Antenna based on Lange coupler

Abstract

The invention discloses an antenna based on a Lange coupler, which comprises an upper-layer reflecting surface and a lower-layer grounding plate, and is characterized in that a rectangular air cavity is formed between the upper-layer reflecting surface and the lower-layer grounding plate; the lower grounding plate is provided with a feed source, the feed source comprises a Lange coupler and a pair of microstrip patches, the input end of the Lange coupler is electrically connected with the transmitting end or the receiving end of the radio frequency transceiver module, and the output end of the Lange coupler is electrically connected with one end of each microstrip patch. The Lange coupler is a 3dB coupler, the 3dB coupler has a wide working bandwidth, the Lange coupler outputs a feed signal with a phase difference of 90 and perfectly serves as two spatially orthogonal feed points, the feed points have a wide impedance bandwidth, the working bandwidth can be improved, the two microstrip patches are orthogonal, two radiation signals are output, resonance frequency bands are overlapped, and the resonance frequency bands are overlapped. And the bandwidth is widened, so that the antenna structure has a wide working bandwidth.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication antenna technology, and specifically relates to an antenna based on a Lange coupler. Background Technology

[0002] In modern wireless communication systems, antennas, as the core components for transmitting and receiving electromagnetic waves, directly determine communication quality, coverage, and system capacity. With the rapid development of technologies such as 5G / 6G, satellite communication, radar, and the Internet of Things, higher demands are placed on antennas' operating bandwidth, gain stability, and beamforming capabilities.

[0003] Currently, traditional patch antennas are widely used as feed sources for various high-performance antenna systems due to their compact structure, low cost, and ease of integration. These patch antennas typically employ a single-point feeding method (such as microstrip line or coaxial probe feeding) to excite a single resonant mode, resulting in a fixed in-phase, equal-amplitude output signal. Although this structure is simple to design and easy to fabricate, its excitation degrees of freedom are limited, making it difficult to flexibly control the amplitude and phase distribution of the radiated field, thus restricting the antenna's bandwidth.

[0004] Therefore, an antenna structure with a wide operating bandwidth is needed. Summary of the Invention

[0005] In view of this, the present invention provides an antenna based on a Lange coupler, the main purpose of which is to solve the problem that existing antennas cannot provide a wide operating bandwidth.

[0006] To address the aforementioned issues, this application provides an antenna based on a Lange coupler, comprising: an upper reflector and a lower ground plane, with a rectangular air cavity provided between the upper reflector and the lower ground plane; A feed source is provided on the lower ground plane. The feed source includes a Lange coupler and a pair of microstrip patches. The input end of the Lange coupler is electrically connected to the transmitter or receiver end of the RF transceiver module, and the output end of the Lange coupler is electrically connected to one end of the microstrip patch.

[0007] In one embodiment of the present invention, the Lange coupler optionally includes: A grounding metal layer is provided, on which a dielectric substrate is disposed. A first microstrip line, a second microstrip line, a third microstrip line, and a fourth microstrip line are disposed in parallel on the upper surface of the dielectric substrate. The first end of the first microstrip line and the first end of the fourth microstrip line are connected by an air bridge, and the first end of the second microstrip line and the first end of the third microstrip line are connected by an air bridge.

[0008] In one embodiment of the present invention, optionally, the edge of the dielectric substrate is provided with a first port, a second port, a third port and a fourth port, the second end of the second microstrip line and the second end of the third microstrip line are respectively connected to the first port by bonding, the second end of the first microstrip line and the second end of the fourth microstrip line are respectively connected to the second port by bonding, the first end of the second microstrip line is connected to the third port by bonding, and the first end of the first microstrip line is connected to the fourth port by bonding.

[0009] In one embodiment of the present invention, the pair of microstrip patches are optionally arranged orthogonally on the lower ground plane.

[0010] In one embodiment of the present invention, optionally, the first port is electrically connected to the transmitting end or receiving end of the radio frequency transceiver module, the second port is electrically connected to the first end of one of the microstrip patches in the pair, the third port is electrically connected to the first end of the other microstrip patch in the pair, and the fourth port is electrically connected to a 50-ohm resistor.

