A dual-sided coupling structure wideband antenna

Abstract

The application discloses a kind of double-sided coupling structure broadband antennas, belong to antenna technical field.Antenna includes dielectric substrate, antenna radiation structure being arranged in substrate front and parasitic coupling structure being arranged in substrate back.Front radiation structure includes feed point ground plane and serpentine bending trace, trace end extends and forms loading branch, and coupling gap is reserved between feed point ground plane, and constitutes capacitive end loading;Back parasitic coupling structure is open-circuit floating metal patch, and forms interlayer capacitive coupling with front radiation structure across dielectric substrate.The application is through the synergistic effect of serpentine slow wave structure, end capacitive loading and double-sided parasitic coupling, effectively reduce antenna loaded Q value, smooth full-band input impedance, while greatly reducing physical size, realize ultra-wideband radiation characteristics.The application can be based on standard printed circuit process mass production, adapt rigid and flexible multiple substrates, and can be widely used in various terminal equipment with wireless transceiver function.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a broadband antenna with a double-sided coupling structure and a wireless communication device using the antenna. Background Technology

[0002] With the rapid development of wireless communication technology, various miniaturized terminal devices have placed extremely high demands on antenna miniaturization, wide bandwidth, low cost, and easy integration. Typical examples include airborne drones, vehicle-mounted terminals, industrial IoT devices, and portable security terminals. These devices often need to cover multiple operating frequency bands simultaneously to achieve multiple functions such as high-definition data transmission, remote control, and data backhaul. At the same time, due to strict limitations in internal space, external structure, and load weight, antennas must possess extremely small size, low profile, and lightweight characteristics.

[0003] In existing technologies, miniaturized antennas of the same type mainly suffer from inherent bottlenecks in two main technical approaches: Conventional single-sided printed monopole antennas rely on linear radiators, have large physical dimensions, are difficult to adapt to narrow installation spaces, and mostly have single-resonant characteristics. Their bandwidth is relatively narrow, usually only 5% to 10% of the center frequency, making it difficult to cover the needs of multi-band communication at the same time. They also have severe impedance fluctuations within the frequency band and poor return loss performance across the entire frequency band.

[0004] Traditional broadband antenna solutions, such as planar inverted-F antennas and dielectric resonant antennas, generally suffer from high profile, large size, and high manufacturing cost, making them unsuitable for the installation requirements of miniaturized and thin terminals. Some solutions require additional lumped matching components, resulting in high insertion loss and poor batch consistency.

[0005] Therefore, how to achieve ultra-wide frequency band coverage and smooth impedance characteristics without additional matching devices under limited size constraints, while being compatible with various substrate processes and adaptable to different types of terminal devices, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] Purpose of the invention To address the shortcomings of existing technologies, the present invention aims to provide a broadband antenna with a dual-coupling structure that achieves miniaturization of the antenna's physical size while significantly expanding its operating bandwidth and smoothing its impedance characteristics across the entire frequency band. This antenna architecture is compatible with various rigid and flexible dielectric substrates and can be mass-produced based on mature printed circuit technology, thus achieving a balance between high performance, low cost, and high adaptability.

[0007] Technical solution To achieve the above objectives, the present invention adopts the following technical solution: A broadband antenna with a dual-coupling structure includes a dielectric substrate, an antenna radiating structure, and a parasitic coupling structure.

[0008] The antenna radiating structure is disposed on the front side of the dielectric substrate, including an antenna feed point ground plane and a serpentine bend trace; one end of the serpentine bend trace is electrically connected to the feed point, and the other end extends to form an end-loading stub; a coupling gap is reserved between the end-loading stub and the antenna feed point ground plane, and a capacitive end-loading is formed through the coupling gap.

[0009] The parasitic coupling structure is disposed on the back side of the dielectric substrate and is at least one open-circuit floating metal patch; the projection of the open-circuit floating metal patch on the dielectric substrate at least partially covers the routing area of ​​the serpentine bend trace, and forms interlayer capacitive coupling with the antenna radiation structure through the dielectric substrate.

