Slot-coupled dual-fed microstrip antenna

Abstract

The application provides a slot-coupled double-fed microstrip antenna and relates to the technical field of slot-coupled double-fed microstrip antennas.The antenna relies on a feed strip line to vertically cross a slot twice in reverse order to respectively complete once feed and twice reverse-phase feed, and the twice slot-coupled feed signals form a forward superposition effect, so that the bandwidth of the microstrip antenna is widened without changing the basic structure of the microstrip antenna, the problem of narrow bandwidth of the existing microstrip antenna is solved, and the performance of the microstrip antenna is improved.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a slot-coupled dual-fed microstrip antenna. Background Technology

[0002] Although slot-coupled microstrip antennas have the characteristics of high isolation, low parasitic radiation, flexible impedance matching and easy integration, they have the drawback of narrow operating bandwidth (usually only 1%~5%), which makes it difficult to meet the application requirements of modern wireless communication systems for wideband antennas. Summary of the Invention

[0003] The purpose of this invention is to provide a slot-coupled dual-fed microstrip antenna to alleviate the technical problem of narrow bandwidth in existing microstrip antennas and improve the performance of microstrip antennas.

[0004] In a first aspect, the present invention provides a slot-coupled dual-feed microstrip antenna, comprising: a radiating patch, an antenna slot layer, and a feed stripline arranged sequentially from the outside to the inside; at least one slot is formed on the antenna slot layer; when a signal is connected to the feed stripline, it crosses the slot twice in opposite directions along the feed stripline, thereby completing a first slot-coupled feed and a second anti-phase slot-coupled feed; the feed signal after the two slot couplings is radiated in phase to the external space via the radiating patch.

[0005] In an optional implementation, the signal transmission path length between the first vertical crossing of the gap and the second vertical crossing of the gap is equal to half the wavelength of the signal in the microwave dielectric substrate.

[0006] In an optional implementation, the feed stripline employs a loop-type routing so that the transmission direction of the signal when it crosses the gap for the second time is opposite to the direction when it crosses it for the first time.

[0007] In an optional implementation, the power supply stripline adopts a one-to-many power divider structure, wherein the main circuit of the one-to-many power divider is used to cross the gap for the first time, and the branch circuit of the one-to-many power divider is used to cross the gap for the second time.

[0008] In an optional embodiment, the antenna slot layer is a metal plate structure, and the slots are formed on the metal plate to achieve electromagnetic signal coupling and transmission.

[0009] In an optional implementation, when multiple slots are opened on the antenna slot layer, the multiple slots are orthogonally distributed, and the feed strip line is matched with each slot to complete the coupling feed.

[0010] In an optional embodiment, a microwave dielectric substrate is disposed between the radiating patch and the antenna slot layer, and between the antenna slot layer and the feed stripline.

[0011] In an optional implementation, it further includes a grounding layer disposed on the side of the feed stripline away from the antenna slot layer.

[0012] In a second aspect, the present invention provides a phased array radar unit, including a slot-coupled dual-fed microstrip antenna as described in any of the foregoing embodiments.

[0013] Thirdly, the present invention provides a mobile terminal including a slot-coupled dual-fed microstrip antenna as described in any of the foregoing embodiments.

[0014] This invention provides a slot-coupled dual-feed microstrip antenna. The antenna relies on the feed stripline to cross the slot twice in opposite directions, completing the first feeding and the second anti-phase feeding respectively. The two slot-coupled feed signals form a positive superposition effect, thereby widening the bandwidth of the microstrip antenna without changing the basic structure of the microstrip antenna, solving the problem of the narrow bandwidth of existing microstrip antennas, and improving the performance of the microstrip antenna. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a slot-coupled dual-fed microstrip antenna provided in an embodiment of the present invention; Figure 2 A schematic diagram of an orthogonal slot and dual-feed feeder provided for an embodiment of the present invention; Figure 3 A schematic diagram of a microstrip antenna based on orthogonal double-slot slot coupling dual feeding is provided for an embodiment of the present invention; Figure 4 This is a schematic diagram of an orthogonal slot and a dual-feed system constructed with a power divider that splits power into two equal parts, provided as an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0020] Example 1 Figure 1 A schematic diagram of a slot-coupled dual-fed microstrip antenna provided in this embodiment of the invention includes: radiating patches arranged sequentially from the outside to the inside (…). Figure 1 (not shown in the image), antenna slot layer 100 and feed stripline 101.

