Microstrip-to-waveguide device and radar level meter

Abstract

The embodiment of the invention provides a microstrip-to-waveguide device and a radar level meter. When the microstrip-to-waveguide device is designed, two antenna units can be arranged in the waveguide cavity of the waveguide structure, and two microstrip transmission lines used for feeding the two antenna units can extend into the waveguide cavity through different microstrip ports arranged on the waveguide cavity and feed the antenna units connected with the microstrip transmission lines respectively. Therefore, the two microstrip transmission lines can be isolated, and the isolation degree of signals transmitted by the two antenna units is improved. Furthermore, a resonance probe can be arranged in the waveguide cavity, and the isolation degree of signals transmitted by the two antenna units is improved through the resonance characteristic of the resonance probe. Through the structural design, components such as a power divider or a hybrid ring do not need to be introduced into a circuit, so that the whole microstrip-to-waveguide device is simpler in structure, good in isolation degree and suitable for equipment such as a radar level meter which requires a radio frequency module to be small in size.

Description

Technical Field

[0001] The present application relates to the field of radio frequency technology, and in particular to a microstrip to waveguide device and a radar level meter. Background Art

[0002] For products such as radar level meters, due to the limited radio frequency space, in the related technology, when designing the antenna of the radar level meter, the scheme of using a shared antenna for both transmission and reception is generally adopted, that is, the same antenna is used to send or receive signals to reduce the volume occupied by the antenna. Since the transmission and reception share the same antenna, in order to avoid mutual interference between the transmitting and receiving signals, it is usually necessary to set up a power divider or a hybrid ring to achieve transmission and reception isolation. The need to add an additional power divider or a hybrid ring will make the overall structure more complicated, port matching more difficult, and high processing accuracy is required. In addition, the lengthened structure will lead to increased signal power loss, which will result in the final isolation not achieving the expected effect. Therefore, it is necessary to provide a solution to achieve the isolation of transmitting and receiving signals, so that the overall structure is simpler and the isolation is better. Summary of the invention

[0003] In view of this, the present application provides a microstrip to waveguide device and a radar level meter.

[0004] According to a first aspect of the present application, a microstrip-to-waveguide device is provided, the microstrip-to-waveguide device comprising 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 arranged on the dielectric substrate; The waveguide structure includes a waveguide cavity, and a first microstrip port and a second microstrip port arranged on the waveguide cavity; The microstrip antenna comprises a first antenna unit, a second antenna unit, a first microstrip transmission line, and a second microstrip transmission line. The first antenna unit and the second antenna unit are located in the waveguide cavity. The first microstrip transmission line extends into the waveguide cavity through the first microstrip port and is connected to the first antenna unit so as to feed the first antenna unit. The second microstrip transmission line extends into the waveguide cavity through the second microstrip port and is connected to the second antenna unit so as to feed the second antenna unit. The resonant probe is located in the waveguide cavity and on the symmetry axis of the first microstrip transmission line and the second microstrip transmission line.

[0005] According to a second aspect of the present application, a radar level meter is provided, wherein the radar level meter comprises the microstrip-to-waveguide device mentioned in the first aspect.

[0006] By applying the scheme provided by the present application, when designing a microstrip to waveguide device, two antenna units can be arranged in the waveguide cavity of the waveguide structure to realize signal transmission and reception. At the same time, in order to avoid mutual interference of the signals transmitted by the two antenna units, two microstrip ports can be arranged on the waveguide cavity, and the two microstrip transmission lines used to feed the two antenna units can be extended into the waveguide cavity through different microstrip ports, and feed the antenna units connected to each other. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, the two microstrip transmission lines can be isolated, and the isolation of the signals transmitted by the two antenna units can be improved to a certain extent. Furthermore, a resonant probe can be arranged in the waveguide cavity, and the isolation of the signals transmitted by the two antenna units can be improved by the resonant characteristics of the resonant probe. Through the above structural design, there is no need to introduce components such as power dividers or hybrid rings in the circuit. Since no redundant components are introduced, the structure of the entire microstrip to waveguide device is simpler and shorter, and the isolation is better, which is suitable for radar level meters and other equipment that require a small volume of antenna modules.