[0011] In one embodiment of the present invention, optionally, the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line have equal line lengths, equal line widths, and equal line spacings.

[0012] In one embodiment of the present invention, optionally, the line spacing of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line is in the range of 0.8-1.15mm, and the line width of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line is in the range of 0.8-1.2mm.

[0013] In one embodiment of the present invention, optionally, a connecting microstrip line is provided on the lower ground plane, one end of the connecting microstrip line is connected to the first port of the Lange coupler, the connecting microstrip line is routed inside the lower ground plane, and the other end of the connecting microstrip line extends to the edge of the lower ground plane and is connected to a pad, the pad being electrically connected to the transmitter or receiver of the RF transceiver module.

[0014] In one embodiment of the present invention, optionally, a support forming a rectangular air cavity is provided between the upper reflective surface and the lower ground plane, the dielectric constant of the support being 2.2 and the loss tangent of the support being 0.0007.

[0015] In one embodiment of the present invention, the dielectric substrate may optionally be made of aluminum oxide or gallium arsenide.

[0016] This invention provides an antenna based on a Lange coupler, comprising an upper reflector, a feed source, and a lower ground plane for the feed source. An air cavity is provided between the upper reflector and the lower ground plane. The feed source includes a Lange coupler and two orthogonally arranged microstrip patches. After receiving an excitation signal, the Lange coupler transmits it to the microstrip patches, which then transmit the signal to the air cavity. The signal resonates within the air cavity and is radiated out through the upper reflector. The Lange coupler is a 3dB coupler, which has a wide operating bandwidth. The output of the Lange coupler outputs a feed signal with a 90° phase difference. Therefore, the output of the Lange coupler perfectly serves as two spatially orthogonal feed points. The feed points themselves have a wide impedance bandwidth, which improves the operating bandwidth. The orthogonality of the two microstrip patches results in two radiated signals, causing the resonant frequency bands to overlap and the bandwidth to be widened. Therefore, using a Lange coupler as the feed source, an antenna structure with a wide operating bandwidth can be achieved.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a structural block diagram of an antenna based on a Lange coupler, which is an exemplary embodiment of the present invention.

[0019] Figure 2a This is a partial structural diagram of a Lange coupler for an antenna based on a Lange coupler, which is an exemplary embodiment of the present invention.

[0020] Figure 2b This is an equivalent model of a Lange coupler for an antenna based on a Lange coupler, which is an exemplary embodiment of the present invention.

[0021] Figure 3The figure shows the parameter results of an antenna based on a Lange coupler, after optimizing the microstrip linewidth range and microstrip line spacing range of the Lange coupler, which is an exemplary embodiment of the present invention.

[0022] in, The labels are as follows: 11-Upper reflective surface; 12-Lower ground plane; 13-Rectangular air cavity; 121-Lange coupler; 122-Microstrip patch. Detailed Implementation

[0023] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0024] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0025] The following is combined Figures 1 to 3 An antenna based on a Lange coupler is described according to some embodiments of the present invention.

[0026] In one embodiment, such as Figure 1 As shown, an antenna based on a Lange coupler includes: an upper reflector 11 and a lower ground plane 12, with a rectangular air cavity 13 provided between the upper reflector 11 and the lower ground plane 12; A feed source is provided on the lower ground plane 12. The feed source includes a Lange coupler 121 and a pair of microstrip patches 122. The input terminal of the Lange coupler 121 is electrically connected to the transmitter or receiver of the RF transceiver module, and the output terminal of the Lange coupler 121 is electrically connected to one end of the microstrip patch 122.

[0027] Specifically, the Lange coupler-based antenna of this application mainly includes an upper reflector, a feed, and a lower ground plane. The feed is disposed on the lower ground plane, and a rectangular intermediate resonant cavity is provided between the upper reflector and the lower ground plane. The lower feed includes a Lange coupler and two microstrip patches. The ground plane is placed below the feed antenna. The feed antenna and the upper reflector are connected by a support, and a rectangular air cavity is formed between the feed antenna and the upper reflector by the support, which serves as the resonant cavity.