[0021] At least one slot 102 is provided on the antenna slot layer.

[0022] After the signal is connected to the feed stripline, it crosses the gap twice in opposite directions along the feed stripline, thus completing the first gap coupling feed and the second anti-phase gap coupling feed in sequence.

[0023] The feed signal after two gap couplings is radiated in phase to the external space via the radiating patch.

[0024] Specifically, the antenna provided in this embodiment of the invention is a multi-layered microstrip antenna. The overall structure, arranged from the outermost side to the innermost side during use, comprises three core functional components: a radiating patch, an antenna slot layer, and a feed stripline. These components are layered to form an integrated antenna body, possessing the basic structural characteristics of a microstrip antenna: low profile and easy integration. The radiating patch, as the carrier of the final electromagnetic wave radiation, radiates electromagnetic signals outwards. The antenna slot layer, located in the middle, has at least one slot, serving as a channel for electromagnetic energy coupling. The feed stripline, located in the innermost layer, receives radio frequency signals and completes the feed transmission.

[0025] When the radio frequency signal is connected to the feed stripline, the signal propagates forward along the feed stripline. When it reaches the slot position on the antenna slot layer, the feed stripline crosses the slot perpendicularly for the first time. At this time, the signal is coupled to the radiating patch through the slot, completing the first slot-coupled feed.

[0026] After the first crossing, the signal continues to propagate along the feed strip for a certain length. Then, the feed strip crosses the same gap again perpendicularly in the opposite direction to the first crossing. In this embodiment, the phase of the signal during the second crossing is opposite to that during the first crossing, thus achieving a second anti-phase gap coupling feed to the same gap. The two feeding processes rely on the gap to achieve the coupling and transfer of electromagnetic energy, constituting the unique dual-feed operating mode of this antenna.

[0027] In other words, the electromagnetic energy generated by the two sequentially completed slot-coupled feeds is essentially in phase after being transmitted to the radiating patch. This energy is then superimposed in phase by the radiating patch and radiated into external space. The signal superposition effect created by the dual feeds improves the antenna's original operating characteristics, thereby achieving the design goals of widening the operating bandwidth and enhancing radiation performance.

[0028] This invention provides a slot-coupled dual-feed microstrip antenna. The antenna relies on the feed stripline to cross the slot twice in opposite directions, completing a primary feed and a secondary anti-phase feed respectively. The two slot-coupled feed signals form a positive superposition effect, thereby widening the bandwidth of the microstrip antenna without changing its basic structure, solving the problem of narrow bandwidth in existing microstrip antennas, and improving the performance of the microstrip antenna.

[0029] In one alternative implementation, the signal transmission path length between the first vertical crossing of the gap and the second vertical crossing of the gap is equal to half the wavelength of the signal in the microwave dielectric substrate.

[0030] Specifically, when an RF signal propagates along a feed stripline, its operating wavelength depends on the relative permittivity of the microwave dielectric substrate used. By pre-calculating the physical length corresponding to half the signal wavelength in the medium, the routing path of the feed stripline between two crossings is designed so that its total length is exactly equal to that half wavelength. In this way, when the signal propagates from the first crossing position to the second crossing position, its phase changes by exactly 180 degrees, thus ensuring that the signal phase at the second crossing is out of phase with that at the first crossing, providing the phase condition for achieving positive superposition of the two feeds.

[0031] In one alternative implementation, the feed stripline employs a loop-type routing so that the transmission direction of the signal when it crosses the gap for the second time is opposite to the direction when it crosses the gap for the first time.

[0032] refer to Figure 1In this embodiment of the invention, after the feed stripline crosses the gap vertically for the first time, it does not extend directly forward but instead bends along a looping path. After the radio frequency signal is connected to the feed stripline, it first crosses the gap vertically along its initial direction of travel to complete the first gap coupling feed. Then, it continues to transmit along the looping path. The looping structure of the line causes the signal's direction of travel to reverse, and finally, it crosses the gap vertically again in the opposite direction, successfully completing the second feed operation. This routing method, in conjunction with the half-wavelength transmission path, ensures the stable operation of the dual-feed, positively superimposed working mechanism.

[0033] In one alternative embodiment, the antenna slot layer is a metal plate structure, with slots formed on the metal plate to enable electromagnetic signal coupling and transmission.

[0034] Specifically, the antenna slot layer is a key functional layer for achieving slot-coupled feeding in microstrip antennas. The antenna slot layer is typically made of copper or other low-resistivity metals. The entire metal sheet forms a complete layer structure, possessing excellent electromagnetic conductivity, high structural strength, and ease of overall stacking and integration, thus meeting the assembly requirements of multi-layer microstrip antennas.