[0007] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0009] Figure 1 It is a side view of a microstrip-to-waveguide device according to an embodiment of the present application.

[0010] Figure 2 It is a top view of a microstrip-to-waveguide device according to an embodiment of the present application.

[0011] Figure 3 It is a schematic diagram of two antenna units of a microstrip-to-waveguide device according to an embodiment of the present application.

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

[0013] Figure 5 It is a side view of a microstrip-to-waveguide device according to an embodiment of the present application. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0015] For products such as radar level meters, due to the limited RF space, their antennas generally adopt a solution of transmitting and receiving shared antennas, so that the same antenna is used to send or receive signals to reduce the volume occupied by the antenna. Since the transmitting and receiving antennas are shared, in order to avoid mutual interference between the transmitting and receiving signals, it is usually necessary to set up a power divider or a hybrid ring to achieve the isolation of the transmitting and receiving signals. The need to add an additional power divider or a hybrid ring will make the overall structure more complicated. In addition, the power divider or the hybrid ring usually requires precise port matching to ensure the transmission efficiency of the signal and reduce the reflection loss. Then it is difficult to achieve perfect matching during the design and processing process, making port matching more difficult and requiring high processing accuracy. In addition, since more components such as power dividers or hybrid rings are added to the circuit, the overall circuit structure will be lengthened, resulting in increased signal power loss, which in turn causes the final isolation to fail to achieve the expected effect.

[0016] A microstrip-to-waveguide device is a conversion device used to connect a microstrip transmission line to a waveguide. Its main function is to convert the signal transmission of a microstrip transmission line to waveguide transmission, or vice versa. A microstrip transmission line is a planar transmission line structure that usually consists 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 of the microstrip line and the dielectric constant of the substrate can be adjusted to meet the requirements of a specific application. Microstrip transmission lines are often used in the design of radio frequency (RF) and microwave circuits, such as microstrip antennas, power dividers, filters, couplers, etc. A waveguide is a closed metal structure used to transmit high-frequency signals. The transmission characteristics of a waveguide are different from those of a microstrip line, so appropriate conversion is required. The microstrip-to-waveguide device provides an efficient way to achieve signal conversion between two different types of transmission lines.

[0017] In the scenario of using microstrip antennas for signal transmission and reception, in order to achieve good isolation of the transmitted and received signals without making the overall circuit structure too complicated, the structure of the microstrip to waveguide device can be improved to achieve isolation of the transmitted and received signals. Based on this, the embodiment of the present application provides a microstrip to waveguide device, which can be set in the waveguide cavity of the waveguide structure. The two antenna units can be used to realize signal transmission and reception. At the same time, in order to avoid mutual interference between the transmitted signal and the received signal and improve the isolation of transmission and reception, two microstrip ports can be set on the waveguide cavity, and the two microstrip transmission lines used to feed the two antenna units can be extended into the waveguide cavity through different microstrip ports, and feed the antenna units connected to each other. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, the two microstrip transmission lines can be isolated, and the isolation of the transmitted and received signals can be improved to a certain extent. Furthermore, a resonant probe can be set in the waveguide cavity. By setting the resonant probe on the symmetry axis, the symmetry of the electromagnetic field distribution can be ensured, thereby reducing mutual interference between the antenna units and improving the isolation of the transmitted and received signals.

[0018] In the embodiment of the present application, two antenna units are used to realize signal reception and transmission. In order 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 realize dual-path feeding to improve the reception and transmission isolation. At the same time, the resonant probe can be further used to improve the isolation of the reception and transmission signals. Through the above-mentioned structural design, there is no need to introduce components such as power dividers or hybrid rings into the circuit. Since no redundant components are introduced, the structure of the entire microstrip to waveguide device is simpler and shorter, and the isolation is better. It is suitable for equipment such as radar level meters that require a small antenna module.