[0010] Furthermore, the serpentine bend trace is composed of multiple parallel traces that bend back and forth, and the spacing and trace width of adjacent parallel traces are set according to the wavelength and impedance matching requirements of the target operating frequency band.

[0011] Furthermore, the end-loaded stub is formed by bending the end of the serpentine routing line in the opposite direction to the grounding direction of the antenna feed point; the width of the coupling gap is set according to the target reactance compensation requirements. Furthermore, the open-circuit floating metal patch is a metal foil unit without DC grounding connection, excited by the front antenna radiation structure through electric field coupling, requiring no independent feeding; the shape and area of ​​the open-circuit floating metal patch are set according to the interlayer coupling strength requirements.

[0012] Furthermore, the antenna adopts a coaxial feeding structure; the inner conductor of the coaxial line is electrically connected to the feeding point of the serpentine bend in the trace, and the outer conductor of the coaxial line is electrically connected to the ground plane of the antenna feeding point.

[0013] Furthermore, the dielectric substrate is made of an insulating dielectric material, and its substrate thickness, relative permittivity, and loss tangent are configured according to the operating frequency band and interlayer coupling strength requirements.

[0014] Furthermore, after size tuning, the antenna can be adapted to any target operating frequency band from the VHF band to the C-band 6GHz range; within the target operating frequency band, the antenna return loss is better than -6dB and the voltage standing wave ratio is less than 3.

[0015] The present invention also provides a wireless communication device, including a radio frequency terminal and a broadband antenna with a dual-coupling structure as described in any of the above claims; the broadband antenna with the dual-coupling structure is electrically connected to the radio frequency port of the radio frequency terminal.

[0016] Furthermore, the wireless communication device is a terminal device with wireless transceiver functionality.

[0017] Beneficial effects Compared with the prior art, the present invention has the following significant technical advancements: (1) Outstanding miniaturization effect: By using a serpentine bending slow wave structure to effectively increase the electrical length of the trace, the physical length of the antenna is reduced by more than 40% compared with the conventional linear monopole antenna in the same frequency band at the same resonant frequency. It has a low profile and is lightweight, making it perfectly suitable for various narrow installation spaces and thin equipment.

[0018] (2) Significant ultra-wideband characteristics: By introducing an additional resonant zero point through end capacitive loading, combined with back parasitic coupling to reduce the effective loaded Q value of the antenna, the dual mechanisms work together to expand the bandwidth; in a typical embodiment, the relative bandwidth can reach 15%~20%, which is more than twice that of a normal single-sided printed antenna, and can simultaneously cover the communication needs of multiple frequency bands.

[0019] (3) Smooth impedance matching: The front radiation mode and the back parasitic mode are distributed alternately and complementaryly cover the working frequency band. With the help of distributed reactance compensation, the input impedance fluctuation in the passband is effectively smoothed out and there is no obvious deterioration at the edge of the frequency band. No additional lumped matching device is required, and the insertion loss is low and the batch consistency is good.