[0035] A slotted structure, typically rectangular in shape, is formed on the surface of a metal sheet through etching or machining. When an RF signal is transmitted along a feed stripline and crosses the slot perpendicularly, the electromagnetic energy on the feed stripline is coupled to the radiating patch through the slot. Compared to traditional feeding methods, the structure of a metal sheet combined with etched slots offers advantages such as low parasitic radiation and high isolation, reducing energy loss during signal transmission and ensuring the efficiency and quality of signal coupling in dual-feed mode.

[0036] In one alternative implementation, when multiple slots are opened on the antenna slot layer, the multiple slots are orthogonally distributed, and the feed strip line is matched with each slot to complete the coupling feed.

[0037] Specifically, when an antenna is configured with multiple slots according to usage requirements such as polarization and radiation range, this embodiment of the invention limits the multiple slots to an orthogonal and symmetrical distribution, for example, presenting an orthogonal double-slot structure. The orthogonally distributed multiple slots are arranged perpendicularly to each other, which can correspond to signal transmission paths of different polarizations, realize dual-polarization operation capability, and expand the applicable scenarios of the antenna.

[0038] Each slot is equipped with an independent feed stripline, which performs two vertical crossings in opposite directions and phases as described above, thus doubly feeding its respective slot. The feeding, coupling, and radiation processes for each slot are independent yet coordinated. Orthogonal slots paired with corresponding feed structures ensure flexible impedance matching for each signal path, further leveraging the broadband characteristics of slot-coupled feeding. Simultaneously, the multi-slot layout further optimizes antenna radiation performance.

[0039] In one embodiment, when two slots are formed on the antenna slot layer, such as Figure 2 As shown, the microstrip antenna includes two orthogonal and symmetrical slots 102 and two polarized single-feed striplines 101 (the radiating patch of the antenna is not shown). Figure 2 As shown in the figure, the two feed strips are independent of each other and have a symmetrical structure, which ensures the performance consistency of dual-polarization operation.

[0040] In one alternative embodiment, it further includes a grounding layer disposed on the side of the feed stripline away from the antenna slot layer.

[0041] Specifically, the ground plane is typically a complete metal plane located at the bottom of the entire multilayer structure (i.e., below the feed stripline). The ground plane and the feed stripline work together to form a complete stripline feed loop, providing an electrical reference potential for stable RF signal transmission. The ground plane also suppresses back radiation, allowing energy to be coupled and radiated primarily forward (in the direction of the radiating patch), thereby improving the antenna's forward gain.

[0042] In one alternative embodiment, a microwave dielectric substrate is disposed between the radiating patch and the antenna slot layer, and between the antenna slot layer and the feed stripline.

[0043] This invention does not impose a specific limit on the number of radiation patches; users can configure them according to their actual needs. It can be one layer or multiple layers. Figure 3 A schematic diagram of a microstrip antenna based on orthogonal double-slot slot coupling dual feeding, provided as an embodiment of the present invention, is shown below. Figure 3 As shown, the antenna as a whole adopts a multi-layer dielectric substrate stacked structure. From top to bottom (or from outside to inside): the first layer is the upper radiating patch 103, made of copper and square in shape; the second layer is the first microwave dielectric substrate 104; the third layer is the lower radiating patch 105, made of copper and square in shape; the fourth layer is the second microwave dielectric substrate 106; the fifth layer is the antenna slot layer 100, made of copper, with two orthogonal and symmetrical slots 102 etched on it; the sixth layer is the third microwave dielectric substrate 107; the seventh layer is the feed stripline 101, made of copper; the eighth layer is the fourth microwave dielectric substrate 108; and the ninth layer is the ground layer 109, made of copper.

[0044] Deploying microwave dielectric substrates between adjacent functional layers is a fundamental structural design element for ensuring the normal operation of multilayer antennas. Microwave dielectric substrates possess specific relative permittivity and loss tangents. On one hand, they can physically isolate and fix radiating patches, antenna slot layers, and feed striplines, maintaining the predetermined spacing and positional relationships between functional layers and improving the overall structural robustness of the antenna. On the other hand, the microwave dielectric substrate is the primary carrier of electromagnetic wave propagation; signals are transmitted within the substrate, effectively constraining the propagation path of electromagnetic energy and reducing interlayer electromagnetic crosstalk and parasitic radiation.