[0019] The following combination Figure 1 and Figure 2 The microstrip to waveguide device provided in the embodiment of the present application is introduced, wherein: Figure 1 is a side view of the microstrip-to-waveguide device, Figure 2 is a top view of the microstrip to waveguide device, as shown in Figure 1 and Figure 2 As shown, the microstrip-to-waveguide device comprises 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 arranged on the dielectric substrate 11.

[0020] A grounding layer is provided at the bottom of the dielectric substrate 11 , and the dielectric substrate 11 may 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 based on actual needs, for example, it can be designed to be circular or rectangular. The first microstrip port 122 and the second microstrip port 123 can be two openings disposed at different positions of the waveguide cavity 121 so as to extend the microstrip transmission line into the waveguide cavity 121. In some embodiments, the first microstrip port 122 and the second microstrip port 123 are disposed at 90 degrees.

[0022] The microstrip antenna 13 includes a first antenna unit 131, a second antenna unit 132, a first microstrip transmission line 133, and a second microstrip transmission line 134. The first antenna unit 131 and the second antenna unit 132 are arranged on the dielectric substrate 11 and are located in the waveguide cavity 121. The first antenna unit 131 can be used to transmit and / or receive signals, and the second antenna unit 132 is also used to transmit and / or receive signals. For example, when the first antenna unit 131 is used to transmit signals, the second antenna unit 132 can be used to receive signals. When the first antenna unit 131 is used to receive signals, the second antenna unit is used to transmit signals. Alternatively, the first antenna unit 131 and the second antenna unit 132 can be used as one antenna, which can switch between transceiver modes. When switched to the transmitting antenna mode, both antenna units are used to transmit signals. When switched to the receiving antenna mode, both antenna units are used to transmit signals. The first antenna unit 131 and the second antenna unit 132 can use coupling antennas to couple the signals transmitted by the microstrip transmission line into the waveguide cavity 121.

[0023] In some embodiments, the first antenna unit 131 and the second antenna unit 132 may be probe antennas. Since the probe antenna has a simple structure, the overall structure and volume 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 unit 131 so as to feed the first antenna unit 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 unit 132 so as to feed the second antenna unit 132.

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

[0026] The first microstrip transmission line 133 and the second microstrip transmission line 134 may be composed of a metal conductor strip on an insulating substrate and an underlying metal ground layer, and the parameters such as the width, shape and dielectric constant of the metal conductor strip and the substrate may be adjusted to meet the requirements of a specific application. In some embodiments, the first microstrip transmission line 133 and the second microstrip transmission line 134 may be CPW (coplanar waveguide) transmission lines, and of course, other forms of transmission lines may also be used, which is not limited in the embodiments of the present application.

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

[0028] Among them, the resonant probe 14 is usually designed as a resonant circuit, which presents high impedance or low impedance at a specific operating frequency. The circuit has extremely strong selectivity at its resonant frequency. When the frequency of the signal matches the resonant frequency, the signal can pass or be reflected, while signals of other frequencies will be suppressed or attenuated. Based on the above characteristics of the resonant probe 14, the resonant probe 14 can be used to isolate the signals transmitted by the two antenna units to avoid mutual interference between the two.

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

[0030] In some embodiments, Figure 3 As shown, the first antenna unit 131 and the second antenna unit 132 are both rectangular patches with cut corners, and the cut corner positions are diagonal positions of the two rectangular patches.

[0031] Generally, the radiation characteristics and coupling mode of the antenna are affected by the shape of the antenna. By cutting the angle of the antenna, the radiation characteristics such as the radiation direction and polarization state of the antenna can be changed, so that the radiation patterns between the two antennas are more separated. In addition, the coupling between the antennas usually occurs in the overlapping area of ​​their radiation fields. Cutting the angle can effectively change the receiving and transmitting directions of the antennas, so that the radiation patterns of the two antennas are offset in space, thereby reducing the degree of cross-coupling. When the radiation patterns of the antennas are different and the directions are separated, the energy exchange between them will be reduced, thereby improving the isolation between the antennas. Therefore, the first antenna unit 131 and the second antenna unit 132 can be cut to change their shapes, thereby changing their radiation characteristics and coupling modes, so as to achieve the purpose of improving the isolation of the signals between the two. In some embodiments, in order to ensure the consistency of the transceiver performance, the cutting position can be the diagonal position of the two rectangular patches, so that the first antenna unit 131 and the second antenna unit 132 after cutting the angle remain symmetrical.