[0020] (4) Strong adaptability and easy mass production: The core architecture is compatible with various dielectric materials such as rigid substrates (such as FR4, high frequency board) and flexible substrates (such as FPC, PI film). It can be mass-produced based on mature printed circuit technology, without the need for special materials and complex assembly processes. The production cost is low and it can be flexibly adapted to different types of terminal devices. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0022] Figure 1 This is a schematic diagram of the front structure of the antenna in the UHF band embodiment of the present invention; Figure 2 This is a schematic diagram of the reverse side structure of the antenna in the UHF band embodiment of the present invention; Figure 3 This is a schematic diagram of the front structure of the antenna in an L-band embodiment of the present invention; Figure 4 This is a schematic diagram of the reverse side structure of the antenna in an L-band embodiment of the present invention; Figure 5 This is a schematic diagram of the front structure of the antenna in a VHF band embodiment of the present invention; Figure 6 This is a schematic diagram of the reverse side structure of the antenna in a VHF band embodiment of the present invention; Figure 7 This is a schematic diagram of the front structure of the antenna in a C-band embodiment of the present invention; Figure 8 This is a schematic diagram of the reverse side structure of the antenna in a C-band embodiment of the present invention; Figure 9 This is a diagram showing the antenna return loss in a UHF band embodiment of the present invention. Figure 10 This is a voltage standing wave ratio (VSWR) diagram of an antenna in a UHF band embodiment of the present invention. Figure 11 This is a diagram showing the antenna return loss of an L-band embodiment of the present invention. Figure 12 This is a voltage standing wave ratio (VSWR) diagram of an L-band embodiment of the present invention. Figure 13 This is a diagram showing the antenna return loss in an FM band embodiment of the present invention. Figure 14 This is a voltage standing wave ratio (VSWR) diagram of an FM band embodiment of the present invention. Figure 15 This is an antenna return loss diagram of a C-band embodiment of the present invention; Figure 16 This is a voltage standing wave ratio (VSWR) diagram of an antenna in a C-band embodiment of the present invention. Figure 17 This is a radiation pattern of an embodiment of the UHF band of the present invention.

[0023] Figure 18 This is a radiation pattern of an L-band embodiment of the present invention.

[0024] Figure 19 This is a radiation pattern of a C-band embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 10 - Dielectric substrate; 20 - Antenna feed point ground plane; 30 - Serpentine bend trace; 40 - End loading stub; 50 - Open-circuit floating metal patch. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0027] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains.

[0028] The terms "first," "second," and similar words used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "comprising" or "including," and similar words, mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including," and do not exclude other elements or objects. The terms "connected" or "linked," and similar words, are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] See Figures 1-8 The first aspect of the present invention provides a dual-coupling broadband antenna, including a dielectric substrate 10, an antenna radiation structure disposed on the front side of the dielectric substrate 10, and a parasitic coupling structure disposed on the back side of the dielectric substrate 10.

[0031] 1. Dielectric substrate The dielectric substrate 10 is made of insulating dielectric material, and its substrate thickness, relative permittivity and loss tangent can be configured adaptably according to the operating frequency band, interlayer coupling strength requirements and equipment installation form.

[0032] In this embodiment, the dielectric substrate 10 is selected as an FR4 epoxy glass cloth substrate as an exemplary solution, with a substrate thickness of 0.6 mm, a relative permittivity of 4.4, and a loss tangent of 0.02. The use of a thin substrate is not only beneficial to the lightweight and low-cost mass production of the antenna, but also a key dielectric layer for constructing interlayer capacitive coupling between the front and back sides.

[0033] In practical applications, the dielectric substrate 10 can also be made of high-frequency rigid materials such as Rogers or PTFE, or flexible dielectric materials such as FPC or PI film, to adapt to different performance requirements and special installation scenarios such as curved surface conformal and wearable applications. The above parameters and materials are merely exemplary configurations and are not intended to limit the scope of protection of this invention.

[0034] 2. Front antenna radiation structure See Figure 1 , Figure 3 , Figure 5 and Figure 7 The antenna radiation structure is disposed on the front side of the dielectric substrate 10, including an antenna feed point ground plane 20, a serpentine bend trace 30 (or a radiating patch), and an end loading stub 40.

[0035] One end of the serpentine bend trace 30 is electrically connected to the feed point, and the other end extends and bends in the opposite direction to form an end loading stub 40. There is a trace gap between the end loading stub 40 and the main body of the serpentine bend trace 30, and a coupling gap is reserved between the end loading stub 40 and the ground plane 20 of the antenna feed point, so as to form a capacitive end loading through the gap coupling.

[0036] The specific dimensions of the trace spacing and coupling gap can be adjusted according to matching requirements. In this embodiment, the exemplary value is 0.7mm or more, which is not a limitation of the present invention.