[0045] In one alternative implementation, the power supply stripline adopts a one-to-many power divider structure, wherein the main circuit of the one-to-many power divider is used for the first crossing of the gap, and the branch circuit of the one-to-many power divider is used for the second crossing of the gap.

[0046] Specifically, when the feed stripline adopts a one-to-many power divider structure, the signal first propagates along the main path of the power divider, completing the initial coupling feed at the first crossing of the gap. Subsequently, the main path signal is divided into multiple branch signals by the power divider nodes, and each branch feeds the stripline with the same power and transmits in parallel. These branches are arranged on both sides of the main path and cross the same gap a second time perpendicularly in the opposite direction to the crossing direction of the main path. Since the transmission path length of each branch signal is half the wavelength of the signal in the microwave dielectric substrate, each branch signal has a definite antiphase relationship with the main path signal, that is, the signal phase at the second crossing is out of phase with the phase at the first crossing, ultimately forming a positive superposition effect of the two feeds.

[0047] Figure 4 This is a schematic diagram of an orthogonal slot and a dual-feed system constructed with a one-to-two power divider, provided as an embodiment of the present invention. Figure 4 The structure includes a main path 1011 with two equally polarized power dividers and branch paths 1012 with two equally polarized power dividers. The branch paths cross orthogonal slots 102 etched on the metal ground on both sides of the main path for the second time. This structure is suitable for high-performance antenna arrays that require multi-channel parallel feeding, such as phased array antenna systems. It can achieve multi-channel synchronous feeding, further improving the overall antenna integration capability and operational stability.

[0048] In summary, this invention proposes a slot-coupled dual-feed microstrip antenna. By constructing a feed line that crosses the slot twice, with the second crossing in opposite directions and phases, a positive superposition is achieved, resulting in a dual-feed effect. Without changing the original basic structure, this effectively widens the antenna bandwidth (by about 5%) and improves antenna performance.

[0049] Example 2 This invention also provides a phased array radar unit, which includes the slot-coupled dual-fed microstrip antenna provided in Embodiment 1 above.

[0050] This invention also provides a mobile terminal, which includes the slot-coupled dual-fed microstrip antenna provided in Embodiment 1 above.

[0051] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0052] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0053] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A slot-coupled dual-fed microstrip antenna, characterized in that, include: The radiating patch, antenna slot layer, and feed strip are arranged sequentially from the outside to the inside. At least one slot is provided on the antenna slot layer; When the signal is connected to the feed stripline, it crosses the same gap twice in opposite directions along the feed stripline, completing one gap coupling feed and two reverse gap coupling feeds in sequence; the signal transmission path length between the first vertical gap crossing and the second vertical gap crossing is equal to half the wavelength of the signal in the microwave dielectric substrate. The power supply stripline adopts a one-to-many equal-division power divider structure, wherein the main circuit of the one-to-many equal-division power divider is used for the first crossing of the gap, and the branch circuit of the one-to-many equal-division power divider is used for the second crossing of the gap. The feed signal after two gap couplings is radiated in phase to the external space via the radiating patch.

2. The slot-coupled dual-fed microstrip antenna according to claim 1, characterized in that, The feed strip adopts a loop-type routing so that the transmission direction of the signal when it crosses the gap for the second time is opposite to the direction when it crosses it for the first time.

3. The slot-coupled dual-fed microstrip antenna according to claim 1, characterized in that, The antenna slot layer is a metal plate structure, and the slots are formed on the metal plate to achieve electromagnetic signal coupling and transmission.

4. The slot-coupled dual-fed microstrip antenna according to claim 1, characterized in that, When multiple slots are opened on the antenna slot layer, the multiple slots are orthogonally distributed, and the feed strip line is matched with each slot to complete the coupling feed.

5. The slot-coupled dual-fed microstrip antenna according to claim 1, characterized in that, A microwave dielectric substrate is disposed between the radiating patch and the antenna slot layer, and between the antenna slot layer and the feed stripline.

6. The slot-coupled dual-fed microstrip antenna according to claim 1, characterized in that, Also includes: A grounding layer is disposed on the side of the feed stripline away from the antenna slot layer.

7. A phased array radar unit, characterized in that, The microstrip antenna includes the slot-coupled dual-fed microstrip antenna as described in any one of claims 1 to 6.

8. A mobile terminal, characterized in that, Includes the slot-coupled dual-fed microstrip antenna as described in any one of claims 1-6.

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