[0032] In some embodiments, the rectangular patch may be cut at a 45° angle. The applicant has found through experiments that when the rectangular patch is cut at a 45° angle, the signals of the two antennas have better isolation.

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

[0034] Of course, in some embodiments, the first antenna unit 131 and the second antenna unit 132 may also use antennas of different shapes, that is, the two may be asymmetric.

[0035] In some embodiments, as shown in Figure 3, the first microstrip transmission line 133 and the second microstrip transmission line 134 are at an angle of 90°, and the first antenna unit 131 and the second antenna unit 132 respectively connected to the first microstrip transmission line 133 and the second microstrip transmission line 134 are also placed at 90°. When the first antenna unit 131 and the second antenna unit 132 are placed at an angle of 90°, the polarization directions of the electromagnetic waves generated by the two are different (for example, the polarization direction of the first antenna unit 131 is horizontal, and the polarization direction of the second antenna unit 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 units is different. At the same time, cross-coupling, phase interference and signal overlap can be reduced, thereby reducing the mutual interference between the signals transmitted by the two antenna units.

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

[0037] Antenna impedance matching refers to adjusting the impedance between the antenna unit and the microstrip transmission line so that the signal can be transmitted from the microstrip transmission line to the antenna unit, or from the antenna unit to the transmission line, to the maximum extent without reflection and energy loss. The purpose of impedance matching is to ensure the effective transmission of the signal and reduce reflection loss, thereby improving the efficiency and performance of the communication system. When the microstrip transmission line is connected to the antenna unit, in order to reduce the loss of the signal, the characteristic impedance of the microstrip transmission line (such as 50Ω, 75Ω) needs to match the input impedance of the antenna unit. If the impedances of the two are equal, the signal can be transmitted from the microstrip transmission line to the antenna unit, or from the antenna unit to the signal transmission line without loss. On the contrary, it will cause signal reflection, and the reflected signal will be superimposed on the incident signal to form a reflected wave. These reflected waves will reduce the transmission efficiency and may cause signal distortion. Since the position of the resonant probe 14 on the symmetry axis is different, it will affect the electric field distribution, radiation pattern, etc. of the antenna unit, and further affect the input impedance of the antenna unit. Therefore, in some embodiments, the position of the resonant probe 14 on the above-mentioned symmetry axis can be dynamically adjusted based on the impedance required by the first antenna unit 131 and the second antenna unit 132 in different scenarios to ensure impedance matching between the above-mentioned two antenna units and the microstrip transmission line, thereby reducing signal loss.

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

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

[0040] Since radar level meters often use electromagnetic waves of higher frequency bands, the higher the frequency band of electromagnetic wave signals, the more serious their losses are. For scenarios where the signal transmitted by the antenna is a signal of a higher frequency band, in the related art, when designing the microstrip to waveguide structure 12, the usual means are to try to avoid introducing components that will increase the loss of electromagnetic wave signals, such as the resonant probe 14. At the same time, considering that the grounding of the resonant probe 14 usually increases the conduction loss, the grounding of the resonant probe 14 is also avoided as much as possible in the related art. In the embodiment of the present application, a new approach is taken. By setting the resonant probe 14 on the symmetry axis of the two antenna units in the waveguide cavity, and the resonant probe 14 adopts a grounding design, the symmetry of the electromagnetic field distribution can be ensured by placing the resonant probe 14 on the symmetry axis, thereby reducing the mutual interference between the two antenna units. This symmetrical design helps to simplify the impedance matching process and improve the matching accuracy. At the same time, the input impedance of the antenna unit can be optimized by adjusting the position of the resonant probe 14 on the symmetry axis and the size of the resonant probe 14, so that it is closer to the required impedance value. That is to say, although this design method increases the conduction loss, it can greatly optimize the impedance matching of the antenna unit, thereby greatly reducing the reflection loss, reducing the overall loss, and indirectly improving the isolation between the antenna units.