[0037] In this embodiment, the antenna uses a coaxial feeding structure for signal feeding. The inner core of the coaxial line is electrically connected to the feeding point of the serpentine bend trace 30, and the outer conductor of the coaxial line is electrically connected to the antenna feeding point ground plane 20.

[0038] 3. Backside parasitic coupling structure See Figure 2 , Figure 4 , Figure 6 and Figure 8 The parasitic coupling structure is disposed on the back side of the dielectric substrate 10 and is an open-circuit floating metal patch 50. The open-circuit floating metal patch 50 is a metal foil unit without DC ground connection, which forms interlayer capacitive coupling with the antenna radiation structure on the front side through the dielectric substrate 10.

[0039] In operation, the open-circuit floating metal patch 50 is excited by the front antenna radiation structure through electric field coupling, requiring no additional feeding structure. The shape, area, and projection overlap ratio of the open-circuit floating metal patch 50 with the front trace can be set according to the target coupling strength requirements. In this embodiment, the projected area of ​​the open-circuit floating metal patch 50 basically covers the entire area of ​​the front serpentine bend trace to maximize the interlayer coupling strength. This scheme is only a preferred embodiment and is not a limitation of the present invention.

[0040] 4. Working principle 4.1 Mechanism of Miniaturization of Serpentine Slow Wave The serpentine bends 30 constitute the slow-wave structure of the antenna. When the radio frequency current propagates along the metal trace, the serpentine folding causes electric and magnetic field coupling between adjacent traces, increasing the equivalent distributed inductance and capacitance per unit length of the transmission line, reducing the electromagnetic wave propagation phase velocity, and effectively extending the electrical length of the trace. Under the same resonant frequency requirements, the physical size of the antenna can be significantly reduced, achieving miniaturized design.

[0041] Meanwhile, the far-field radiation excited by the reverse current in adjacent traces causes partial destructive interference, which can introduce a controllable resonant zero point and help extend the antenna's operating bandwidth.

[0042] 4.2 Mechanism of End-Loading Reactance Compensation The end-loaded stub 40 and the antenna feed ground plane 20 are coupled through a gap to form a capacitive end-load, which can be equivalent to a parallel LC resonant network composed of a short-circuit inductor and an energy storage capacitor, introducing an additional resonant zero in the antenna circuit.

[0043] By leveraging the frequency response characteristics of parallel LC networks, it can perform reactance compensation for the low-frequency capacitive reactance and high-frequency inductive reactance of the antenna, smooth the input impedance fluctuations at the edge of the passband, suppress the deterioration of return loss at both the high and low frequency ends of the passband, and optimize the broadband matching effect.

[0044] The formula for calculating the equivalent inductive reactance of a short-circuit stub is shown in equation (1): (1) In equation (1), Ls is the equivalent short-circuit inductance, and Z0 is the characteristic impedance of the transmission line. Where L is the phase constant and L is the physical length of the short-circuit stub. This is the operating angular frequency.

[0045] The external Q value of the parallel resonant circuit is shown in equation (2): (2) In equation (2), Ceq is the equivalent energy storage capacitor of the patch, and G0 is the radiation conductance; the larger the short-circuit inductance Ls, the smaller Qe is, and the stronger the bandwidth expansion effect.

[0046] 4.3 Two-sided coupling Q-reduction frequency topology mechanism The open-circuit floating metal patch 50 on the back side of the dielectric substrate 10 is excited by the electric field coupling of the front antenna radiation structure. When the substrate thickness is thin, a strong distributed capacitance characteristic is formed between the front and back sides, which is equivalent to a built-in distributed LC matching network.

[0047] The relationship between the interlayer coupling coefficient and the equivalent mutual capacitance is shown in equations (3) and (4): Capacitive coupling coefficient: (3) In equation (3), Cm is the mutual capacitance between the front and back sides, C1 and C2 are the equivalent capacitances of the front and back sides themselves, and the larger kc is, the stronger the equivalent coupling.