[0028] The upper reflective surface is a metal-dielectric composite plate or a simple metal grid, exhibiting partial reflection and partial transmission. It serves as both the aperture for the second radiation and the upper wall of the resonant cavity. The lower ground plane is a single piece of metal, providing global ground potential and simultaneously acting as the common base plate and reflector for the Lange coupler and microstrip patches. Together with the upper reflective surface, it forms the upper and lower walls of the resonant cavity. The Lange coupler is a 3 dB 90° quadrature coupler, outputting signals of equal amplitude and 90° phase. The input of the Lange coupler is connected to the transmitter or receiver of the RF transceiver module, and the output of the Lange coupler is connected to two orthogonally placed microstrip patches. The Lange coupler is used to excite the orthogonal microstrip patches, which then transmit the signal, achieving dual-polarization feeding.

[0029] A microstrip patch consists of two rectangular metal patches etched on the same dielectric substrate and placed orthogonally to each other. They receive two orthogonal signals from the Lange coupler, radiate energy into a rectangular air cavity, and then radiate it into space again through the upper reflective surface.

[0030] When a signal is received at the input of the Lange coupler, the coupler converts the signal into a signal of equal amplitude and 90° phase, and transmits it to the microstrip patch. The microstrip patch is excited and sends the signal into the air cavity. One or more specific electromagnetic resonant modes are established within the air cavity, and the signal reflects back and forth within the air cavity. The upper reflector acts as both a "mirror" and a "window" for the standing waves within the cavity, directly radiating signals that meet the conditions outward. Signals that do not meet the conditions continue to reflect back and forth within the resonant cavity until the conditions are met, at which point the signal is radiated outward by the upper reflector, thus completing the antenna's signal transmission function.

[0031] A support is provided between the upper reflective surface and the lower ground plane to form a rectangular air cavity. The dielectric constant of the support is 2.2 and the loss tangent of the support is 0.0007.

[0032] Compared with the prior art, this application provides an antenna based on a Lange coupler, including an upper reflector, a feed source, and a lower ground plane where the feed source is disposed. An air cavity is provided between the upper reflector and the lower ground plane. The feed source includes a Lange coupler and two orthogonally arranged microstrip patches. After receiving the excitation signal, the Lange coupler transmits it to the microstrip patch, and the microstrip patch transmits the signal to the air cavity. The signal resonates in the air cavity and is radiated out through the upper reflector. The Lange coupler is a 3dB coupler, which has a wide operating bandwidth. The output of the Lange coupler outputs a feed signal with a 90° phase difference. Therefore, the output of the Lange coupler perfectly serves as two spatially orthogonal feed points. The feed points themselves have a wide impedance bandwidth, which can improve the operating bandwidth. The orthogonality of the two microstrip patches outputs two radiated signals, causing the resonant frequency bands to overlap and the bandwidth to be widened. Therefore, an antenna using a Lange coupler as a feed source can achieve an antenna structure with a wide operating bandwidth.

[0033] In one embodiment, the Lange coupler includes: A grounding metal layer is provided, and a dielectric substrate is disposed on the grounding metal layer. A first microstrip line, a second microstrip line, a third microstrip line, and a fourth microstrip line are disposed in parallel on the upper surface of the dielectric substrate. The first end of the first microstrip line and the first end of the fourth microstrip line are connected by an air bridge, and the first end of the second microstrip line and the first end of the third microstrip line are connected by an air bridge. The edge of the dielectric substrate is provided with a first port, a second port, a third port, and a fourth port. The second end of the second microstrip line and the second end of the third microstrip line are respectively connected to the first port by bonding. The second ends of the first microstrip line and the second ends of the fourth microstrip line are respectively connected to the second port by bonding. The first end of the second microstrip line is connected to the third port by bonding. The first end of the first microstrip line is connected to the fourth port by bonding.