[0041] Figure 4 is a cross-sectional view of the microstrip-to-waveguide device. In some embodiments, Figure 4 As shown, the waveguide cavity 121 is also provided with a waveguide port 124, and the microstrip-to-waveguide device is connected to the waveguide tube via the waveguide port 124. That is, the waveguide structure 12 can adopt a three-port design, two of which are microstrip ports for introducing the microstrip transmission line into the waveguide cavity 121, and the other port is a waveguide port for connecting to the waveguide tube to guide the transmission of the electromagnetic signal.

[0042] In some embodiments, the axes of the first microstrip port 122 , the second microstrip port 123 , and the waveguide port 124 form an angle of 90° with each other.

[0043] In some embodiments, the waveguide cavity is a circular waveguide cavity. Of course, the waveguide cavity may also be a rectangular, square or other shaped waveguide cavity, which is not limited in the embodiments of the present application. When the waveguide cavity is a circular waveguide cavity, the waveguide tube may also be a circular waveguide tube. When the waveguide cavity is a rectangular waveguide cavity, the waveguide tube may be a rectangular waveguide tube.

[0044] In order to further introduce the microstrip-to-waveguide device provided in the embodiment of the present application, it is explained below in conjunction with a specific embodiment.

[0045] The following combination Figure 5 The microstrip-to-waveguide device provided in this embodiment is introduced.

[0046] The microstrip to waveguide device comprises 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 arranged on the dielectric substrate 11. A grounding layer is arranged at the bottom of the dielectric substrate 11, and the waveguide structure 12 adopts a three-port design, wherein the three ports are 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 circular waveguide, and the three ports are three openings opened in the waveguide cavity at 90 degrees to each other. The microstrip antenna 13 comprises a first antenna unit 131, a second antenna unit 132, a microstrip transmission line 1 (133 in the figure) connected to the first antenna unit 131, and a microstrip transmission line 2 (134 in the figure) connected to the second antenna unit 132. The first antenna unit 131 and the second antenna unit 132 are located in the waveguide cavity 121, and the microstrip transmission line 1 extends into the waveguide cavity 121 through the microstrip port 1 and is connected to the first antenna unit 131, so as to feed the first antenna unit 131. The microstrip transmission line 2 extends into the waveguide cavity 121 through the microstrip port 2 and is connected to the second antenna unit 132, so as to feed the second antenna unit 132. The microstrip transmission line 1 and the microstrip transmission line 2 are at an angle of 90°, and the first antenna unit 131 and the second antenna unit 132 are rectangular patches with a 45-degree cut angle, and the cut angle position is the diagonal position of the two rectangular patches. The first antenna unit 131 and the second antenna unit 132 are symmetrically arranged, and their symmetry axes are the symmetry axes of the microstrip transmission line 1 and the microstrip transmission line 2. In order to allow the first antenna unit 131 and the second antenna unit 132 to generate electromagnetic waves with different polarization directions and improve the transmit-receive isolation, the first antenna unit 131 and the second antenna unit 132 are arranged at 90 degrees.

[0047] The resonant probe 14 can be disposed on the dielectric substrate 11 by vias and welding, and is located in the waveguide cavity, and the resonant probe 14 is located on the symmetry axis of the first antenna unit 131 and the second antenna unit 132, and its position on the symmetry axis is determined based on the impedance required to be matched by the first antenna unit 131 and the second antenna unit 132, and the first antenna unit 131 and the second antenna unit 132. The resonant probe 14 adopts a grounding design.