[0048] Inductive coupling coefficient: (4) In equation (4), Km is the mutual coupling inductance between the front and back sides, and L and L2 are the equivalent inductances of the front and back sides, respectively. The larger Km is, the stronger the equivalent coupling. According to coupled resonance theory, the total coupling coefficient of the two resonant elements is k, and the unloaded Q value of the element is Q0. Then the effective loaded Q value QL satisfies:

[0049] The larger the coupling coefficient k, the smaller the effective loaded Q value QL. Since a coupling copper foil is added to the back of the antenna in this patent, the equivalent capacitance cm is larger, therefore the coupling coefficient k is larger, and the corresponding Q value is smaller. From the antenna relative bandwidth formula, we can see that:

[0050] The smaller the Q value, the larger the relative bandwidth of the antenna, thus achieving ultra-wideband radiation characteristics.

[0051] Meanwhile, the front radiating structure and the back parasitic patch are excited to form independent resonant modes. The resonant frequency points corresponding to the two sets of modes are arranged in an alternating manner, complementing each other to cover the working frequency band. This can smooth the input impedance across the entire frequency band, ensuring that the impedance within the frequency band does not deviate drastically from 50Ω, resulting in better overall return loss.

[0052] 5. Performance Verification of Examples This invention verifies the performance of the solution through physical embodiments in four typical frequency bands. All prototypes have been fabricated and fully tested. See [link / reference]. Figures 9-19 All indicators met the standards. The following embodiments are merely preferred implementation schemes used to illustrate the technical effects of the present invention and are not intended to limit the scope of protection of the present invention; by adjusting the electrical dimension parameters and substrate configuration, this solution can be adapted to more operating frequency bands and application scenarios.

[0053] 5.1 UHF Band Example This embodiment is optimized for the 830MHz~960MHz UHF band and is suitable for scenarios such as remote control and industrial IoT data transmission.

[0054] Core configuration: FR4 substrate thickness 0.6mm, serpentine routing uses multiple parallel branches to bend back and forth, adjacent routing spacing is 0.9mm for example, end coupling gap is 0.7mm for example, and parasitic patch on the back covers the entire routing area.

[0055] Actual performance: The operating frequency band covers 830MHz~960MHz, the in-band return loss is better than -6dB, and the voltage standing wave ratio is less than 3; the radiation efficiency and gain performance within the frequency band are stable, and the uniformity of the omnidirectional radiation pattern is good.

[0056] 5.2L band example This embodiment is optimized for the 1.3GHz~1.6GHz L-band and is suitable for scenarios such as high-definition image data transmission and broadband private network access.

[0057] Core configuration: The overall architecture is completely consistent with the UHF implementation, only the electrical dimensions of each component are reduced according to the L-band wavelength ratio; the spacing between adjacent traces is 1.1mm for example, and the parasitic patch on the back is scaled synchronously.

[0058] Actual performance: The operating frequency band covers 1.3GHz~1.6GHz, the in-band return loss is better than -6dB, and the voltage standing wave ratio is less than 3; the radiation efficiency and gain performance are excellent, and the omnidirectional radiation characteristics are stable.

[0059] 5.3 VHF Band Example This embodiment is optimized for the 87.5-108MHz VHF band and is suitable for access scenarios such as radio, campus broadcasting, and emergency broadcasting.

[0060] Core configuration: The overall architecture is completely consistent with the UHF implementation, only the electrical dimensions of each component are increased according to the wavelength ratio of the VHF band; the spacing between adjacent traces is 1mm for example, and the parasitic patch on the back is increased accordingly.

[0061] Actual performance: The operating frequency band covers 87.5-108MHz, with in-band return loss better than -2.5dB and voltage standing wave ratio less than 7. Compared with common 750mm long telescopic antennas, it has a size advantage and features miniaturized broadband characteristics.

[0062] 5.4C Band Example This embodiment is optimized for the 5.15-5.85GHz C-band and is suitable for scenarios such as WiFi communication, data transmission, and high-definition image transmission.