[0034] Specifically, the substrate material is aluminum oxide or gallium arsenide.

[0035] The core structure of the Lange coupler is based on a multilayer dielectric structure: the bottom layer is a ground metal layer, which is covered by a dielectric substrate; microstrip lines (i.e., cross-finger lines) are directly fabricated on the upper surface of this dielectric substrate, usually consisting of four parallel and closely arranged microstrip lines, with air bridges or metal wires (bonding wires) used to cross-connect the endpoints of these microstrip lines.

[0036] These four microstrip lines are arranged in parallel, and are sequentially named the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line. The left end of each microstrip line is called the first end, and the right end is called the second end. Four ports are located on the edge of the dielectric substrate: port P1 (input), port P2 (through), port P3 (coupling), and port P4 (isolation). The left ends of the first and fourth microstrip lines are connected by an air bridge; these two ends are short-circuited and merged into a single electrical node. Similarly, the right ends of the second and third microstrip lines are connected by an air bridge; these two ends are short-circuited and merged into a single electrical node.

[0037] The left ends of the second and third microstrip lines are connected to the first port via bonding wires, the right ends of the first and fourth microstrip lines are connected to the second port via bonding wires, the right end of the second microstrip line is connected to the third port via bonding wires, and the right end of the first microstrip line is connected to the fourth port via bonding wires.

[0038] It can be seen that: the first and third ports are a pair, representing the two ends of the parallel connection between the second and third microstrip lines, respectively. The second and fourth ports are also a pair, representing the two ends of the parallel connection between the first and fourth microstrip lines, respectively. The first and fourth ports (input and isolation) are diagonal ports, with no direct internal connection between them, thus offering the highest isolation. The second and third ports (straight-through and coupling) are another pair of diagonal ports, where energy is transferred between these two pairs of lines through electromagnetic coupling.

[0039] The first and third ports are symmetrical, as are the second and fourth ports, and the short-circuit boundary conditions of the two sets of parallel lines are consistent. This symmetrical structure can offset the effects of parasitic capacitance and inductance caused by frequency variations, allowing impedance matching and mode coupling stability to cover the octave range, achieving a wider operating bandwidth. For example, a Lange coupler with a center frequency of 12 GHz can easily achieve an octave bandwidth of 8–16 GHz.

[0040] Electromagnetic fields couple between adjacent lines, exciting two independent transmission modes: odd and even modes. After the signal is input from the first port, energy is simultaneously excited by coupling two sets of parallel microstrip lines (the first and fourth microstrip lines form one set, and the second and third microstrip lines form another set). The phase accumulation of the odd and even modes in the two sets of lines is different. After a coupling segment of a specific length, the superposition results in a phase difference of exactly 90° between the output signals at the second port (straight-through) and the third port (coupled).

[0041] The first and fourth microstrip lines are connected in parallel, and the second and third microstrip lines are connected in parallel, forming two sets of symmetrical "double-line structures". The equivalent characteristic impedance of each double-line is half that of a single microstrip line, and the input energy can be evenly distributed to the second and third ports, theoretically each receiving 50% of the energy, corresponding to a power coupling degree of 3dB.

[0042] The core difference between the Lange coupler in this application and ordinary two-wire couplers and branch-line couplers lies in its unique interdigitated cross-connection structure. It electrically cross-connects four parallel microstrip lines, thereby achieving 3dB tight coupling and octave-level ultra-wide operating bandwidth on a single-layer planar circuit, which is difficult to achieve with traditional two-wire structures. This solves the problems of narrow bandwidth of branch-line couplers and the difficulty in manufacturing ordinary coupling lines.

[0043] The Lange coupler structure diagram of this application is as follows: Figure 2a As shown, a directional coupler includes four ports, and any four-port coupler can be converted into a directional coupler. Figure 2b The equivalent model in the figure is shown. Ports 1, 2, 3, and 4 in the figure correspond to the input, through, coupled, and isolated terminals of the coupler, respectively. Energy in the coupler is input through input port 1, then a portion of the energy is directly output through through port 2, while another portion of the energy is output through coupled port 3 via a 1 / 4 wavelength coupling line structure. Isolation port 4 is completely isolated and has no energy output.

