 of less than -20 dB and a stable S11 below -15 dB between the low-frequency elements.

[0049] The dual-frequency S-parameters and gain patterns of a conventional patch antenna S11 and the multi-frequency, co-aperture antenna of the present invention were simulated and verified using the electromagnetic simulation software HFSS. The S11 model consists of four low-frequency elements and 32 high-frequency elements. The high-frequency elements each contain three high-frequency decoupling networks, each consisting of four high-frequency elements. The positions of the remaining high-frequency elements are determined by optimizing the high-frequency antenna array pattern. The low-frequency elements are 12mm*12mm in size, the high-frequency elements are 4mm*4mm in size, the substrate material is Rogers RO4350B, the dielectric layer 1 is 1.2mm thick, and the dielectric layer 2 is 3.2mm thick.

[0050] The results are as follows Figure 3 and Figure 4 shown. Figure 3 is the standing wave pattern of the low-frequency antenna unit without loading the high-frequency antenna unit, from Figure 3 It can be seen from the figure that as the scanning angle of the low-frequency antenna unit increases, the antenna standing wave deteriorates seriously. Figure 4 The standing wave pattern of the low-frequency antenna unit of the multi-frequency common aperture antenna of the present invention is shown in FIG. Figure 4 It can be seen that as the scanning angle of the low-frequency antenna unit increases, the antenna standing wave is improved, thereby improving the performance of the low-frequency unit.

[0051] In summary, the present invention effectively reduces the mutual coupling between low-frequency antenna units while realizing multi-frequency co-aperture integration, improves the radiation consistency of low-frequency antenna units within a wide scanning angle range, and enhances the overall communication and detection performance of the antenna.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-frequency co-aperture antenna based on a decoupling mechanism, characterized in that: The antenna comprises: at least one low-frequency antenna unit, configured to radiate or receive signals in a first frequency band; At least one high-frequency antenna unit, arranged on an aperture plane shared with the low-frequency antenna unit, for radiating or receiving signals in the second frequency band; The high-frequency antenna unit exhibits a current absorption or current guiding effect in the first frequency band, and is used to regulate the near-field distribution between the low-frequency antenna units to obtain coupling suppression with directivity or shielding effect in the first frequency band.

2. The antenna according to claim 1, wherein The high-frequency antenna unit is adjusted through structural parameters to achieve current absorption or current guiding effect in the first frequency band.

3. The antenna according to claim 2, wherein The structural parameter adjustment includes: adjusting the size of the high-frequency patch so that it has an equivalent electrical length in the first frequency band to excite the parasitic current mode, introducing a slot structure at the edge of the patch to guide the current distribution path, and adding a resonant arm or a metal additional structure around the patch to enhance its ability to absorb or guide low-frequency near-field electromagnetic energy.

4. The antenna according to claim 1, wherein The difference between the radiation performance of the high-frequency antenna unit in the second frequency band and in the independent working state is within the acceptable range set by the engineering project and does not affect the performance of the high-frequency antenna unit as the main radiation structure.

5. The antenna according to claim 1, wherein The low-frequency antenna unit includes multiple linearly arranged low-frequency units, and the low-frequency unit is a patch antenna; the high-frequency antenna unit is a slot antenna or a slot array antenna; wherein the high-frequency antenna unit surrounds the low-frequency antenna unit in a mirror-symmetrical or interlaced arrangement.

6. The antenna according to claim 5, wherein The antenna includes a metal layer 1, a dielectric layer 2, a metal layer 2, a dielectric layer 2, a metal layer 3 and a substrate arranged from top to bottom; wherein the high-frequency antenna unit is arranged in the metal layer 1, and the low-frequency antenna unit is arranged in the metal layer 2, and the high-frequency antenna unit and the low-frequency antenna unit are connected to the metal layer 3 through a probe.

7. The antenna according to claim 5, wherein The high-frequency antenna unit is divided into a high-frequency decoupling network and a high-frequency unit; wherein, the high-frequency decoupling network is used to form a decoupling network to suppress the coupling of the low-frequency antenna unit; the high-frequency unit is randomly distributed by optimizing the directional pattern of the high-frequency array.

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