Microstrip-to-waveguide transition apparatus and radar level transmitter

Abstract

The embodiments of the present application provide a microstrip-to-waveguide transition apparatus and a radar level transmitter. The microstrip-to-waveguide transition apparatus comprises a dielectric substrate, a waveguide structure, a microstrip antenna, and a resonant probe, wherein the waveguide structure, the microstrip antenna, and the resonant probe are all disposed on the dielectric substrate; the waveguide structure comprises a waveguide cavity, and a first microstrip port and a second microstrip port provided on the waveguide cavity; the microstrip antenna comprises a first antenna element, a second antenna element, a first microstrip transmission line, and a second microstrip transmission line; the first antenna element and the second antenna element are located within the waveguide cavity; the first microstrip transmission line extends into the waveguide cavity by means of the first microstrip port and is connected to the first antenna element so as to feed the first antenna element; the second microstrip transmission line extends into the waveguide cavity by means of the second microstrip port and is connected to the second antenna element so as to feed the second antenna element; and the resonant probe is located within the waveguide cavity, and is positioned on an axis of symmetry between the first microstrip transmission line and the second microstrip transmission line.

Description

Microstrip waveguide device and radar level gauge Technical Field

[0001] This application relates to the field of radio frequency technology, and more specifically, to a microstrip waveguide device and a radar level gauge. Background Technology

[0002] For products such as radar level gauges, due to limited radio frequency space, the antenna design for radar level gauges generally adopts a shared transmit and receive antenna scheme, that is, using the same antenna to transmit or receive signals in order to reduce the volume occupied by the antenna. Summary of the Invention

[0003] In view of this, this application provides a microstrip waveguide device and a radar level gauge.

[0004] According to a first aspect of this application, a microstrip-to-waveguide device is provided. The microstrip-to-waveguide device includes a dielectric substrate, a waveguide structure, a microstrip antenna, and a resonant probe. The waveguide structure, the microstrip antenna, and the resonant probe are all disposed on the dielectric substrate. The waveguide structure includes a waveguide cavity and a first microstrip port and a second microstrip port disposed on the waveguide cavity. The microstrip antenna includes a first antenna element, a second antenna element, a first microstrip transmission line, and a second microstrip transmission line. The first antenna element and the second antenna element are located within the waveguide cavity. The first microstrip transmission line extends into the waveguide cavity through the first microstrip port and connects to the first antenna element to feed the first antenna element. The second microstrip transmission line extends into the waveguide cavity through the second microstrip port and connects to the second antenna element to feed the second antenna element. The resonant probe is located within the waveguide cavity and is located on the axis of symmetry of the first microstrip transmission line and the second microstrip transmission line.

[0005] According to a second aspect of this application, a radar level gauge is provided, the radar level gauge including the microstrip waveguide device mentioned in the first aspect above.

[0006] By applying the scheme provided in this application, when designing a microstrip-to-waveguide device, two antenna elements can be placed within the waveguide cavity of the waveguide structure for signal transmission and reception. To prevent interference between the signals transmitted by the two antenna elements, two microstrip ports can be provided on the waveguide cavity. Two microstrip transmission lines, used to feed the two antenna elements, can extend into the waveguide cavity through different microstrip ports and feed their respective connected antenna elements. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, they can be isolated, thus improving the signal isolation between the two antenna elements to a certain extent. Furthermore, a resonant probe can be placed within the waveguide cavity; the resonant characteristics of the probe further enhance the signal isolation between the two antenna elements. Through this structural design, it is unnecessary to introduce components such as power dividers or hybrid loops into the circuit. The absence of unnecessary components makes the entire microstrip-to-waveguide device simpler and more concise, with better isolation, making it suitable for devices such as radar level gauges that require small antenna module sizes.

[0007] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 is a side view of a microstrip waveguide device according to an embodiment of this application.

[0010] Figure 2 is a top view of a microstrip waveguide device according to an embodiment of this application.

[0011] Figure 3 is a schematic diagram of two antenna elements of a microstrip waveguide device according to an embodiment of this application.

[0012] Figure 4 is a cross-sectional view of a microstrip waveguide device according to an embodiment of this application.