[0063] Core configuration: The overall architecture is completely consistent with the L-band implementation, only the electrical dimensions of each component are reduced according to the L-band wavelength ratio; the spacing between adjacent traces is 1.1mm for example, and the parasitic patch on the back is scaled synchronously.

[0064] Actual performance: The operating frequency band covers 5.15-5.85GHz, the in-band return loss is better than -6dB, and the voltage standing wave ratio is less than 3; the radiation efficiency and gain performance are excellent, and the omnidirectional radiation characteristics are stable.

[0065] The detailed measured data for the UHF and L-band frequencies in this example are shown in the table below: It should be noted that the operating frequency band of the dual-coupling structure broadband antenna of the present invention includes, but is not limited to, the UHF band, VHF band, C band, and L band mentioned above. While ensuring the miniaturization of the antenna, the operating frequency band of the dual-coupling structure broadband antenna of the present invention can achieve broadband characteristics covering 50-6000MHz.

[0066] Table 1. Antenna gain and efficiency of the dual-coupling structure broadband antenna of the present invention in UHF, L, and C bands.

[0067] In summary, the dual-coupling broadband antenna of this invention employs coaxial feeding and includes a dielectric substrate, an antenna radiating structure on the front side of the substrate, and a parasitic coupling structure on the back side of the substrate. The front radiating structure comprises a feed ground plane and a serpentine bend trace, with the trace's end extending to form a loading stub. A coupling gap is reserved between the stub and the feed ground plane, forming a capacitive end loading. The back parasitic coupling structure is an open-circuit floating metal patch, forming interlayer capacitive coupling with the front radiating structure through the dielectric substrate. This invention effectively reduces the antenna's loaded Q value and smooths the full-band input impedance through the synergistic effect of the serpentine slow-wave structure, the capacitive end loading, and the dual-coupling, achieving ultra-wideband radiation characteristics while significantly reducing the physical size.

[0068] Furthermore, the present invention also provides a wireless communication device, including a radio frequency terminal and a dual-coupling structure broadband antenna as described in any of the preceding claims; the dual-coupling structure broadband antenna is electrically connected to the radio frequency port of the radio frequency terminal. The wireless communication device is a terminal device with wireless transceiver functionality.

[0069] For example, taking airborne wireless communication as an application case, the airborne wireless communication equipment includes an airborne communication radio frequency terminal and a broadband antenna with a double-sided coupling structure as described in any of the first aspects of the present invention. The antenna adopts a double-sided coupling form to realize a broadband antenna, which can realize an ultra-wide frequency band of 1.3GHz~1.6GHz in the L-band and 830~960MHz in the UHF band. It can meet the needs of L-band image and data transmission, UHF band remote control and communication. Of course, the antenna of the airborne wireless communication equipment of the present invention is not limited to the above frequency bands. Different frequency bands can be used by changing the trace length. The present invention focuses on the design of key electromagnetic mechanisms such as double-sided electromagnetic coupling on thin dielectric substrate, double-sided coupling parasitic resonance, and integrated coupling branch reactance compensation, and realizes the broadband characteristics of the antenna. It can simultaneously meet the radio frequency performance requirements of long-distance image transmission links and remote control. Specifically, it can be applied to various airborne communication terminals such as surveying, power inspection, security reconnaissance, and logistics distribution. Based on double-sided printed circuit boards, the antenna can achieve mass production at a lower cost, which completely solves the industry pain points of insufficient bandwidth, large size, poor adaptability and poor matching performance of existing UAV antennas.