[0044] In one embodiment, a pair of microstrip patches are orthogonally arranged on the lower ground plane. The first port is electrically connected to the transmitter or receiver of the RF transceiver module, the second port is electrically connected to the first end of one of the microstrip patches, the third port is electrically connected to the first end of the other microstrip patch, and the fourth port is electrically connected to a 50-ohm resistor.

[0045] Specifically, the first port of the coupler is directly electrically connected to the transmitter or receiver of the RF transceiver module, responsible for inputting or receiving RF signals. The second and third ports of the coupler are connected to two orthogonal microstrip patches, respectively. The fourth port of the coupler is connected to a 50Ω matching load, which can absorb reflected signals and parasitic energy generated during coupling. The fourth port and the input port are diagonally isolated ports, with extremely high isolation. The load setting further optimizes the port matching performance of the coupler, reduces signal reflection, and improves the broadband stability of the entire feeding system. The microstrip patches are the feed radiation elements of the antenna. The two patches are independently fed, corresponding to the two output ports of the Lange coupler, respectively. They can maintain a stable phase relationship over a wide bandwidth, breaking the narrowband limitation of traditional in-phase feeding. The orthogonal arrangement can form two spatially perpendicular radiation polarization directions. Combined with a feed signal with a 90° phase difference, circularly polarized radiation can be achieved.

[0046] The output port of the Lange coupler itself has a wide impedance bandwidth, and the spatially orthogonal feed point (orthogonal port of microstrip patch) usually also has a natural wide impedance characteristic. Matching the two can achieve the broadband performance of the entire feed system.

[0047] In one embodiment, the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line have equal line lengths, equal line widths, and equal line spacings. The line spacing of the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line ranges from 0.8 to 1.15 mm, and the line width of the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line all ranges from 0.8 to 1.2 mm.

[0048] Specifically, this application uses alumina as the dielectric substrate for the microstrip line and employs ε r The following formula applies when fabricating a 3dBlange coupler on a 9.6 alumina substrate: W / H=0.107, S / H=0.071, L=λ / 4 Where W is the microstrip linewidth, S is the spacing between microstrip lines, H is the thickness of the microstrip line substrate, and λ / 4 is a quarter wavelength at the center frequency of the operating bandwidth.

[0049] We can deduce that H = 15.0 mil, W = 1.605 mil, and S = 1.605 mil; and since the center frequency is 12 GHz, L = 100 mil.

[0050] Based on the above parameters, the parameters of the Lange coupler were set and simulation was performed. The simulation results show that the input VSWR was not lower than 1.2 in all ranges from 8 to 16 GHz, and the insertion loss at the center frequency f0=12 GHz was 3.282 dB, which is greater than 3.1 dB.

[0051] Therefore, the above parameter settings failed to meet the required specifications for the 3dBLange coupler.

[0052] Based on the study of the basic working principle of the Lange coupler, it is found that the microstrip linewidth ratio W / H and the microstrip slot width ratio S / H affect the coupling coefficient C. After determining the basic parameters of the microstrip, only the microstrip linewidth W and the microstrip line spacing S can be optimized. The range of the microstrip linewidth W variable is set to 0.8~1.2, and the range of the microstrip line spacing S variable is set to 0.8~1.15. Simulations are performed on the Lange coupler with modified parameter ranges, and the results are as follows... Figure 3 The optimization results shown in the figure indicate that the parameters of the coupler are within the designed range after optimization, and can be used in the subsequent antenna feeding section.

[0053] In one embodiment, a connecting microstrip line is provided on the lower ground plane. One end of the connecting microstrip line is connected to the first port of the Lange coupler. The connecting microstrip line is routed inside the lower ground plane. The other end of the connecting microstrip line extends to the edge of the lower ground plane and is connected to a pad. The pad is electrically connected to the transmitter or receiver of the RF transceiver module.