[0013] Figure 5 is a side view of a microstrip waveguide device according to an embodiment of this application. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] For products like radar level gauges, due to limited radio frequency space, their antennas typically employ a shared transmit / receive antenna scheme. This allows the same antenna to transmit or receive signals, reducing the antenna's footprint. Because of this shared antenna, a power divider or hybrid loop is usually required to achieve transmit / receive isolation and prevent signal interference. Adding a power divider or hybrid loop increases the overall structure complexity. Furthermore, power dividers or hybrid loops typically require precise port matching to ensure signal transmission efficiency and reduce reflection loss. Achieving perfect matching during design and manufacturing is difficult, making port matching even more challenging and demanding high manufacturing precision. The addition of more components like power dividers or hybrid loops lengthens the overall circuit structure, leading to increased signal power loss and ultimately resulting in a failure to achieve the desired isolation level.

[0016] A microstrip-to-waveguide (MSB) device is a conversion device used to connect microstrip transmission lines to waveguides. Its main function is to convert signal transmission from a microstrip transmission line to waveguide transmission, or vice versa. A microstrip transmission line is a planar transmission line structure, typically composed of a metal conductor strip on an insulating substrate and an underlying metal ground layer. Parameters such as the width and shape of the conductor strip and the dielectric constant of the substrate can be adjusted to meet specific application requirements. Microstrip transmission lines are commonly used in the design of radio frequency (RF) and microwave circuits, such as microstrip antennas, power dividers, filters, and couplers. A waveguide, on the other hand, is a closed metallic structure used to transmit high-frequency signals. The transmission characteristics of waveguides differ from those of microstrip lines, thus requiring appropriate conversion. The MSB-to-waveguide device provides an efficient way to achieve signal conversion between these two different types of transmission lines.

[0017] In scenarios where microstrip antennas are used for signal transmission and reception, to achieve good isolation between transmitted and received signals without making the overall circuit structure overly complex, the structure of the microstrip-to-waveguide device can be modified to achieve signal isolation. Based on this, this application provides a microstrip-to-waveguide device that can house two antenna elements within the waveguide cavity of the waveguide structure. These two antenna elements can be used for signal transmission and reception. To avoid mutual interference between transmitted and received signals and improve transmission-reception isolation, two microstrip ports can be provided on the waveguide cavity. Two microstrip transmission lines feeding the two antenna elements can extend into the waveguide cavity through different microstrip ports and feed their respective connected antenna elements. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, they can be isolated, thus improving the isolation between transmitted and received signals to a certain extent. Furthermore, a resonant probe can be placed within the waveguide cavity. By placing the resonant probe on the axis of symmetry, the symmetry of the electromagnetic field distribution can be ensured, thereby reducing mutual interference between antenna elements and improving the isolation between transmitted and received signals.

[0018] In this embodiment, two antenna units are used to transmit and receive signals. To improve the isolation of the signals transmitted by the two antenna units, a dual microstrip port design of the waveguide cavity can be used to achieve dual-path feeding, thereby improving the transmission and reception isolation. At the same time, a resonant probe can be used to further improve the isolation of the transmitted and received signals. With the above structural design, it is not necessary to introduce components such as power dividers or hybrid rings into the circuit. Since no extra components are introduced, the structure of the entire microstrip to waveguide device is simpler and has better isolation, making it suitable for devices such as radar level gauges that require small antenna module sizes.

[0019] The microstrip-to-waveguide device provided in this application embodiment will be described below with reference to Figures 1 and 2. Figure 1 is a side view of the microstrip-to-waveguide device, and Figure 2 is a top view of the microstrip-to-waveguide device. As shown in Figures 1 and 2, the microstrip-to-waveguide device includes a dielectric substrate 11, a waveguide structure 12, a microstrip antenna 13, and a resonant probe 14. The waveguide structure 12, the microstrip antenna 13, and the resonant probe 14 are all disposed on the dielectric substrate 11.

[0020] The dielectric substrate 11 has a ground layer at its bottom, and the dielectric substrate 11 can be a high-frequency substrate.

[0021] The waveguide structure 12 includes a waveguide cavity 121 and a first microstrip port 122 and a second microstrip port 123 disposed on the waveguide cavity 121. The shape of the waveguide cavity 121 can be flexibly designed according to actual needs; for example, it can be designed as a cylinder or a cuboid. The first microstrip port 122 and the second microstrip port 123 can be two openings disposed at different positions on the waveguide cavity 121 to allow a microstrip transmission line to extend into the waveguide cavity 121. In some embodiments, the first microstrip port 122 and the second microstrip port 123 are arranged at a 90-degree angle.