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

[0049] In the embodiment of the present application, by designing two different microstrip ports in the waveguide cavity, the microstrip transmission line for feeding the first antenna unit 131 and the microstrip transmission for feeding the second antenna unit 132 are extended into the waveguide cavity 121, and the two microstrip transmission lines can be isolated in different channels, thereby reducing the interference of the receiving and transmitting signals and improving the isolation of the receiving and transmitting signals. At the same time, by arranging the resonant probe 14 in the waveguide cavity, the resonance characteristics of the resonant probe 14 can be used to further improve the isolation of the receiving and transmitting signals. In addition, by designing the first antenna unit 131 and the second antenna unit 132 with a cutting angle, the radiation characteristics, coupling modes, etc. of the two can be changed, thereby further improving the isolation of the two. In this embodiment, by combining the three methods of dual-port design, setting the resonant probe 14, and antenna cutting angle, the isolation of the receiving and transmitting signals can be greatly improved, and there is no need to introduce a power divider or a hybrid ring to achieve receiving and transmitting isolation, which can reduce the complexity and processing difficulty of the entire circuit structure, so that the designed microstrip to waveguide device can achieve the advantages of simple structure, low loss, high isolation, etc. Moreover, since the structure inside the entire waveguide cavity is highly symmetrical, the consistency of the power transmission and receiving performance can be guaranteed.

[0050] In addition, the present application also provides a radar level meter, which includes the microstrip-to-waveguide device mentioned in any of the above embodiments.

[0051] A radar level meter is a device used to measure the level (height) of liquid or solid materials. It determines the level by emitting electromagnetic waves (radar waves) and analyzing the reflected signals of the waves. The main function of the antenna of the radar level meter is to emit electromagnetic waves and receive electromagnetic waves (radar waves) emitted by the object. The above-mentioned microstrip to waveguide device can achieve signal isolation between the transmitting antenna and the receiving antenna in the radar level meter, and has a simple structure and low loss.

[0052] Among them, the solutions of the above-mentioned embodiments can be freely combined to obtain new solutions when there is no conflict. Due to space constraints, 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 can be computer-readable instructions, data structures, modules of programs, 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 technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0054] For the device embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[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, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0056] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprises a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0057] The method and device provided in the embodiments of the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A microstrip to waveguide device, characterized in that: The microstrip-to-waveguide device 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 arranged on the dielectric substrate; The waveguide structure includes a waveguide cavity, and a first microstrip port and a second microstrip port arranged on the waveguide cavity; The microstrip antenna comprises a first antenna unit, a second antenna unit, a first microstrip transmission line, and a second microstrip transmission line. The first antenna unit and the second antenna unit are located in the waveguide cavity. The first microstrip transmission line extends into the waveguide cavity through the first microstrip port and is connected to the first antenna unit so as to feed the first antenna unit. The second microstrip transmission line extends into the waveguide cavity through the second microstrip port and is connected to the second antenna unit so as to feed the second antenna unit. The resonant probe is located in the waveguide cavity and on the symmetry axis of the first microstrip transmission line and the second microstrip transmission line.

2. The microstrip-to-waveguide device according to claim 1, characterized in that: The first antenna unit and the second antenna unit are both rectangular patches with cut corners, and the cut corner positions are diagonal positions of the two rectangular patches.

3. The microstrip-to-waveguide device according to claim 2, characterized in that: The cutting angle of the rectangular patch is 45°.

4. The microstrip-to-waveguide device according to claim 1, characterized in that: The first antenna unit and the second antenna unit have the same shape, and the first antenna unit and the second antenna unit are symmetrically arranged.

5. The microstrip-to-waveguide device according to claim 4, characterized in that: The first antenna unit and the second antenna unit are arranged at 90 degrees.

6. The microstrip-to-waveguide device according to claim 1, characterized in that: The position of the resonant probe on the symmetry axis is determined based on one or more of the following: The impedance required to be matched between the first antenna unit and the second antenna unit, and the isolation between the first antenna unit and the second antenna unit.

7. The microstrip-to-waveguide device according to claim 1, characterized in that: The resonant probe is grounded.

8. The microstrip-to-waveguide device according to claim 1, characterized in that: The waveguide cavity is also provided with a waveguide port, and the microstrip-to-waveguide device is connected to the waveguide tube via the waveguide port.

9. The microstrip-to-waveguide device according to claim 1, characterized in that: The waveguide cavity is a circular waveguide cavity.

10. A radar level meter, characterized in that: The radar level meter comprises the microstrip-to-waveguide device according to any one of claims 1-9.

Images