[0054] Specifically, the connecting microstrip line is a dedicated RF transmission channel between the first port of the Lange coupler and the RF transceiver module. The connecting microstrip line is arranged inside the lower ground plane. The internal routing method saves space on the ground plane surface and avoids mechanical interference with components such as orthogonal microstrip patches and air cavity supports. It is compatible with the miniaturized integrated design of the entire antenna. The end of the connecting microstrip line extends to the edge of the lower ground plane and is made into a pad. The pad connects to the transmitter or receiver of the RF transceiver module.

[0055] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this application will be apparent to those skilled in the art.

[0056] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0057] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0058] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application.

[0059] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0060] Specific embodiments of this application are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in a variety of substantially any suitable detailed structures.

[0061] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0062] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. An antenna based on Lange coupler, characterized in that, The utility model relates to a rectangular air cavity antenna, comprising: An upper layer reflecting surface and a lower layer grounding plate are provided with a rectangular air cavity between the upper layer reflecting surface and the lower layer grounding plate; A feed source is arranged on the lower layer grounding plate, the feed source comprises a Lange coupler and a pair of microstrip patches, an input end of the Lange coupler is electrically connected with a transmitting end or a receiving end of a radio frequency transceiver module, and an output end of the Lange coupler is electrically connected with one end of the microstrip patch.

2. The Lange-coupler-based antenna of claim 1, wherein, The Lange coupler comprises: A ground metal layer is arranged on the ground metal layer, and a dielectric substrate is arranged on the upper surface of the dielectric substrate, the first end of the first microstrip line and the first end of the fourth microstrip line are connected through an air bridge, and the first end of the second microstrip line and the first end of the third microstrip line are connected through an air bridge.

3. The Lange-coupler-based antenna of claim 2, wherein, The edge of the dielectric substrate is provided with a first port, a second port, a third port and a fourth port, the second end of the second microstrip line and the second end of the third microstrip line are respectively connected to the first port through a bonding mode, the second end of the first microstrip line and the second end of the fourth microstrip line are respectively connected to the second port through a bonding mode, the first end of the second microstrip line is connected to the third port through a bonding mode, and the first end of the first microstrip line is connected to the fourth port through a bonding mode.

4. The Lange-coupler-based antenna of claim 3, wherein, The pair of microstrip patches are arranged on the lower layer grounding plate in an orthogonal manner.

5. The Lange-coupler-based antenna of claim 4, wherein, The first port is electrically connected with the transmitting end or the receiving end of the radio frequency transceiver module, the second port is electrically connected with the first end of one microstrip patch in the pair of microstrip patches, the third port is electrically connected with the first end of another microstrip patch in the pair of microstrip patches, and the fourth port is electrically connected with a 50-ohm resistor.

6. The Lange-coupler-based antenna of claim 4, wherein, The line length, the line width and the line distance of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line are equal.

7. The Lange-coupler-based antenna of claim 6, wherein, The line distance of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line ranges from 0.8 to 1.15 mm, and the line width of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line ranges from 0.8 to 1.2 mm.

8. The Lange-coupler-based antenna according to any one of claims 1-7, wherein, A connecting microstrip line is arranged on the lower layer grounding plate, one end of the connecting microstrip line is connected with the first port of the Lange coupler, the connecting microstrip line is routed inside the lower layer grounding plate, the other end of the connecting microstrip line extends to the edge of the lower layer grounding plate and is connected with a solder pad, and the solder pad is electrically connected with the transmitting end or the receiving end of the radio frequency transceiver module.

9. The Lange-coupler-based antenna according to any one of claims 1-7, wherein, A support constituting the rectangular air cavity is arranged between the upper layer reflecting surface and the lower layer grounding plate, the dielectric constant of the support is 2.2, and the loss tangent of the support is 0.0007.

10. The Lange-coupler-based antenna according to any one of claims 2-7, wherein, The material of the dielectric substrate is alumina or gallium arsenide.

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