[0022] The microstrip antenna 13 includes a first antenna element 131, a second antenna element 132, a first microstrip transmission line 133, and a second microstrip transmission line 134. The first antenna element 131 and the second antenna element 132 are disposed on a dielectric substrate 11 and located within a waveguide cavity 121. The first antenna element 131 can be used to transmit and / or receive signals, and the second antenna element 132 is also used to transmit and / or receive signals. For example, when the first antenna element 131 is used to transmit signals, the second antenna element 132 can be used to receive signals; when the first antenna element 131 is used to receive signals, the second antenna element is used to transmit signals. Alternatively, the first antenna element 131 and the second antenna element 132 can function as a single antenna capable of switching between transmit and receive modes. When switched to transmit mode, both antenna elements are used to transmit signals; when switched to receive mode, both antenna elements are used to transmit signals. In some embodiments, the first antenna element 131 and the second antenna element 132 can be coupled antennas to couple the signals transmitted through the microstrip transmission line into the waveguide cavity 121.

[0023] In some embodiments, the first antenna element 131 and the second antenna element 132 may be probe antennas. Since probe antennas have a simple structure, the overall structure and size of the entire device can be simplified.

[0024] The first microstrip transmission line 133 extends into the waveguide cavity 121 through the first microstrip port 122 and is connected to the first antenna element 131 to power the first antenna element 131. The second microstrip transmission line 134 extends into the waveguide cavity 121 through the second microstrip port 123 and is connected to the second antenna element 132 to power the second antenna element 132.

[0025] In some embodiments, the first microstrip transmission line 133 and the second microstrip transmission line 134 are at a 90-degree angle, so that the first antenna element 131 and the second antenna element 132 are also at a 90-degree angle, so that the polarization directions of the electromagnetic waves generated by the two are different, thereby reducing interference.

[0026] The first microstrip transmission line 133 and the second microstrip transmission line 134 can be composed of a metal conductor strip on an insulating substrate and a bottom metal ground layer. The width, shape, and dielectric constant of the metal conductor strip and the substrate can be adjusted to meet the requirements of specific applications. In some embodiments, the first microstrip transmission line 133 and the second microstrip transmission line 134 can be CPW (coplanar waveguide) transmission lines, or other forms of transmission lines can be used. This application does not limit the specific forms of transmission lines used.

[0027] The resonant probe 14 is disposed on the dielectric substrate 11 and located inside the waveguide cavity 121, and the resonant probe 14 is located on the axis of symmetry of the first microstrip transmission line 133 and the second microstrip transmission line 134.

[0028] The resonant probe 14 is typically designed as a resonant circuit, exhibiting high or low impedance at a specific operating frequency. This circuit has strong selectivity at its resonant frequency; when the signal frequency matches the resonant frequency, the signal can pass through or be reflected, while signals of other frequencies are suppressed or attenuated. Based on these characteristics of the resonant probe 14, it can be used to isolate the signals transmitted by the two antenna elements, preventing mutual interference.

[0029] When the resonant probe 14 is placed on the axis of symmetry of the first microstrip transmission line 133 and the second microstrip transmission line 134, the electromagnetic coupling between the first antenna unit 131 and the second antenna unit 132 can be ensured to be symmetrical. The signals transmitted by the two antenna units will propagate in a symmetrical manner in the structure, thereby reducing the signal interference or crosstalk that may be caused by asymmetrical coupling, which helps to improve the isolation of the signal.

[0030] In some embodiments, as shown in FIG3, the first antenna element 131 and the second antenna element 132 are both rectangular patches with chamfered corners, and the chamfered corners are symmetrically truncated corners of the two rectangular patches.

[0031] Typically, the radiation characteristics and coupling mode of an antenna are affected by its shape. By chamfering the antenna, its radiation direction and polarization can be altered, resulting in greater separation of the radiation modes between two antennas. Furthermore, antenna coupling usually occurs in the overlapping region of their radiation fields. Chamfering effectively changes the receiving and transmitting directions of the antennas, causing a spatial shift in their radiation modes and reducing cross-coupling. When antennas have different radiation modes and divergent directions, energy exchange between them decreases, thus improving isolation. Therefore, chamfering the first antenna element 131 and the second antenna element 132 can change their shapes, thereby altering their radiation characteristics and coupling mode to improve signal isolation. In some embodiments, to ensure consistent transmit and receive performance, the chamfering position can be a symmetrical chamfering position between two rectangular patches, ensuring that the first antenna element 131 and the second antenna element 132 remain symmetrical after chamfering.

[0032] In some embodiments, the rectangular patch can have a 45° chamfer. The applicant has found through experiments that when the rectangular patch has a 45° chamfer, the signals from the two antennas exhibit good isolation.