[0070] In summary, this invention provides a dual-coupling broadband antenna, comprising a dielectric substrate; an antenna radiating structure disposed on the front side of the dielectric substrate, the antenna radiating structure including an antenna feed point ground plane and a serpentine bend trace connected to the feed point, the end of the serpentine bend trace having an antenna end loading structure, the antenna end loading structure being coupled to the antenna feed point ground plane to form an equivalent short-circuit load; and a parasitic coupling structure disposed on the back side of the dielectric substrate, the parasitic coupling structure being an open-circuit parasitic coupling patch, the open-circuit parasitic coupling patch and the antenna radiating structure forming a dual-coupling capacitive resonant cavity separated by the dielectric substrate. This invention, through the synergistic effect of the serpentine trace, dual-coupling capacitive coupling, and end loading design, effectively reduces the loaded Q value of the antenna, smooths the frequency band input impedance, and expands the operating bandwidth while achieving antenna miniaturization.

[0071] Although the present invention has been disclosed above, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A broadband antenna with a dual-plane coupling structure, characterized in that, This includes dielectric substrates, antenna radiating structures, and parasitic coupling structures; The antenna radiating structure is disposed on the front side of the dielectric substrate, including an antenna feed point ground plane and a serpentine bend trace. One end of the serpentine bend trace is electrically connected to the feed point, and the other end extends to form an end-loaded stub. A coupling gap is reserved between the end-loaded stub and the ground plane of the antenna feed point, and a capacitive end-load is formed through the coupling gap; The parasitic coupling structure is disposed on the back side of the dielectric substrate and is at least one open-circuit floating metal patch; the projection of the open-circuit floating metal patch on the dielectric substrate at least partially covers the routing area of ​​the serpentine bend trace, and forms interlayer capacitive coupling with the antenna radiation structure through the dielectric substrate.

2. The broadband antenna with a double-sided coupling structure according to claim 1, characterized in that, The serpentine bend trace is composed of multiple parallel traces that bend back and forth. The spacing and trace width of adjacent parallel traces are set according to the wavelength and impedance matching requirements of the target operating frequency band. The current direction in adjacent traces is opposite, and the equivalent distributed inductance and distributed capacitance per unit length are increased through electromagnetic coupling.

3. The broadband antenna with a double-sided coupling structure according to claim 1, characterized in that, The end-loaded stub is formed by bending the end of the serpentine trace in the opposite direction to the grounding direction of the antenna feed point; the width of the coupling gap is set according to the target reactance compensation requirements and is used to adjust the equivalent reactance value of the end-loaded section.

4. The broadband antenna with a double-sided coupling structure according to claim 1, characterized in that, The end-loaded stub is formed by bending the end of the serpentine trace in the opposite direction to the grounding direction of the antenna feed point; the width of the coupling gap is set according to the target reactance compensation requirements and is used to adjust the equivalent reactance value of the end-loaded section.

5. The broadband antenna with a double-sided coupling structure according to claim 4, characterized in that, The shape and area of ​​the open-circuit floating metal patch are set according to the interlayer coupling strength requirements.

6. The broadband antenna with a double-sided coupling structure according to claim 1, characterized in that, The antenna adopts a coaxial feeding structure; the inner conductor of the coaxial line is electrically connected to the feeding point of the serpentine bend in the cable, and the outer conductor of the coaxial line is electrically connected to the antenna feeding point ground.

7. The broadband antenna with a double-sided coupling structure according to claim 1, characterized in that, The dielectric substrate is made of insulating dielectric material, and its substrate thickness, relative permittivity and loss tangent are configured according to the operating frequency band and interlayer coupling strength requirements.

8. The broadband antenna with a double-sided coupling structure according to any one of claims 1-7, characterized in that, After size tuning, the antenna can be adapted to any target operating frequency band from VHF band to C-band 6GHz; within the target operating frequency band, the antenna return loss is better than -6dB and the voltage standing wave ratio is less than 3.

9. A wireless communication device, characterized in that, It includes a radio frequency terminal and a dual-coupling structure broadband antenna as described in any one of claims 1-8; the dual-coupling structure broadband antenna is electrically connected to the radio frequency port of the radio frequency terminal.

10. The wireless communication device according to claim 9, characterized in that, The wireless communication device is a terminal device with wireless transceiver functionality.

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