[0033] In some embodiments, the first antenna unit 131 and the second antenna unit 132 may be the same antenna unit, that is, both have the same shape and material. In this case, the first antenna unit 131 and the second antenna unit 132 may be symmetrically arranged, wherein the axis of symmetry of the first antenna unit 131 and the second antenna unit 132 coincides with the axis of symmetry of the first microstrip transmission line 133 and the second microstrip transmission line 134, that is, the axis of symmetry is the midline of the angle formed by the first microstrip transmission line 133 and the second microstrip transmission line 134.

[0034] In some embodiments, the first antenna element 131 and the second antenna element 132 may also employ antennas of different shapes, i.e., they may be asymmetrical.

[0035] In some embodiments, as shown in FIG3, the first microstrip transmission line 133 and the second microstrip transmission line 134 are at a 90° angle, and the first antenna element 131 and the second antenna element 132, which are respectively connected to the first microstrip transmission line 133 and the second microstrip transmission line 134, are also placed at a 90° angle. When the first antenna element 131 and the second antenna element 132 are placed at a 90° angle, the polarization directions of the electromagnetic waves generated by the two are different (for example, the polarization direction of the first antenna element 131 is horizontal, and the polarization direction of the second antenna element 132 is vertical). That is, the electromagnetic waves generated by the two will oscillate in different directions, so that the electric field distribution between the two antenna elements is different. At the same time, it can also reduce cross coupling, phase interference and signal overlap, thereby reducing the mutual interference between the signals transmitted by the two antenna elements.

[0036] In some embodiments, the position of the resonant probe 14 on the axis of symmetry can be determined based on the impedance that the first antenna element 131 and the second antenna element 132 need to be matched, and / or the isolation between the first antenna element 131 and the second antenna element 132.

[0037] Antenna impedance matching refers to adjusting the impedance between the antenna element and the microstrip transmission line to maximize signal transmission from the microstrip transmission line to the antenna element, or from the antenna element to the transmission line, without reflection or energy loss. The purpose of impedance matching is to ensure efficient signal transmission and reduce reflection loss, thereby improving the efficiency and performance of the communication system. When a microstrip transmission line is connected to an antenna element, to reduce signal loss, the characteristic impedance of the microstrip transmission line (e.g., 50Ω, 75Ω) must match the input impedance of the antenna element. If their impedances are equal, the signal can be transmitted losslessly from the microstrip transmission line to the antenna element, or from the antenna element to the signal transmission line. Conversely, if the impedances are not equal, signal reflection will occur. The reflected signal will superimpose with the incident signal, forming reflected waves. These reflected waves will reduce transmission efficiency and may cause signal distortion. Since the position of the resonant probe 14 on the axis of symmetry can affect the electric field distribution and radiation mode of the antenna element, and thus affect the input impedance of the antenna element, in some embodiments, the position of the resonant probe 14 on the axis of symmetry can be dynamically adjusted based on the impedance required by the first antenna element 131 and the second antenna element 132 under different scenarios, so as to ensure impedance matching between the two antenna elements and the microstrip transmission line and reduce signal loss.

[0038] In some embodiments, the position of the resonant probe 14 on the aforementioned axis of symmetry can also be determined based on the isolation between the first antenna element 131 and the second antenna element 132. For example, the isolation between the first antenna element 131 and the second antenna element 132 when the resonant probe 14 is located at different positions on the aforementioned axis of symmetry can be determined, and the resonant probe 14 can be set at the position with the maximum isolation.

[0039] In some embodiments, the resonant probe 14 is grounded.

[0040] Since radar level gauges often use higher frequency electromagnetic waves, the higher the frequency of the electromagnetic wave signal, the more severe the signal loss. For scenarios where the antenna transmits a higher frequency signal, the conventional approach in related technologies, when designing microstrip-to-waveguide structures, is to avoid introducing components that increase electromagnetic signal loss, such as the resonant probe 14. Furthermore, considering that grounding the resonant probe 14 usually increases conduction loss, related technologies also try to avoid grounding the resonant probe 14. However, this embodiment takes a different approach. By placing the resonant probe 14 on the axis of symmetry of the two antenna elements in the waveguide cavity, and by grounding the resonant probe 14, the symmetry of the electromagnetic field distribution can be ensured, thereby reducing mutual interference between the two antenna elements. This symmetrical design helps simplify the impedance matching process and improve matching accuracy. Simultaneously, by adjusting the position and size of the resonant probe 14 on the axis of symmetry, the input impedance of the antenna element can be optimized to be closer to the desired impedance value. In other words, although this design increases conduction loss, it can greatly optimize the impedance matching of the antenna elements, thereby significantly reducing reflection loss, reducing overall loss, and indirectly improving the isolation between antenna elements.

[0041] Figure 4 is a cross-sectional view of the microstrip-to-waveguide device. In some embodiments, as shown in Figure 4, the waveguide cavity 121 is also provided with a waveguide port 124, through which the microstrip-to-waveguide device is connected to the waveguide. That is, the waveguide structure 12 can adopt a three-port design, where two ports are microstrip ports for introducing microstrip transmission lines into the waveguide cavity 121, and the other port is a waveguide port for connecting to the waveguide and guiding the transmission of electromagnetic signals.

[0042] In some embodiments, the axes of the three ports—the first microstrip port 122, the second microstrip port 123, and the waveguide port 124—are at 90° angles to each other.

[0043] In some embodiments, the waveguide cavity is a cylindrical waveguide cavity. In other embodiments, the waveguide cavity may also be a cuboid, cube, or other shape, and this application does not impose any limitations. When the waveguide cavity is cylindrical, the waveguide tube may also be a cylindrical waveguide tube; when the waveguide cavity is cuboid, the waveguide tube may be a cuboid waveguide tube.

[0044] To further illustrate the microstrip waveguide device provided in the embodiments of this application, the following explanation is based on a specific embodiment.

[0045] The microstrip waveguide device provided in this embodiment will be described below with reference to Figure 5.

[0046] The microstrip-to-waveguide device includes a dielectric substrate 11, a waveguide structure 12, a microstrip antenna 13, and a resonant probe 14, all of which are disposed on the dielectric substrate 11. A ground layer is provided at the bottom of the dielectric substrate 11. The waveguide structure 12 adopts a three-port design, with microstrip port 1 (122 in the figure), microstrip port 2 (123 in the figure), and waveguide port (124 in the figure). The waveguide cavity 121 of the waveguide structure 12 is a cylindrical waveguide, and the three ports are three openings at 90-degree angles to each other within the waveguide cavity. The microstrip antenna 13 includes a first antenna element 131, a second antenna element 132, a microstrip transmission line 1 (133 in the figure) connected to the first antenna element 131, and a microstrip transmission line 2 (134 in the figure) connected to the second antenna element 132. The first antenna element 131 and the second antenna element 132 are located within the waveguide cavity 121. Microstrip transmission line 1 extends into the waveguide cavity 121 through microstrip port 1 and connects to the first antenna element 131 to power it. Microstrip transmission line 2 extends into the waveguide cavity 121 through microstrip port 2 and connects to the second antenna element 132 to power it. Microstrip transmission lines 1 and 2 form a 90° angle. The first antenna element 131 and the second antenna element 132 are rectangular patches with 45-degree chamfers, the chamfers being symmetrically positioned on the left and right sides of the two rectangular patches. The first antenna element 131 and the second antenna element 132 are symmetrically arranged, with their axis of symmetry being the axis of symmetry of microstrip transmission lines 1 and 2. To allow the first antenna element 131 and the second antenna element 132 to generate electromagnetic waves with different polarization directions and improve transmit / receive isolation, the first antenna element 131 and the second antenna element 132 are arranged at a 90-degree angle.

[0047] The resonant probe 14 can be disposed on the dielectric substrate 11 by means of vias and soldering, and is located in the waveguide cavity. The resonant probe 14 is located on the axis of symmetry of the first antenna element 131 and the second antenna element 132, and its position on the axis of symmetry is determined based on the impedance matching required between the first antenna element 131 and the second antenna element 132 and / or the isolation between the first antenna element 131 and the second antenna element 132. The resonant probe 14 is grounded.

[0048] Waveguide port 124 is used to connect to a waveguide so as to guide the transmission of electromagnetic signals using the waveguide.

[0049] In this embodiment, by designing two different microstrip ports within the waveguide cavity to extend the microstrip transmission line feeding the first antenna element 131 and the microstrip transmission line feeding the second antenna element 132 into the waveguide cavity 121, the two microstrip transmission lines can be isolated in different channels, thereby reducing interference between transmitted and received signals and improving the isolation between transmitted and received signals. Simultaneously, by setting a resonant probe 14 within the waveguide cavity, the resonant characteristics of the resonant probe 14 can be utilized to further improve the isolation between transmitted and received signals. Furthermore, by chamfering the first antenna element 131 and the second antenna element 132, their radiation characteristics and coupling modes can be altered, further improving their isolation. In this embodiment, by combining the dual-port design, the resonant probe 14, and the antenna chamfering, the isolation between transmitted and received signals can be significantly improved without the need for a power divider or hybrid loop to achieve isolation. This reduces the complexity of the overall circuit structure and the difficulty of fabrication, resulting in a microstrip-to-waveguide device that achieves advantages such as simple structure, low loss, and high isolation. Furthermore, due to the highly symmetrical structure inside the entire waveguide cavity, the consistency of power generation and reception performance can be guaranteed.

[0050] In addition, this application also provides a radar level gauge, which includes the microstrip waveguide device mentioned in any of the above embodiments, as well as a signal processing unit, a power supply unit, and a housing.

[0051] A radar level gauge is a device used to measure the level (height) of liquids or solid materials. It determines the level by emitting electromagnetic waves (radar waves) and analyzing the reflected signals. The main function of the radar level gauge's antenna is to emit electromagnetic waves and receive electromagnetic waves (radar waves) emitted back from the object. Using the microstrip waveguide device described above, signal isolation between the transmitting and receiving antennas in the radar level gauge can be achieved, resulting in a simple structure and low loss.

[0052] The solutions in the above embodiments can be freely combined to obtain new solutions when there is no conflict. Due to space limitations, they will not be listed one by one here.

[0053] The embodiments of this specification may take the form of a computer program product implemented on one or more storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing program code. Computer-usable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to: phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0054] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0055] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The methods and apparatus provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A microstrip-to-waveguide device, comprising a dielectric substrate (11), a waveguide structure (12), a microstrip antenna (13), and a resonant probe (14), wherein the waveguide structure (12), the microstrip antenna (13), and the resonant probe (14) are all disposed on the dielectric substrate (11); The waveguide structure (12) includes a waveguide cavity (121), and a first microstrip port (122) and a second microstrip port (123) disposed on the waveguide cavity (121); The microstrip antenna includes a first antenna element (131), a second antenna element (132), a first microstrip transmission line (133), and a second microstrip transmission line (134). The first antenna element (131) and the second antenna element (132) are located inside the waveguide cavity (121). The first microstrip transmission line (133) extends into the waveguide cavity (1221) through the first microstrip port (122) and connects to the first antenna element (131) to power the first antenna element (131). The second microstrip transmission line (134) extends into the waveguide cavity (121) through the second microstrip port (123) and connects to the second antenna element (132) to power the second antenna element (132). The resonant probe (14) is located inside the waveguide cavity (121) and on the axis of symmetry of the first microstrip transmission line (133) and the second microstrip transmission line (134).

2. The microstrip-to-waveguide device according to claim 1, wherein, The first antenna element (131) and the second antenna element (132) are both rectangular patches with chamfered corners, and the chamfered corners are symmetrically positioned on the left and right sides of the two rectangular patches.

3. The microstrip-to-waveguide device according to claim 2, wherein, The rectangular patch has a 45° chamfer.

4. The microstrip-to-waveguide device according to any one of claims 1 to 3, wherein, The first antenna unit (131) and the second antenna unit (132) have the same shape and are arranged symmetrically.

5. The microstrip-to-waveguide device according to claim 4, wherein, The first antenna unit (131) and the second antenna unit (132) are arranged at 90°.

6. The microstrip-to-waveguide device according to any one of claims 1 to 5, wherein, The position of the resonant probe (14) on the axis of symmetry is based on The required impedance matching between the first antenna element (131) and the second antenna element (132) and / or the isolation between the first antenna element (131) and the second antenna element (132) are determined.

7. The microstrip-to-waveguide device according to any one of claims 1 to 6, wherein, The resonant probe (14) is grounded.

8. The microstrip-to-waveguide device according to any one of claims 1 to 7, wherein, The waveguide cavity (121) is also provided with a waveguide port (124), and the microstrip to waveguide device is connected to the waveguide through the waveguide port (124).

9. The microstrip-to-waveguide device according to claim 8, wherein, The axes of the first microstrip port (122), the second microstrip port (123), and the waveguide port (124) are at a 90° angle to each other.

10. The microstrip-to-waveguide device according to any one of claims 1 to 9, wherein, The waveguide cavity (121) is a cylindrical waveguide cavity.

11. A radar level gauge, comprising the microstrip waveguide device as described in any one of claims 1-9.

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